CONSERVATION OFRUINS

Prelims-H6429.qxd 10/14/06 3:15 PM Page i

Butterworth-Heinemann Series in Conservation and Museology

Series Editor: Andrew OddyBritish Museum, London

Consultants: Sir Bernard FeildenDirector Emeritus, ICCROM

Page Ayres CowleyConservation Architect, New York

David BomfordNational Gallery, London

John FidlerEnglish Heritage, London

C.V. HorieManchester Museum, University of Manchester

Sarah StaniforthNational Trust, London

Jeanne Marie TeutonicoThe Getty Conservation Institute, Los Angeles

David SaundersBritish Museum, London

Published titles: Architectural Tiles: Conservation and Restoration (Durbin)Chemical Principles of Textile Conservation (Timár-Balázsy, Eastop)Conservation and Restoration of Ceramics (Buys, Oakley)Conservation of Building and Decorative Stone (Ashurst, Dime)Conservation of Furniture (Rivers, Umney)Conservation of Historic Buildings (Feilden)Conservation of Leather and Related Materials (Kite, Thomson)A History of Architectural Conservation ( Jokilehto)Lacquer: Technology and Conservation (Webb)The Museum Environment, 2nd edition (Thomson)Radiography of Cultural Materials, 2nd edition (Lang, Middleton)Tapestry Conservation: Principles and Practice (Lennard, Hayward)The Textile Conservator’s Manual, 2nd edition (Landi)Upholstery Conservation: Principles and Practice (Gill, Eastop)

Related titles: Contemporary Theory of Conservation (Mun~oz-Vin~as)Digital Collections (Keene)Digital Heritage: Applying Digital Imaging to Cultural Heritage (MacDonald)Fragments of the World: Uses of Museum Collections (Keene)Historic Floors (Fawcett)Managing Conservation in Museums (Keene)Materials for Conservation (Horie)The National Trust Manual of HousekeepingNatural Materials: Sources, Properties and Uses (DeMouthe)Organic Chemistry of Museum Objects (Mills, White)Pigment Compendium: Dictionary (Eastaugh, Walsh, Siddall, Chaplin)Pigment Compendium: Optical Microscopy (Eastaugh, Walsh, Siddall, Chaplin)Pigment Compendium CD (Eastaugh, Walsh, Siddall, Chaplin)Restoration of Motion Picture Film (Read, Meyer)Risk Assessment for Object Conservation (Ashley-Smith)Structural Aspects of Building Conservation (Beckman, Bowles)

Knowlton Church and Rings are a good example of a Scheduled Ancient Monument in England. Located

in the ancient landscape of Cranborne Chase and surrounded by barrow cemeteries and earthworks, the church

is eleventh century but much altered in the fourteenth century. Remarkably, it stands within a well-preserved

ceremonial Neolithic Henge monument of c. 2500 BC. Consolidation of flint core work, tamping and

pointing, the use of rendered brick structural supports and bronze corbel bars are classic interventions of the

Ancient Monuments Division of the Ministry of Public Building and Works (c. 1950). Scale by Sam the

retriever.

Prelims-H6429.qxd 10/14/06 3:15 PM Page ii

CONSERVATION OFRUINS

Edited by John Ashurst

AMSTERDAM • BOSTON • HEIDELBERG • LONDON • OXFORD • NEW YORK • PARIS

• SAN DIEGO • SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO

Butterworth-Heinemann is an imprint of Elsevier

Prelims-H6429.qxd 10/14/06 3:15 PM Page iii

Butterworth-Heinemann is an imprint of Elsevier Ltd

Linacre House, Jordan Hill, Oxford OX2 8DP

30 Corporate Road, Burlington, MA 01803

First edition 2007

Copyright © 2007, Elsevier Limited. All rights reserved

No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form

or by any means electronic, mechanical, photocopying, recording or otherwise without the prior written

permission of the publisher

Permission may be sought directly from Elsevier’s Science & Technology Rights Department in Oxford,

UK: phone (+44) (0) 1865 843830; fax (+44) (0) 1865 853333; email: permissions@elsevier.com.

Alternatively you can submit your request online by visiting the Elsevier website at

http://elsevier.com/locate/permissions, and selecting Obtaining permission to use Elsevier material

Notice

No responsibility is assumed by the publisher for any injury and/or damage to persons or property as a matter

of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions

or ideas contained in the material herein. Because of rapid advances in the medical sciences, in particular,

independent verification of diagnoses and drug dosages should be made

British Library Cataloguing in Publication Data

A catalogue record for this book is available from the British Library

Library of Congress Cataloguing in Publication Data

A catalogue record for this book is available from the Library of Congress

ISBN 13: 978-0-75-066429-5

ISBN 10: 0-75-066429-0

For information on all Butterworth-Heinemann publications

visit our website at www.books.elsevier.com

Typeset by Charon Tec Ltd (A Macmillan Company), Chennai, India

www.charontec.com

Printed and bound in Italy

Prelims-H6429.qxd 10/14/06 3:15 PM Page iv

Acknowledgements vii

List of contributors ix

Foreword xvClifford Price

Figure credits xvi

Preface xviiiGionata Rizzi

Introduction – continuity and truth xxivJohn Ashurst

Short storyThe demise, discovery, destruction and salvation of a ruin xxx

1 Conservation concepts 1Jukka Jokilehto

2 Stability and survival 10Chris How

3 Condition surveys of masonry ruins 44Graham Abrey

4 Philosophy, technology and craft 82John Ashurst and Colin Burns

5 Preventive conservation of ruins: reconstruction, reburial and enclosure 146Catherine Woolfitt

6 The ecology of ruin sites 194Sara Ferraby

7 Submerged ruins 212Jason Bolton

8 Implementing conservation works on ruins 234Sara Ferraby and David Odgers

9 Interpretation and display of ruins and sites 246Amanda White

10 Case studies 264Case Study 1: Guildford Castle, UK 265Catherine Woolfitt, John Ashurst and Graham Abrey

Case Study 2: Masada, Israel 279John Ashurst, Asi Shalom and Catherine Woolfitt

Case Study 3: Gosport Railway Terminal, UK 296Margo Teasdale

Epilogue 306John Ashurst

Appendix 1 Materials and techniques 309

1.1 Traditional lime production 310

1.2 Lime mortar and plaster in ruin sites 312John Ashurst and Colin Burns

1.3 Tools for joint and core treatment 314John Ashurst and Colin Burns

Appendix 2 Structural interventions 319

2.1 Temporary supports 320John Ashurst and Colin Burns

2.2 Permanent supports (core buttress) 322John Ashurst and Colin Burns

2.3 Cantilever support 324John Ashurst and Colin Burns

2.4 Re-alignment of leaning wallCymer Abbey, Dolgellau, Wales 325Jon Avent

Appendix 3 Implementation of work – personnel selection 331Tadg Buckley

Appendix 4 Visitor perceptions (The Alamo, San Antonio, Texas) 332John Ashurst with Bruce Winders and Rachel Sabino-Gunaratna

Appendix 5 Monitoring and maintaining abandoned ruins and sites 339Asi Shalom

Index 341

Contents

v

Prelims-H6429.qxd 10/14/06 3:15 PM Page v

I met a traveller from an antique landWho said: Two vast and trunkless legs of stoneStand in the desert. And near them on the sandHalf sunk, a shattered visage lies, whose frownAnd wrinkled lip and sneer of cold commandTell that its sculptor well those passions readWhich yet survive stamped on those lifeless things,The hand that mock’d them and the heart that fed;And on the pedestal these words appear:‘My name is Ozymandias, king of kings:Look on my works ye mighty and despair!’Nothing beside remains. Round the decayOf that colossal wreck, boundless and bare,The lone and level sands stretch far away.

(Percy Bysshe Shelley, Ozymandias of Egypt, 1817)

Prelims-H6429.qxd 10/14/06 3:15 PM Page vi

My first and most important acknowledgement is tomy contributor authors. Without them this wouldhave been a much smaller and less interesting anduseful book, and would have lost much of its author-ity and value. Without exception they are peoplewith whom I have had the great pleasure to work ortrain with in a wide range of situations, times andsites, and all of whom have taught me something newabout the fascinating, compelling and important sub-ject of this book.

I count it a true privilege to know each one ofthem.

Graham Abrey • Jason Bolton • Colin Burns • Sara Ferraby • Chris How • Jukka Jokilehto • DavidOdgers • Gionata Rizzi • Asi Shalom • Margo Teasdale• Amanda White • Catherine Woolfitt

Particular and special thanks are due to GillianReading, who has worked tirelessly on the fabric ofthis book and has more than made up for my lack ofIT skills.

My second acknowledgement is to all those whohave contributed to my love and knowledge of his-toric buildings and especially those buildings with‘special needs’ which have so much to teach us, thebuilding ruins and their sites.

The list which follows is a dangerous one, becausethere will be omissions which I will later rememberand regret. But I list them as well as I can with-out their titles but with my enduring thanks andappreciation.

The architects

Bill Adams • Alejandro Alva • Bernard Ashwell • T. A. Bailey • John Barnes • Corinne Bennett • KeithBlades • Patricia Brock • Eric Brown • Oran Campbell• Bob Chitham • Barry Clark • Raymond Connelly

• Bill Cutting • Richard Davies • Maggie Davies • Patrick A. Faulkner • Bernard Feilden • John A.Fidler • Brian V. Field • Percy Flaxman • Reshat Gega• Emil Godfrey • Harry Gordon-Slade • Neil Hynde• David Heatt • John Kaye • John Knight • DerekLindstrom • Graham Luckes • John Ludlow • IngvalMaxwell • Iain McCaig • Anna McPherson • PeterMiller • Neil Moffat • Dick Oram • DonovanPurcell • Norman Riley • Zygmund Skrobanski •Gail Sussman • Harold Yexley

The archaeologists and historians

Zaki Aslan • Peter Burman • John Charlton • PeterCurnow • Roy Gilyard-Beer • Hermione Hobhouse •Tom James • Ehud Netzer • Stuart Rigold • GaetanoPalumbo • Geoff Parnell • Nicholas Stanley Price •John Stewart • Arnold Taylor • Michael Thompson •John Weaver • Pamela Wedgwood • Geoff West •Judith West

The building surveyors

Chris Wood • Elizabeth Vause

The engineers

Leonard W. Ashurst • Ian Hulme • Ralph Mills

The scientists

Lesley Arnold • John Beavis • Leo Biek • MikeBowley • Brian L. Clarke • Tony Coote • Francis G.Dimes • Peter Ellis • Sophie Godfraind • YosefHatzor • David B. Honeyborne • Elaine Leary •Frank Matero • John Musty • Sara Pavia • JohnPickering • Clifford A. Price • Barry Richardson •Brian Rideout • John Savory • Giorgio Torraca

Acknowledgements

Prelims-H6429.qxd 10/14/06 3:15 PM Page vii

viii Acknowledgements

The craft supervisors and craftspeople

Alfie Bowen • Brian Bowen • Peter Cameron •Donald Coleman • Tom Dorrington • Jack Every •Bert Ferrar • Bill Fryer • Alun Griffiths • RobinHumpleby • Goff Hutchinson • Arthur Jones • TrevorLancelot • Jim Lissenden • Tony Mannion • DonMcRae • David Mullins • Pascal Mychalysin • FredPowell • Henry Rumbold • David Sleight • RayStockdale • George Symcox • Bill Taylor • TedThomas • Derek Willey • Gerry Williams • TommyYoung

The conservators

Robert Baker • Keith Blackney • Ian Constantinides •Nick Durnan • John Gentles • Seamus Hanna •Hugh Harrison • Helen Hughes • Bill Martin •Ruth McNeilage • Torquil McNeilage • AlexandraOchterlony • Martin O’Connor • Manjit Phull •Rachel Sabino-Gunaratna • Ziggy Searchfield • RabSnowdon • Keith Taylor • Alan Teagle • Jan Teagle

In Ireland

Chuck • John • Roger • Robert • Tadg

In Israel

Dorit Shalom • Orit Bortnick • Kimi Maman • Nissan • Schmuel • Basemath • Tamar • EilanCampbell

In most of the above categories

Jeanne Marie Teutonico

Other friends and associates

Bob Hough • Keith Fairfax • Ugo Spano • BobBennett • Eithan Campbell • Peter Minter • TonyMinter • Lyndsay Keniston • Bryan Hodgeman

The dogs

Sam • Meg • Bryony • Finch

Finally, my thanks are due to Stephani Havard, Com-missioning Editor for Elsevier, who has been greatlyencouraging and patient during the production ofthis text, and to Sarah Vanstone and Jackie Holding.

Prelims-H6429.qxd 10/14/06 3:15 PM Page viii

Professor John Ashurst is a chartered architect who has spentmost of his professional life working on historic buildings. In theearly part of his career he joined the Ancient Monuments Divisionof the Ministry of Public Buildings and Works and remained withthe organisation through its several changes, culminating in pri-vatisation as the Historic Buildings and Monuments Commissionfor England, better known as English Heritage. For the greaterpart of this period he was architect in charge of the Research andTechnical Advisory Service and took particular interest in theconservation of ruins in the care of the state. For many years hehas been actively involved in teaching and site training, and isauthor of numerous technical notes and books including, withFrancis G. Dimes, The Conservation of Building and Decorative Stone,published by Butterworth-Heinemann. Since 1991 he hasworked in private practice as a consultant on historic buildingsand their sites and has had a particular interest and involvement inthe historic sites of Israel. His other interests are eighteenth cen-tury history, theatre, film and the graphic arts.

Colin Burns is a master stonemason and served his apprentice-ship on the Isle of Portland in Dorset, England. He has spent thelast 35 years in the field of masonry conservation. The greater partof that time has been with the Directorate of Ancient Monumentsand Historic Buildings, later English Heritage, where he worked with John Ashurst in the Research andTechnical Advisory Service. He is a well-known and respected teacher of practical masonry conservation, par-ticularly for his speciality in site training on the conservation of ruins. He has contributed to the conservationof ruins training programmes in Ireland, Albania and Israel. His varied interests include the practice and historyof quarrying.

Graham Abrey is a chartered building surveyor accredited inconservation by the Royal Institute of Chartered Surveyors. Hegained considerable practical experience in the repair of historicbuildings as a supervisor and project manager for a UK stonemasonry company. He obtained a Postgraduate Diploma in build-ing conservation and subsequently worked as an independent con-sultant in the repair and conservation of masonry buildings beforeco-founding Ingram Consultancy Ltd in 1999. Graham uniquelycombines an extensive knowledge of traditional building materialsand repair techniques with essential professional project manage-ment and documentation skills. He has travelled widely in theHimalayan region and has a passionate interest in its cultures.

List of contributors

ix

Prelims-H6429.qxd 10/14/06 3:15 PM Page ix

Jason Bolton has a background in architectural conservation science,heritage risk management, commercial diving and archaeology. He hasrecently completed doctoral research on the deterioration of coastalstone monuments, and has authored a wide range of books, technicalstudies, papers and articles since he began in private practice as anArchitectural Conservation Consultant in 1997. Research interestsinclude the weathering, decay, cleaning, repair and conservation ofstone, brick and mortar masonry structures, the interaction of islandand coastal environments and historic buildings and materials, medievalmortar technology, quarrying and sources of building materials, and thetechnology and design of Irish stone monuments.

Sara Ferraby is a chartered building surveyor with a background of proj-ect management in Historic Royal Palaces in England. She has considerableexperience in conservation contract procedures and documentation, and ofusing these coupled with proper supervision and good communication toensure the maintenance of high standards on site. This translation of con-servation requirements into practice on site has given her a particular inter-est in the development of accredited practical conservation training. She iscommitted to the protection of the countryside and its wildlife, is interestedin all equestrian pursuits and regularly competes at affiliated dressage withher Hanoverian horse Leonardo.

Chris How studied Civil Engineering with aStructural Engineering bias at West Ham College ofLondon University. He carried out a variety of inves-tigation and design works, which included bridgedesign in Cornwall, before migrating to Australia in1970. Since 1973 he has lived and worked in thepioneer region of South-West Victoria, most of thistime as a Consulting Engineer in his own practice.Chris is now semi-retired and is busy indulging a fascination for historic buildings and their problems,which stems from 3700 site tests around the area, and a large number of structural investigations onpioneer structures. He is a team player who enjoysthe interaction with heritage architects, builders,conservationists and historians. He is a member ofAustralia ICOMOS, a member of the Institution ofCivil Engineers, and the Institution of Engineers,Australia.

x List of contributors

Prelims-H6429.qxd 10/14/06 3:15 PM Page x

List of contributors xi

Dr Jukka Jokilehto was born in Finland, where he firstworked as architect and city planner. In 1971, he attendedthe International Architectural Conservation Course atICCROM in Rome, and was later made responsible forthe Architectural Conservation Programme, reaching theposition of Assistant to the Director General. Many of theworld’s conservation practitioners came to know him inthis role and benefited from his guidance and enormousexperience of international conservation. Retired in1998, he has been Advisor to ICOMOS on theUNESCO World Heritage Convention. Internationallyknown as a lecturer, he has written on conservation the-ory and practice, including A History of Architectural Conservation (Butterworth, 1999), and is an accomplishedviolinist.

David Odgers graduated with a degree in chemistry,then spent several years working on the fringes of industry before becoming an apprentice conservator at Wells Cathedral under Professor Robert Baker, where helearned the value of the conservator becoming as knowl-edgeable about the object to be treated as any doctorshould be about their patient. He later built on this experience to become one of the founder members ofNimbus Conservation in 1984 and from 1991 until 2005Managing Director of the company, employing over 40craftsmen and conservators. He was responsible for con-servation works to many important historic buildings andmonuments, including archaeological sites. He is now an independent consultant, an Accredited Conservator,well-known trainer in conservation subjects, and a keen cricketer.

Gionata Rizzi graduated in architecture from thePolytechnic of Milan before specialising in buildingconservation at ICCROM and at the University ofYork, where he obtained an M.A. with a thesis onmasonry ruins. Assistant to Sir Bernard Feilden inRajasthan, he has been involved in many projects ofarchitectural conservation in Italy, France, Spainand the Middle East. As a consultant to UNESCO,ICCROM and WMF he worked on various WorldHeritage Sites, including the Templete Mudéjar inGuadalupe (Spain), a project that won a EuropaNostra Prize. For the Getty Conservation Institute hedeveloped a proposal for a shelter on a hieroglyphicstairway of a Maya pyramid. He is now working inItaly on Herculaneum, on the façade of Parma’sCathedral, and on the archaeological site of PiazzaArmerina in Sicily. He has taught ArchitecturalConservation in Milan and Geneva, and is a guest lecturer at the University of Pennsylvania.

Prelims-H6429.qxd 10/14/06 3:15 PM Page xi

Asi Shalom is an archaeologist and site conservator. Asi wasone of the founders of the Conservation Department in theIsrael Antiquities Authority in 1989. He is a graduate inConservation Studies of the School of Archaeology, HebrewUniversity, Jerusalem, and has also trained in Italy. Hefounded and has managed the Archaeology ConservationCenter since 1995, and has participated in and led over 60conservation projects throughout the country, such asMasada, Qumeran, the Spice Road Caravansaries, Mosiacs ofMemphis, City of David – Jerusalem and various Classicaland Biblical sites. Asi’s many interests include early tech-nologies, especially the culture and work of the Nabateans.He has developed and manages a successful olive farm in the

north of the Negev and is author of a new manual for archaeologists, Excavation and Conservation on Archaeo-logical Sites.

Margo Teasdale is a planner with a first degree in Canadian Studies andHistory and a masters in Environmental Studies from York University inToronto. Her early professional life was spent with the Ontario HeritageFoundation, during which time her activities included key heritage sitessuch as Fort York and the Music Building in Toronto. She also preparedreports for the Canadian Pacific and Canadian National Rail on savingOntario’s railway stations. She subsequently worked for the OntarioMinistry of Culture and Communications on grant projects in theToronto region. In England she obtained an M.Sc. in HistoricConservation at Oxford Brookes and Oxford Universities and a Diplomain Urban Planning. She has since worked as a conservation officer withBath and North-East Somerset, and as a senior conservation officer with Hampshire County Council. Herlifelong interest is the protection of the natural environment and the effects of climate change.

Amanda White is a chartered building surveyor with a post-graduatediploma in the Conservation of Historic Buildings from the ArchitecturalAssociation. Amanda joined English Heritage’s Research and StandardsGroup in September 2004 from Historic Royal Palaces, where she workedas a Project Surveyor at Hampton Court Palace. Amanda assists the ChiefConservation Architect in setting, promoting and monitoring EnglishHeritage’s maintenance standards for the estate in its care. Her concernabout the lack of craft skills in the heritage sector leads her to visit schoolsas a Construction Industry Training Board construction ambassador tostimulate interest in the national heritage and in training programmes. Sheis a keen traveller and enjoys walking and swimming.

xii List of contributors

Prelims-H6429.qxd 10/14/06 3:15 PM Page xii

List of contributors xiii

Catherine Woolfitt is an archaeologist and archi-tectural conservator, and co-founder and director ofIngram Consultancy Ltd, a practice dedicated to theconservation of historic buildings and ancient monu-ments. Since completion of her training at Queen’sUniversity in Canada in the fields of ClassicalArchaeology and Art Conservation, she has pursuedher interest in history and specialised in the conser-vation of historic building fabric – survey, record-ing, analysis, repair and surface treatment. She hashad a long-term involvement and maintains anongoing interest in the history and archaeology ofthe Mediterranean region and of her ancestral homein North Wales. Catherine is a member of theInstitute of Field Archaeologists and of the UKInstitute of Conservation. Spare time is devoted to the conservation of her sixteenth century Somersetfarmhouse and garden.

Rachel Sabino-Gunaratna is Assistant Conservator of Objects andSculpture at The Museum of Fine Arts, Houston. Rachel has carried outinternships at the Metropolian Museum of Art, J. Paul Getty Museumand Corning Museum of Glass and successfully managed a private prac-tice in London. Her interests include gardening, bookbinding andenquine pursuits.

Gillian Reading runs her own administrative sup-port company out of offices shared with IngramConsultancy on the Fonthill Estate in Wiltshire. Shehas worked as personal assistant to John Ashurst,Catherine Woolfitt and Graham Abrey of IngramConsultancy for the last three years and has a clientbase of 10 –15 small to medium size businesses inthe area. Gillian spends time away from her com-puter running or walking with her Jack Russell dog,Finch.

Prelims-H6429.qxd 10/14/06 3:15 PM Page xiii

This page intentionally left blank

Foreword

The conservation literature contains many books onearthen architecture, stone and historic buildings.Few of them, if any, deal specifically with ruins, andthis volume fills the gap admirably. Similarly, theconservation profession has many gifted people butthere are few, if any, who are better qualified thanJohn Ashurst to bring such a book into being.

One of my first encounters with John was atTintern Abbey. Its immaculately maintained appear-ance contrasted markedly with photographs fromthe previous century, when it was covered with ivy,the archetypal romantic ruin. We were applying arange of biocides to control algae and lichen, seeingwhich worked best and lasted longest. I doubtwhether it occurred to either of us to question whatwe were doing, or to set the evident need for main-tenance into the wider context of conservationethics and principles. Conservation then was largelya matter of finding the right material for the job.

This book reflects the changes that have takenplace in the intervening years. It contains much

practical advice, but it also maps out some of thewider context in which conservators now operate.

John’s first book Stone Preservation Experiments,co-authored with Brian Clarke and published bythe Building Research Establishment in 1972,marked a turning point in approaches to stonepreservation. It was meticulously researched andrecorded, but few people who read the prefacewent any further. The preface ended with thememorable words ‘None of the treatments has hadany overall beneficial effect in retarding decay onany of the sites’. Why read on? This volume, bycontrast, will be quarried repeatedly by studentsand experienced practitioners alike. It provides, inthe words of Gionata Rizzi’s preface, a ‘closeencounter with ruins’: an encounter that willinform and invigorate on every occasion.

Clifford PriceProfessor of Archaeological Conservation

Institute of Archaeology, University College London

xv

Prelims-H6429.qxd 10/14/06 3:15 PM Page xv

Figure Page number Source/Credit

Frontispiece ii, xvi John AshurstJerash xxiii Gionata RizziI.2 xxv-xxvii John AshurstI.3 xxviii Michael WilliamsI.4 xxviii Agence photographique Roger-ViolletShort story xxxii-xlii John AshurstPevensey xxxix John AshurstKirby Hall xxxix Graham AbreyHatshepsut xxxx Asi ShalomParthenon xxxx Catherine WoolfittTel Beit She’an 1 John AshurstStoa of the Athenians 1 Catherine WoolfittPompeii 2 Catherine WoolfittHerculaneum 2 Gionata Rizzi2.0 10 John Ashurst2.1 12 John Ashurst2.2 13 Chris How2.3 14 John Ashurst2.4 –2.7 14 –17 Chris How2.8–2.10 17–18 John Ashurst2.11–2.22 20 –24 Chris How2.23 25 John Ashurst2.24 – 62 26 – 43 Chris How3.0 44 Graham Abrey3.1–3.10 55 Graham Abrey3.11 57 John Ashurst3.12–3.14 62, 63, 67 Graham Abrey3.15, 3.16 69, 72 Graham Abrey, based on drawings by WS Atkins3.17 73 Graham Abrey3.18 74 Graham Abrey and John Ashurst3.19 75 Plowman Craven Associates3.20 77 Graham Abrey and John Ashurst4.0 82 Catherine Woolfitt4.1– 4.5 84 –90 John Ashurst4.6, 4.7, 4.8 91, 92 Colin Burns4.9– 4.17 92–100 John Ashurst4.18– 4.27 101–105 Colin Burns4.28– 4.35 106 –110 John Ashurst4.36 – 4.38 111–112 Colin Burns4.39– 4.43 112–116 John Ashurst4.44, 4.45 117, 118 Colin Burns4.46, 4.47 118, 119 John Ashurst4.48, 4.49 120, 121 Colin Burns4.50 – 4.69 122–139 John Ashurst4.70 140 Asi Shalom4.71–5.76 141–144 John Ashurst5.0 1465.1 149 Graham Abrey

Figure credits

Prelims-H6429.qxd 10/14/06 3:15 PM Page xvi

Figure Page number Source/Credit

5.2–5.4 151–153 Catherine Woolfitt5.5 154 Asi Shalom5.6, 5.7 155, 156 Catherine Woolfitt5.8 157 John Ashurst5.9–5.13 161–165 Catherine Woolfitt5.14, 5.15 166, 167 Courtesy of Museum of London Archaeology Service5.16, 5.17 169, 170 John Ashurst5.18 172 Graham Abrey5.19–5.23 173–180 Catherine Woolfitt5.24, 5.25 181, 182 Orit Bortnik5.26 182 John Ashurst5.27, 5.28 183, 184 Courtesy of the Austrian Archaeological Institute5.29, 5.30 185 John Ashurst5.31 186 –189 Catherine Woolfitt6.0 194 Courtesy of The Blackburn Museum6.1– 6.8 196 –203 John Ashurst6.9 204 Colin Burns6.10 – 6.12 205, 206 John Ashurst6.13 210 Sara Ferraby and John Ashurst7.0 212 John Ashurst7.1–7.12 213–229 Jason Bolton7.13 230 Courtesy of the Archaeological Diving Company7.14, 7.15 231, 232 Jason Bolton8.0 234 Colin Burns8.1 236 John Ashurst and Colin Burns. Reproduced courtesy of Getty

Conservation Institute8.2–8.8 237–245 John Ashurst9.0 246 Asi Shalom9.1 250 John Ashurst9.2 251 Amanda White (2005)9.3a 252 John Ashurst9.3b 252 Elisabeth Vause9.4, 9.5 253, 254 John Ashurst9.6, 9.7 256, 257 Helen Thomas (2005)9.8 258 John Ashurst9.9, 9.10 259 Peter Ranson9.11 262 John Ashurst10.0 264 John Ashurst10.1–10.14 266 –278 Catherine Woolfitt10.15, 10.16 279, 280 INNPA10.17–10.20 281–285 John Ashurst10.21–10.24 286 –289 Asi Shalom10.25 289 John Ashurst10.26 290 Catherine Woolfitt10.27–10.30 291–293 John Ashurst10.31–2.33 293–294 Asi Shalom10.34 –10.45 295–305 John Ashurst11.0 306 John AshurstAppendix 1 309–311 John Ashurst, first appeared in Mortars, Plasters and Renders in

Conservation (1983), J. Ashurst, Ecclesiastical Architects’ and Surveyors’Association, London

Appendix 2 319–324 John AshurstAppendix 2 326 –330 Information provided by Mann Williams acting as term consultants

for CADWA4.1 332 John AshurstA4.2–A4.4 335–336 Reproduced with permission of the Daughters of the Republic of TexasA4.5, A4.6 337 Rachel Sabino-Gunaratna

Figure credits xvii

Prelims-H6429.qxd 10/14/06 3:15 PM Page xvii

Knowlton Church and Rings are a good example of a Scheduled Ancient Monument in England. Located in the ancientlandscape of Cranborne Chase and surrounded by barrow cemeteries and earthworks, the church is eleventh century butmuch altered in the fourteenth century. Remarkably, it stands within a well-preserved ceremonial Neolithic Henge monu-ment of c. 2500 BC. Consolidation of flint core work, tamping and pointing, the use of rendered brick structural supportsand bronze corbel bars are classic interventions of the Ancient Monuments Division of the Ministry of Public Building andWorks (c. 1950). Scale by Sam the retriever.

Prelims-H6429.qxd 10/14/06 3:15 PM Page xviii

Rocks impregnable are not so stout, norGates of steel so strong, but time decays.

(Shakespeare, Sonnet 65)

Ruins: buried cities brought to light by archaeologistsin every part of the world; sacred temples dedicatedto divinities that we have ceased to worship; towers,forts, strongholds, military defences made useless bythe unremitting development of new weapons;industrial plants and factories no longer compatiblewith modern techniques of production and aban-doned like the carcasses of huge old-fashioned cars;buildings that have been gnawed, mutilated andreduced to a state that bears no relation to their orig-inal purpose; buildings that have sometimes deterio-rated to a point where their original form can hardlybe recognised; buildings that only survive in the formof isolated fragments.

Ruins are everywhere. They form a considerablepart of our architectural heritage and, actually, evenof the World Heritage List: they are preserved asruins, maintained as ruins and visited by a growingnumber of people who, in ruins, see values, signifi-cance and meaning – in spite of their condition.

In spite of their condition or because of their condi-tion? Henry James1 puts it clearly: ‘It has often seemed tome … that the purest enjoyment of architecture was to be hadamong the ruins of great buildings’. True, although theenjoyment he describes is probably not only architec-tural: the interest in archaeological ruins and the tastefor architectural fragments go far beyond the histor-ical and artistic importance the remains of a givenbuilding may have; as the ephemeral traces of thehuman activity on earth, ruins are actually among themost evocative icons of times past.

Indeed, the ‘enjoyment of ruins’ seems to thrivein contemporary sensitivity nourished, as it is, by

many aspects of our mentality: the aesthetic pleasurein the patina of time, the romantic sensitivity for thework of man reconquered by nature, the positivistinterest in architecture denuded of ornament andobservable in its bare ‘anatomy’, the taste for thepart wrenched from its context, for the unity turnedinto pieces, for the isolated fragment.

As a matter of fact, this fascination of contemporaryculture for ruins appears to have its roots in at least twocenturies of history of ideas. A crucial moment for thedevelopment of such sensitivity is perhaps to be seenin the great excitement that seized Europe whenWinckelmann, before being murdered in 1769, beganto reveal to Northern Europe the extraordinary dis-coveries of Pompeii and Herculaneum. It is difficultto imagine a historical moment when European cul-ture could have reacted with greater interest to thediscovery of a buried city: eighteenth century sens-ibility was by then ready to become excited at theromantic notion of the ruin, while neoclassical anti-quarian taste was anxious to find in archaeologicalremains new material for its aesthetic. From the endof the eighteenth century, and for a period that was tolast many years, an avalanche of writers, thinkers andartists descended upon Pompeii and Herculaneum:Goethe visited the excavations in 1787, Stendhal in1817 (‘The strangest thing I have seen on my journey …;one feels transported into antiquity …’); and subsequentlyChateaubriand, Taine and Gautier. Thus, in a fewdecades, the aesthetics of the bella ruina, the literarysensibility for the ‘pleasing decay’, the poetry of ruins,received a strong impulse that would have a profoundeffect on the history of taste.

***

Ruins, however, do not only attract for romantic rea-sons. Actually, at the very same time as the romantic

Preface

Gionata Rizzi

xix

Prelims-H6429.qxd 10/14/06 3:15 PM Page xix

emotion primed by the discovery of Herculaneum, acompletely different attitude inspired the scholarswho saw in the archaeological excavation a chance tostudy classical antiquity in the field: remains to beobserved, buildings to be measured, objects to becatalogued just as naturalists were doing, in thoseyears, with the flora and fauna of tropical forests.Since then, endless drawings of ruins, in Europe, inAfrica, in the Middle East, have been produced withthe evident desire for scientific precision; drawingsmade in the same style as a treatise on anatomy – clear,precise, perfectly rendered in watercolours – wherethe interest in architecture is clearly higher than thepictorial taste for wear and tear.

These were the type of drawings that young Frencharchitects studying in Rome at the Villa Medici wereasked to make as part of their training, and it is on thatbasis that they had to draw the hypothetical recon-struction of the buildings in their original state, in itspristine form: this work of restitution, this backward itin-erary from the fragment to the whole, was to have afundamental effect on the study of ancient architec-ture, a starting point and a testing bench for archaeo-logical restoration, still in its infancy.

What in fact these scholars did was to use arch-aeological remains as ‘anatomical specimens’ ofarchitecture.

Architecture, at least until the advent of theModern Movement, never shows how it is built.There are certainly periods where the gap betweenthe load-bearing structure and the architectural formis very thin, but even in the case of gothic cathedrals,where the gap is reduced to a minimum, the struc-tural core is well hidden beneath layers of plaster andpaint. Indeed, most of western architecture from theRenaissance to the nineteenth century is charac-terised by a kind of representation of the structuralform: columns, pilasters, capitals, cornices and entab-latures – all the elements of classical vocabulary – referdirectly to the tectonics of a building and to its struc-tural articulation; generally, however, these elementshave nothing to do with what makes the buildingstand up. The Romans were maybe the first to ‘hide’,behind a decorative apparatus of stucco and marble,an independent structure made of concrete: sincethen, for much of the architecture that we admire, wecan only attempt to guess at its anatomy.

Ruins are fascinating even for this: they reveal howthey were built. Once the cloak of the finishes hasbeen removed, ruins unmask their entrails: the mater-ials of which they are built, the structural principlesthat determined their design and the techniques thatmade their construction possible. It is perhaps noaccident that the architects of the Renaissance spent

their time drawing ruins: while their notes and draw-ings seem to focus on proportion and mathematicalratios, one can bet they were paying great attentionto building technique and that from the close obser-vation of ruins they learned many lessons about theancient structures.

***

But what is, in fact, a ruin? An art historian, anarchaeologist and an architect would probably answerin different ways, depending on the specific work thateach specialist is required to carry out and on the cultural, technical and scientific approach of eachdiscipline: a case study for a given period of history ofarchitecture, an opportunity to analyse the relation-ship between the standing building and the stratig-raphy of its surroundings, a challenge forconsolidation and conservation. If, however, onewanted to conform to the evidence and formulate adefinition that would be suitable for a dictionary, itwould be tempting to answer ‘a ruin is a buildingwhich, having lost substantial parts of its architecturalform, has ceased to function as such’. Elementary, butfull of implications: a building that has lost its naturaldefences (roof, windows, plaster, etc.), unarmedagainst the ravages of atmospheric agents and conse-quently more vulnerable to the destructive effects oftime; a building that has stopped to fulfil its functions,to shelter human activities and which, in a sense, hasbegun its journey towards progressive decline andfinal disappearance – here, between architecture andnature, in a sort of no man’s land, lies the ruin.

An entire book would not be enough to describehow ruins are created. There are different reasonsunderlying the formation of a ruin and differentcauses that trigger off the process. The medieval ruinsscattered through the English countryside (Fountains,Rievaulx, Byland, etc.; they seem created on purposeto explain the term ‘picturesque’) originated when,after the dissolution, the lead of the roofs was rippedoff to be reused elsewhere; and, by the time conserva-tion was taking its first conscious steps, they hadalready become celebrated landmarks.

In other cases, natural phenomena of extreme vio-lence have condemned entire cities: Jerash, one of themost extraordinary urban structures of the Romanempire, with its famous circular forum, was shakenby an earthquake of such intensity that it never man-aged to recover and was abandoned soon afterwards.Ephesus, like many other cities in antiquity, was condemned by the silting up of rivers and ports, a lessspectacular cause, but just as inexorable.

Added to these is the destruction caused by man during wartime, either in the course of military

xx Preface

Prelims-H6429.qxd 10/14/06 3:15 PM Page xx

operations designed to destroy strategic objectives orwith the deliberate aim of striking at the enemythrough the mutilation of its cultural heritage. In gen-eral, these types of ruins are quickly repaired in theattempt to heal the injuries of a war: the bridge ofMostar, after its single arch of stone was shelled andreduced to just two macabre stumps, has been entirelyreconstructed; sometimes, however, a monument hitby a bomb is voluntarily turned into a ruin and, aswith Coventry cathedral, becomes a memorial.

Experience shows that a piece of architecture, leftto itself, does not take long to begin its journeytowards wear and tear: a few decades is all that is nec-essary for a leak to open up in a roof; a century ofabandonment is enough to cause the initial collapseof the walls in a castle or to transform a monasteryinto an impenetrable tangle of brambles and rubble.After this it is simply a question of time before, as aneighteenth century writer2 put it, ‘nature takes itsrevenge and, through the assaults of vegetation, reconquerswhat man has built’. But the way a ruin is formed –whether, little by little, it gradually silts up and isbrought to light after centuries as a disinterred burialor, still above ground, is reduced to a bleached skele-ton by the sun and rain – has a great influence onhow it is perceived, used and eventually conserved.

Ruins that – thanks to their size and to the qual-ity of their materials – never disappeared under-ground often became part of modern urban fabric.Either reused for new purposes or treated as quar-ries of building materials, these structures keep afunction and mix with the architecture of the livingcity: the stones of the roman amphitheatre of Milan,dismantled in the sixth century, were used to buildthe foundation of the nearby church of SanLorenzo; in Lucca the amphitheatre lent its radialwalls to the houses that grew on the tiers while thearena dissolved into the piazza; medieval Rometurned into houses the arches of the Teatro diMarcello; in Tarragona (Spain) the vaults of the hip-podrome form part of the medieval city wall;Diocletian’s palace has become the historic centre ofSplit; and so on, with endless examples.

Other ruins, instead, emerge from the archaeo-logical digs after centuries of oblivion; when they areexcavated they may risk to suffer the same fate asthose Egyptian mummies which, brought to lightafter thousands of years, disintegrate in front of theeyes of the discoverers. But they are immediatelyrecognised as monuments, treated as cultural objects,studied and conserved with due consideration for thehistoric, artistic and documentary value they bear.

An interesting case, in this respect, is representedby Pompeii and Herculaneum which, although

considered almost a prototype of the archaeologicalremains, are actually an exception, for they haveceased to be buildings but, in a way, have neverbecome ruins. As everyone knows, they wereburied overnight during the eruption of the Vesuvio,Pompeii by showers of lapilli and Herculaneum by ariver of boiling mud which filled every hollowspace. What makes these sites special is that the waveof liquid sludge, an amalgam of water and volcanicash, solidified as tuff and protected the buildings –with their finishes and their content – for centuries.As a result, the remains that archaeologists broughtto light, especially in Herculaneum, are like fossils asthey appear when one breaks open the stone thatconceals them: pieces of architecture that emergedfrom the tuff like the imprisoned forms thatMichelangelo imagined to liberate, stroke afterstroke, from a marble block.

***

Is it good to restore a ruin? The question is lessrhetorical than it might seem at first sight. The factthat a ruin cannot be restored, in the sense of taken backto its original state, is obvious. To start with, there is aphilological problem: with the exception of monu-ments built of large blocks of stone, which can bere-erected with great precision like a gigantic three-dimensional jigsaw puzzle, the original state is usuallyunknown. One can obviously make hypotheses onthe grounds of solid archaeological evidence andcareful stylistic comparisons, but they are hypothesesnonetheless. To reconstruct what has been lost basedon these arguments may lead to the ‘invention’ of amonument that has never existed. And even when it was possible to determine with absolute certaintythe original state of the building, the lack of originalfinishes, of original details, of original colours wouldgive the reconstruction an artificial and unrealappearance. This is what has happened at Babylon,where the reconstructed portions resemble a film setmore than a real ruin of a real city.

In reality, the problem is not solely the corres-pondence to the original form: even when philo-logically correct, the reconstruction of somethingthat no longer exists is, to a certain extent, a fake.Or, if we want to stay away from any theoreticalconsideration, the problem is that the more a ruin isrestored, the more it loses its authenticity; the moreits evocative power is diluted, the more its archaeo-logical truth is blurred.

Authenticity and archaeological truth: theyappear to be among the most intrinsic values ofruins, but are the ruins we see really authentic? Notalways. What one often fails to realise is that sites

Preface xxi

Prelims-H6429.qxd 10/14/06 3:15 PM Page xxi

like Ephesus, the Parthenon or Pompeii have beenrestored for hundreds of years and have by now along history as historic monuments. In that period oftime, frescoes have been detached from the walls,stones have been replaced, columns have been re-erected, walls reconstructed. In Ephesus, more thana century of restoration work by the AustrianArchaeological Institute has shaped the excavatedremains into the present site; the Parthenon isalmost unrecognisable in the photos taken beforethe work of Balanos; in Herculaneum, 200 years ofrestoration have gradually transformed the ancientfabric into a mixture of authentic and reconstructed,where modern additions merge inexorably with theoriginal buildings (a recent study demonstrates thatnearly 50 per cent of what we see today was builtbetween 1930 and 1950).

In fact, in an attempt to preserve them as found, topresent them as ruins, many remains have beenreshaped and retouched several times. Odd as it maysound, more ruins than we suspect are made-up ruins.

***

If it is impossible to restore a ruin to its original shape;if, on the other hand, the romantic idea so welldescribed by Gilpin – ‘it’s time alone which meliorates theruin, which gives it the perfect beauty’ – cannot be put intopractice for it leads to a growing and continuingprocess of deterioration; if authenticity is so easily lostby the attempt to restore the elements that made thebuilding stable in an open environment; then we canonly try to protect it against further decay and preserveit as it is. But this is precisely where the contradictionsand ambiguities begin. In order to preserve a brokenartefact as it is, one needs to provide it with newdefences that never belonged to it and never existed;thus, to prevent an archaeological remain from disin-tegrating completely, one may have to put up shelters,to build buttresses, to reinstate a bit of masonry, toconstruct some sort of capping at the top of the walls;in other words, one has to make all those alterations,more or less visible, that can guarantee the survival ofa ruin. Indeed, Viollet-le-Duc’s much-criticised defi-nition, according to which restoration would consistof turning a monument into a state in which it mayhave never existed, seems to be the fate which ruinsare unable to avoid: a conserved ruin is always, in away, an artifice.

We have reached the core of the problem: up towhich point – it is the question that torments thepractitioners who deal with ruins – is it legitimate toalter the original in order to preserve it? And to whatextent must restoration work be visible and distinct

from the original? Should the restored parts mergewith the rest and become unrecognisable or shouldthey strike the eye of the observer? And lastly, shouldthe consolidated parts be made using ancient mater-ials and techniques or with modern ones?

All these questions arise from the awareness thatmuch of the value of ruins lies in the sense of tran-sience they emanate. This is perhaps the main point ofambiguity: we want to preserve a ruin without oblit-erating the offences of time, we want to slow downdecay to enjoy for longer their presence: what weactually want to do is to keep them suspended ‘in themiddle of the ford’, no longer architecture and not yetnature. Maybe our real attempt when we work onthese fragile fragments is to take them away from theirtemporal dimension: not without reason has the con-servation of ruins been defined as a respectful kidnapping.

It is clear by now that conserving a ruin is a cul-tural activity. It is a cultural activity because it has todo with cultural objects and because it has to dowith our sense of the time past. All cultural activityis controversial and as in all cultural activities thereare no ready-made recipes. Trying to define what isa ‘proper restoration’ is probably vain: there is nosuch intervention that satisfies all the criteria of anabstract idea of ‘conservation correctness’, that isirreproachable both from a theoretical and a tech-nical point of view: each site has a different story,each case calls for a specific approach. And, what ismore, the same ruin can be treated in different ways.

Once again, Herculaneum is a telling example:the presence, along with masonry structures, of wallpaintings, mosaics and stucco creates a problem thatleads to a painful dilemma – is it better to put theentire archaeological area under a modern shelter,turning the site into a museum and losing for ever itsoutstanding urban value, or to detach and displayelsewhere the decorative apparatus that cannot sur-vive unprotected, denying the special quality thatHerculaneum possesses and losing at once what theeruption miraculously preserved? Probably a lessdramatic alternative can be found, but one whichrequires following the slippery path between exces-sive reconstruction and insufficient protection,which involves reconstructing more than is desirableand verging on falsification.

Even anastylosis, which one would think to bethe least critical degree of intervention, raises manyproblems and much controversy. Apart from thecorrect interpretation of archaeological evidence,one can actually argue on the phase and the extentto which a monument should be restored if not onthe worth of remounting scattered elements that lay

xxii Preface

Prelims-H6429.qxd 10/14/06 3:15 PM Page xxii

for centuries on the ground. In addition to this, onecan debate about the due level of respect of theoriginal static behaviour of buildings and, in seismicareas, about the earthquake response the re-erectedstructure must have. An interesting case, to give butone example of the inherent uncertainties of anasty-losis, is the Propylaeum of the temple of Artemis inJerash. More than 90 per cent of the original piecesof the monumental entrance had survived and theirposition could be determined with accuracy; a morecareful analysis, however, indicates that the entabla-ture had been taken down in Roman times and thatthe pediment was possibly never positioned. Shouldone envisage to reconstruct what has never col-lapsed but was deliberately dismantled?

Indeed, in conserving a ruin, it is impossible to beneutral. Experience teaches that, no matter howcautiously the work is designed, a conserved ruinalways bears the traces of the intervention carriedout. So different is, for instance, the way to treat aruin from country to country that, by looking at it,one can almost guess the nationality of the archi-tects who did the work.

But if one cannot be neutral – as a musician cannotbe neutral, though fully respectful of the score – one

can at least try to be elegant and effective. To do sowe need the best acquaintance with all the possibletechniques of repair and stabilisation developed inyears of activity all over the world. After that, wehave to rely on a profound knowledge of the archi-tectural body we set to conserve: of its form, of itshistory, of the history of past intervention; on a per-fect insight of its structural behaviour, on a solidunderstanding of the materials it is built of and on adeep comprehension of the mechanisms of decay.

Only this ‘close encounter’ with the remains to beconserved can hopefully be of assistance in definingthe most appropriate conservation strategy and toguide the battle against the silent work of time withthe technical and intellectual elegance ruins deserve.

It’s this close encounter with ruins that JohnAshurst and his authors offer to us in this book.

Gionata Rizzi

References

1. English Hours, Elibron Classics, 2005.2. Ercole Silva, Dell’arte dei giardini Inglesi. Milan, 1801.

Preface xxiii

Jerash. The circular forum of Roman Jerash, substantially and mortally damaged by an earthquake.

Prelims-H6429.qxd 10/14/06 3:15 PM Page xxiii

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxiv

The doors are locked for the last time and the gates pad-locked. As months pass and no-one comes back, there areunmistakable signs of change. The mice grown bolder inthe house and their feet and tails leave trails in the accu-mulating dust. Foxes and badgers become less wary aboutappearing on the unkempt lawn, and wasps feed unhin-dered on the fallen showers of plums.

Then there are visitors. By day they come and breakout the fireplaces of marble and polished limestone andload them onto trucks for sale in London. The gadroonedurns go next from the balustrades and the lions of Istrianlimestone from the gate piers.

By night they come with ladders and prise out theheavy cast lead gutters from behind the parapets and fromthe roof ridges. These mortal wounds are made in secret,and the high walls and great trees which gave the houseits seclusion and privacy now conceal a crime and themaking of its end.

Crime because the building is protected by law andmay not be damaged or demolished without consent. Butthe law is for those who respect it.

The heavy rains of autumn find access through theopen gutters and ridges and lie on the floor of the ChineseChippendale bedroom. Pooling there for a time the waterbegins to penetrate more deeply into the house, and lies onthe back of the rich plaster ceiling of the saloon, swellingthe lath and softening the keys. Late in the wet winter theceiling begins to sag and crack, and one of the plaster scal-lops of the Lyttelton family falls to the floor in a scatter oflime and cobweb and dust. The painted plaster panels ofthe wall, perhaps the work of Biagio Rebecca, are nowdecorated with black strands of mycelium …

In the gutters, the feet of the Baltic fir rafters and theplates on which they sit grow sodden. They might still besaved, but exchanges of letters and proposals and counterproposals take time and wood-rotting fungi are finding thewet and summer-warm roof space a congenial environmentin which to grow. As negotiations enter their second year,the stair begins to collapse and a ridge to sag. When the

first section of the roof falls in, the jackdaws in the coldchimney are the only witnesses.

Curiously, from the wilderness outside that was once agarden, the house looks remarkably intact, and almostunaltered except for dark water stains under the parapetsand some broken glass. But already it is no longer ahouse, it has become a ruin.

( John Ashurst, The Story of Pit Place)

Why should we want to conserve ruins as ruins?They have no practical use unless they are somehowrepaired and restored to functional buildings again.And ruins have been adopted and adapted for newuses throughout history or have been restored totheir original, or supposed original, form and appear-ance. These kinds of interventions are really betterdescribed as the conservation and/or restoration ofhistoric buildings, rather than of ruins, on whichsubject an abundance of literature, philosophical,historical and technical, exists. For instance, BernardFeilden’s Conservation of Historic Buildings1 not onlyremains a standard reference after nearly 25 years, butis still a hard act to follow. A book this wide ranging inits scope and so comprehensive in its detail is challeng-ing to addition, even though there have been refine-ments and developments in the quarter century sinceits publication, most notably in recording, in inves-tigative techniques and in conservation technologies.But the present book is concerned with a differentsubject, in spite of inevitable overlaps. In writing, now,about the conservation of ruins after nearly 40 years ofworking with them, I am far more conscious than Iwas once of the differences between the conservationof buildings and the conservation of ruins.

One of the great changes in the last few decades, in addition to the technology just described, is theconsiderable amount of interest shown by the build-ing professions in conservation training, and the greatnumber of degree courses and short courses whichhave been developed to provide for that interest. Onlyhistory will fully show how much the interest and thetraining have benefited our historic buildings andhow they contributed to the quality of their survival.But thus far, on the conservation and treatment of

xxv

Introduction – continuity and truth

John Ashurst

Figure I.1 Massive Herodian masonry forming the revet-ment around the Temple Mount. Huge stones, sawn to size,were also used in the first (Solomon’s) Temple, some over7 m on face.

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxv

ruins, I believe the impact of this interest has not beengreat. This may simply be a reflection of the relativeimportance most conservation personnel afford toruins in comparison with whole historic buildings,and perhaps a vaguely held belief that looking after abroken building must be much the same but probablya lot simpler. Significantly, training of the professionshas not been matched by skills training; and whenskills are discussed, the focus is generally on the revivalof traditional crafts, rather than on teaching practicalconservation skills.

The conservation of ruins is, as Gionata Rizzi’spreface has shown, a wholly illogical practice in someways, and is at variance with what most of us aretrained to do. Architects, surveyors and builders menddamaged buildings and make them useful again. Astonemason rightly takes pride in his or her ability tocopy the moulded stone of a cornice and replace it.Not to do so, only to stitch and pin and treat the sur-face of a ravaged detail is, on the face of it, a curiousand rather unsatisfactory pursuit. Yet in doing so, aphysical unit of history has been secured; multiply itmany times and an entire ruin, for all its scars and lackof essential elements, can still exist. But, to return tothe original question, should we want it to? Often, weknow that we want to, but we do not know why, asubject explored extensively and imaginatively byLowenthal.2 Whatever the complexity of the reasons,we need these physical links with our past, and for themost part need to believe that they are substantially‘authentic’. ‘Unless we are able to look back we willnot be able to move forward’ is a piece of ancientSumerian wisdom which has not outlived its rele-vance and which cultivates a respect for our past, andthe past of others.

Whatever our understanding and perceptions ofhistory, ruined buildings and their sites are somehowand somewhere woven into them. Unlike smallerartefacts, which are movable and may be protected,studied and enjoyed in museums, the ruin and its siteare inseparable. Even those few ruins which havebeen small enough to move lose much of their valueand meaning in the process. The site is the reason forthe ruin’s existence; it was the site that provided secu-rity or shelter, needed to the guarded, offered prof-itability and prosperity, or instilled awe or inspiredby the beauty of its natural setting. The site and ruinmay be thought of as unread, or partially read,books. The more respectfully they have been treated,the more information there will be to read. Carefullyconserved, they will remain for future readers to rein-terpret in the light of more knowledge and under-standing. Carelessly or ignorantly handled the pages

will be spoiled and confused; obliterated they will bemore irretrievably lost than books burned in theOpernplatz in 19333 or at any other time when thedeliberate destruction of information and ideas hasbeen attempted.

The ruin and its site often remain under-appreciatedand not sufficiently understood as sources of infor-mation, but once recognised as such the archaeo-logical and conservation work which is carried outinevitably becomes more thoughtful and profes-sional. Sometimes, even after decades or centuries ofstudy, a site can still yield information and shouldnever be considered as fully and finally read. Theexample of the Temple Mount in Jerusalem may bequoted in this context (Figure I.2). Few locationshave attracted so much attention so continuously,and few have had such a long, complex and violenthistory. Even today, the systematic unravelling andrecording of the building history of the Temple andits curtilage is made prodigiously difficult by physi-cal, ideological and religious divisions. Throughouthistory there are examples of individuals, movementsor cultures endeavouring to manipulate historythrough ‘selective archaeology’. But archaeology is ascience which must, above all, provide, through itstechnology, its techniques and its professionalism, atrue record of what survives. The evidence so pro-duced may well remain the subject of debate andmaybe of disagreement, but it must be unadulterated.Tampering with the evidence for whatever reason,either archaeological or in the way standing ruins areconserved, is inexcusable. Archaeologists and con-servators, of all people, must understand this, what-ever external pressures may be applied to avoid ordistort the facts.

One of Jerusalem’s many epic moments in historywas the major destruction in the first century AD(CE). Already damaged by zealot factions during theJewish revolt against Rome, the city was besieged byTitus with the greater part of the occupying army ofJudea, consisting of four legions with auxiliaries.4

Following circumvallation of the upper city, the siegeended with the systematic demolition of much of thecity and, especially and symbolically, of the Temple.This was the Temple raised by Herod the Great onthe ruins of Solomon’s Temple, which had com-menced in 20 or 19 BC5 (BCE), was still being builtduring the time of Jesus.6 The completion of thisrich and massive structure was not completed untilaround 50 AD (CE), only some 20 years before itsdestruction. Archaeology has uncovered many of themassive stones of the Temple and of other buildingson the Temple platform lying in the Herodian street7

xxvi Introduction

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxvi

(see Figure I.2), below the western wall and in otherlocations, a graphic record of the demolition work ofLegio X Fretensis, complementing the historicalrecord of the event.8 But much that still needs to beknown lies within the Temple Mount and, for com-plex reasons, out of reach. In such circumstances, andhowever frustratingly, it is important that what sur-vives remains undisturbed and not investigated in anyway other than openly, cooperatively and profession-ally, so that the information remains intact for othersto read in the future.

The vexed issue of ‘authenticity’ recurs from timeto time in the chapters of this book. ‘Is it original?’the visitors ask of the historic site they have come tosee. Why, generally, do we need to believe that whatwe keep is ‘authentic’ and not a copy, however wellmade? This philosophical issue does not need to beresolved (if it ever can be) before we engage in thephysical activities of uncovering and conserving, pro-vided we work on the assumption that we must notalter, or remove, or add to, unless we have no otheroption of securing and saving our subject. And if we

Introduction xxvii

Figure I.2 Demolition material from the Temple and other buildings thrown down into the street below the western wall.

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxvii

do, we must make an accurate and honest record ofwhat we have done and our reasons for doing so.

Authenticity in the case of a relatively ‘new’ ruinis interesting because the cause of its ruination is still within living memory and authenticity cantherefore, for a time at least, be critically monitored.Nineteen-thirties images of the Church in the villageof Oradour Sur Glane in the Haute-Vienne depart-ment of France have an air of timeless tranquillity;

its devastated condition seen in Figure I.4 is not theresult of a fire caused by an electrical fault or a light-ning strike, but as an act of reprisal against localresistance by a Regiment of the Second Waffen-SSPanzer Division Das Reich on their route north tomeet the Allied invasion of Normandy in 1944. Notjust the church, into which the women and childrenhad been driven, but the whole village was destroyedby fire, with most of its inhabitants and their visitors

xxviii Introduction

Figure I.3 The ruin of the Church at Oradour Sur Glane as it is today.

Figure I.4 The Church at Oradour Sur Glane. Photograph taken in November 1994.

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxviii

who happened to be present on 4 June. Even to aworld inured to violence this event had, and has,such a peculiar horror that the need to commemo-rate that summer day by the preservation of theentire village as a ruin seemed imperative. There is anew Oradour Sur Glane close by now, and a com-memorative centre to provide information (Centrede la Memoir, Oradour Sur Glane), but the build-ings and streets remain as they were left, devastatedand silent, and can still be visited by some whoknew them whole. Figure I.3 shows the church as itis today, the smoke blackening washed away, theopen wallheads consolidated and protected withroof tiles. The instruction in the streets is ‘Silence’,the message ‘Souviens-toi’ (‘Remember’).

Other ruin sites witnessed other tragedies long out-side living memory and likely to remain unknown,but a site such as Oradour, where much (although not all) is known about the event, has a particularpoignancy and presents a particular challenge in termsof conservation. Here it is not the significance of thebuildings that merits their retention, but the signifi-cance of an event. A memorial could record, but notrecall with the same immediacy and power as the bro-ken buildings. The buildings are likely to outlive theliving witnesses who remain, but how long and howeffectively they can record the original reason for theirretention depends on how skilful and how sensitivethe ordinary physical processes of maintenance andconservation continue to be. A restoration or recon-struction of destruction would be pointless. There arestill those who can say ‘no, it was not this way’.Authenticity may still be experienced in the ruins ofOradour, even with the softening of time, but howlong their evocative power can remain has much to dowith the quality of their conservation.

More familiar material than Oradour is the usualsubject of this book, such as the conservation of for-tifications, temples, abbeys and houses of architec-tural, historical and social significance surviving asruins. The sites used as illustrations only represent asmall proportion of the ruin types which can befound around the world, but the aim is to try toaddress principles and practices which can be appliedto any site, however far its form and materials may befrom those found in this book. For those who wantto enjoy the diversity and splendour of the world’sruins there are books such as Rose Macauley’s ThePleasure of Ruins,9 or Charlotte Trumpler’s The Pastfrom Above.10

When the idea of this book, for me, was first con-ceived, I am not sure. But it had something to do with

the loss of an old house of singular character which Iknew well, hidden in a landscaped quarry of unusualbeauty, adorned with relics of Henry VIII’s NonsuchPalace. Just as Henry’s builders had made use of thestone of Merton Abbey, following its dissolution, tobuild Nonsuch, so Nonsuch, the ‘non-pareil’, wasdestroyed to pay the prodigious gambling debts ofBarbara, Lady Castlemaine, and so, finally Pit Place,the house in the Epsom quarry, was destroyed bydevelopers needing to turn a liability into a profit. Allthree buildings had, in their prime, a sense of perma-nence, but now survive as little more than archivalrecords and some archaeology. All three stood, for atime, abandoned and prey to looting, and becameruinous in a relatively short space of time throughcommercial need, if not necessity. The rapid declinefrom splendour to ruin, described at the beginning of this introduction, is somehow always shocking,although parts of a building may be a long timedying.11 However, and importantly, the process ofdecline can sometimes be interrupted. That act, orseries of acts, of interruption or intervention is one ofthe subjects of this book. The conservation of ruins, asfar as we can achieve it, should be about the continu-ity of truth. In practical terms, this is to say that theevidence of the past which the ruins represent shouldbe so accurately and painstakingly observed andrecorded, and so well protected and maintained thattheir true story will survive.

References

1. Feilden, B. M. (1982). Conservation of HistoricBuildings. Butterworths.

2. Lowenthal, D. (1985). The Past is a Foreign Country.Cambridge University Press.

3. Evans, R. (2003). The Coming of the Third Reich.Allen Lane.

4. Webster, G. (1969). The Roman Imperial Army. Adamand Charles Black.

5. Roller, D. W. (1998). The Building Program of Herodthe Great. University of California Press.

6. Gospel of Luke.7. The New Encyclopaedia of Archaeological Excavations in the

Holy Land, Vol. II. Simon & Schuster.8. Bellum Judaicum Josephus Flavius.9. Macauley, R. (1977). The Pleasure of Ruins. Thames

& Hudson.10. Trumpler, C. (2005). The Past from Above. Francis

Lincoln Publishers.11. Bevan, R. (2005). The Destruction of Memory.

Reaktion Books.

Introduction xxix

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxix

Preliminary survey.

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxx

This story shows how one small building, part of an ancient settlement, was abandoned, neglected, and fellinto a ruin state. This regression slowed as the building became buried, finally becoming largely stable untilmodern times, when it was uncovered as part of an archaeological project. Exposed and recorded, the sitewas left again and its regression continued rapidly. Poor quality interventions exacerbated its demise.Finally, intelligent conservation was carried out and the building was re-buried as the best means of ensur-ing its survival.

Preliminary survey

The preliminary survey must include not only remains showing above or just below the ground but also awider analysis of the topography and climatic conditions in the area, such as changing heights, water move-ments and natural drainage, seasonal winds, naturally protected areas and a general assessment of rocks, soiland vegetation over the site. Topographical and climatic conditions and the accessibility of the site werecritical factors affecting its first settlement. These conditions must be appreciated and understood as a crit-ical part of the analysis of the site and the history of its development.

The illustration on the left indicates the location of a small building standing high on the hillside abovedisturbed ground indicative of a medium size settlement. There was a backdrop of ancient terraced hillsidesand the distinctive profile of an old volcano. At the base of the hill slope is a shallow lake navigable only toshallow draft boats.

xxxi

Short story

The demise, discovery, destruction and salvation of a ruin

John Ashurst and Asi Shalom

First published in Hebrew ‘Excavation and Conservation on Archaeological Sites’ Asi Shalom Archaeology Conservation Centre Sede

Boker Academy Negev Region Israel.

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxxi

1 The complete building

A small cult temple was constructed high on the hillside above a small town located on the waters edge. Itwas constructed of the local limestone with composite walls 0.75 m thick. The internal space was coveredwith a stone vault capped with lightweight lime concrete and a pitched tiled roof. The internal surfaceswere covered in plaster and richly painted. The floor was covered with limestone, ceramic and marblemosaic. The town and its temple were abandoned following a minor eruption of the nearby volcano andthe silting up of the waterway which brought trade to the town.

xxxii Short story

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxxii

2 Phase one deterioration

After a few years of disuse roof tiles become loose and fall. The weak fill of lime and tufa above the vaultattracts soil forming plants, and their roots exploit fine cracks in the concrete and invade the joints of thevault. Externally, soil is gradually washed down against the upper retaining wall and is scoured from underthe shallow foundation of the lower wall. Water begins to have access to the heart of the walls, movingbetween the tails of the stones and the core.

Short story xxxiii

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxxiii

3 Phase two deterioration

Earth tremors cause the undermined low wall to lean forward and the unrestrained vault to crack along itslength, causing many of the roof tiles to slide to the ground. This is followed by the collapse of the centreof the vault which allows large stones to fall, in places smashing the mosaic floor. Plaster at floor levelbecomes intermittently saturated, softens and loses its decorated surface. Water is able to pour through theopen roof and settle over the floor area.

xxxiv Short story

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxxiv

4 Phase three deterioration

There is now a progressive loosening of the vault stones, which depend now only on the adhesive qualities ofthe mortar to remain in position. Further collapse of the weakened vault creates piles of stone and debris on thefloor. Water now has free access to the decorated wall plaster. Accumulation of soil and stone washed downfrom the hill above bring about the collapse of the top courses of the upper wall, adding to the accumulationof stone within the building. Some of the fallen stone carries with it the decorative painted plaster frieze.

Short story xxxv

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxxv

5 Phase four deterioration

There is now little more to fall. Accumulations of stone and soil create relatively stable conditions over theruined temple. However, deep rooting trees and shrubs readily colonise the loose debris and, as they con-tinue to grow, exploit the wall cores. Small mammals and reptiles occupy the site with its numerous naturalcavities. This is the site in the condition found by the archaeological team. Priorities have to be establishedand time and cost estimates prepared for the work of uncovering and recording. A minimal budget is pro-vided for temporary supports and partial back filling. The likelihood is that this small contingency sum willbe spent during the excavation and nothing will be left for protection.

xxxvi Short story

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxxvi

6 Archaeology as an informing force

The site is studied contextually and specifically, carefully recorded and systematically excavated. The strat-ification, construction, materials, artefacts and sequence of building and destruction become clear. After aperiod of further analysis reports are prepared and archived, perhaps suggesting a further season of excava-tion if funds are available. No money is left for any temporary protection, and it is confidently predictedthat not much deterioration can take place in one year. The site is left in a dangerous condition and is reg-ularly visited by souvenir hunters.

Short story xxxvii

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxxvii

7 Archaeology as a destructive force

The site has provided all the information considered necessary for the historic record and is left abandoned.No money can be made available for further excavation and a period of neglect begins. Excavated materialfrom the interior of the temple had provided a counterfort against the pressure of soil, loose rock and watermoving down the hillside. Now the spoil has been removed, the rear wall collapses. Water ponds under thefoot of the lower wall encouraging its subsidence. Water moving through the composite walls loosens theface work from its core. Water ponds on the mosaic floor and micro-organisms begin to colonise the paintedplaster surfaces. Cut roots of vegetation growing on the wall begin to support new growth. Small mammalsreturn to the site and begin to burrow into loose fill. The plaster is totally unprotected and detaches from thewalls. Within a few years nothing significant will be left on the site for further study and re-appraisal.

xxxviii Short story

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxxviii

8 Ignorant repair as a destructive force

In an attempt to consolidate the excavated building and leave it open to view, the responsibility for the sitepasses to a maintenance team with no experience other than general building repair. The walls are cappedwith cement based mortar and open joints are packed with cement grout and mortar. Fallen stones arepicked up and set back on the wall heads with no understanding of their original provenance. Cement mor-tar is also used to form fillets against broken plaster edges and to patch lacunae in the mosaic floor. The plas-ter edges are painted with water soluble adhesive. The lower wall is underpinned with stone and concreteblock. Water still collects in all the low spots of the site. Drainage channels are formed along the base of thewalls and are lined in cement mortar. This kind of work not only completely confuses the surviving evi-dence of the original building but plays a real part in encouraging its destruction with the use of totallyincompatible and inappropriate materials.

Short story xxxix

Introduction-H6429.qxd 10/14/06 4:26 PM Page xxxix

9 Correct conservation as a benign intervention

If the site is considered important enough to leave open, perhaps because it is part of a tourist route, goodconservation practice can be used to protect the excavated building, always providing there are adequatefunds to carry out conservation maintenance for the indefinite future. Alternatively, the site may need tobe temporarily consolidated because the archaeological investigation is not complete. Loose stones remain-ing in situ can be wedged with stone pins and a weak, compatible lime mortar. Small roots can be removedand large, woody growths cut back as close as possible to the surface of the masonry. Open joints and wallcaps can be consolidated with compatible lime mortar, often a putty lime with ceramic powder. Water col-lecting hollows in the mosaic floor can be covered with geo-textile membrane and levelled with sand. Wallswhich are leaning or have inadequate support can be buttressed with sand bags. Decisions need to be madeabout who carries out this work. The archaeologists may need to carry out immediate emergency supportworks. Full conservation work needs to be carried out by trained conservators.

xl Short story

Introduction-H6429.qxd 10/14/06 4:26 PM Page xl

10 Reburial

Where no funds are available for adequate conservation works and especially when the future of the site isuncertain, careful reburial after recording is often the wisest option, even when there is local opposition to theidea. Even reburial, however, will require some of the protective support and intervention of the kind whichcan be carried out by the archaeologists. The whole of the excavated area needs to be covered with gener-ously lapped geo-textile membrane before returning the spoil to the site. Providing there is a generous cover-ing of soil over the walls there is no reason why their outline should not be readable above the ground, andthere may be significant benefits in being able to see the position of the building. In some situations tempo-rary land drainage may be installed to divert water from sensitive areas as part of the reburial plan. This pro-tection recreates the relatively stable conditions in which the ruined building survived for many centuries.

Short story xli

Introduction-H6429.qxd 10/14/06 4:26 PM Page xli

xlii

Short story

Pevensey. The Roman Fort of Anderida (late C 300) was one of a line of forts along the south and east coasts of England set up tocontrol Saxon activity at sea and prevent incursions on land, an enterprise which failed generally but spectacularly in this particularlocation, with the massacre of the defending garrison. The site was adopted and modified following the Norman conquest, PevenseyCastle being formed within the Roman curtain. In 1940, the site was again adopted and modified with the installation of concretegun emplacements in anticipation of German invasion. All periods are legible and conserved.

Kirby Hall. The construction of Kirby Hall began in 1570 and may have been completed by 1575. Modifications and additions topart of the house were made in the 1630s. As a partial ruin it provides useful information on construction methods and materials ofthe time and on the alternations, but its real significance lies in its architectural importance to the Elizabethan period and the influ-ence it had an later domestic architecture. Plans to re-floor and re-roof the whole of the house have been made from time to time buthave been abandoned.

Introduction-H6429.qxd 10/14/06 4:27 PM Page xliii

Hatshepsut. The terraced mortuary temple of Hatshepsut (Makare Hatshepsut 1503–1452 BC), located in the Theban hills, wasknown to Napoleon and partially explored during the 19th century. This spectacular site has been fully exposed for almost 100 years,since the work of the Egyptian Exploration Society in 1906 –1909. The condition monitoring of a site of such antiquity and impor-tance in terms of natural weathering and erosion and of visitor impact is critical to the quality of its ongoing survival and for future study.

Parthenon. The Parthenon is the most famous of the 5th century BC buildings on the Athenian Acropolis and retains its spectacularbeauty and sense of power in spite of multiple phases of use and alteration, from church to mosque and, disastrously, to munitions store.Although there have been periods of substantial restoration in the 19th century the Parthenon remains a testament to the ingenuity,refinement, sophistication and skill of its creators, Pheidias the culptor and Iktinos and Kallikrates its architects. This site and its orig-inal context is of such importance that unpicking of 19th century interventions is seen as entirely justified.

Introduction-H6429.qxd 10/14/06 4:27 PM Page xliv

Tel Beth-Shean is a mound covering some ten acres on a high hillat a strategic road junction in the Jordan Valley. An ancient cityoccupied from Late Neolithic times it was not conquered by theIsraelites at the time of their first occupation of the land. When theIsraelites were defeated on Mount Gilboa (circa. 1005 BCE) thePhilistines brought the bodies of Saul and his sons to Beth-Sheanand impaled them on the walls (“Your beauty, O Israel, is slain onyour high places! How have the mighty fallen”. Lament of Davidfor Saul, King of Israel, and his sons, Second Book of Samuel).The Roman city is seen in the foreground.(Photo John Ashurst)

The Stoa of the Athenians at Delphi was erected by the Athenianssome time after 478 BC to house the trophies taken during theirnaval victories over the Persians. Tradition has included amongstthese trophies the ropes used by the Persians to lash together theirbridge of ships across the Hellespont. Seven monolithic Ioniccolumns, some original polygonal masonry and the stylobate intowhich the commemorative inscription was cut still survive.(Photo Catherine Woolfitt)

There are many facets to the significance of ruin sites which are explored in the book. One of these is the association of sites with per-sonalities and events of history, of which the above are examples.

Ch01-H6429.qxd 10/14/06 3:14 PM Page 1

Pompeii. Buried in a shower of ash as Vesuvius erupted (see Preface page xv). Some work of anastylosis has been carried out (seeChapter 5).

Herculaneum. Buried in boiling mud from the same eruption (see Preface, pages xv, xvi). Some modest protection in the form of tiledpentices has been provided (see Chapter 5).

Ch01-H6429.qxd 10/14/06 3:14 PM Page 2

One is often faced with the significance given to

words used to define the approaches to the conserva-

tion of the built heritage. One such pair of words is:

principles vs. theory of conservation–restoration.

We could see these two concepts as complementary.

A principle can be defined as: ‘origin; primary ele-

ment; fundamental truth; a general fact by virtue of

which an instrument operates’. Theory, instead,

would describe: ‘a mental scheme of something, or of

the method of doing it; a system of ideas held as an

explanation of phenomena accepted as accounting

for the known facts’ (Oxford English Dictionary).

Conservation principles are generally brief statements

summarised in various conservation charters and rec-

ommendations (such as those of UNESCO and

ICOMOS). Conservation theory instead can be seen as

the description of the methodology that should be

followed, starting with the identification of the her-

itage resource, the definition of its character, signifi-

cance and condition, and the development of

projects or programmes required for its appropriate

conservation and eventual rehabilitation. This theory

results from the evolution in the critical thought and

experience in the conservation of different types of

properties. While the main lines of the theory will be

generally applicable, it is obvious that each property

requires due attention, taking into account not only

its individual character and condition, but also its

physical and social–cultural context. In fact, in many

cases, conservation of similar properties in differing

circumstances may result in different solutions. It is

therefore necessary to base any conservation

approach on a coherent methodology, as described in

the conservation theory.

Evolution of modern conservationthought

Modern conservation thought and the consequent

theory result from the various developments that took

place especially in the eighteenth and nineteenth cen-

turies. This was seen particularly in the identification

of values, and consequently the significance of heri-

tage to society. On the basis of this development,

F. W. Nietzsche (1844–1900) concluded that the rela-

tivity of cultural values is fundamentally dependent on

human beings as members of society. Nietzsche stated

that the former concept of absolute and universal val-

ues imposed by religion had been replaced by values

that were the product of human culture. Hence, his

famous: ‘Gott ist tot!’ (i.e. God is dead!). The concept

of ‘Der Übermensch’ was referred by him to man in his

being in the new reality and with his new obligations

defined by and for the will to power. In this context,

man is expected to take full responsibility for his own

being, and found this in generating values. Values,

in fact, become a product of society. Therefore, also

the identification of heritage and its safeguarding

fundamentally depends on the awareness of values and

significance.

The approaches to conservation have evolved

over the past two centuries or so, and there have

been different schools of thought:

● All though this period, the traditional approachto existing building stock continued, involvingrepairs, changes as well as demolition, dependingon the emerging requirements and the needs ofthe users. It also meant continuity in the use oftraditional techniques and materials, rather than

3

Chapter 1

Conservation concepts

Jukka Jokilehto

Ch01-H6429.qxd 10/14/06 3:14 PM Page 3

introducing modern industrial methods. However,with time, this approach has been increasingly‘corrupted’ due to the impact of increasing ‘glob-alisation’ in society.

● From the end of the eighteenth century, theredeveloped two lines of thought, both based onemerging heritage values but looking at the issuesfrom different angles. One of these was the so-called stylistic restoration (i.e. restoration ofstylistic integrity), later introducing a line calledhistoric restoration (i.e. restoration based on his-torically certified evidence).

● The second line of thought emerged as a protestmovement, an ‘anti-scrape’ approach, which thenevolved into the modern conservation movement,based on the recognition of the irreversibility oftime, and the specificity of human activity subjectto cultural values and social–economic context.

● From the 1880s, there emerged a third line ofthought, taking note of the previous, and suggest-ing a compromise. This so-called philologicalrestoration compared an ancient monument or his-toric structure to a manuscript. Modern restor-ation should respect the text inherited from thepast, and any additions should be clearly readable.In the 1920s, this approach evolved into the so-called scientific restoration, which emphasisedthe importance of scientific methods in restoration.With time, this approach tended to eliminate thecultural issue, stressing material evidence comple-mented with archival research. This approach hasalso stressed the pragmatic adherence to principles.

● Over the early decades of the twentieth century,there matured an approach that was spelled outin the aftermath of the Second World War. Thisapproach could be called the modern conserva-tion theory (or ‘modern restoration theory’),which recognised the specificity of each heritageobject, introducing a critical methodology basedon sound judgement regarding its character andsignificance.

● Since the 1970s, there has been yet another line ofthought and action, this time related to the socialand natural environments. On the one hand, thishas emphasised the ecological aspects in anyexploitation or change in the natural environment.On the other hand, the approach has broadenedthe concept of cultural heritage to the built envi-ronment, also taking into account the human andsocial context. This has introduced the ‘culturallyand environmentally sustainable develop-ment’, which has become a major concern in theworldwide context today.

From stylistic restoration to modernconservation theory

In the nineteenth century, one of the leading figures

in the development of ‘restoration’ principles was

the French architect E. Viollet-le-Duc. His defin-

ition of restoration was the following:

The term Restoration and the thing itself are both mod-

ern. To restore a building is not to preserve it, to repair,

or to rebuild it; it is to reinstate it in a condition of

completeness which may never have existed at any

given time.

While his numerous followers and disciples have

often caused more destruction than conservation,

one of Viollet-le-Duc’s merits should be seen in his

attention to the development of restoration method-

ology. To him, restoration was a form of archaeology

as well as being ‘pure science’. Even though some-

times carried away on hypotheses, in most cases he

correctly documented and recorded the structures

before any restoration, analysing all available evi-

dence. In the case of Carcassonne, he carried out a

long archaeological analysis of the ruined fortifica-

tion, before any work. His restoration of the defence

walls was limited to completing the upper parts –

previously dismantled by the people – and his inter-

vention remains clearly readable with respect to pre-

vious construction phases.

In many cases, however, emphasis on stylistic unity

led to complete reconstruction, which became a fash-

ion in many countries of Europe and even outside.

There thus developed a counterpoint, the ‘conserva-

tion movement’, which has generally been identified

in the figure of John Ruskin, but which also had other

protagonists in various countries. Ruskin emphasised

life in historic buildings, claiming that ‘Restoration’

(i.e. actually reconstruction) would definitively abol-

ish the spirit of time:

That which I have above insisted upon as the life of the

whole, that spirit which is given only by the hand and eye

of the workman, can never be recalled. Another spirit may

be given by another time, and it is then a new building …

(Ruskin, The Seven Lamps of Architecture,

1849 vi: xviii)

His disciple, the socialist and arts and craftsman,

William Morris, took Ruskin’s message and stated

4 Conservation of Ruins

Ch01-H6429.qxd 10/14/06 3:14 PM Page 4

words that have since become the trademark of the

Society for the Protection of Ancient Buildings

(SPAB) that he founded:

… to put Protection in the place of Restoration, to stave

off decay by daily care, to prop a perilous wall or mend

a leaky roof by such means as are obviously meant for

support or covering, and show no pretence of other art,

and otherwise to resist all tampering with either the fab-

ric or ornament of the building as it stands; if it has

become inconvenient for its present use, to raise another

building rather than alter the old one; in fine to treat our

ancient buildings as monuments of a bygone art, created

by bygone manners, that modern art cannot meddle

with without destroying.

(Morris, 1877)

These ideas were clearly reflected in the intentions of

Camillo Boito (1836 –1914) when he wrote a circu-

lar letter (in 1883) on behalf of the Italian Ministry

addressed to the officers responsible for ancient monu-

ments. He expressed the principle:

Historic buildings should be consolidated rather than

repaired, repaired rather than restored, taking great pains

to avoid any additions or renovations.

He also demanded:

Modern work and new materials to be kept to the min-

imum and to differ from the historic, in harmony with

artistic appearance ... contributions of all historic periods

to be respected; exception can be made and parts removed

if these are manifestly of minor importance compared to

forms that they cover.

These principles became the first Italian charter on

restoration, and many of the ideas were later integrated

in another charter, written by Gustavo Giovannoni

(1873–1947) after the international meeting in Athens

in 1931 (published in 1932). Giovannoni emphasised

the scientific character of restoration work, and main-

tained that historic phases should not be eliminated or

falsified by additions that might mislead scholars. He

stressed the importance of regular maintenance and

appropriate use. The monuments should be kept

in situ, and any alterations should be kept to the min-

imum, simple in form, and carefully documented. He

also introduced training in restoration at the school of

architecture, which was established in the 1920s.

The question of values had already been analysed

by Alois Riegl, the chief conservator in the

Austro-Hungarian Empire, in a study in 1903, where

he distinguished between a memorial (Gewollte

Denkmal) vs. historic building (Ungewollte Denkmal),

one being built in order to remind people about

something, the other instead being associated with

historic values later on in its ‘life’. Riegl identified two

categories of values: memorial values (age value, his-

toric value, intended memorial value) and present-day

values (use value, art value, newness value, relative art

value). Riegl also coined the concept of Kunstwollen,

which means that each period or each culture has its

particular conditions, within which artistic produc-

tion achieves its character. In this context, there is

mutual influence between an artist and his society.

Riegl’s thinking was well received in Italy, where

his thought was continued, for example, by G. C.

Argan (1909–94), who dealt especially with works of

art, and introduced the concepts of ‘conservative

restoration’ and ‘artistic restoration’. In conservative

restoration, priority would be given to consolidation

of the material of the work of art and prevention of

decay. The emphasis would be on maintaining the

status quo of the object. In artistic restoration, instead,

a series of operations would be undertaken, based on

the historical–critical evaluation of the work of art.

The aim in this case would be to re-establish the

aesthetic qualities of the disturbed object. This could

involve reintegration of losses (lacunae) and even the

removal of parts that were not considered essential

from the historic or artistic point of view. Obviously

such interventions needed to be founded in critical

judgement based on the quality and significance of the

work concerned. In this regard, priority was often

given to aesthetic demands of the work, but on the

other hand each work had to be taken case by case.

Cesare Brandi, the first director of the Italian

Central Institute of Restoration (Rome, 1938), wrote

the fundamental text clarifying the modern theory of

restoration (Teoria del restauro, 1963). He distinguished

between the restoration of ‘common, industrial prod-

ucts’ (where the purpose was to put them back into

use) and works of art. The restoration of the latter he

defines as a methodology that depends chiefly on aes-

thetic and historic values:

Restoration consists of the methodological moment of

the recognition of the work of art, in its physical consist-

ency and in its twofold aesthetic and historical polarity,

in view of its transmission to the future.

Conversation concepts 5

Ch01-H6429.qxd 10/14/06 3:14 PM Page 5

The theory of Brandi emphasises restoration as

methodology, based on a critical judgement. Brandi

maintained that a ruined structure should be under-

stood as a fragment of architecture. In line with

Ruskin, Brandi also stressed the limits of any reinte-

gration. He was against the so-called ‘archaeological

restoration’, which would be simply based on some

principles. Instead, he stressed the requirement of a

thorough analysis and identification of the meaning

of each element within the whole – just as in any

other historic structure.

International framework forconservation policies

From the period following the Second World War,

there has been increasing international collaboration

in the protection and conservation of cultural and

natural heritage. A milestone in this regard was the

World Heritage Convention of UNESCO in 1972,

which has since involved most countries of the

world in the process of clarifying culturally and

environmentally sustainable conservation policies

and strategies. The World Heritage List, while

being strictly limited to sites considered of out-

standing universal value, has become a model which

is having an increasing impact also in the rest of her-

itage. One of the most interesting features of this

convention has in fact been the interaction between

culture and nature, a parallel that may well benefit

both in the long run. The convention encourages

the development of effective and active measures to

be taken for the protection, conservation and pres-

entation of heritage integrated in the life of the

community. It has also promoted debate on various

fundamental issues in conservation, such as the con-

cepts of authenticity and integrity, and, even more

fundamentally, the convention has promoted the

exploration of new types of heritage that risk being

neglected and destroyed. As a result, the World

Heritage List with its over 700 entries is gradually

being enriched with an increasing variety of items,

ranging from traditional rice fields to sacred moun-

tains, or from historic railways to canal systems and

pilgrimage routes. There is an increasing tendency

to identify larger areas such as historic towns or

cultural landscapes rather than single structures and

monuments, which obviously will increase the

variety of stakeholders responsible for their conser-

vation and development.

In this international context, it will be increasingly

important to identify the values and methods of

intervention. In terms of values, we can see two basic

categories:

● Cultural values. Identity value and emotive valuebased on recognition; relative artistic and relativetechnical values based on evidence and research;and rarity value, which is more of an administra-tive nature, and based on statistics.

● Contemporary socio-economic values. Economicvalue based on heritage as resource; functionalvalue and usefulness of the property; educationalvalue, tourism, social value, awareness, and thepolitical value that often depends on the prior-ities of the ruling regime.

The ICOMOS Training Guidelines of 1993 empha-

sise that conservation works should only be entrusted

to persons competent in these specialist activities. In

fact, education and training in the conservation and

restoration of the built heritage has become a recog-

nised activity in society. According to the 1993 guide-

lines, such training should produce, from a range

of professionals, conservationists who are able to

cope with a great variety of tasks, such as ‘reading,

understanding and interpreting’ historic structures

and areas. Particular attention is given to communica-

tion between specialists and non-specialists, consider-

ing that the different sectors of society would be

required to have informed participation in the conser-

vation process. Conservationists should be able to

make balanced judgements based on shared ethical

principles, accepting responsibility for the long-term

welfare of the heritage.

The same ICOMOS Training Guidelines define

‘conservation’ as follows:

The object of conservation is to prolong the life of cultural

heritage and, if possible, to clarify the artistic and histor-

ical messages therein without the loss of authenticity and

meaning. Conservation is a cultural, artistic, technical

and craft activity based on humanistic and scientific stud-

ies and systematic research. Conservation must respect

the cultural context.

(Par. 3)

As mentioned above, conservation is a process consist-

ing of the identification, understanding, interpretation

6 Conservation of Ruins

Ch01-H6429.qxd 10/14/06 3:14 PM Page 6

and presentation of heritage. It will necessarily include

several phases:

● Survey (inspection and documentation of heri-tage, its historical setting, physical and culturalenvironment).

● Definition (a critical–historical definition andassessment of the significance of the heritageresource within its setting and regarding relevantcultural, social and economic considerations).

● Analysis (examination of the resource using scien-tific methods, the diagnosis of its physical consis-tency, material, structure, risks, vulnerability andspiritual significance).

● Strategy and implementation (short-term andlong-term plans and programmes for the conser-vation and management of change; monitoring,regular inspections, cyclic maintenance and envir-onmental control).

A necessary tool to acquire knowledge of cultural

heritage in all the necessary aspects is provided by

recording. Recording is an essential part of the con-

servation process, in order to get to know the place

concerned and its physical condition, and subse-

quently to monitor any changes occurring over time.

It is necessary for the management of a heritage site,

programming maintenance and timely repair, as well

as any time a new restoration or rehabilitation proj-

ect is launched. Recording should be understood in

the broad sense so as to meet all the requirements,

from the inventory to research and site projects. It

will thus include inspections, reports and graphic

records, as well as scientific data on the condition and

behaviour of the building within its social, cultural

and environmental context. It is obvious that records

should be properly deposited in safe places, possibly

with a second copy in another location, and made

available for relevant consultation and research regard-

ing the site. Results should also be published (see:

ICOMOS, Principles for the Recording of Monuments,

Groups of Buildings and Sites, 1996). The survey phase

is fundamental for the identification of the resource

and its significance, and vital for the definition of what

should be preserved and what are the limits of change.

It includes detailed inspections and reports, and the

relevant graphic documentation and scientific analy-

ses. The task is to define the structural system, the

historical phases of construction and change, the con-

dition of the building and the causes of decay.

The test of authenticity

Sites that are inscribed on the World Heritage Lists are

expected to pass the ‘test of authenticity’ in relation

to design, material, workmanship or setting. This

demand is not only relevant to the moment of nom-

ination, but remains always valid in the process of con-

servation and eventual change. Authenticity means

that an historic building should be seen as a true testi-

mony of the culture or traditions that it represents.

The Nara conference of 1994 indicated that while the

word ‘authentic’ was not necessarily used in all lan-

guages, it was possible to find corresponding words to

express the intent. The Nara Document on Authenticity

has further emphasised that ‘the diversity of cultures

and heritage in our world is an irreplaceable source of

spiritual and intellectual richness for all humankind’

(Par. 5). Living cultures are subject to a continuous and

dynamic process of change; the values and meanings

that each culture produces need to be re-appropriated

by each generation in order to become a tradition that

can be handed over to the next. As a result of such cul-

tural process, each moment on an historic timeline is

characterised by its specificity, reflected in all that is

conceived and built. Authenticity is expressed in the

tangible and intangible aspects of a building, including

historic changes and additions.

The Venice Charter invites us to safeguard historic

structures ‘no less as works of art than as historical evi-

dence’ (Art. 3). In relation to the artistic aspect, it

would refer to the building as a genuine result of the

human creative process. This can be verified in the

quality of design and execution, but requires critical

comparison with similar works of the same culture.

Authenticity in this sense is at the root of the defini-

tion of the outstanding universal value. Another

aspect of authenticity refers to the historic structure

in its quality as historic document. Due attention is

required to safeguard not only the quality and aesthet-

ics of the surface, but also the material and structure,

which document the workmanship and different

phases of construction in the past.

The Venice Charter notes that the concept of mon-

ument ‘applies not only to great works of art but also

to more modest works of the past which have acquired

cultural significance with the passing of time’ (Art. 1).

Even if we may be able to build a replica of some-

thing that has been lost, the cultural meaning of the

new work is different from the old. The Venice

Conversation concepts 7

Ch01-H6429.qxd 10/14/06 3:14 PM Page 7

Charter therefore recommends that any indispens-

able new work should be ‘distinct from the architec-

tural composition and must bear a contemporary

stamp’ (Art. 9).

Condition of integrity

The condition of integrity in relation to cultural sites

should be understood in the relevant historic context

describing the state that a particular place has acquired

by the present time. Integrity can be referred to

visual, structural and functional aspects of a place. It is

particularly relevant in relation to cultural landscapes

and historic areas, but even a ruin can have its historic

integrity in its present state and its setting.

The visual integrity of a building or an area

indicates what is visually relevant to its historically

evolved condition in relation to its context. The iden-

tification of the visual integrity of an historic building

should take into consideration not only its architec-

tural character but also the impact of historic time.

Building materials such as stone, brick and timber

obtain patina of age as a result of the ageing process

and weathering. Replacement, reintegration and other

types of treatments of such surfaces require a sensitive

eye and an understanding mind in order not to lose

the historically established visual integrity of the place:

Replacements of missing parts must integrate harmo-

niously with the whole, but at the same time must be

distinguishable from the original so that restoration does

not falsify the artistic or historic evidence.

(Venice Charter, Art. 12)

The structural integrity refers to the mutual relation-

ship that links the different elements of an historic

structure or area. Any change to such balance should

be carefully thought out, and based on a sound judge-

ment of the values and priorities in each case. In an

historic building, the question of structural integrity is

particularly relevant when discussing consolidation

and reinforcement. Nature is a laboratory that tends

to reveal the faults and weaknesses of human con-

structions. It is therefore important to give due con-

sideration to structural integrity, particularly in areas

subject to seismic action. Experience has shown most

traditional structures in seismic areas can resist

earthquakes if in a good state of repair. Failure gener-

ally results from poor condition due to lack of proper

maintenance. Even modern reinforcement in an

historic building may turn out to be destructive if not

carried out with full understanding of the behaviour

of the existing structure. This leads us to stress the

importance of follow-up and monitoring in order to

learn from experience and improve for the future.

This is also one of the reasons for ‘reversibility’; one

should be able to repeat a treatment when necessary.

Architecture is conceived in reference to a func-

tional scheme, the basis for social–functional integrity.

Altering the function of or introducing new uses to

historic buildings and areas may often cause conflicts.

It is necessary, therefore, to establish limits on the

modifications that such function might cause, and

recognise the character of an historic building as the

basis for rehabilitation. The notion of functional

integrity is particularly relevant in relation to large sites

and landscapes, where traditional functions may be

challenged by the introduction of modern technology

and new priorities. It is useful for an appropriate bal-

ance in the policies of development and conservation,

with due regard to the character of traditional uses.

Even museum use is a new function in an historic

building, and often imposes radical changes, e.g. for

requirements of safety and security.

The concept of integrity is equally relevant in rela-

tion to ruins or architectural remains. Archaeological

sites are often inside the urban area of a city or in its

immediate vicinity. Such areas are a major concern.

For example, in Jerash, the lack of liaison between

archaeological site managers and the community has

resulted in an uncontrolled expansion of residential

areas around the archaeological site. This has been the

main reason why the site was deferred from being

nominated to the World Heritage List of UNESCO.

Sites whose existence has been revealed through

urban archaeology in the middle of an already existing

living city, such as Beirut, have been subject to major

campaigns, but unfortunately too often with scarce

results. The conflicts of public and private interests in

the management and change of the territory are gen-

erally linked with high economic interests, where his-

toric values may well be given much less attention

than the construction of business centres. In suburban

areas, the historic integrity of archaeological sites is

subject to high risks due to frequent conflicts with the

interests of developers on privately owned land.

Conservation of cultural heritage is increasingly

seen in the context of parallel approaches that have

emerged in the past decades, including the policy of

8 Conservation of Ruins

Ch01-H6429.qxd 10/14/06 3:14 PM Page 8

human sustainable development as a complement to

development based on economic factors. In fact,

progress should take into account cultural, social,

economic and functional resources and values, strik-

ing a balance in order to identify the most appropri-

ate approach. Sustainable society should be based on

a long-term vision and it should ensure continuity of

renewal processes within the scope of social justice.

The built and cultural heritage resources are a great

potential, offering new alternatives and new strat-

egies for the future. The preparation and setting up of

appropriate strategies need to start from appropriate

knowledge and understanding of the history and the

resource potentials of an area, aiming at a balanced

integration of all relevant issues within the planning

process.

Further reading

Feilden, B. M. (1982). Conservation of Historic Buildings.Butterworth, Oxford.

Feilden, B. M. and Jokilehto, J. (1993). Management Guide-lines for World Cultural Heritage Sites. ICCROM, Rome(reprinted in 1998).

Jokilehto, J. (1999). A History of Architectural Conservation.Butterworth-Heinemann, Oxford (reprinted in 2002).

Conversation concepts 9

Ch01-H6429.qxd 10/14/06 3:14 PM Page 9

Ch02-H6429.qxd 10/16/06 2:24 PM Page 10

Introduction

This chapter is not about hi-tech solutions or state-of-the-art analysis, but rather a call to recogniseand respect the fundamentals governing the slideleading to deterioration and ruin. These are mosteasily recognised in the various causes of damage tostanding buildings which if left unattended developinto future ruins the mechanical forces that set upthe decline process, continue to operate and willaccelerate and be exacerbated by the loss of essentialelements such as roofs, floors and the buttresses ofwalls on ruins and standing buildings alike, and needto be identified and addressed wherever possible.

This chapter is also a warning to limit engineeringinterference, as far as possible, to measures consistentwith the historical context and original constructionmethods. Not all old buildings are well conceived, andduring investigations the quirks of individual builderssurface on a regular basis. However, an honesty ofapproach to the remedial measures to be adopted, andstaying within the historical context, is preferable tothe creation of a new synthetic hybrid, and usuallyprojects the most sympathetic resolution. This presup-poses that a conservation engineer will not only haveadequate structural experience, but will also be famil-iar with historical forms of construction, the natureand characteristics of traditional building materials, beable to identify the intervention measures likely tohave been used for stabilising structures in the past, andwill understand and work within the parameters of aclear conservation philosophy and policy. In fact, this isthe essential definition of the ‘conservation engineer’.

There is a real need to have such a ‘conserva-tion engineer’ involved at an early stage of any

investigation. Working within the team, he or shecan help identify the original structural model,untangle the historical modifications, and identifythe structural effectiveness of the structure as pre-sented. The requirements for engineering informa-tion and archaeological reference both involvelimited excavation early on, and often the questionof foundation stability can be assessed during thedigging of trial pits in the first phase of investigation.

Why do structures fail?

The road leading to ruin is as much the cause ofhuman failings as it is of nature. In a new country likeAustralia, where this chapter is being written, thegems of a fragile heritage have often been squanderedby a deliberate policy of neglect and a refusal to spenda dollar which will not give an immediate return.Ironically, a small amount of timely maintenancewould have added many thousands of dollars in valueto assets that can frequently be seen reduced to ruins.The many grace and favour historic homesteads,often set in fine, landscaped gardens, are now receiv-ing renewed interest, and sell for sums which recog-nise their true worth.

Human inactivity or misguided intervention, not,of course, unique to Australia, figure high on the listof reasons why failures occur. It is possible to sum-marise these reasons into two groups as follows:

Human causes

● Neglect● Quarrying, or ‘robbing’ from ruins● Fire● Mistreatment of structural members● Vandalism and war● Design inadequacies.

Natural causes

● Rain and water action● Ground movements

11

Chapter 2

Stability and survival

Chris How

Opposite page Kilve Chantry. The Chantry at Kilve,Somerset, UK is a group of buildings of the 15th century need-ing further investigation but at substantial risk of deteriorationand local collapse. The illustration shows an applied restraint tothe lean of the gable wall as a means of retaining it in position inanticipation of later masonry consolidation.

Ch02-H6429.qxd 10/16/06 2:24 PM Page 11

● Thermal stresses and frost● Vegetation and root damage● Rodent activity● Wind erosion.

The two lists are subjective, and will vary betweencountries and locations. It is far more common tohave a combination of elements involved rather thanone individual cause. The sad thing about the firstgroup is that, apart from education, there is little thatcan be done to change human behaviour.

Thus, leaving aside the human aspects, which havebeen discussed elsewhere, the effects of nature itself arenow examined with appropriate engineering actionsthat can be taken to modify and ameliorate them,thereby ensuring a degree of stability to assist the long-term structural survival.

Planning for cyclic conditions

Stability is not found in nature, which runs its coursein a series of cycles, and which we need to recogniseand allow for in advance. These natural cycles affectour weather in the seasons of the year to a variableextent, but the years themselves run into a series ofcycles of flood and drought, extremes of heat andextremes of cold. The records show that even today’schanges in climate pattern have had their precedentsin the historical past. Recognition of the cyclical

nature of climate and its consequences on ruins andcomplete buildings alike is the first key to planningfor stability. The forces of nature cannot be coun-tered, as these are too major, but mitigation plans canbe made and potentially exacerbating interventionscan be avoided. It is common-sense policy to assesseach site with the same care we would expect to giveto that for a new structure, and so far as circumstancesallow, to install appropriate control measures.

The role of rain and water

In almost all climates, by far the greatest single factorin distress to structures is water in one form oranother. Figure 2.1 illustrates the role of water and thevarious ways it constitutes a degradation regime of itsown in a simple gable wall end. It is good to remem-ber that rain is usually a weak cocktail of acids, somedue to fixation of atmospheric elements and othersdue to pollution in the atmosphere. Rain can fall withappreciable force due to wind action and act to scourout previously softened or weakened pockets of limemortar. This phenomenon becomes more apparenton stone such as basalt than on an alkaline masonry,such as limestone or marble.

Of course, the building solution to these prob-lems would be to provide a properly maintainedroof, incorporating collection and discharge features,

12 Conservation of Ruins

Figure 2.1 Rain degradation regime: a typical case.

Ch02-H6429.qxd 10/16/06 2:24 PM Page 12

which would protect the structure below. Manyillustrations in this book show how rapidly the lossof adequate roofing leads to a ruin situation. The nat-ural inclination of engineers is to encourage repair orre-installation of proper roofing, and thereby pro-tect the structure from further ravage. Where this isnot possible, or desirable for philosophical reasons,buildings with broken wall tops or of very high cul-tural value or high sensitivity, ruins are best conservedby provision of a free-standing modern roof. A simpleexample made from readily available materials isshown in Figure 2.2, but numerous alternative con-figurations are possible and can be adapted to suitlocal conditions (see Chapter 5).

Even in the case of well advanced deterioration, itis possible to intervene in saving structural ruins by acombination of techniques shown in Figure 2.3 butcritical to their ongoing survival is control of water,not only the roof but raindrop bounce, standingwater and drenched vegetation. A critical zone existswhich extends up 450 –500mm above ground levelaround the wall perimeter. This is where the com-bined effects of direct rain, seepage, drift down theface, raindrop bounce, wind and often frapping fromvegetation, all act together to denude the lowercourses of mortar. Unfortunately, it is this zone which

is most critical to the lateral stability of the wall as awhole, analogous to a bottom hinge. Left unattendedfor long enough this denuded zone causes a lean out-ward of the whole wall, and is often accompanied bya curl of the wall face as mortar is dissolved within theexternal faces of the bedding joints. These two effectscombine to cause a lateral shift at the top of the wall,which when a roof exists, is then resisted by the wallplate attachment. Unless a capping course or top per-imeter beam has been provided, the opposing forcesinitiate a crack at the top of the wall running into thewall core, which progressively loosens. Frequentlythis is accompanied by rain penetration at the eaveslevel as the geometry of the top of the wall distorts,and water trickles into the loosened core carryingparticles lower down into the wall body, blocking thenatural aeration of the core open-rubble work. Local-ised moisture build-up becomes evident internally,and eventually the build-up of pressure, acting onweakened bed joints, forces bulges to develop in theexternal face.

A typical reaction by engineers unfamiliar withhistoric construction is to grasp at underpinning as asolution to the problem. There are cases where thiswill be necessary, but normally addressing the repoint-ing of the wall from below ground level, progressively

Stability and survival 13

Figure 2.2 Example of simple free-standing roof.

Ch02-H6429.qxd 10/16/06 2:24 PM Page 13

14 Conservation of Ruins

Figure 2.3 Wall alignment by jacking.

Figure 2.4 Schematic of conservation principle on end gable wall.

Ch02-H6429.qxd 10/16/06 2:24 PM Page 14

to the top of the wall, may be all that is necessary andis the correct solution. Where it is feasible and prac-tical to do so, the wall can sometimes be levered backinto place using adjustable props in the procedureshown in Figure 2.3. This may sometimes need to beaccompanied by grouting of the core, as is describedin Chapter 4. Small deformations evident in therealigned wall surface do not need to be corrected.

Identification

The above description of distress caused to thestructure may be evidenced by the following phe-nomena (see Figure 2.1):

● Walls are out of plumb and leaning outward, acondition which can often be seen by eye alone

● There is an accompanying curl outward andconcavity lessening towards the top

● Transverse walls show near vertical cracks, whichwiden towards the top

● Open or significantly degraded mortar jointsoften exist at the base of the wall

● Internal horizontal cracks develop near the topof the wall

● Internal damp spots may match external bulges● If roofs are present, underpurlins or secondary

timbers lodged onto the end walls often showcorresponding cracks on the external face.

In addition to the roof question, which may not beappropriate for most care of ruins situations, certainfundamentals of approach require consideration forthe site investigated. For instance:

● Ground should slope away from the base of wallsfor a minimum distance of 1.2 metres, to a fall ofat least 50 mm

● On an upslope side, a cut-off drain or a gradedswale should be provided, and be able to dis-charge away from the structure

● A clean surface of gravel or maintained turfshould be provided to the graded margins

● In flood plain situations, some capacity for therapid draining away of floodwater needs to beconsidered, in addition to provision for normalsurface flows

● Pointing should permit free surface flow to cap-pings and vertical faces alike

● Hollow core grouting needs to be considered toback up cappings where necessary.

These recommendations clearly have archaeologicalimplications which may make them difficult to imple-ment but may also be ultimately useful in clarifying

original contexts, facilitating legibility and enhancingpresentation.

Remedial action

Wherever possible the desirable solution of roofingthe ruin or structure should be given active consid-eration. In a reversible ruin situation, where a lim-ited reconstruction is possible and constitutes a validoption, then the following checklist is useful:

● Correction of lean and curl to the wall by theadjustable prop method. Larger structures can betackled in the same way, using major shores to thewalls, from which jacking forces can be applied

● Where static analysis suggests resultant forcesmay result in minor tensional stresses, provisionof a non-obtrusive ring beam, or substantial con-tinuous top plate, should be considered

● Core grouting, in circumstances indicating partialcore collapse, should follow the procedures givenelsewhere with respect to first washing out sandsand fines.

Ground movement

A vast amount of research has been carried out onthe subject of soils, and a basic understanding ofsoils is key to understanding most of the phenomenaencountered in the field.

From an engineering standpoint, soils are interest-ing as the foundation medium and are classified intotwo main groups:

● Non-cohesive or granular soils, such as sands andgravels, which are classified by grain size.

● Cohesive soils or clays, which are sticky and canbe moulded. These are classified according totheir swelling and shrinkage characteristics.

Apart from certain types of loess and some sediments,limited to arid zones, which can exhibit some strangefeatures such as collapsing under load, granular soilsare not overly concerning. Within the range of ruinedstructures likely to be encountered, problems such asbearing capacity will have been resolved long before.

Clays, on the other hand, are an ongoing source ofproblems as all clays move to a greater or lesser extent.This is because of their ability to store water withinthe cellular structure of the clay particles, categorisingthem into ‘highly reactive’, ‘medium reactive’ or ‘low reactive’ clays. The clay particles are microscopicplatelets, which change shape and dimension as wateris stored or lost. The usual analogy is that a dry clay

Stability and survival 15

Ch02-H6429.qxd 10/16/06 2:24 PM Page 15

platelet starts as a breakfast plate and changes to a soupbowl with the uptake of water, and this feature isresponsible for the swelling and shrinking of a claysubgrade.

There is a variation in the extent to which variousclays shrink and swell, dependent on the chemistryof the original parent rock. For example, clays derivedfrom basalt sources are more reactive than fromgranitic sources, and the least reactive, for instance, arethose derived from the earlier series of mudstones.

Water is lost from a clay subgrade due to evapor-ation to the surface, and to root action through thefine hair-like roots of major plants such as trees. It isnecessary here to introduce the last contender in thesoil types, namely silts. Silts are very small individualparticles of the parent rock of spherical shape, butbelow the level of individual grain identification, andthey behave differently to both clays and sands. Beingvery small they are carried to the top of the soil profileand normally form a band between the topsoil–humus layer and the clay below. There is an ongoingtransfer of materials from the surface down to the claylayer by worm action, and as part of this process siltgets transferred downwards, resulting in a mixed bandof silty clay sitting directly over the clay proper.

These upper profiles provide a blanket to the claybelow, protecting and limiting the extent of evapor-ation, and hence shrinkage. Depending on the effect-iveness of this blanket, the clay subgrade swells andshrinks to a greater or lesser degree, following the sea-sonal variation of wetting and drying in a laggingsequence caused by the time taken for water to storewithin the particles. The effect of both decreases withdepth below the clay surface and hence foundingdeeper into the clay is preferred to shallower found-ing, as can be deduced from Figure 2.5.

It was well understood in antiquity, from an empir-ical basis, that founding should be on the firmest layerwithin the soil profile and hence finding poorly

founded structures or ruins tends to be unusual,although these do occur.

It is important when investigating a new site, par-ticularly if sited onto clays, to bear in mind the generalgeology of the area, the level of weathering and thelocation of the site within the local topography. Sitesoccupying hill sides or tops, apart from being closerto the underlying rock, will sit onto clays formed byin situ weathering (Figure 2.6), whereas those on val-ley floors would normally sit onto clays, which haveshifted downhill under the combined influences ofgravity, frost and water transport.

The tiny platelets comprising the clay particles arerandomly organised within the parent rock andweathering in situ leaves the skeletal structure (includ-ing the microstructure) unaltered; hence the swell-ing and shrinking forces are randomised. Those claysshifted downhill become remoulded to some extent,and achieve a partial orientation as the platelets slidetogether. However, clays laid down by freshwateraction are fully oriented as shown in Figure 2.7. Thisis the worst combination from a structural aspect,since all the platelets now lie in the horizontal plane,resulting in vertical swelling and shrinking being maxi-mised. Ancient clays of saltwater deposit do not alignas evenly as those laid down in freshwater lakes, as aresult of ionic interaction.

16 Conservation of Ruins

Figure 2.5 Typical clay soil and seasonal vertical soil move-ments.

Figure 2.6 Deep in situ residual clay weathering showingresidual basalt boulders.

Ch02-H6429.qxd 10/16/06 2:24 PM Page 16

It follows from all of the above that an adequateblanket of topsoil and silt should be maintained as faras possible.

Trees, however pose a major threat to stability ofruins and standing structures alike, and large, vigor-ous, deciduous trees particularly so. Figure 2.8shows the dramatic ground movements, which canbe caused by the introduction of a large elm tree.

Figures 2.9 and 2.10 both show a simplified rela-tionship between vertical movement and the treeheight-to-distance ratio. From these two examples asimple rule has been developed for new structures,that the closest they should be from a large tree isequivalent to its full mature height. Where a groupof trees exist, or are intended, then this needs to beincreased by 50 per cent, since the tree roots are incompetition with each other and reach further intheir search for moisture.

To avoid cyclic ground movement affecting ruinsor structures founded onto clays, large trees shouldnot be permitted close to them. Since the phenom-enon exists in reverse also, the cutting down of alarge tree nearby may cause heave developing overthe next three or four years. Any clearing of trees on

a clay subgrade should be carried out well in advanceof other remedial or conservation work, or provisionmade for follow-up work during subsequent years.The potential conflict here between structural neces-sity (or advisability) and site ecology and presenta-tion is obvious, and must be discussed and assessedby the conservation team.

Identification

A masonry structure protects the ground below fromdrying out and a reserve of moisture will have built upafter a few years. During dry months, or particularlyextended periods of drought, the loss of moisture tothe atmosphere will cause a clay subgrade to shrinkaround the structure, which evidences itself first at thecorners. This relative movement causes the corners toappear to drop, creating diagonal cracks radiatingupward and outward from the mound edges.

Trees will cause a similar but unsymmetrical effect iflocated close to a corner, or may cause a central panelto drop if central to a wall. Typical cracking patternsassociated with these three conditions are shown inFigure 2.8.

Stability and survival 17

Figure 2.7 Clay particle orientation.

Figure 2.8 Distress cracking on clay subgrades.

Ch02-H6429.qxd 10/16/06 2:24 PM Page 17

Silts

Silts have a special characteristic of being dispersive inthe presence of water, which, put simply, means thatthey undergo a sudden and drastic loss of strength.They also have a second characteristic of being sus-ceptible to laitance when subjected to fairly minorvibration as water makes its way to the surface, this

action being the prelude to the silt soil turning into athick fluid resembling porridge. The mere presenceof silt should ring alarm bells in regard to any form ofconstruction. Silt normally is associated with clays inonly thin bands, but in certain circumstances can befound in deeper pockets up to 600mm deep, sittingabove a clay subgrade.

Identification

Correct identification of silt is vital to determining asafe foundation depth, as what appears as hard as mud-stone when desiccated can turn to a soupy consistencyduring wetter months when a high local water tablepersists. Most silts contain a proportion of clay par-ticles, and a simple jar test gives a quick indicativeresult. To do this, a sample is placed into a small glassjar, which is then almost filled with water and shaken.The silt particles will settle within a few minutes,whereas the colloidal clay particles will stay in suspen-sion for some hours. Unless the silt proportion, whichusually is lighter in colour, is only a very small percentage, then deeper founding is necessary.

18 Conservation of Ruins

Figure 2.9 Variation in settlement with distance.

Figure 2.10 Settlement versus distance/height ratio.

Ch02-H6429.qxd 10/16/06 2:24 PM Page 18

Remedial action

● Provide means of intercepting winter seepageflows by cut-off drains or swales if archaeologicallyappropriate

● Discharge downpipes well away from buildingsor ruins on their downhill side

● Renew footings or underpin to safer strata if ruinis reversible.

Slumping

The folding of soil as it slumps down a hillside is acommon feature in steep hilled country, and thesefolds are normally referred to as ‘sheep tracks’. Theyare another example of the cyclic wetting up duringperiods of heavy rain, which, due to the added weightof water, can increase the density of the upper layers ofsoil by up to 60 per cent. As described above, theupper layers are composed of mainly permeable soils,whereas on clay or rock hillsides an impermeableinterface lies below, which creates a slip surface. Slowdraining of water causes the upper layers to increase inweight as water is absorbed, and further rain then actsto lubricate the slip surface.

When buildings are sited on the brow of slopes,any change to the drainage at the top of the slope willupset the status quo and can lead to an adverse effect.

Seismic effects

Most people are familiar with the concept of a shockwave emanating from an epicentre below groundbeing the source of a seismic event. For the purpose ofconsidering the forces developed against structures,this shock wave can be considered as travelling atground level, which, in effect, laterally displaces theground and objects attached to the ground. Theseobjects experience a momentary shift, or series ofshifts, with intermediate replacements, in the directionof the wave propagation. It follows from this thatanything which has an appreciable part of its massabove the ground surface, such as tall trees, columns orwalls, will be at risk from its own dead weight. Thisis because inertia will try to retain the bulk of massin its former position, whilst the base of the objectis forced to displace due to the ground-level wave.Slender, flexible objects, such as tall reeds, saplings,etc. are at low risk, even if quite tall, as they are able tobend to accommodate the shock wave. Medium totall trees do not fare so well, whereas rigid structures,such as most buildings, all suffer a degree of damage.

Because the shock wave passes across the structurein a continuous succession of increments, each

element in a wall, say, will suffer compressive, thentensional, forces. A low-height, rubble-cored wall mayappear to survive fairly well from the experience,and be seen to lose some outer masonry blocks. Infact, the whole core will have been rumbled by thepassage of the wave, and much core mortar will havebeen detached or de-bonded with the core stones.

This basic mechanism was recognised by someancient peoples who specialised in the constructionof interlocking masonry able to absorb the alternat-ing forces developed by the shock wave, and builtwithout loose core material to be disturbed by it.The high seismic resistance of the Inca ruins andthose at Rhodes, etc. show how very effective thistype of masonry has proved to be.

Tall structures built of conventionally coursedmasonry, and which lie parallel to the wave front,will sway due to inertia and are likely to topple. Asthe inertia of the above ground mass resists the iner-tia, a secondary shear zone is initiated, which due toprimary stress distribution will occur above groundlevel. With a homogeneous material, the initialcompression will spread at 45 degrees upwards, anda horizontal shear will be initiated since no furthermaterial exists to accept the compression. In simpleterms, a column 1400 mm in diameter is likely toshear at about 1200 –1600 mm above its base, andsuch shear will tend towards a joint where the resist-ance is least. Some concomitant stone damage willalso occur, and this will be at a sloping shear plane onthe leeward edges, but will be minor.

In active seismic areas, which experience only low-level tremors, such as south-eastern France, someruins display timber beams built into masonry walls atregular vertical intervals, which are seismic attenu-ation devices. These are often mistaken for former lin-tels abandoned due to alterations. Further south inEurope, the Balkans, etc., these timbers occur in ver-nacular architecture, as full perimeter ties, rather likebond-beams in concrete masonry. The timber tiebeams provide a tensional capacity, which the masonrylacks, and some minor flexural capacity. These fea-tures, coupled with the softer, fibrous nature of thetimber, help to redistribute some of the ground wavestresses, and to absorb some of the shock by localbending and by dampening.

This same phenomenon helps to explain theRoman fascination for bands of brickwork withintheir masonry buildings.

Some minor tensional capability is available fromthe brick layers via the mortar bonding, and the fre-quently repeated layers, as for example in the Baths ofConstantine in Arles shown in Figure 2.11, provide

Stability and survival 19

Ch02-H6429.qxd 10/16/06 2:24 PM Page 19

a cumulative capability for tension between the lay-ers. The different dynamic response of fired brick, asopposed to masonry, has a dampening effect also. Ascan be seen, the brick courses extend the full widthof the walls.

In the low seismic areas of southern France, thereare many examples in vernacular architecture of taper-ing walls or buttresses, with splayed quoins, whichreduce the effects of minor tremors. These have oftenbeen added to with quite massive sloping buttresses,which taper towards their tops, and provide the sameeffect (Figure 2.12).

A similar add-on seismic buttress can be seen hereprovided to the seventeenth century church atManosque, France (Figure 2.13). Notice the neat, butmassive, buttress of extra large quoins which has beenadded to stabilise the fine limestone ashlar work ofthe façade, which shows signs of having been shakenand cracked by an earth tremor. The position of thecrack and loose joints, just back from the corner,indicates that the shock wave passed from right toleft. This is borne out by signs of light spalling to theashlar faces of the two town gateways, which lie onthe same axis of the wall shown. This is typical of lighttremor damage and it shows how the masonry dam-age will accumulate on the lee side of the pressurewave, as the masonry rebounds, thereby realisingtensional forces in the masonry. An examination ofbuilding complexes damaged by seismic activity willillustrate these principles.

Some experiments have been made of reinforcingre-erected ruined columns with steel rods throughtheir centres. This has a potential for further worsedamage to occur, than if solely pegged together in theclassical manner. In the event of a seismic occurrence,grouting of the rods is likely to initiate a secondaryshear plane starting from the centre of the rod group,

20 Conservation of Ruins

Figure 2.11 Baths of Constantine, Arles.

Figure 2.12 Tapered corner designed to reduce the effects ofminor earth tremors.

Figure 2.13 Massive added buttress to wall fractured duringseismic activity, Manosque, France.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 20

and should therefore be avoided. As the magnitude ofa future seismic event is unpredictable, a satisfactorymodel for analysis may not be possible, and it may be better policy to avoid this type of refinement. The probability of a lightning strike to the top of a reinforced column is a further factor to consider.

Lightning strikes

Any tall ruin will attract lightning, and the riskincreases in open situations, where the ruin is at a rela-tively high elevation. Lightning produces between 10and 100kA in a period of less than one-hundredth ofa second, and in a poor conductor has a significantheating effect. Trees hit by lightning, being poorconductors of electricity, sometimes split due to thetracking path being partly internal, where there is areserve of moisture, and instant vaporisation intosteam creates an explosive force. On occasions the heatgenerated will also set the tree afire. Hence, stainlesssteel reinforcing rods will heat up with a lightningstrike, and if epoxy grouted in position, the heat gen-erated will melt the epoxy. If the reinforcing rods arein a group then the current will flow through all rods,simultaneously generating a powerful magnetic field,which will pull the rods violently together throughthe melting epoxy. In a worst case scenario, this sud-den force could split the top and bottom column sec-tions longitudinally into several fragments. In a lessercase scenario, the discharge of current at the base islikely to track across the surface of the stone pedestal,and if marble, some electrolysis may occur with con-sequent surface damage.

Conductors should be external to the monumentin question, and solid copper for preference, as anyhollow formation will collapse inwards. In sandy soilthe best earthing is a buried copper grid, but thismay need to be quite extensive and may be imprac-ticable in an archaeologically sensitive context.

Omission of a conductor will sooner or later leadto lightning causing some damage, as was caused bya strike in 2003 to a conical roof to Cesis Castle inLatvia (Figure 2.14), which had been replaced in the1890s. Little damage has been caused in this case, asthe vertical transmission of the electrical energy hasdissipated into several of the sloping timber props.Although nominally dry, residual moisture in thetimber has been vaporised from those parts of thetimber retaining the most moisture, such as the cen-tral pith, and at the cross beam intersections.

Both of the props nearest the camera show thesplintering effect caused by the sudden release ofenergy as moisture turns instantaneously to steam.

Climatic effects

Wind, sun and frost contribute to degradation indifferent ways in different places, and modificationsto avoid moisture traps, which invite frost damage,necessary in northern Europe, are less important inmost parts of, say, Australia or North Africa. Tem-perature cycles of expansion and contraction rarelyseem to affect massive constructions of masonry inlime mortar. There is a heat sink to the interior ofthe wall, and the lime mortar is relatively soft with adegree of elasticity. Over a large surface area this isusually sufficient to absorb the expansion forces.Cement mortar, on the other hand, is a whole orderstronger, and thermal movements in cement mortarmasonry can cause brittle cracking which, in brick-work, often leads to surface spalling. It is as well toremember that reinforced concrete is technicallypossible because of the similar coefficients of expan-sion of steel and concrete. Even in a relatively modest climatic range, such as Cornwall or Brittany,a 33-metre-long bridge deck will have a movementrange of nearly 40 mm. Care needs to be taken,therefore, in introducing a dissimilar material, suchas Portland cement concrete, into masonry ruins,particularly in situations where direct solar heatingis likely. The natural flexibility of lime mortared

Stability and survival 21

Figure 2.14 Evidence of lightning strike, Cesis Castle,Latvia.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 21

22 Conservation of Ruins

masonry with its inherent advantages over modernmaterials needs to be respected.

Limestone masonry is quite forgiving of solar radi-ation. Igneous masonry, however, heats up rapidly inhot conditions, and due to poor conductivity withinthe stone, heat stresses set up in layers below theexposed surface. Basalt in particular, being dark incolour and a good insulator, frequently shows symp-toms of defoliation (‘onion-peeling’), and shouldthere be a mortar deficiency in the surrounding joints,heat sink to the wall interior is lessened, increasing thesurface effect. Since quoins often pinch-up as mortarloss occurs, the mechanical effect thus developedcompounds the effect of the temperature stresses.Consequently, the sharp arrises of basalt quoins oftenspall off in west-facing buttresses. This is a furtherconsequence of poor maintenance, particularly ofrepointing being left unattended.

The direct stresses due to temperature, which causethe typical onion-peeling of stone, occur at nightwhen cooling causes the outside layers to shrink,whilst the interior of the stone is still hot. Thus, it ismost pronounced in desert conditions, where theclear air allows rapid heat radiation loss after sundown.Granite columns sometimes found in Roman ruins

can show a variation of this effect (Figure 2.15). Hotdays followed by cold nights cause microfracture ofthe exterior layers, and condensation or rain runningdown the column penetrates the very small cracks,which can then freeze as temperatures plummet. Thiscauses localised damage mainly around the columnbases. Lesser damage occurs at the top of the columnswhere a small reservoir of water collects between thetop of the column and the capital.

Sometimes it is possible to ameliorate the condi-tions around a site by judicious planting, giving anelement of shade during the day, some shielding, anda small heat output after dark, effectively allowingthe stone a longer time to transfer heat load to theoutside layers.

Frost

The collection of water generally within the sedi-mentary stone masonry of standing ruins can lead tospalling of face stonework similar to the above, andthis type of damage can be seen in Figure 2.16 of aseventeenth century chateau which was gutted dur-ing the French Revolution. Frost damage is limited

Figure 2.15 Granite column showing temperature-related‘onion-peeling’. Figure 2.16 Frost damage in saturation zone created by

fallen rubble.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 22

Stability and survival 23

Figure 2.17 Frost damage related to the creation of an eigh-teenth century terrace behind an existing bastidon wall.

Figure 2.18 Common frost damage caused by accumulationof soil.

to the base of the tower walls where fallen rubbleallowed the masonry to remain wet. This demon-strates the need for attention to detail to any exposedwall tops and to the removal of moisture traps.

To avoid this type of damage, filling behind retain-ing walls should not be done without first installing afree draining layer directly behind them. Figure 2.17shows how the creation of a chateau terrace duringthe eighteenth century has left a clear outline of thestep in terrace level behind the older bastidon wall,shown by the resultant frost damage. Figure 2.18shows a combination of frost and salt damage tobrickwork due to mounding soil behind a brick wall.

Similarly, attention needs to be given to ingress ofmoisture at the roof or capping level. Moisture pene-tration at the top, in most materials, permeates downtowards ground level, and if not fully dried out, thebases of these structures become susceptible to frostdamage.

This is particularly dangerous to ruins, due to thefact that loss of support is involved at ground level,and as the structure seeks to re-balance the forces act-ing from above, a point is reached where the appliedstress is sufficient to shear the stone above. Cracks canbe seen developing above the eroded levels of theRoman Theatre in Orange (Figures 2.19 and 2.20).

The Baltic tower (Figure 2.21) built by the LivonianOrder has been successfully stabilised and protectedfrom further damage, in spite of being 700 mm outof plumb, by provision of a non-intrusive roof andflashings. The openings have been kept through theflashings, retaining some of the realism of the historicapertures, and the use of boarding to close in thestructure is not jarring to the sense of the ruin.

Salt damage to brickwork

In Australia a fragile ecology has become unbalancedalong some major river systems, raising salinity lev-els and increasing the extent of previous salt pancountry. It is here that some of the worst ‘salt damp’

Figure 2.19 Stress cracking of the Roman Theatre at Orange(1).

Ch02-H6429.qxd 10/16/06 2:25 PM Page 23

24 Conservation of Ruins

problems occur. Typically the lower courses of pio-neer bricks in historic structures suffer almost com-plete collapse into powder as salt from groundwateris drawn by evaporation into the structure of theclay, which progressively eats away the faces of thebricks.

In Europe, however, especially in those countrieswith long cold winters, de-icing salt will cause thesame effect when it is taken up as a saline solutionduring thaw, as seen in buildings surrounding theOld Arsenal in Riga (Figure 2.22).

Spreading salt to de-ice paths and steps aroundruins and historic complexes needs to be done withgreat caution if there is any brickwork present.

Wind

Damage by wind alone is seen to its greatest effecton leeward surfaces, wherever sharp edges projectinto the wind stream. This is due to the downstream

vortices induced immediately behind any sharp edge,and the vortex intensity relates to wind speed and thesharpness of the traversed edge. The vortices pro-duced are of higher velocity than the stream itself,and are typically of the order of 1.5–2.0 times thegenerating wind speed.

Two other features need to be borne in mind withrespect to vortex effect and Figure 2.23 helps to

Figure 2.20 Stress cracking of the Roman Theatre at Orange (2).

Figure 2.21 Wall head protection of Baltic tower, Latvia.

Figure 2.22 De-icing salt damage, Old Arsenal, Riga.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 24

explain the phenomena. Firstly, it should be notedthat downstream of the corner or edge, the standingvortex generated will establish, for a given windspeed and direction, a reversal in direction of flow atthe downstream face of the masonry.

This causes suctional forces to develop against theleeward face, similar to the effect over an aircraft wing,for the short section close to the corner. The suc-tional forces drag any loose mortar free of the joints,and hence increase the chance of arris damage as

Stability and survival 25

Figure 2.23 Vortex scour and deflected wind.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 25

26 Conservation of Ruins

noted above. It should also be noted that wind isnever constant in either speed or direction for long,as it constantly veers and backs in short time cycles,reacting to major forces in the atmosphere. Hence theconstantly changing effects of the vortices aggravatethe extent of scouring on the downstream face. Fric-tion with the ground decreases, causing wind speedto increase with height. Tall ruins, such as towers orruined abbey naves, should have carefully rounded-offtops and shoulders where dressed for water shedding,etc. These rounded edges help maintain a laminarcondition to the airstream, which restricts thedevelopment of vortices.

Judicious planting around very exposed sites willhelp to drop the wind speed and lift the airstream tosome extent. This not only creates a more visitorfriendly environment, but can also reduce weather-ing to the fabric.

The second effect, which can be recognised bothin ruins and standing buildings alike, is that of windchannelling, such as shown in Figure 2.23. The effectsof other walls, roofs or objects, if at a suitable angle tothe wind stream, can divert part of the stream, effect-ively deflecting it against a leeward corner, whichmight otherwise be sheltered to some extent. Hence,

certain parts of a structure can receive wear over awider range of wind directions, and localised winddegradation will be more severe.

Figure 2.24 demonstrates the basic effects of windvortex erosion in a high wind area, although littleerosion occurs on the mine chimney, because thesmooth profile restricts the development of vortices;the square base structure has noticeable corner ero-sion just where the vortices are generated.

Figure 2.25 shows localised erosion to a roundchimney, where downstream vortices have impingedon the surface, these being spun off the adjacent edgeof the engine house ruin in the foreground.

In certain very severe cases, as occur frequently inmaritime situations, some thought should be givento providing wind-break fences within a complex ofruins. Obviously there is a visual trade-off involvedhere, but occasions will arise of frequently visitedsites needing them. They are best made of verticalbattens about 30 –35 mm wide and spaced apart aclear distance of 40 – 45 mm. They need to be1700 –2100 mm above ground level, and the topsshould not be capped with a rail, but left as protrud-ing fingers. This type of fence has been tested inhigh-wind areas and works efficiently to ‘kill’ the

Figure 2.24 Chimney base showing effects of wind vortexerosion.

Figure 2.25 Localised erosion related to downstream vortices.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 26

stream speed by the simple process of generatingopposing vortices.

Allies of degradation

In spite of the beneficial advantages of selectedplanting given above, there is no doubt that natureis not neutral but active at all times in the generalprocess of decay to ruins and structures alike. Plantroots, whether of climbers like ivy or ordinary treeroots, are active in lifting, breaking into masonryand increasing surface acidity (Figure 2.26). For allthese reasons, the mature height rule given abovefor clays could be applied equally to maintaining asafe distance of trees away from masonry structures.

Birds and rodents provide active allies in the deg-radation process. Rats, being omnivorous, are active inany benign climate where a food source is available,and exploit any weakness in a ruin or building, such ashollow core work or soft backfill. They are also happyto cohabit with humans, unlike shy rabbits. Theyoccasionally cause problems of settlement immedi-ately below footings by leaving voids, usually in stables, shops, etc. They can leave pathways facilitatingwater penetration and later subsidence. These prob-lems remain hidden when the building decays to ruinstatus, but continue to exist until changing circum-stances lead to a collapse.

From a financial aspect, the damage caused bybirds is much more important as their activities takeplace in the most inaccessible locations, and henceare more expensive to reach and rectify. In Australia,the strong beaks of cockatoos have no difficulty cut-ting body holes through 300 mm of soft sandstone inhigh, undisturbed locations such as church towers,and I have seen several examples. Even small birds

such as starlings and jays cause damage too, as theyexploit small openings and dislodge mortar.

Simple stratagems, such as plastic snakes placed insuitable locations, or cut-outs of black crows, can beemployed to scare birds away from critical points.The ecology of ruin sites is discussed in Chapter 6.

Disasters

These tend to monopolise public thinking, almostto the exclusion of the vast number of highly suc-cessful designs from antiquity. Well-known cases arepromoted by popular television and press in a super-ficial education process. It seems that most peopleare aware that the dome of the Santa Sophia col-lapsed after only 21 years, but few know that it wasdue to an earthquake. Very few realise that the modi-fied dome has now stood for over 1400 years andwithstood several earthquakes since.

Similarly the famous collapse of the nave at Beauvais is given undue prominence against, say, the technically brilliant, and aesthetically beautiful,strainer arch solution used for the Salisbury Cathedralspire support.

Earthquakes aside, the balance of structural forceswas well understood and catered for in the past, andcollapses occur usually through structural alter-ations. These are outside the intentions of the originaldesign, and hence change the structural conditions,sometimes creating a new set of stresses. We candetect changes in the behavioural pattern of struc-tures because they leave clues of how the new set ofstresses are redistributing as the altered structuresrespond to different forces.

A background knowledge of the area, its historyand geology is very important to an assessment ofstability and its possibilities. In an area with a historyof colonisation, there will be layers of historicchanges, perhaps in the form of terraces, ditches andunderground conduits, which can sometimes accountfor an unexpected reaction from a ruin or structure.Mine shafts and sealed adits, in mining areas, fallinto this category, with some alarming conse-quences. These too leave their own sets of clues, andthe search for evidence then extends well beyondthe structure itself.

Human failings

Surprisingly, inadequate footings do not figure largein a listing of failures. Human intervention not inkeeping with the original design affects the long-term stability of a structure and can initiate a process

Stability and survival 27

Figure 2.26 Tree root lift.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 27

28 Conservation of Ruins

of decline. Fortunately the response of most antiquestructures is usually slow as they seek to readjust, andthere will be an ongoing process of load-sharing toother members or sections of masonry. The alteredbehavioural pattern can then be identified by a subtle set of clues in cracks and earlier repairs. New introduced elements can also force a series of readjustments by the main structure, beyond the capacity of the original structure to cope. Theintroduction of extensive elements of reinforcedconcrete needs to be well thought out in advance, asthey have very different responses and flexural qual-ities to traditional materials.

Mistreatment is possibly the greatest factor inweakening of structures and ruins, leading to deg-radation. Once a ruined building is seen as a materialsource, expediency and economic greed overcomeany compunction or restraint. This has been the con-sistent story of history generally. From a structuralstandpoint, the most attractive spoils are also thoseproviding key elements of support, such as quoinsfrom corners or buttresses, arch and voussoir stones,roofing, etc. This makes it all the more important forgovernments to take the necessary steps to protectsites from plundering.

Fire

Few natural stones can cope with the high tempera-tures generated by fire. Volcanic ash, solidified by thepozzolano effect into a lightly cemented soft rock, isone of the few, and it can sustain heat with no sig-nificant change. Most other natural stone either cracksdue to unequal heating expansion forces or mayundergo chemical change should the temperature gethigh enough.

The big difficulty for the conservation engineer isthat key structural elements such as lintels are oftenthe most exposed during a fire, and frequently crackas a result. Cracked lintels frighten engineers, and thepragmatic solution for a reversible ruin would be tocut a new one from the same stone source. This is notalways easy or possible. For ruins, where the stone willhave obtained a patina of wear or algae discoloration,repair in situ is always possible, even if this requires thatthe real structural lintel must be concealed behind.Repair of fire-damaged masonry is covered elsewherein the main text.

Timber can accept a degree of charring, but it isnecessary to remember that timber exposed to atemperature of 180°C for any period of time suffersthermal degradation and, in extreme cases, totalembrittlement. Even at lower temperatures, wherecycling of temperatures has occurred, reduction in

timber strength of over half is possible. The charringof timbers does not necessarily render them unsatis-factory, but a rough guide is that a two-hour fireusually results in a charring level of 20 mm, hence itis pointless attempting to conserve timbers less than140 mm on the lesser axis. The retention of originaltimbers is frequently of great historic interest, asmuch can be gleaned from joint detailing, dimen-sions, saw signatures, etc. However, this is a processfor individual selection and will require the expertiseof a structural engineer experienced in this field, andalternate structural support must often be provided.

Vandalism and war

From a conservation aspect these two have much inparallel; however, fences and other barriers aimedagainst intruders intent on damage are unlikely tostop a determined, armed and trained force of sol-diers. Ruins are often massive enough to withstand amedium level of blast, as it is quite difficult to collapsemost ancient structures without a well-thought-out,and accurately placed and timed, deployment ofexplosives. It therefore comes down to protectinghigh-value ruins against normal gunfire and shrapnel,which will significantly disfigure any stonework. Thisis easiest accomplished with protective sandbagging.Because this will give the appearance of a strong-point, or signals bunker, monuments should beclearly marked in bright colours and their presenceadvised to the enemy through the Red Cross, orother neutral authority, as has happened several timesin past engagements.

Determined vandals are very difficult to stop, andsee barriers as a challenge to their objective. Damageof this nature could be on the increase, and moni-toring systems may be of more effect than directprotection.

Forces in balance

When a structure is assessed it is necessary to know if itis stable and, from a long-term perspective, whetherthe forces are in balance. The immediate static situ-ation can be read from the clues left by cracks and pre-vious repairs, but these do not give a clear picture as towhether there is a dynamic element present. Freshcracks or spalling may infer recent movement, but thisbecomes a matter of opinion, and some quantitativeevidence is needed if a prediction of further movementis required. On occasions the provision of fundingfor remedial works may depend solely on this criteria.

When a ruin structure is inspected for the firsttime it is important to fully record the situationphotographically and by measurement of the cracks

Ch02-H6429.qxd 10/16/06 2:25 PM Page 28

present. More sophisticated forms of monitoringmay be recommended. It is good practice always tocarry a crack gauge, and set up preliminary pointswhich can be measured and recorded, markingthese with an indelible pen so they can be easilyfound again. This process can be invaluable, as itremoves the subjective element. Cracks seen instrong sunlight look very different on a dull day orin shadow. An absolute surety comes with a care-fully recorded set of measurements, which cannotbe disputed, and if a programme of measurementsover specific intervals is available, then often a pat-tern to movement can be discerned.

Should an initial visit suggest that cracks are stillopening then installation of the plastic window typetell-tale is worthwhile (Figure 2.27). These comeready graduated and are made to span across cracks,and the relative movement in two planes can be plot-ted directly as a trace.

Should major movements be involved, then modern survey equipment can be used for the samepurpose over extensive areas. This usually involvesthe installation of permanent pins or marks, in liaisonwith the conservation team, and will be necessaryfor major structures. It is time-consuming, expensiveand will normally involve years of monitoring,rather than months.

The seasonal movement of clays has been explainedabove, and a monitoring programme for ruins orstructures sited onto clay subgrades will need to takeaccount of seasonal changes and long-term climaticeffects. For example, a crack measured during wintermay be considerably wider by the next autumn, butwill have partly closed up again by spring. For thisreason an ongoing monitoring programme will usu-ally be necessary.

Transfer of forces

The ultimate destination of all forces developed by astructure is to the ground. Just as we take all of our

weight through our feet, so does a structure throughits footings. The analogy can be taken further in thatthe load onto our toes is, for most of the time, greaterthan on our heels. Thus it is also for most walls, oreven an individual column should it be receivingsome other load. If there is a change in the distribu-tion of foundation forces at ground level, this toepressure will be the first affected. This regularly occursdue to softening of the ground at the base of a wall, ortrenching in front, or loss of face mortar (Figure 2.28).The structural forces will attempt to redistribute loadto compensate for the loss of support by increasing thetoe compression, which often involves a forward rota-tion of the wall.

In Figure 2.28 it can be seen that the front wall sep-arates as the wall leans forward, and tension cracksopen in the return walls. This phenomenon increasesthe stress on the toe, as a consequence of which a sig-nificant vertical shear acts on the face of the structure,as demonstrated by the spectacular shear cracks on thebuttress shown in Figure 2.29.

Stability and survival 29

Figure 2.27 Graduated tell-tale bridging a fracture.Figure 2.28 Forward lean of wall with tension cracks show-ing in return wall.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 29

Regrettably, this realisation fails to get home tolarge numbers of professionals, and it is not unusualto find excavations carried out at the toe of walls,with no regard to the tons of force from a cupola orvault at its top. It is important to realise that, innearly all cases, the greatest vertical stress will be hereat the toe and that there will be a corresponding horizontal component also. Even more common isthe gross disregard given to discharge of roof water,which invariably happens just where it can do thegreatest damage: at the toe of the wall. Some basicfacts are worth recapping in this regard, if we look atsome primary structural components.

The mechanism of structural components

Wall systems

All walls are subject to wind forces and they alsoexperience, on a regular basis, additional stresses dueto heating (often asymmetrical), shrinkage, unequaldrying due to sun or wind, and the destructive actionof frost. The mechanics of how a wall responds tothese forces essentially classify walls into two groups:

● Free-standing walls, or● Panel walls.

Thus, from a structural perspective, free-standing wallsare vertical cantilevers from a base or foundation,which in turn redistributes forces to the ground. Inthis regard it is of no concern to us whether the wall istwo metres long or 200 metres long, with respect tothe structural mechanics. Of course, the wall length isa factor in expansion and affects wind pressure devel-opment, but otherwise does not figure in how thestructure reacts.

For long-term stability a conservative height-to-thickness ratio is required, and since masonry in limemortar is deemed to have zero tensional capability,then the wind and secondary forces become distrib-uted and absorbed by the wall’s mass.

Free-standing walls in well-known locations, suchas Haddenham in Buckinghamshire, have a height-to-width ratio of less than 5:1, and have some abilityto absorb temperature effects. For example, theHaddenham walls (Figure 2.30) are built of wichert,a chalk marl and straw mixture.

Panel walls are created by the insertion of piers orbuttresses to a free-standing wall, or by a change indirection which accomplishes the same thing. Thus,an open-top garden wall becomes a panel supportedon three sides with the insertion of buttresses. Thepiers or buttresses accept the greater part of the windforces and transfer these to the ground. The top edgespans as a beam and transfers the top reactions to thebuttresses and hence to the ground.

A panel supported on four sides is more efficientstill, as the wall can then span in two directions: topto bottom and side to side. This is the normal casewithin a multi-storey structure, where the horizontalsupports are provided either by the suspended floorsor by the roof and ceiling diaphragms. Panel walls,being more efficient, are often thinner than free-standing walls. In ruin situations, the timber floorshave often rotted out and what masonry remains isunder-catered for with respect to the forces developed.Some ruins present opportunities for the introduc-tion of a diaphragm, for example as was done in theGuildford Castle restoration (see Chapter 10), whichprovided a stiffened roof diaphragm inserted belowthe top of wall level. This is altogether a nice resolu-tion as the one item provides weather protection, astiffened diaphragm and creates useful visitor displayspace.

This type of resolution may not always be prac-tical, and some other disguised support may becomenecessary. Highly visible visitor inspection platforms,for example, are immediately read as modern andnecessary items, without any detraction from theruin authenticity.

30 Conservation of Ruins

Figure 2.29 Shear cracks in buttress of leaning wall base.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 30

A simple rule has been adopted in the past forsome codes of practice, which is that a wall panelsupported on four sides should not exceed 28 squaremetres. This is a useful guide in assessing wall slen-derness for stability, but obviously will often needsome further structural analysis, particularly if thewall is thicker than normal. Where massive ruins areconcerned, such walls frequently have solid cores. Inthese cases the walls are able to develop an archingeffect in response to wind loads, etc. Hence a wallthat is two metres thick, spanning a horizontal dis-tance of 14 metres, has a plan aspect ratio of 7,

which is about the limit for development of arching.A degree of caution should be used as, even withwalls of this thickness, the core construction plays abig part in the overall stability.

Before leaving this subject, mention should bemade of various zigzag or serpentine walls, such asthe garden walls at Bramfield Hall in Suffolk. Thesegain their stability from the part buttress or fin effectcreated by their plan outline, where part of the walllength is able to provide an opposing counterfort tothe applied force, hence giving the wall greater overall stability.

Retaining walls

In monuments and sites these will invariably followthe thickness-to-height ratio of 1:3 or exceed it. Thewall capability is enhanced if the face is laid backrather than being vertical. They are not designed to carry a water load, which if it occurs can triplethe force acting on the back of the wall. Surfaceflows must not be diverted behind mass-retainingwalls without provision being made for collectionthrough a culvert discharge. Neither must the naturalporosity of a wall be altered, for example by pressuregrouting, without some provision for weepholesbeing made.

The effect of inadequate provision for drainageand discharge of water from behind a wall can beseen in the bailey of the ruined Baltic castle shown inFigure 2.31. The earth backfill collects water, whichthen exerts a much higher active pressure on the backof the wall, and maintains the mortar in a damp con-dition. The wall then fails through a combination ofincreased loading, weakened mortar and frost dam-age to mortar and masonry alike. The top of the wallis well protected by a capping, but continuous cap-pings in long lengths, particularly if composed ofcement mortar, can experience expansion and tem-perature stresses large enough to lift the capping fromoff the masonry.

It is usually possible to insert weepholes at thebase of a wall in unobtrusive positions, and to drillvertical holes from above to link with them whichcan be filled with drainage media. These must notbe too small a diameter or they will quickly clog, ortoo far apart for the respective soil permeability todrain effectively.

Very occasionally, an arched retaining wall isfound, often ashlar faced, and which functions on asimilar principle to a dam. This does not mean thatit will accept a water load, however, and the sameprecautions as above apply.

Stability and survival 31

Figure 2.30 Wichert wall at Haddenham, Bucking-hamshire.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 31

Corbels

These depend on a cantilever effect and must haveadequate back weight in order not to topple. Inworking around corbels temporary propping shouldbe provided, until a safe amount of masonry has beenlaid above their back projections and has had time tocure. The corbel projection with respect to depth isalways very conservative, 1:1 or less, to avoid initiat-ing a tensional stress in the stone (Figure 2.32).

Arches

The purest expression of structural efficiency is seenin Roman or Norman arches, and the transfer offorces at the cut faces of the arch ring voussoirs iseven around the semicircle. All arches terminate witha horizontal thrust, but the semicircular form pro-duces the least. Arches may terminate with either aninclined springing (as below) or a horizontal one,from off capitals or off sleeper pads. Greater careneeds to be taken in supporting the arch weight if thespringing is horizontal.

The Pont Julien, taken out of service in 2005 andbuilt between 24 BC and 14 AD, demonstrates the enormous strength and longevity of the semi-circular arch when built of dimensioned masonry(Figure 2.33).

After such a long period in service, loss of mortarand wear of the stones is having an effect, and theflood spillway arch keystone can be seen dropped inFigure 2.34. The arch remains safe, and it is theapproaches and spandrel filling which have sufferedmost from regular flooding and earth tremors, caus-ing spreading of the spandrel walls.

The opposite effect can be seen in Figures 2.35and 2.36, where both arches are close to failure dueto spreading at the springing points. In both casesshown the distortion is towards the springing offer-ing the least lateral support. It can be readily seenthat a flatter arch significantly increases the horizon-tal forces.

This brings in an important concept of flatterarches, which is that of containment within a mass ofmasonry. When a loss of lateral support develops, theresidual horizontal thrust from the arch will cause the

32 Conservation of Ruins

Figure 2.31 Retaining wall failure under earth and water pressure.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 32

weakened outside panels to push outwards, resultingin cracks in the masonry above the arch, allowingmoisture penetration, which hastens the process.

If there is adequate support from one side, but theother side is near a corner return, then a lurch to oneside will result, as seen in Figure 2.37. Where the

Stability and survival 33

Figure 2.32 Corbel projections.

Figure 2.33 Semicircular arches at Pont Julien.

Figure 2.34 Dropped keystone at Pont Julien.

Figure 2.35 Arch close to failure due to spread at springinglevel.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 33

34 Conservation of Ruins

horizontal thrust is balanced by a second span, or bya large mass of masonry containing the arch, this lossof shape cannot occur.

Very flat arches develop significant thrust at thespringing points, even when lightly loaded, as seenin Figure 2.38. It can be seen that there is an asym-metrical displacement, towards the unsupportedabutment, pushing some of the masonry from off itsbed and allowing the arch to drop at the centre.

Relieving lintels and blind arches

Relieving lintels normally take the form of an arc situ-ated above the real lintel, be it timber or masonry,and these are used to relieve the loading which wouldotherwise fall onto the lintel below. They are com-monly mistaken for signs of a modified opening andcan cause some pedantic, if erroneous, statements.For this reason, and because they vary in form, someexamples are shown here.

The first is a dry-stone ‘borie’ (Figure 2.39),which has been dated as pre-Christian era and of atype which goes back to 3500 BC. Although it has a

renewed timber lintel, the relieving arch above it isprobably original.

Relieving lintels are often of brick inserted intostone masonry. They do not always form so completean arc as the ones shown in Figure 2.40, and oftenretain a decorative element.

Figure 2.36 Arch close to failure moving towards the areaoffering least lateral support.

Figure 2.37 Asymmetric movement of arch.

Figure 2.38 Thrust of flat arch.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 34

They frequently conform to the general typeshown in Figure 2.41. Just as with arches, adequatecontainment by masonry to each springing is neces-sary for the development of full structural potential.

Blind arches

Blind arches are a variation of the same, but have amore important structural function in that theyactively distribute loadings towards specific points,where other members have been provided to caterfor major loadings. Perhaps the best known of theseare the blind arches around the Pantheon in Rome(Figure 2.42), dating from 80 AD, and which con-firm the faith that Roman builders had in semicircular

arches as a structural solution. These distribute the loads from the dome onto a series of majorpilastered piers in the interior periphery, therebyenabling a series of side niches. Note also the smallsemicircular relieving lintel inserted above the win-dow. One might call this a belt and braces approach,but since the building has stood since 80 AD, suchcriticism would be impertinent.

Cupolas and vaults

These are both forms of arch from a structural per-spective, and are dependent on a balance of forcesthroughout the construction. A simple explanationof balance is that the resultant of the forces in playmust pass through the middle third of the surfacepresented. As with arches, voussoir masonry can be

Stability and survival 35

Figure 2.39 Relieving arch in dry-stone borie.

Figure 2.40 Brick relieving arches in stone masonry.

Figure 2.41 Typical relieving arch above timber lintel.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 35

36 Conservation of Ruins

adjusted in size and shape to ensure the resultingforces comply with this rule.

The half cupola in Figure 2.43 forms an apse,which exerts an appreciable horizontal force ontothe adjacent structure. This is the Caldarium apse ofthe Baths of Constantine, which takes its supportfrom the massive arch which separates it from theTepidarium. The remains of a springing for a seconddome, visible top right, shows how the balance offorces would originally have been achieved.Nevertheless, the apse remains intact, and the delib-erate use of brickwork ribs shows how the loadingfrom the apse roof was directed onto the pillars between the windows.

The same method is used in a diagonal form in afirst century Roman vault (Figure 2.44), and the

inherent strength is achieved by a mix of brick ribsand regularly shaped limestone.

Rubble construction, however, with roundedstones of different size and shape, has none of theseadvantages and, when used in relatively thin elem-ents, as in an arch, is reliant on the mortar to transferforces evenly from stone to stone. When dealingwith this type of construction, extensive supportfrom below is necessary for safety reasons if the mor-tar is at all weakened.

Even with dimensioned masonry strengthened byribs at regular intervals, if the end wall moves due toweathering, then the vault will crack in its weakestplane. This is what has happened in Figure 2.45, andthe second bay has similarly cracked at the midpointbetween ribs as the stresses are shared by the struc-ture into the locations providing the least resistance.

Figure 2.43 Half cupola, Baths of Constantine.

Figure 2.44 Diagonal brick ribs in Roman vault.

Figure 2.45 Cracked vault related to wall movement.

Figure 2.42 Blind arches in the walls of the Pantheon.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 36

Dissimilar materials and theirconsequences

Mass concrete

Pouring mass concrete gives rise to problems ofsupport, shrinkage and heat output when it is usedin large volumes. In new construction, one of themost common forms of site collapse is due to failureto adequately cater for wet concrete. This acts as afluid of very high density, and when vibrated thewet concrete mobilises its full fluid effect and alsotransmits some of the vibration energy onto theboxing. Temporary support needs to be over-cateredfor in respect of the calculated forces, in order toavoid shift in alignment and displacement of timbersor wedges with load. Similarly, masonry walls usedas front shuttering to wet concrete should be bracedat close intervals and as a rule of thumb the pourheight should never exceed 900 m.

It is best to avoid concrete as a backing medium ifpossible, but in those circumstances when it is used,allowance must be made for about 1 mm of shrink-age for every 2.5 m length of concrete. This maymean pouring concrete in short lengths betweenstop ends to avoid fracture or stress to more fragilemasonry, and a limit of 4 – 6 m should be taken as amaximum. Heat output of large volumes of con-crete, such as in bridge decks or dam construction, isan unlikely scenario with ruin conservation, but it isimportant to remember the relatively large heat out-put associated with the chemical reaction of curingconcrete.

Reinforced concrete

When used in most structural elements, there is abalance of steel reinforcing within the cross-section.If long lengths are provided with reinforcement inone face only, as occurs often with top-course bondbeams, then a small amount of curl will result as theconcrete shrinks when curing. For this reason, theinstallation of top-course bond beams and cappingsneeds to be undertaken in short lengths to allowtime for the concrete to shrink, or some balancingreinforcement added to the opposite face. A min-imum period of five days should be allowed betweenpours. It is good practice to provide expansion ormovement joints in situations like this, as they provide an extra degree of tolerance to shrinkage also.

Adequate concrete cover to the steel is very import-ant, as the start of rust will lead to severe problems

later. Consideration should be given to providing galvanised reinforcement in doubtful cases.

Rust growth in steel and iron

Rust growth is unfortunately a very commondestructive agent in more recent structures, particu-larly amongst industrial ruins. It was a practice inVictorian times to attempt to strengthen some tallmasonry structures, such as church towers, by theinsertion of wrought iron or rolled steel strapsembedded into the masonry. These were intendedto function like a bond beam, but they have in factbeen a source of endless trouble.

Rust growth occurs to steel and iron alike andexhibits as layers of rust similar to the leaves of anuncut book, as can be seen in Figure 2.46. Note howsmall bolts can burst open large blocks of concrete asthey rust. The formation of the ferrous oxide layerincreases the thickness of first one, then successiveleaves. Where steel packers have been left in masonrycourses they can lift many metres of building above,and it is not unusual to find a 20-mm vertical gap inthe bedding joints, which when dug out reveals thepresence of a strap or piece of steel plate.

These gaps then promote the ingress of moisture,leading to further direct damage due to stresses inthe masonry, accompanied by increases in dampness.Examples of the lifting effect caused by a thinpacker, and direct damage to an end gable, wherethe stub of a steel gantry beam has been left in place,are shown in Figures 2.47 and 2.48.

Wrought iron rusts in much the same manner assteel, and unfortunately iron cramps (or ‘dogs’) wereused in the Middle Ages and by the Romans for join-ing stone panels and blocks together. Several blocks

Stability and survival 37

Figure 2.46 Damage caused by rust growth.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 37

38 Conservation of Ruins

on the weather side of the Roman triumphal arch(Figure 2.49) have been exploded by rust growth ofconcealed wrought iron cramps (more stable bronzecramps were often used, but caused damage of anotherkind, as they were extensively robbed, involvingbreaking open of the stone/arches).

The same effect is seen in the medieval tomb inFigure 2.50 at every joint, and as an additional con-sequence of the rust build-up, the increased stressapplied to the thin Purbeck Marble has initiated ashear crack on the outside face of the stone endpanel, which is about to spall off.

Both the Roman and medieval builders were awareof the problem and often used poured lead or fixedlead wrapping to the iron tines. This was not alwaysadequate, and sometimes omitted.

The simple message is that iron or steel is notcompatible with masonry, and should be removedwherever detected, and before damage becomes toosevere. Where considered necessary, steel fixings incontact with masonry should be stainless steel(316L), and it should also be noted that galvanisingwill not survive long in a high alkaline environmentsuch as occurs with most mortars.

Figure 2.47 Jacking effect of thin steel packer.

Figure 2.48 Cracking due to corrosion of a steel gantrybeam.

Figure 2.49 Corrosion damage from Roman iron cramps.

Figure 2.50 Corrosion damage from medieval iron cramps.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 38

Vitrified bricks

Heroic efforts are being made in Latvia to preservethe national heritage since it gained independencein 1991, but the absence of some materials, and thelack of choice with others, has caused problems. Thesehave resulted in modern pressed, cellular bricks, firedto higher temperatures, being used in conservationwork, to fit with the historical context of brick-work used in the late Livonian period.

Modern bricks in a restoration context bring twoparticular problems to the fore:

● Brick growth, caused as newly kilned bricksabsorb moisture from the atmosphere

● Brittle fracture exacerbated by the cellular structure.

Just as it is necessary to provide expansion joints inconcrete, so it is also with modern bricks in moderncement mortar, which suffer the double effect ofbrick growth and thermal expansion. Hence there isa danger of the cladding to the ruin core, seen inFigure 2.51, moving differentially to the core mater-ial of rubble and lime mortar.

The chimney in the background, which is part ofthe modern restoration, should be noted also, as afurther example of frost damage.

Where there are substantial anchors to each end ofa brick wall or panel, such as a junction with a toweror a large mass of core, the movement in the brickface will accumulate towards the centre. This canclearly be seen in Figure 2.52 at the arch and in thewall in the background.

In its initial phases brick growth tends to be lim-ited to the face exposed to the atmosphere, andshould this also be the one subject to maximum solareffect, then significant shear forces develop on thelongitudinal axis. The cellular nature of the bricksused can be clearly seen as the whole brick face hassheared off in several instances. In such a severe win-ter climate, the voids, which collect water due to theimpermeability of the cement mortar, will spall offlater with frost action, as has occurred with thechimney already noted above.

These examples serve to reinforce the necessity ofkeeping to traditional methods and to like materialsas far as is possible and practical.

Stability and survival 39

Figure 2.51 Problems with new vitrified brick, Latvia.

Figure 2.52 Brick growth, Latvia.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 39

Inappropriate interventions (or how to make things worse)

Masonry and embedded steel

It should be obvious from the above examples thatany attempt to stabilise masonry by using steel cramps,straps or bolts has the potential to cause more damagethan it prevents. There may be some disbelief thatsuch techniques are still being applied, but some far-ranging examples are shown here.

Each buttress, to this mid-1500s building inSaxony (Figure 2.53) is different, showing forwardlean to the front façade over a long period of time.This has increased the toe pressures to each pier,with a concomitant horizontal component acting onthe bed joints, tending to open them. The solutionhas been to insert long steel straps.

The pier at the opposite end of the same building(Figure 2.54) shows how ineffective this solution is,as all three anchor stones have cracked and spalled,and the growth at a join has forced open the perpendjoint, displacing the quoin.

A similar scenario is about to unfurl at this medi-eval Kloster (Figure 2.55), also in Saxony, a recentlyreversed ruin. Extensive restoration work by way ofpressure grouting has been undertaken, which will beevident for a long time to come. The works have leftin place iron strap ties to each of the buttress pad-stones, which will cause cracking later.

The Cornish jetty (see Figure 2.56), subject toviolent storms, has been reinforced with steel straps,all of which have severely rusted and cracked thegranite edge copings, in a classic counter-productive

measure. The extent of rust growth can be gaugedby the size of the cracks in these major stones. Theyare currently being replaced with stainless steel.Note how the lead embedding has not relieved therust growth stresses.

Exposed steel and condensation

The relatively dry environment in the south ofFrance is subject to large nocturnal temperaturedrops throughout the year. Lightly protected steel

40 Conservation of Ruins

Figure 2.53 Forward lean of masonry façade in Saxony.

Figure 2.54 Long steel cramp failures showing crackedanchor stones.

Figure 2.55 Cramps left in place post-grouting, Saxony.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 40

Stability and survival 41

will not last long before corrosion sets in due to reg-ular evening dew formation. It follows that exposedgirding bands, such as those seen in a Gallo-Romanmonument near St Remy, should be of non-corrosive metal (Figure 2.57). This is an area subjectto minor earth tremors, and was possibly an expedi-ent solution from the past. It begs the question offurther expense to replace the bands when rustedthrough, and leaves significant local staining whichis difficult to eradicate.

Figure 2.58, also showing a site in Provence, showsa steel beam insertion into finely crafted masonry, inwhich a small amount of rust growth has managed tocrack three of the supporting pier stones. It is pre-cisely because the seat cannot be painted that regularcondensation will cause rust at the steel–masonryinterface, and to the top surface also. The rust growthto both surfaces is increasing the direct pressure at theseat, and creating a couple forcing flexure into thebeam. The two effects together are well demon-strated by the crack pattern to the pilaster cap. Theleverage has then forced a shear spall to the face of thesecond pilaster stone, which has relieved the eccen-tric force, causing the increased pressure to centraliseto the third stone down, which has split on the centre line.

Figure 2.58 Cracked masonry related to corrosion ofunmaintainable steel beam insertion, Provence.

Figure 2.56 Granite cracking and steel straps, Cornwall.

Figure 2.57 Iron girding bands, St Remy.

Ch02-H6429.qxd 10/16/06 2:25 PM Page 41

Loss of support

One of the areas of most concern to the conservationengineer is the lack of appreciation of danger withwhich laymen and some professionals approach excav-ation close to walls, and the bland assumption thatbecause things stand for a short time, long-term sta-bility is assured. Figure 2.59 captures that momentwhen the collapse of an undermined wall has alreadyoccurred, but the suspension of disbelief holds strongwith the handyman. Although the wall shown inFigure 2.60 is undermined on both sides, part has collapsed and a section of concrete facing hasdetached, the assumption still holds that a skim ofconcrete 60mm thick will hold up a granite wall ofsome tonnes. In neither case did further damageoccur, but it could easily have been otherwise, and inthe latter case irreparable damage was done to hand-made bricks of high historic value. It is easy to be wise

after the event, and the magnificent work done bythe French Centre des Monuments Nationaux isbeyond criticism. Here, however, at the Chateau deLacoste of the Marquis de Sade (Figure 2.60), therock bolting seen in the picture is unlikely to worklong term. There is a shear face visible in a relativelysoft rock, and as work is currently in progress somedirect support from firm rock at cutting level wouldbe the best long-term solution.

The pillaging of monuments in southern France hasbeen widespread for centuries, and the shear volumeof conservation work to be undertaken is enormous.This expedient solution seen at Barbegal to theEygalileres Aquaduct (Figure 2.61) can therefore beforgiven as public safety is still a primary considera-tion. The use of a masonry prop to an arch is of doubt-ful effect, however, and the time spent on it could havebeen directed to reinstatement of the missing voussoirsand minimal pressure grouting (see Chapter 4). Thesuperior construction of this third century aquaducthas left it mainly intact, whereas the adjacent CaperonAquaduct, which can be seen intruding into each sideof the frame, has essentially collapsed.

Tensional bands or ties in brickwork

The aftermath of the Second World War has left alegacy of expedient solutions in much of easternEurope, where occupation was continued by Sovietforces until recent times. The need to stabilise ruinsuntil repairs or reconstruction could be effected led tomany stopgap measures such as steel tie bands arounda church stairwell in Riga Old Town (Figure 2.62).

42 Conservation of Ruins

Figure 2.60 Rock bolting at Chateau de Lacoste.

Figure 2.59 Undermined wall and collapse.

Figure 2.61 ‘Temporary’ masonry support.

Ch02-H6429.qxd 10/16/06 2:26 PM Page 42

Stability and survival 43

In each of the three bands shown in Figure 2.62,it can be seen that the tension in the bands has pulledin a course of bricks, shearing the mortar in the

process, and leaving the remaining brickwork proudof the course held. To this has now been added theproblem of rust growth after so many years since thewar. The rust growth has increased the steel bandthickness, and hence the tension, resulting in furthertangential force developing, which increases therelative distress.

Conclusion

An understanding of the underlying processes, whichgovern deterioration, together with a knowledge ofthe inherent strengths which ruins exhibit, are funda-mental to the conservation process. Small, subtlechanges around a site can often assist in stabilising a ruin, slow its deterioration, and prolong its life. Adequate background knowledge, awareness of a site’shistory and of the various types of alterations likely tohave been carried out in the past can shorten an inves-tigation and save both time and money.

A conservation engineer, competent in more thanjust structural analysis, is an asset to any investiga-tion, but needs to be called in early to be effective.

Engineers in the conservation field are a privilegedgroup, who are given the opportunity to see andadmire the work of those mainly unknown builderswho have gone before. We have a duty to deal sensi-tively with their work with understanding, and recog-nising their original intents. If we treat their workwith respect and a degree of humility, then we shallcome to see that, even if we do not exactly stand onthe shoulders of giants, we still owe them a huge debt.

Figure 2.62 Steel tie bands, Riga Old Town.

Ch02-H6429.qxd 10/16/06 2:26 PM Page 43

Ch03-H6429.qxd 10/14/06 3:19 PM Page 44

Overview

Understanding the condition of masonry ruins, andthe scope and methods for repair and conservation,may at first glance seem similar to the approach takenfor the conservation of historic buildings, but thereare significant differences. These differences include:

● The behaviour of a masonry ruin is different tothat of an intact building structure.

● Ruins seldom have a roof to protect the walls andinterior fabric and are therefore subject to moreintense weathering and decay mechanisms, whichfrequently promote more widespread and long-term patterns of decay, such as voided wall cores.

● Ruins are seldom given adequate inspection andmaintenance. The consequent absence of a historyand track record of inspection and repair docu-ments can create uncertainty regarding the rate ofongoing decay and the success of past repair work.This often leads to inappropriate specification offuture work.

● Ruins are often complex structures involving lessfamiliar construction methods and materials thatare often locally sourced. When combined withmore intense patterns of weathering and decay,the solutions to long-term conservation can beless clear and heavily reliant on specialist know-ledge and experience.

Bearing this in mind, how should a condition sur-vey of masonry ruins be approached?

The success of a condition survey and futurephases of conservation and repair are dependent

on development of an analytical approach wherethe cause, pattern and extent of structural move-ment, weathering and decay are recorded, enablingproposals to be made based on sound experience.Where new or unfamiliar decay patterns are encoun-tered, solutions should be tested using trials beforefull-scale implementation. A balanced approach shouldbe developed which recognises the distinct proper-ties of the original fabric; when solutions cannot be found, temporary repairs or protection can pro-vide a way of delaying or slowing deterioration orloss until reliable methods have been developed.

The conservation and repair of ruins in the UnitedKingdom and elsewhere is facing a less certain futurebecause the availability of funds in the short and longterm is becoming increasingly limited. New methodsof long-term conservation will need to be found andrecent controversial work has included the reinstate-ment of roofs and wall plaster to ruined structureswhich once depended on these simple elements fordurability.

This chapter will encourage an analytical approachby examining the various methods of undertakingcondition surveys using illustrations of survey workto a range of ruins, including low-lying wall frag-ments, standing rubble walls and complete but roof-less elevations.

Introduction

The intention is not to set down a prescriptiveapproach but to draw on the experience of the authorin undertaking surveys to ruined structures. Architectsand surveyors will create their own approach bearingin mind who will use the survey and always bearing inmind the conservator or crafts people who will bereading the schedule of work or drawings. Could theyidentify the location and scope of the defect easily?The scope and content of the final survey documentscan be tailored to the end user. In many instances

45

Chapter 3

Condition surveys of masonry ruins

Graham Abrey

Opposite page St Lukes. Illustration from the ConditionReport on the masonry facades of St Lukes Church, London(1727–1733), showing extensive settlement and structuralintervention in the form of steel frame bracing, masonry repairand replacement and joint and fracture filling. The ruined churchwas fully adapted to a new use, and the external shell is nowsupported and protected, forming the home of the LondonSymphony Orchestra.

Ch03-H6429.qxd 10/14/06 3:19 PM Page 45

survey documents are prepared without consideringwho will need to use them. Clients, property man-agers and potential funders will not want to read thefull details of the report but wish to obtain a compre-hensive overview which includes cost and time impli-cations and summarises future stages. Consents bodies,conservators, craftspeople and contractors will need tounderstand clearly the detail. For instance, if the con-dition survey is to be used as the basis for a future pro-gramme of work, then those who will be repairing orconserving individual elements are probably the mostimportant.

This chapter is written primarily for the surveyorundertaking the ruin survey and the client intendingto commission a survey by developing a survey brief.

The need for condition surveys

When funds available for the upkeep of ruins andmonuments are becoming increasingly limited, it isparticularly important to be clear about the contri-bution that condition surveys make to the long-term conservation of the site, and where they fallwithin the hierarchy of expenditure.

Condition surveys are a means of:

● Understanding the condition of the monumentat a point in time

● Monitoring conditions over a period of time byreview and analysis of past and present survey data

● Reviewing the success of past interventions suchas adaptation and conservation and repair work

● Understanding the most cost-effective methodsof conserving a monument in the medium andlong term.

Condition surveys are the foundation of long-termconservation in its broadest terms. A history of con-dition surveys, starting with the archaeological excav-ation report and followed by the development ofprogrammes of conservation and possibly adapta-tion, provides for essential understanding of successand failure. On this basis, future maintenance andcare of the site can be progressively refined with the aim of minimising intervention and maximisingcost-effectiveness.

Experience has shown that surveys are frequentlycommissioned without reference or access to amaintenance record; work is often needlessly orinappropriately carried out, resulting in unnecessary

intervention to the historic fabric of the site andwasted resources.

Future sustainability of our historic sites is depend-ent on public support and interest. Many of our his-toric sites are under the guardianship of governmentagencies, local government authorities and non-government organisations (NGOs – charities, trusts,etc.) and unless they can demonstrate real publicbenefit the level of available funds will continue todiminish.

It is important that the aims and objectives of thecondition survey are clearly understood and set downin the commissioning brief.

Stabilising or arresting accelerated decay of the siteis of prime importance, but other objectives such asincreasing legibility, visitor access and commercialopportunities (e.g. as a venue for public functions)may all be necessary and justifiable provided the phys-ical conservation of the site remains of paramountimportance. It is true that without fulfilling the publicdesire to visit the site or capitalise on the site’s earningpotential, the future may be uncertain, but a balancemust be struck which tips in favour of the physicalconservation of the fabric.

The special nature of masonry ruins

Ruins are very special places – they are fragmentaryremains of an earlier culture, civilisation or way oflife that, in most cases, no longer exists. They pro-vide a window for the visitor to look through and to visualise how things had once been. They areoften romantic places which appear impermanentand unspoilt by modern times. They can be a havenfor wildlife, providing homes and sources of foodfor a variety of flora and fauna, often rare and of special scientific interest in their own right(Figure 3.1).

These perceptions and ideals of ruins as natural,unspoilt or romantic places within visitors’ mindsoften create special challenges for the surveyor to leaveintact (Figure 3.2). Most visitors like ruins to remainas ruins and do not wish them to appear clean andnew, or obviously repaired in their appearance.

Ideally, the conservation strategy should seek tomaintain the existing environment and natural bal-ance, but there are occasions when intervention isnecessary for the long-term well-being of the monu-ment; when this occurs, programmes of work shouldbe devised to leave a very light, almost imperceptible,footprint of repair on the site.

46 Conservation of Ruins

Ch03-H6429.qxd 10/14/06 3:19 PM Page 46

Condition surveys of masonry ruins 47

Figure 3.1 Celtic settlement of Chysauster in Cornwall: sites can become home to a wide range of flora and fauna, increasing thediversity of interest and importance.

Figure 3.2 The Great Tower at Guildford Castle in Surrey: ruins are often romantic places which create special challenges for thesurveyor to leave intact.

Ch03-H6429.qxd 10/14/06 3:19 PM Page 47

Recent review of the soft wall capping at siteswithin the United Kingdom1 has generally foundthem to be beneficial (Figure 3.3). This is good newsfor the natural site ecology and will, it is hoped, pro-vide a springboard for botanists and ecologists tobecome more frequently involved in the conservationof ruins and their sites (see Chapter 6).

The conservation and repair of masonry ruinsoccupies a very small and highly specialised sector of

the construction industry with a limited number ofprojects completed annually, restricting the develop-ment and refinement of experience within the indus-try as a whole.

There is an increasing tendency to rebury arch-aeological ruins, since this is the most cost-effectiveway of preserving them. If we are to conserve ruinswithout reburial, we must consider how the remainscan be protected in a cost-effective and sympathetic

48 Conservation of Ruins

Figure 3.3 Soft wall capping has been found to be beneficial for the protection of standing wall remains, enhancing site ecologyand providing a long-term, low-maintenance conservation solution.

Ch03-H6429.qxd 10/14/06 3:19 PM Page 48

way. The reinstatement of missing protective ele-ments, such as roofs and wall plasters, should be con-sidered as part of a long-term strategy.

What makes ruins uniquely vulnerable?

● Ruins usually lack protective elements such asroofs, wall plasters, harling coats, or even theiroriginal facings of stone or brick, allowinguncontrolled water ingress to the core of fabric(Figures 3.4 –3.7).

● Exposure to the weather over prolonged periodswithout the benefit of protective elements oftenleads to decay characteristics which are either notseen in functioning buildings or are hidden andnot easily identified. For example, alveolar wea-thering of stone is often associated with ancientstructures where time and exposure to the effectsof wind-driven sand or salts has created pockets oferosion in the masonry face (Figure 3.8). This pat-tern of decay is not normally associated with oftenyounger functioning buildings and would notnormally be within the experience of a designeror specifier of work to more modern buildings.Water ingress into a wall head over a prolonged

period can create voids through the masonry corewhich have the potential to destabilise the wall andare frequently inconspicuous from visual inspec-tion of the external wall face.

● Ruins frequently lack a maintenance record whichpermits monitoring and review of condition overthe medium and long term.

● Ruins often lack sufficient funding and this fund-ing often fluctuates with changes in political pol-icy and public interest.

● Ruins can be situated in remote locations, whichhinders access to the site and to high-level masonryelevations.

● Ruins may incorporate materials or constructiontechniques which are unusual and outside normalexperience.

● The conservation and repair of ruins cannot con-sist of a single, isolated programme of work, butrequires the same ongoing inspection and main-tenance as any historic building; however, manyprojects are undertaken in isolation without anycommitment to future funding or programmes ofwork. The surveyor must inform the guardians ofa ruin about future site requirements, must seek to

Condition surveys of masonry ruins 49

Figure 3.4 Mourneabbey, Cork, Republic of Ireland: the absence of protective roofs and wall plasters leaves ruined walls vulner-able to uncontrolled water ingress and invasive, destructive plant growth.

Ch03-H6429.qxd 10/14/06 3:19 PM Page 49

achieve long-term conservation objectives withlimited funds, and should encourage guardians tolook to the future by possibly setting up trustfunds or endowments to finance future ongoingmaintenance.

● Conservation and repair of ruins requires an under-standing of specialist conservation techniqueswhich may not be widely employed within theconstruction industry. It is often difficult to find

suitably skilled personnel to undertake the work,particularly if such personnel are to be sourcedlocally, and it is difficult to establish proven trackrecords of success. In some instances establishedconservation methods may not be appropriate, sothe surveyor will need to form new ideas whichshould be centred on site-based investigation andtesting, including mock-ups or exemplars wherenecessary.

50 Conservation of Ruins

Figure 3.5 The West Front of the Priory Church, Newstead Abbey, Nottinghamshire: where protective roof coverings have beenlost and cannot be reinstated, the ruin will often require more frequent monitoring and maintenance than protected elements.

Ch03-H6429.qxd 10/14/06 3:19 PM Page 50

The influence of condition surveys onthe well-being of the site

Condition surveys can be highly influential docu-ments with a profound effect on the future of the site.It is therefore important that the appointment of thesurveyor be carefully considered and based on aproven track record of relevant and successful experi-ence. Selecting a professional practice of repute isinsufficient; it is the individual who will be undertak-ing the survey, preparing the recommendations and

specification that is essential, since this advice willdirectly influence future work (Figures 3.9 and 3.10;also see Chapter 5, Waterlow Park).

Survey should include review and discussion beforefinal recommendations are formed – this is normallyundertaken between co-workers, but in someinstances wider review may be appropriate. Misplacedrecommendations can and have frequently had adetrimental affect on masonry ruins, leading to accel-erated decay and early failure of both original fabricand repairs.

Condition surveys of masonry ruins 51

Figure 3.6 Newstead Abbey: the standing remains of the West Front of the Priory Church. The wall is now exposed on boththe external and the internal elevations, increasing the potential for rainwater ingress and decay. Carefully considered and well-exe-cuted conservation work is required to reduce the maintenance burden, but maintenance and inspection levels of the masonry willalways be comparable to, or exceed, those of a building with protective elements still in place.

Ch03-H6429.qxd 10/14/06 3:20 PM Page 51

Specifying appropriate conservationwork

Policies of minimum intervention should be adoptedwherever possible, but this approach should not beconfused or advocated solely on the basis of idealisticprinciples, but must be tempered with sound prac-tical experience. A balance must be struck and thisneeds to be guided by a developed understanding ofhow the ruin originally functioned within the nat-ural environment as an intact building, and how thisfunction has changed as the building has become a ruin. It is worth noting that in many cases the condition and rate of decay of a ruin stabilised whenthe remaining structure became naturally buried.Archaeological excavation and re-exposure of the ruinin an exposed climate will typically increase the levelsof decay once again.

Historically, buildings were constructed as flexiblestructures using earth, lime or gypsum mortars in acomposite construction which accommodated gradual

movement. It is important that this flexibility bemaintained or reinstated in any repair work. This canoften be achieved by filling and deep tamping openjoints with new earth, lime or gypsum mortars or by grouting voids within the wall with low-strengthgrouts based on hydraulic lime and bentonite. Thereis now a proven track record in using this approach –after all, buildings were historically repaired usingmaterials that were locally sourced and closelymatched the original materials.

Rigid repair solutions which advocate the use ofstainless steel pins set in resin grouts, or reinforced con-crete beams and buttresses are often problematic in themedium and long term since they create localised stiff-ness within the structure, resulting in pressure pointswhich can cause cracking and displacement. Thesemethods have often, in the past, been put forward as a‘minimal intervention’ approach, and at first glancethey may be more localised than grouting or repoint-ing, but once installed they are very difficult to removeor reverse. If some form of localised strengthening is

52 Conservation of Ruins

Figure 3.7 Waterlow Park in London: ruined seventeenth century viewing platform with brick piers, part of a formal garden land-scape. Lack of maintenance to the structure and surrounding garden led to the partial collapse of the wall and loss of the wrought ironscreen and decorative sculpture.

Ch03-H6429.qxd 10/14/06 3:20 PM Page 52

required this can be achieved using more sympatheticmethods. Rigid stainless pins set in resin can be substi-tuted by flexible wire stitches set in a hydraulic limegrout. Reinforced ordinary Portland cement concretewall heads can be replaced, in certain circumstances,by reinforced hydraulic lime concrete. Hard mortarcaps can be replaced with soft, organic wall caps.

Whenever considering recommendations as partof a condition survey it is important to base theadvice on a thorough understanding of the func-tional design of the original building and the influ-ence of decay upon the fabric. Recommendationsmust always be made with the long-term well-beingof the site in mind.

Condition surveys of masonry ruins 53

Figure 3.8 Alveolar weathering of White Mansfield sandstone. The age, weathering, and lack of maintenance and repair over thelifetime of a ruin are often associated with advanced patterns of decay.

Ch03-H6429.qxd 10/14/06 3:20 PM Page 53

The skill and experience of the‘surveyor’

The ideal surveyor of ruined structures would be anarchitect, building surveyor, craftsperson, archaeolo-gist, materials analyst and ecologist all rolled intoone. In reality, there are very few people who haveall these skills. Many competent practitioners may

possess detailed experience in possibly half of thesefields, with some understanding of the other areas. Incertain instances, the surveyor’s skills will need to besupplemented by other consultants, such as ecolo-gists, craftspeople and conservators.

A detailed understanding of building pathology,i.e. the causes and effects of building and materialsdecay, is essential. Condition survey is, in essence, an

54 Conservation of Ruins

Figure 3.9 Waterlow Park: sixteenth and seventeenth century lower terrace garden walls after removal of invasive plant growth.The upper section of the wall had collapsed.

Ch03-H6429.qxd 10/14/06 3:20 PM Page 54

investigation of failures caused by one or a number ofmechanisms which may include: unresolved structuralstresses, missing architectural elements, decay ofmaterials caused by a number of environmental factorssuch as frost, thermal or moisture content functions,surface contamination, poor design, the use of pastinappropriate materials or repair techniques in earlierrepair work, or a change in the local environment.

Success of a condition survey is based on the devel-opment of an analytical understanding of the ruin andits site.

Required skills may include those of:

● Building surveyor – recording and analysis ofdecay patterns

● Archaeologist – to understand the significance andchronology of the site

Condition surveys of masonry ruins 55

Figure 3.10 Waterlow Park: the lower terrace wall following conservation and repair. Condition survey had determined that thelong-term survival of the wall was dependent on reinstating the missing wall head to shed rainwater and protect the brickwork below,but other significant benefits included improved legibility of the structure and enjoyment by the visiting public.

Ch03-H6429.qxd 10/14/06 3:20 PM Page 55

● Historian – an understanding of social and politicalhistory

● Architectural historian – an understanding of styleand detail

● Architect – understanding of architectural formand function but also how best to present andinterpret, appreciate the monument and its site

● Structural engineer – understanding and inter-pretation of structural movement, distortion andcracking of the ruin

● Stonemason, plasterer, artisan● Materials analyst.

The contractor as a consultant

Contractors are a valuable resource which should be used more widely during the survey process.Experienced contractors who specialise in the conser-vation and repair of historic buildings and ancientmonuments can offer practical experience in theimplementation and execution of repair work. Advicecan be given on suitability and application of repairtechniques, site access, programming and completionof the work, availability of resources, and cost budgets.

Early consultation with contractors during the sur-vey process can bring efficiency and focus to a projectby avoiding inappropriate selection of work methodsor impractical programmes and costs.

The use of experienced contractors should not beseen as a challenge to the skill and experience of asurveyor but an added dimension which comple-ments the surveyor’s approach. Advice can be soughton a wide variety of subjects, including conservationand repair techniques, material selection, scope andimplementation of work, feasibility of an approach,costs and programme. The contractor may, forinstance, be a building conservator, an archaeologist,scaffolder or access supplier.

One of the most important and underused areaswhere a contractor can bring invaluable experienceduring the survey process is in site-based investigation.Visual inspection can frequently be enhanced byeither non-invasive or invasive investigation. Evensimple site investigation, such as removing later mortar repointing or a few facing stones, can providea clearer understanding of the condition of the wallcore, for example. Unless the wall core is in a soundcondition there is little point carrying out superficialwork to the external facings.

The contractor’s involvement may be in severalphases, starting with site investigation and moving onto trials to test ideas and feasibility of repair methods,

for example grouting voids within a wall core or con-struction of soft wall cappings to protect exposed wallheads. Development of site trials into a sound andpractical approach, demonstrated by an exemplar ofwork, will enable tendering contractors to see andunderstand exactly what is required.

Expenditure on commissioning a contractor as partof the consultancy team is normally cost-effective andfrequently prevents delays on obtaining consent, ten-dering and commencing work on site. The contractorcan be commissioned either as a subconsultant to thesurveyor or as a direct commission to the client work-ing under the direction of the surveyor.

Understanding the need for andavailability of maintenance work

All structures need to be maintained. The long-termconservation of ruins is dependent on finding a bal-ance between expensive conservation techniqueswhich may be sacrificial, or offer limited short-termdurability and long-term measures such as reinstatingmissing roofs or wall plasters.

Condition survey reports should not simply pro-vide advice for the short term, but should consider thelong-term future of the site. Even if the adviceextends beyond the client brief it is important to atleast plant the seed of an idea or commitment for thefuture with the guardians of the site to bring a realisa-tion and prevent possible unproductive expenditureon short-term measures which may be of limited use.

Prerequisites for a condition survey

Removing plant growth

In all condition surveys, with the possible exceptionof a feasibility study, plant growth should be carefullyremoved as far as possible to reveal the condition ofthe underlying structure. Removing plant growth can,however, involve significant risk to the monumentand to the personnel undertaking the task, so it shouldbe cautiously undertaken with only surface growthremoved. Plant growth within the wall should be leftand only removed as part of the programme of con-servation and repair. In some cases removal will resultin localised collapse. Small-scale plant growth canoften be removed by the surveyor undertaking thesurvey. More extensive growth should be removed in advance of the survey under the direction of

56 Conservation of Ruins

Ch03-H6429.qxd 10/14/06 3:20 PM Page 56

the surveyor (but see Chapters 4 and 6). Natural orintended soft wall cappings, other plant-based protec-tive coverings and plants of special or scientific inter-est should be removed where possible, and reinstatedonce the condition survey has been completed. Insome cases the advice of an ecologist should be soughtand plants only removed under their supervision.

Access

The success and value of a survey often depends sig-nificantly on the type of access available. Good accesswill produce more reliable results than poor or limitedaccess. Access to remote sites can present unique chal-lenges. Access to high-level masonry can be difficultto achieve but without undertaking this work thebenefits of the survey will be greatly reduced. Howaccess is to be achieved should not be left to the sur-veyor who is tendering for the condition surveywork. Methods and possibly the design of site accessshould be predetermined so that genuinely competi-tive tenders are received. Access can be one of themost expensive elements of a condition survey and

differing proposals for access arrangements can distortthe relative cost benefits of tender submission.

Site-based investigation

Site investigation is not normally a prerequisite to acondition survey but may follow an initial feasibilitysurvey which has defined the need for investigationwork, such as trial pits. Reference to archaeologicalexcavation reports, where they are available, fre-quently provides valuable information which mayreduce the need for further investigation work.

Documentary research

Recommendations for future repair and conservationwork should avoid obscuring archaeological evidencewherever possible. The surveyor therefore needs adeveloped understanding of the architectural andarchaeological significance of the structure so thatinformed decisions can be made. Review of past andcurrent archaeological reports is an important part ofthe initial research process and may provide important

Condition surveys of masonry ruins 57

Figure 3.11 Detail of masonry wall at Rushen Abbey on the Isle of Man. Invasive plant growth should only be removed fromthe monument under the supervision of the conservation architect or surveyor to avoid further damage.

Ch03-H6429.qxd 10/14/06 3:20 PM Page 57

information on the condition of the site at the pointof excavation.

Reviewing extant survey reports

Where sites have been excavated some time ago, pastphases of conservation and repair and maintenancework will usually have been undertaken and referenceto this past work is invaluable. Reference to records ofpast survey and repair will help to understand the rateof ongoing deterioration, the success of past repairmethods and any future requirements. However, it isa regrettable fact that post-excavation maintenance issometimes minimal or non-existent, and that recordsmay be sketchy or missing. In these situations experi-ence in recognising past intervention becomes particularly important.

Elevation drawings and photographic records

Condition surveys can produce large volumes of datawhich are difficult to understand. Graphic presenta-tion of survey information by annotating drawings orphotographs is a good way to present a clear overviewof the general condition. Presentation methods andformats of condition surveys are discussed in greaterdetail at the end of this chapter.

Survey limitations

It is important to understand what can be achieved bya condition survey and why it is carried out.Condition surveys cannot provide a totally accurateaccount of the condition and extent of repair workwhich is necessary. They should, however, be ascomprehensive an assessment of condition and scopeof repair as possible to reduce unknown or unantici-pated future failures and expenditure.

Condition surveys rely overwhelmingly on visualinspection and analysis, and to a very limited extenton equipment and scientific analysis. This is why it isso important to commission a surveyor who has aproven and demonstrable track record of relevantexperience.

Visual analysis is, of course, limited to surface evi-dence, but experience recognises and can often inter-pret superficial indicators such as fracturing and localareas of decay. As a survey progresses, the evidenceoften builds up in such a way that accurate predictionscan be made.

Ground-level surveys are severely limited byremoteness from the subject. Using binoculars or afield scope increases the detail which can be seen, butthis remains two-dimensional. Two-dimensionalimages can severely limit perception and understand-ing. On a practical note, holding binoculars for a dayis extremely fatiguing and progress can be slow.

Visual survey becomes much more useful withproximity to the subject. Seeing detail in threedimensions and being able to touch and feel surfacesincreases understanding of the condition very signifi-cantly. Close inspection using access facilities such asscaffolding or aerial access platforms is always desirableand will enable a more accurate understanding of thecondition of the buildings to be reached at an earlystage in the project.

Table 3.1 illustrates the level of accuracy whichmay be anticipated with different survey types basedon field experience. The level of accuracy increaseswith close inspection and site investigation. Wherelower levels of accuracy are achieved, higher contin-gency sums should be allowed for the unknown.

Basic surveys

Ground-level surveys (basic or preliminarysurveys)

A basic survey is a useful tool providing an overviewof the condition of a site, normally as a preliminarystage in a wider programme of survey and investiga-tion. Basic surveys are also frequently undertakenwhere work is carried out adjacent to a ruin, forexample in the construction of a visitor centre, whereit is necessary to record and monitor the condition ofthe ruin before and during construction. A basic sur-vey is typically comparatively inexpensive to under-take and can limit expenditure in the early stages of aproject, which may not proceed further.

Ground-level surveys are often used for a simple(limited) scope of work – for example, to understand

58 Conservation of Ruins

Table 3.1 Typical accuracy of various survey methods

Survey type Level of Level of accuracy (%) contingency (%)

Ground level survey 50 –70 30 –50Close inspection 70 –90 10 –30Close inspection with site-based investigation 80 –90 10 –20

Ch03-H6429.qxd 10/14/06 3:20 PM Page 58

the condition of a single section of a ruined structureand plan for a small package of conservation work.They can also be used where a monument is regularlymaintained and the aim of the condition survey isone of monitoring past repair and conservationwork. For masonry ruins a basic survey is not nor-mally particularly useful because of the limited accessfrom ground level. Budget constraints should notdictate the type of survey; a more appropriate typefor ruins is typically a detailed condition survey, par-ticularly where a programme of conservation andrepair is planned.

Feasibility studies (options appraisal)

A feasibility study, also commonly described as anoptions appraisal, is a useful tool to explore variousoptions for repair, adaptation or presentation of a site.An options appraisal may also be used to investigatethe need for a more detailed condition survey, whichmay include phases of research and site-based investi-gation. The study would normally commence with alimited amount of background research to identify the broad history of the site; this may, for instance,include social history and architectural history.Feasibility studies are useful when considering ways ofprotecting a vulnerable site, or creating new visitoraccess or facilities.

Feasibility studies would normally be undertakenfrom ground level, but closer access can be specifiedin the client brief, dependent again on the projectobjectives.

Example of report content:

● Summary● Client brief – it is always advisable to include the

client brief within the report, since it places thereport in context for future readers who may beunfamiliar with the project

● Historical background – based on research intothe social and architectural history of the site

● Options appraisal – discussion of the variousoptions for repair, alteration, reuse or presentationof the site

● Condition assessment – a broad assessment of con-dition usually based on ground-level inspection,identifying the general levels of decay rather thanspecific detail

● Conclusions – summarising conclusions whichcan be drawn from the appraisal

● Recommendations – recommendations for theway forward.

Optional work can frequently include:

● Budget costs● Reports by other specialist subconsultants, such

as ecology, paint research● Preliminary or conceptual design work.

Property management surveys

Quadrennial and quinquennial surveys

Quadrennial or quinquennial surveys are undertakenon a four- or five-yearly cyclical basis, and are used tomonitor condition and undertake maintenance andrepair work on a planned and preventative basis.They may identify the need for a major programmeof conservation work, but they should not be used to identify or quantify the full scope of defects andmethods of repair which are necessary for pro-grammes of conservation and repair. The format andcontent of quinquennial surveys are normally set outby the property owner, such as local and central gov-ernment authorities and non-government organisa-tions, who have a large portfolio of properties and sitesin their care. Quinquennial survey reports normallyidentify key defects using a descriptive account ratherthan scheduling and quantifying individual defects. Aquinquennial report also normally requires an assess-ment of the progress of decay or deterioration, thesuccess of past repair work and a note of outstandingwork by comparison with the previous survey report.A quinquennial survey regime is very useful for thelong-term management of a site, since it allows prop-erty managers to accurately assess and monitor thedecay of a site and the possible impact of visitors.They are, however, distinct from detailed conditionsurveys, since they do not go into as much detail and do not aim to schedule each and every defect.The report content is similar to a detailed conditionsurvey but would normally exclude a schedule ofdefects.

Comprehensive surveys

Detailed surveys (building survey or fabric survey)

Detailed surveys are normally undertaken when the condition of a site is not well understood, forexample where maintenance records do not exist, or

Condition surveys of masonry ruins 59

Ch03-H6429.qxd 10/14/06 3:20 PM Page 59

where they are vague or incomplete. Alternativelythey are used where a comprehensive programme ofconservation and repair is planned.

Detailed surveys are commonly referred to asbuilding surveys, building fabric condition surveys or fab-ric surveys, and consist of a detailed visual inspectionof all elements of building fabric and frequently itssurrounding site. Comprehensive surveys can alsobe described as a ‘stone-by-stone’ inspection, indi-cating that a high level of detail is required. Sincethis type of survey is intended to be comprehensivein nature, it is normally based on close inspectionusing either scaffolding or aerial access platforms(mobile elevated work platforms). The survey

document would normally include a descriptiveaccount of the condition, the principal defects andtheir causes, and a detailed schedule or tabulatedrecord of individual defects with recommendationsfor repair. The typical report content for a detailedbuilding fabric survey is shown in Figure 3.2. This, ofcourse, would be adapted to suit the monument andits site and the survey objectives. A more detailedaccount of the schedule of defects is included later inthis chapter.

Detailed condition surveys will aim to provide acomprehensive understanding of the condition ofthe ruin, but they can also include further optionalwork, which may be deemed necessary to provide

60 Conservation of Ruins

Table 3.2 Example of the content of a detailed condition survey report

1.0 Report Summary1.1 Schedule of the Structures included in the Survey1.2 Description of the Structures1.3 Construction and Materials1.4 Inaccessible Parts1.5 Summary of General Condition1.6 Recommendations for Further Investigation1.7 Recommendations for Further Specialist Advice

2.0 Description of Defects – Structures2.1 Masonry Walls2.2 Floors2.3 Surfaces Finishes2.4 Protective Structures/Coverings2.5 Past Repairs

3.0 Description of Defects – The Site3.1 Landscape3.2 Invasive Plant Growth3.3 Site Drainage3.4 Visitor Impact

4.0 Description of Defects – Services4.1 Electrical Supplies and Fixed Installations4.2 Fuel Supplies and Heating Installations

5.0 Recommendations5.1 For Immediate Action5.2 For Completion within Two Years5.3 For Completion within Five Years5.4 For Completion within Ten Years5.5 Monitoring Work5.6 Adequacy of Routine Maintenance

Appendices1 Schedule of Defects2 Photographs3 Survey Drawings4 Preliminary Specifications

Ch03-H6429.qxd 10/14/06 3:20 PM Page 60

a comprehensive understanding and to meet clientrequirements.

Examples of optional work include:

● Tabulated record of all defects, including pro-posals for repair and conservation.

● Invasive site investigation involving removal ofstones, mortar joints, etc.

● Non-destructive investigation, possibly includingscanning to detect the presence of iron cramps,thermal imaging to map the pattern/path of wateringress, or ground penetrating radar used in someinstances to detect subsurface voids, for examplehypocaust systems.

● Camera survey and testing of drainage.● Electrical testing of appliances, for example site

lighting, etc.● Material sampling, for example mortar analysis,

petrographic analysis of stone types.● Production of record drawings. Record drawings

are a very useful resource to assist in understand-ing the condition of the monument, to aid inter-pretation, and to record the location and extentof defects.

Schedule of defects

A schedule of defects is simply a tabulated record ofevery individual defect identified by the survey(Figures 3.12 and 3.13). The record would normallycontain the information shown in Table 3.3.

Site-based investigation

Site-based investigation can be very useful to estab-lish methods of construction, to check, validate orclarify theories for causes of decay, or to investigateand establish archaeological evidence. Site investiga-tion can either be invasive (for example, involve tem-porary removal of fabric such as the deconstructionof part of a wall head to reveal the condition of thewall core construction beneath) or non-invasive(such as thermal imaging to indicate the presence ofvoids within a wall). Invasive investigation is fre-quently discouraged in favour of non-invasive inves-tigation but, in fact, carefully thought out invasiveinvestigation undertaken by experienced personnelcan produce much more relevant information andunderstanding, providing a valuable insight into thenature of any repair work which may be necessary.The scope of investigation work must, of course, becarefully controlled to minimise intervention. It is veryimportant that any investigation work be accurately

and comprehensively recorded and the record keptwith the site maintenance file. It is frequently the casethat phases of survey and investigation work arerepeated time after time, without reference to earliercondition survey reports, leading to unnecessarywork and loss of original fabric.

Structural surveys

There are occasions when structural assessmentbeyond the training and skill of the surveyor will be necessary. In these cases a structural engineershould be appointed as part of the condition surveybrief to advise the surveyor and produce a supple-mentary report. The structural engineer, like thesurveyor, should have a demonstrable track record ofrelevant skill and experience, since any repair shouldaim to maintain the qualities of the original con-struction, which are typically flexible structures,quite unlike modern rigid or semi-rigid structures(see Chapter 2).

The timing of a condition survey

Detailed condition surveys should be carried out atthe earliest opportunity, either before project concep-tion or at the start of the project design stage. Detailedcondition surveys should not be left until a contractorhas been appointed to carry out the programme ofconservation and repair or when access scaffolding hasbeen erected for the work. This is far too late and willbring increased risk of delay and cost increase while acontractor is waiting for the scope of work to be con-firmed and access scaffold is erected. It is often arguedthat detailed surveys should be undertaken either bythe designer (surveyor, architect or conservation con-sultant) once access scaffolding has been erected bythe contractor or once the consultant has beenappointed to carry out the conservation and repairwork. This approach is fraught with danger anduncertainty. It is normally much more cost-effectiveto carry out a detailed condition survey as a prelim-inary task before tender documents are written andthe contractor has been appointed.

Analytical approach

Condition survey of masonry ruins has the samefoundations as condition surveys to any form of build-ing or structure. That is, to gain an understanding of

Condition surveys of masonry ruins 61

Ch03-H6429.qxd 10/14/06 3:20 PM Page 61

Figure 3.12 St Luke’s Church in London. An example of a tabulated ‘schedule of defects’ from a detailed condition survey. The schedule formed the basis for a phased programmeof conservation work.

Ch03-H6429.qxd 10/14/06 3:20 PM Page 62

Figure 3.13 The West Front of the Priory Church at Newstead Abbey. For structures with complex decay mechanisms requiring a variety of conservations and repair solutions, tabu-lated schedules of defects can be illustrated with drawings and photographs to assist in conveying information and understanding.

Ch03-H6429.qxd 10/14/06 3:20 PM Page 63

the condition, the rate of decay and relative perform-ance of the materials over time by a process of visualanalysis. Additional analysis can be undertaken using acombination of techniques, such as laboratory testingand comparison of data from a series of condition sur-vey reports, but condition assessment will largely bebased on visual inspection of the building fabric onsite.

An analytical approach leads to a comprehensiveunderstanding of the monument, its condition andits conservation requirements.

The starting point is an understanding of theform and function of the monument. Ideally, thisshould include both architectural and social formand function, its construction, and its history of dis-use and decay. Often, monuments are in a ruinedcondition and gaining an understanding of the ori-ginal form and function is necessary to interpret theircondition and establish the range of conservationmeasures that are appropriate. It is often the case thatmuch of the original evidence has been lost or radi-cally reduced by decay. Cross-referencing similarsites is often necessary.

Analysis of the structural condition of a ruinedbuilding requires a detailed understanding of itsoriginal complete form and how the loss of elementssuch as roofs, vaults, buttresses and towers has influ-enced its current state. Condition survey may deter-mine that some reinstatement of collapsed or missingmasonry is necessary to provide critical support, or

wall head protection to ensure the sustainability ofthe monument.

An analytical approach will provide a detailed,considered awareness of the conservation and repairrequirements. Within the report should always be a summary of the short-, medium- and long-termneeds. If sacrificial treatments are to be used, theexpected life of those treatments and the futurerequirements for inspection, monitoring and main-tenance should be set out.

Approach to the survey of virgin sites

Sites that have not been subject to repair since the midto late nineteenth century, before the advent of artifi-cial Portland cement, are particularly special places,which are becoming increasingly rare in WesternEurope. These sites could be described as ‘virgin sites’because, although repair is commonly present, it isvery likely to have been carried out using local mater-ials and methods which closely match and are sympa-thetic to the original building fabric. It is a greatprivilege to work on these sites, where a great deal canbe learnt for the benefit of the site, the conservation ofmasonry ruins in general, and the surveyor.

Condition survey of virgin sites will often requiredetailed site-based analysis to develop an intimateunderstanding of the original design, methods of construction and materials, and the type, purpose,methods and materials of subsequent repair work.

64 Conservation of Ruins

Table 3.3 Information contained in a schedule of defects record

Item The defect number to permit easy referencing

Location or grid Condition surveys can frequently identify hundreds or thousands of defects so it is impor-reference tant that the location of each individual defect can be easily found by future users of the

condition survey report. See Survey drawingsElement and defect Describe briefly the architectural element, possibly its construction if this adds to the description understanding of the decay character or the method by which it will be repaired and then a

description of the defect and its cause. The description should be succinct and relevant. See Report format

Recommended repair A schedule of defects should always include repair recommendations. It is easier to identify a repair approach at the time of a survey with an informed mind than at a later date when the report has been submitted and subsequent users are trying to identify a repair type

Size and quantity The size of the defect, or the repair, and the quantity should always be included. Unfortunately, many surveys seem to lack this information, reducing their accuracy and worth, creating uncertainty in planning for subsequent work

Comments/additional It is always good to include this extra column for any information that may be relevant to information the individual itemPhoto reference Include the reference number of photographic illustrationRepair priority Include the priority – for example, immediate, within 2 years, within 5 years, within 10 years

Ch03-H6429.qxd 10/14/06 3:20 PM Page 64

A controlled level of invasive investigation is fre-quently beneficial and would include removal of mor-tars for basic analysis on site and possibly moredetailed analysis in a laboratory, removal of loose ordisplaced materials such as stones and plaster frag-ments for analysis and characterisation. Site-basedanalysis will frequently be supplemented by docu-mentary research. It is important that the site berecorded sufficiently to record its special nature, butalso to further contribute to the understanding offuture conservation work.

Approach to previously repaired sites

There are a great number of sites where repair workhas been carried out using cement-based mortars,grouts, concretes, resins and metal reinforcement. Insome cases, these have been successful, or at leastwithin the relatively short time period since therepairs have been carried out. There are, however, asignificant number of sites where modern repairmethods and material have had an adverse effect onthe original fabric. It is important to establish as faras possible the site’s repair history from documen-tary sources before starting the site-based survey.Past survey reports or documents from earlier phasesof repair will provide a better understanding ofwhere and when repair work has been undertakenthan site inspection alone. With all condition surveywork it is important to review the performance ofpast repair work and it is especially important tounderstand the impact of modern repair techniques.After all, modern repair materials and methods havea relatively short history of up to 150 years, whilsttraditional materials and methods and repair workhave a track record of centuries and in some casesmillennia.

It is essential that the condition and performanceof the original building fabric and later repair workbe the basis for developing ideas and recommenda-tions for future conservation work. It is essential toremember that the fabric is likely to have undergonemany centuries of ‘performance testing’ with expos-ure to the environment, plundering and sometimesreuse. This is a significant test which should allowjudgements to be made about the timescales anddurability of the existing structure and new repairwork. We have a comprehensive history of the dur-ability of traditional materials (such as stone andlime), and we should therefore be confident thatnew repair work using lime, earth or gypsum mor-tars and local materials will last many centuries ifcorrectly specified and carried out.

Understanding the significance of sitearchaeology

Conservation of the ruin is not confined to the preser-vation of the ruin or site as a whole, but also includesthe conservation of its detail. During the course of thecondition survey it is important to identify and under-stand the subtleties of detail and their contribution tothe special interest of the site. Buildings’ archaeologyis an intrinsic part of condition survey of ruins andfrequently condition survey will add to the archae-ological understanding of the site.

Recommendations for conservation and repairshould aim to preserve and enhance an understand-ing of a buildings’ archaeology. At times difficultissues arise. Do you cover up or conceal detail fromearlier phases or should you leave it exposed? Whererestoration of detail is required, for example rein-statement of protective wall plasters, possibly essentialfor the long-term sustainable conservation of the site,what do you cover and what do you leave exposed?A balance must be struck based on a developedunderstanding of the site, its archaeology, architec-tural history, its significance and long-term conser-vation needs. In some cases it is preferable to coverup or protect vulnerable detail to ensure its long-term survival, where ongoing or new exposure tothe environment will limit its future survival. Thedifficult question is how long will something sur-vive if it is left exposed and will there be an unsus-tainable maintenance burden?

Developing an analytical approach

Before commencing the survey, prepare a checklistof the subject items to be covered in the survey. Thiswill maintain a logical framework during the surveywith helpful prompts to ensure that all items arecovered. The scope of survey work can seem verycomplex and daunting, but by breaking the surveydown into a series of logical elements or tasks it is possible to work progressively through manage-able sections to develop a thorough and compre-hensive analysis. It is surprising how a pattern ofunderstanding develops when a series of observa-tions link together the causes and effects of decayand the remedial action. Consider using identifica-tion marks or abbreviations in the survey notes tohighlight significant or fundamental points whichneed further investigation during later stages of thecondition survey or detailed discussion in the final

Condition surveys of masonry ruins 65

Ch03-H6429.qxd 10/14/06 3:20 PM Page 65

report. For example, when carrying out the surveya series of questions need to be asked:

● What is the building? What is its date, functionand type?

● How is it constructed?● What are the materials?● What is missing? For example, capping stones,

roof, buttresses, etc.● Which elements are significantly decayed?● Are protective finishes missing, such as plaster or

limewash?● Are structural elements missing?● Are weathering elements missing?● What elements are significantly or dangerously

decayed?● What are the causes of decay?● How have past repairs performed?● What corrective action is necessary?● What conservation and repair techniques are

appropriate?● What repair materials are required?

In general, the construction and architectural formneed to be understood before analysing the type andcauses of decay.

Decay is frequently caused by a combination of factors. Often, there is a primary or root cause andthen several secondary causes or factors. For example,uncontrolled water ingress into a structure is consid-ered a primary cause of decay since, without water,other decay mechanisms such as soluble salt crystalli-sation, freeze–thaw cycles or invasive plant growthwould not occur. ‘Controlled’ water ingress, for exam-ple surface saturation in heavy rain, is normally accept-able provided the water can freely evaporate out of thestructure during warmer, drier weather. Therefore, byaddressing primary causes of decay many secondarymechanisms can be resolved or managed.

The next, often difficult, issue to resolve is howto record the scale or scope of the decay. For exam-ple, if salt-related decay is found in ten areas, shouldthis be recorded as one item or ten separate items?This question can only really be answered by theperson undertaking the survey and the approachwill vary from one site to the next or even from onedecay mechanism to another. In general, it is betterto group the defects together within the writtenreport under a summary of the zones and causes ofdecay, and to record the defects individually withthe schedule of defects, so that future readers maysee the scope and pattern of common defects andalso be able to judge the rate of ongoing decay.

Adopting a methodical approach will provide cer-tainty and confidence. A condition survey reportshould make a substantiated case for interventionwhere it is necessary.

Bite-sized chunks

With large surveys, for example a detailed survey ofa complex of buildings, the survey should be carriedout in ‘bite-sized chunks’. The survey should com-mence with an overview of the whole site for famil-iarisation, but Phase 1 may be limited to a singlebuilding. Once this survey is complete and writtenup, the next building may be surveyed. Managingthe survey process in this way prevents informationoverload, which easily occurs on large surveys dueto the number and complexity of defects. Even largebuildings such as ruined abbey churches or largebathhouse structures should be surveyed in manage-able ‘bite-sized chunks’. If subsequent surveys leadto revision of some initial ideas and proposals, theseearlier surveys can then be amended. Requests tosubmit survey reports in several stages should beresisted, since later surveys and the development ofunderstanding may influence views that have beenexpressed in earlier reports. The report should ideal-ly be submitted as one homogeneous text or a seriesof volumes in one submission.

The ideal condition survey is carried out fromaccess scaffolding, allowing sufficient time for con-sideration and revisiting the site before removing thescaffold. Survey carried out in conjunction with siteinvestigation work will provide better understandingof the condition of the masonry core and otherunseen areas. This will involve careful removal ofmortar joints and isolated stones, and in some casescarrying out trial work such as grouting, to aid theunderstanding of the presence and distribution ofvoids within the wall and assess the potential successof grouting and consolidation work.

Access scaffolding

The accuracy of condition survey is greatly enhancedby close visual inspection. One of the easiest ways of achieving access at all levels across the ruin is toerect scaffolding (Figure 3.14). Scaffolding is veryadaptable and can be constructed to accommodateunusual building forms. With suitable design it canovercome problems encountered with soft ground orobstacles at ground level which need to be bridged.

66 Conservation of Ruins

Ch03-H6429.qxd 10/14/06 3:20 PM Page 66

Scaffolding is a temporary structure which must berestrained to stop it moving, especially with windload, and it must therefore be tied down for stability.Wherever possible, scaffolding should not be tied tothe ruin using physical anchor ties which are drilledinto the masonry nor ties that pass through openingsand clamp to the structure. It is preferable that noloads be transferred onto the monument. Alternativemethods for providing stability and restraint to tem-porary scaffoldings should be considered, such as buttressed scaffolds with Kentledge weight at theirbase or ground anchors to hold down the scaffold.Ground anchors are increasing in popularity sincethey can be permanently installed using stainless unitsthat can be left in the ground and reused in thefuture, although they may have an impact on below-ground archaeology.

Scaffold is effective in providing close access andallows several people to work in one area at a time.The building elevations as a whole are slightly

obscured by the scaffold framework, but this can beovercome with some agility by the surveyor, who attimes may need to crouch or lie down on the scaf-fold to inspect items at platform level. Aerial accessplatforms do not obscure elevations in this way andcan be easier to work with, but they frequentlyallow only a limited number of people to work inthe platform. If drawings are to be produced as partof the survey these should ideally be completedbefore the scaffold is erected, since modern surveymethods using theodolites and electronic distancemeasuring devices or rectified or stereo photogra-phy are much quicker to complete if the elevation isfree of obstructions.

The use of scaffolding is normally limited not bythe ground conditions or access around the ruin, butby the ability of the scaffold lorry to park in closeproximity to the walls where scaffolding will be con-structed. Scaffolding contractors are understandablyreluctant to carry the equipment too far before it is

Condition surveys of masonry ruins 67

Figure 3.14 Rushen Abbey on the Isle of Man. Access scaffolding should be considered as a means of providing close access for acondition survey. The closer the access, the greater degree of accuracy and certainty that can be achieved by condition survey.

Ch03-H6429.qxd 10/14/06 3:20 PM Page 67

erected. Vehicle access to the site is an importantconsideration and will undoubtedly be needed forlater phases of conservation and repair, so temporaryor permanent solutions may need to be put in placebefore survey work commences. On soft ground,temporary roads or trackways formed of purpose-made aluminium panels can be laid down and takenup on completion of the project. Where vehicleaccess is simply not possible, scaffolding equipmentcan be flown in using helicopters.

Aerial access platforms (mobile elevatedwork platforms or MEWPs)

Aerial access platforms are a convenient and usuallycost-effective method of close access. Depending onthe height of the ruin and the distance which needs tobe bridged to reach the ruin (the outreach), machinescan either be self-propelled or mounted on a lorry.Larger machines which achieve greater height andoutreach are normally lorry mounted (Figure 3.15).Aerial access platforms, even small units whichachieve a maximum height of 10 metres, are heavy in weight to counterbalance the load which is lifted.Mobile platforms therefore require a solid levelground (with no risk of subsurface voids) to operatefrom. It is important to anticipate the risk of voids inthe ground surrounding the ruin and preliminarygeomatic surveys using ground penetrating radar orresistivity are advisable if the make-up of the site is unclear. The route across the site must also be reasonably level and firm, otherwise a temporaryroadway will be required.

The key advantage of aerial access platforms overscaffolding is their flexibility, especially the largerlorry-mounted machines. They can traverse obstruc-tions in front of the ruin and even extend up over theruin and drop down the other side to provide accessacross significant areas of vertical and horizontal ele-vations. They can even telescope down barrel vaultsto inspect the underside of the vault, provided thereis access for the platform and boom to safely enter.They avoid contact with the ruin but get closeenough for the surveyor to touch the surface.

Surveys from aerial access platforms often demandgreater discipline when adopting a methodicalapproach, due to the absence of scaffolding lifts, andhorizontal reference points and close proximity tothe building face, which can lead to disorientation.To avoid this, it is often useful to divide the buildinginto horizontal bands following the lines of architec-tural mouldings, such as string courses, band courses,

floor levels (defined by a line of windows), plinths,etc. It can be difficult and sometimes impossible totake this approach when dealing with plain masonryelevations, for example rubble walls without archi-tectural detail. In these instances, orange string linescan be temporarily pinned into mortar joints acrossthe elevation to provide horizontal reference lines towork to. When adopting this approach, set out thelines at two-metre spacing so that they approximatethe position of scaffold levels for ease of reference forconservators who will need to locate the defects dur-ing a later programme of repair. In some cases it willbe easier to survey a wall in vertical bands, but thesurvey data should be translated into horizontalbands in the office when the survey is written up. Inthis case orange string lines can simply be droppeddown the wall face and retained in place by weightsat the top and bottom (bricks or stones).

Ground level

Ground-level surveys provide limited access andtherefore limited ability to identify defects or deter-mine their causes. As far as possible, close inspectionshould be advocated.

Ladders and mobile access towers

Ladders are useful but limited, since they can onlysafely be used by two people, one person supportingthe base of the ladder, and for a limited height. Theyshould not be relied upon to provide detailed inspec-tion above ground level but should only be used tosupplement ground-level observations. Ladders areparticularly problematic on ruin sites due to thenature of the surrounding ground, which is fre-quently uneven or soft, and the greater possibility ofinstability of the masonry at high level.

Mobile access towers can be useful for site-basedinvestigation, but again their use is frequently limitedby the ground conditions.

Tools and equipment

● Clipboard. A4 size for a note pad and checklist, andA3 size for the survey drawings. In wet weatherclear plastic covers are needed to prevent damageand loss of valuable notes.

● Hammer and a few sharp chisels. Removing smallsections of mortar for visual examination and

68 Conservation of Ruins

Ch03-H6429.qxd 10/14/06 3:20 PM Page 68

Condition surveys of masonry ruins 69

Figure 3.15 Lorry-mounted aerial access platforms are frequently the most flexible means of providing access for close inspection.Large machines, which are more than adequate for the height of the monument, provide the additional ability to reach over obstruc-tions in front of the monument and minimise the need to reposition the vehicle frequently during survey.

possibly detailed analysis is often very useful indeveloping understanding of masonry condi-tions. Sharp chisels are also very useful to care-fully scrape away surface soiling or decay toreveal the colour and composition of mortars.Care must be taken and only small quantities

should be removed. Approval from statutoryauthorities should always be sought before remov-ing anything from a protected site.

● Hand-held � 10 magnification lens for site-basedidentification of materials to help build under-standing, familiarity with different materials,

Ch03-H6429.qxd 10/14/06 3:20 PM Page 69

especially mortar types, and for comparison ofmaterials.

● A knife or plasterers’ small tool is useful for carefullyremoving surface debris to investigate joints andvoids.

● Sample bags. It is always advisable to carry a selec-tion of sample bag sizes. They should be sealableand have space for writing a label so that prov-enance can be written directly onto the bag witha waterproof pen.

● Tape measure. A small three- or five-metre-longmeasuring tape is absolutely essential and a larger30-metre tape desirable. A digital ‘measuringtape’ such as a Leica Disto is also extremely useful.

● A torch is essential for looking into dark corners andholes. Head torches are very handy, especially inpoorly lit interiors, since they leave hands free tocontinue writing.

● Camera. Digital cameras are becoming increasinglypopular and allow more efficient and flexible use ofphotographic illustrations with a report or surveydrawings. A good-quality compact digital cameraof at least five megapixels with a zoom lens from 28to 100mm is ideal. Digital SLR with a com-bination of wide-angle, zoom and telephoto lensesprovides even greater opportunities for good-quality illustrations.

● A small waterproof rucksack to keep tools and sur-vey information secure.

● Walking boots or safety boots are essential to protectankles and provide support to feet and legs. Theyalso reduce fatigue, which is a common problemwhen standing and surveying over consecutivedays.

● Sunglasses. Not only desirable, but often essential,since they reduce fatigue and prevent eye strainon sunny days. Surveying light-coloured mater-ials such as limestones, marbles and plaster onsunny days is particularly difficult without good-quality sunglasses.

● Suitable clothing for the particular site environ-ment. Warm waterproof clothes for cold, wet climates. Long light clothing which is sun resist-ant for warm or hot climates and sunscreen. Awide-brimmed hat is absolutely essential in hotclimates.

● Lunch and drinks. This may seem an unlikelyequipment requirement but it is frequently for-gotten and can save a significant amount of non-productive time if it is necessary to leave the sitein search of sustenance. Always take a packed

lunch with plenty of water and maybe a flask ofhot coffee!

● Personal protective equipment. Depending on thecondition of the site, a variety of personal pro-tective equipment is essential. A comprehensivekitbag of safety equipment should always be takenon a survey, including as a minimum: safety helmet,high-visibility vest or safety jacket, safety boots,gloves, eye protection, eyewash, first aid kit, mobiletelephone. For safety reasons it is important thatsite surveys should be undertaken by two people,especially at ruined sites or where access equip-ment is being used. Where sites are safe to allowsurveys by a single person it is advisable to leavean itinerary with an office or home contact andto call in by telephone at regular intervals.

Methodology

It is good practice to develop and use a standardapproach to condition survey. For example, carryout the inspection from left to right, working acrossthe elevation in horizontal bands. Horizontal bandsare ideally two metres high to match the standardheight of access scaffolding, but this is frequentlydifficult to achieve when working from aerial accessplatforms or with ground-level access. In theseinstances use horizontal architectural lines, such asstring courses, window sills and heads to define hor-izontal bands (see Figure 3.16). To assist with iden-tifying the location of defects, vertical grid linesshould be superimposed onto the elevation. Again,these can follow vertical architectural features suchas columns, piers, buttresses or window and dooropenings. On long monolithic wall elevations whichare devoid of architectural features, for example rub-ble stone walls, this is challenging and can only bepractically achieved by dropping string lines downthe façade at predetermined intervals, for example attwo-metre centres.

When surveying wall heads the same approachshould be used but the vertical face of the wall headshould be inspected at the same time, at least to a one-metre zone to assess the condition. Decay of wallheads is seldom limited to the horizontal surface. It isimportant to survey the sky surface and both verticalfaces. It is often useful to inspect the complete wallhead with both vertical faces at an early stage, sincethis will build understanding of overall conditions andprovide insight into decay patterns further down thewall face.

70 Conservation of Ruins

Ch03-H6429.qxd 10/14/06 3:20 PM Page 70

Condition surveys of masonry ruins 71

Survey of low-lying wall remains is undertaken in asimilar way, working systematically along the wall, butthe much lower vertical height can often be coveredin one pass.

Survey of floors is undertaken following the samediscipline of working from left to right and top tobottom. Start in the top left-hand corner and workin bands across the floor. Floors allow greater flexi-bility since you can superimpose a grid line acrossthe floor using either orange string or survey rangingpoles carefully laid onto the floor surface.

Survey drawings

Elevation and plan drawings are an invaluable asset inclearly conveying survey information. As a minimumthey can clarify location by either identification of adefect marked on the drawing or by reference to asurvey grid that has been superimposed onto thedrawing. Annotation of defects onto drawings usingshading and hatching also conveys the condition ofthe building and scope of work that may be required,and is useful in discussions with the client, other con-sultants or a consent-granting body that may not havefirst-hand experience of the condition of the site. Inmany instances it may not be possible to identifyevery individual defect on elevation drawings, sincethe large number would create an overly complex,possibly illegible, drawing. The use of survey grids ispreferable, possibly combined with a separate draw-ing to show the principal decay patterns. Defect ref-erence numbers can also be annotated onto the surveydrawings, but again this frequently creates an overlycomplex or confused drawing. It is also worth con-sidering the cost of annotating drawings. Survey gridsare more cost-effective to produce than detailedannotated drawings and have been successfully usedto direct conservators to defect locations to under-take repairs (Figures 3.16 –3.18).

Where drawings are extant these should be madeavailable to the surveyor before commencement ofthe survey so that they may be prepared in advanceof the site inspection. If drawings do not exist, thepreparation of simple sketch elevations that are notto scale can help to identify defect locations and orien-tate the reader of the condition survey report. Thepreparation of either accurate survey drawings orsketches should be encouraged as part of the condi-tion survey brief.

Annotated survey drawings constitute a valuableaddition to the property maintenance file and are a

useful visual indicator of how the condition of a ruinhas stabilised or deteriorated over time.

Rectified photographs

In the absence of line drawings, rectified photo-graphs of the elevations of a ruin can be used toidentify the location and scope of defects (Figure3.19). In general, they are more useful to superim-pose survey grids onto than for annotation ofdefects, since the level of detail in a photograph canprevent clear identification of individual repairs;they can, however, be used to indicate the generalscope of recommendations, for example locationswhere repair to wall heads is required or whererepointing or grouting of fractures is necessary. Aerialphotographs can be used in place of site plans, espe-cially where low-level wall remnants exist.

If rectified photographic elevations exist as wellas line drawings, the surveyor will benefit fromusing both, since the photographs will provide avisual record of the appearance of the ruin at a point in time.

Where the production of survey drawings willform part of the client brief for a condition survey,it is also useful to consider commissioning rectifiedphotography as part of the drawing production.Rectified or stereo photography can reduce the timeneeded on site to obtain survey data by reducing theneed to take levels and survey targets across the ruin.Scaled line drawings are then produced by tracingover the rectified photographic image, which isimported into a computer-aided design package.Greater accuracy is achieved by specialist surveyingcompanies using stereo images that are accuratelytraced over using a combination of specialist machinesand software.

Three-dimensional scanners have also broughtsignificant benefits to the production of scaled linedrawings and are becoming increasingly accurateand capable of identifying points in space on a 10 mm � 10 mm grid. They can also providethree-dimensional models that illustrate distortionand lean in ruins and surrounding typography,which in the right circumstances can bring valuableclarity to the condition of the ruin in the local envi-ronment. These models can also be developed to aidpresentation of the site to visitors.

Where digital data is produced this should alwaysbe supplied in a format that is commonly used, suchas AutoCAD.dwg format or .dxf format.

Ch03-H6429.qxd 10/14/06 3:20 PM Page 71

Figure 3.16 Newstead Abbey West Front. An example of a condition survey drawing overlaid with grid lines to locate defects within a small, identifiable area. The plan layout ofthe finials has also been added to the drawing so that each grotesque sculpture can be numbered and referenced.

Ch03-H6429.qxd 10/14/06 3:20 PM Page 72

Figure 3.17 St Luke’s Church in London. A condition survey drawing with grid lines. In this example key defects have been annotated into the drawing to convey the scope ofrepair. Blue shading represents areas of stonework which are well bonded to the brick structure behind. Areas of white represent voids behind the stonework which require grouting. Thetower was not included in the sway of masonry voids.

Ch03-H6429.qxd 10/14/06 3:21 PM Page 73

Figure 3.18 Waterlow Park in London. Simple elevation drawings have been done by hand to assist in conveying the scope and nature of defects identified in the condition survey.The drawing was prepared based on basic site measurement and photographs.

Ch03-H6429.qxd 10/14/06 3:21 PM Page 74

Condition surveys of masonry ruins 75

Figure 3.19 Guildford Castle. Rectified photographs can be used in the absence of elevation drawings.

Ch03-H6429.qxd 10/14/06 3:21 PM Page 75

The survey process

Survey preparation

● Preliminary site visit. It is always advisable to com-plete a brief site visit before commencing the sur-vey. This is normally essential to cost survey work,but a preliminary visit is essential in understandingaccess requirements or restrictions, and the generalapproach to the survey.

● Research. Review of extant condition survey reportsand archaeological papers and reports before commencing the survey provides backgroundunderstanding. Archaeological excavation reportsare particularly useful, since they frequently pro-vide a baseline of condition to understand the rateof decay of the buildings.

● Drawings. Obtain drawings of the site in advanceof the survey so that working drawings may beprepared for use on site.

● Identify source and availability of materials. It is notalways possible to identify the construction mater-ials before commencing the site survey but it canbe useful, especially if the original materials are nolonger available, since this may influence theapproach to repair which is developed during thesurvey.

● Prepare survey record sheets. Record sheets used torecord survey information should be prepared inadvance, particularly tabulated record sheets for aschedule of defects.

● Backup records. Always take at least one spare setof record sheets, drawings and notebook.

Becoming familiar with the site

On arrival at the site, time should always be madeavailable to understand its layout and complexities.Becoming familiar with the site may take anythingfrom several hours to a few days, depending on thescale, during which time notes and photographs needto be taken while an understanding of the site isdeveloped.

Report format (content)

When writing the report it is important to bear inmind who will read it.

The readership of a condition survey report canbe very broad, so it is important that it be written as a comprehensive technical appraisal in a clear

digestible form. Technical language may be used but this should be defined and explained so that thedocument may be understood by a less informedreader. It is advisable to use photographic and sketchillustrations to convey or illustrate information in areadily digestible form (Figure 3.20).

The report should be written using concise lan-guage. The subjects should be set out in short para-graphs, numbered for ease of reference. Headingsand subheadings should be used to break up the textand permit speed reading and quick location of rel-evant information.

76 Conservation of Ruins

Example of a condition survey report

text illustrating the use of short para-

graphs with number referencing

Abstract – survey report

Granite walls3.2.1 In general, the granite walls are in sta-

ble condition, but past repointingusing cement-based mortars has pro-moted increased levels of decay byreducing the ability of water to evapo-rate out of the walls. It appears that the external elevations of the churchand tower were repointed during theearly 1930s by a local contractor. Inmany areas the repointing appears to be stable, but close inspection revealsperimeter detachment of the mortarfrom the granite with shrinkage andmovement cracking. The completerepointing of all external granite masonrywith a mortar based on hydraulic limewill be necessary to reduce long-termdecay and permit the joints to ‘breathe’(Photographs 11 and 12).

3.2.2 Some structural cracking has occurred,particularly around building corners,but reference to past condition surveyreports suggests this is a long-standingdefect. A structural engineer should be consulted to determine the cause of cracking and approve the scope of repair proposed here, as well as toadvise whether any further measuresare necessary. It is recommended thatfracturing in the masonry walls bemonitored to confirm if movement hasstabilised.

Ch03-H6429.qxd 10/14/06 3:21 PM Page 76

Figure 3.20 Graphic illustrations greatly improve the ability to convey information in a survey report. It is advisable for the writer of a condition survey report to put himself or her-self in the place of the reader – can the text be clearly understood?

Ch03-H6429.qxd 10/14/06 3:21 PM Page 77

78 Conservation of Ruins

Formatting styles, such as variation of font types,styles or sizes, should be used to aid clarity and legi-bility. If the text appears less dense and is brokendown into digestible pieces, this will help the readerto understand and assimilate the information.Illustrations can help to summarise information.Use of bullet points to emphasise or summarise keyinformation or conclusions is also helpful.

Survey documents which will be archived for thelong term should be printed on archival qualitypaper. Drawings for archiving should be printed onpolyester film. Digital copies of the report on popu-lar and accessible file formats such as Adobe pdfshould be provided.

Writing a survey or client brief

The survey brief should be a clear, logical and concisebriefing document. It should set out the aim andobjectives which are to be met by the survey. Thetype of survey and methods for undertaking the workshould be broadly outlined with the intended accessarrangements. Alternatively, the client might seekproposals for access arrangements from the surveyorstendering for the work, but this should be discour-aged to prevent disparity between the tender submis-sions. In practice, it is far more effective if a decisionhas been made about the preferable methods andarrangements for accessing the site and work face inadvance. This will avoid ambiguity in the fee tendersubmissions that are received and will permit com-parison between the tender submissions.

It must be stressed that tenders should only besought from practices or individuals which have aproven track record of experience. Speculativeenquiries to companies of unknown experience willbring a high degree of risk to the client and will oftenbe less cost- and time-effective.

Below is an illustration of the typical content of aclient brief.

Example of report text illustrating the

use of formats and bold text titles to

assist with speed reading

Abstract – Survey Report

PRE-CONTRACT WORKThe following items of work should be com-pleted as a prerequisite to carrying out eachphase, to ensure smooth and cost-effectivemanagement:

1. Preparation of a Scaffold Design.Scaffolding costs represent a significant partof the project costs and can vary consider-ably depending on the way in which scaf-folds are constructed. For a contractor toaccurately cost scaffolding provisions theymust be fully informed of any restrictionsthat will be placed upon them when work-ing on a site protected as a scheduledancient monument. English Heritage nor-mally requires scaffold structures to be freestanding without relying on support orrestraint from the scheduled monument.To ensure that each contractor prices a sim-ilar proposal and that pre-agreed scaffoldingarrangements are followed, it is recom-mended that an experienced scaffold engin-eer be appointed to prepare a suitabledesign for inclusion in the tender docu-ment. Advanced preparation of the scaffolddesign will also minimise any risk of delaysat the start of the project whilst scaffoldingissues are resolved.

Example of typical content of a client

brief

Client aim● To understand in detail the condition of the

ruined structures on the site and the needfor maintenance and repair during the next10 years.

Survey objectives● Identify the need for emergency repairs to

prevent risks to health and safety and toavoid significant loss to the building fabricin the immediate future.

● Identify the need for further repairs tominimise decay and prevent further loss ofthe building fabric during the next 5–10years.

● Identify a long-term approach to sustain-able conservation of the site over the next20 –50 years.

● Comment on the success of past repair andmaintenance work, and make recommen-dations for any modification or change inapproach.

Ch03-H6429.qxd 10/14/06 3:21 PM Page 78

Condition surveys of masonry ruins 79

● Provide a budget for each phase of recom-mended conservation and repair, and iden-tify if there is any financial benefit inbringing forward future phases of work toform a single project.

● Prepare a specification for conservationand repair methods and materials to assistin obtaining statutory consent for futurework.

The siteProvide a brief description of the site and itshistory, initially as a functioning building andsubsequently as a ruin. The statutory listing orprotection of the site should also be identifiedand a copy of the listing/scheduling documentincluded.

Background informationExtant archaeological and condition surveyreports should be listed and made available,together with drawings and rectified photo-graphs. If a maintenance regime is in place,details should also be provided.

Survey methodThe type of survey and access methods shouldbe set out. For example, the survey is to bebased on close visual inspection from accessscaffolding, which will be installed by theclient to each building elevation and madeavailable for the surveyors use for a period of6 weeks. If a scaffolding design has been pre-pared this should be sent to the surveyor forinformation.

It is difficult to determine the need forinvasive or non-invasive investigation work inadvance, but the client brief may request thata provisional sum be allowed. The cost valueof the provisional sum should be stated in thebrief.

The need for any laboratory-based analysiswork should be identified, for example mor-tar disaggregation or microscopy. Again, theobjectives of this work should be identified. If the need for specialist analysis is unclear, a provisional sum could be stated in the brief.

Survey scopeThe scope of the survey work should be iden-tified. This can normally be summarised inone or two brief paragraphs, followed by a listof building and site elements which areincluded. For example:

● ‘Carry out a detailed condition survey ofall standing masonry ruins within the siteconfines as defined on the enclosed draw-ing IC-22024-SPL-01-00. It is the inten-tion of the survey to identify all visibledefects to the masonry construction. Thesurvey is to be based on a combination ofdetailed inspection from scaffolding towersand ground-level inspection in all remain-ing areas where scaffolding is not located.Where ground-level inspection is carriedout it is anticipated that the surveyor willuse the experience gained from areas ofdetailed inspection to reasonably predictthe probable condition and scope of repairwhich can be anticipated.’

Access arrangementsIf complex access arrangements are necessary,it is advisable to set these out in a separate sec-tion, with a description of the specific type ineach location.

Appropriate skill and experienceA proven track record of experience shouldalready have been established before the clientbrief has been sent to the tenderers, but it isadvisable to request that the individuals whowill undertake the work be identified in thetender submission and that a curriculum vitaebe provided.

ProgrammeA programme for the work should be iden-tified. This may include the start date, theperiod for completing the site-based surveyand the date for submission of the completedreport.

Survey reporting (deliverables)The condition survey is to be presented as an A4 format bound document with colour

Ch03-H6429.qxd 10/14/06 3:21 PM Page 79

80 Conservation of Ruins

Reference

1. Wood, C. (2005). Soft Capping: Justifying A Return tothe Picturesque. Context No. 90, July.

Sources

Abrey, G. (2000). The Terraced Garden Walls of WaterlowPark. Report on the condition of the brick terraced garden wallswith recommendations for conservation and repair. Prepared forLondon Borough of Camden, Parks and Open Spaces(unpublished).

Abrey, G. (2002). The West Front of the Priory Church,Newstead Abbey: Report on the condition of the Priory Churchwest front with recommendations for a phased programme of con-servation and repair. Schedule of Defects. Prepared forNottingham City Council (unpublished).

Abrey, G. and Woolfitt, C. (2004). Kirby Hall. Analysis and interpretation of the great stair. Prepared for EnglishHeritage (unpublished).

Abrey, G., Ashurst, J. and Woolfitt, C. (1999). St Luke’sChurch. Report on the condition of the masonry façade with rec-ommendations for conservation and repair. Prepared for StLuke’s Centre Management Company and LevittBernstein Architects (unpublished).

Abrey, G., Ashurst, J. and Woolfitt, C. (2002). The WestFront of the Priory Church, Newstead Abbey: Report on thecondition of the Priory Church west front with recommendationsfor a phased programme of conservation and repair. Preparedfor Nottingham City Council (unpublished).

Ashurst, J. (1999). St Molagga’s Church. Preliminary conditionassessment of standing masonry ruins. Prepared for CorkCounty Council (unpublished).

Ashurst, J. (2000). The Knights Hospitaller’s Church ofMourneabbey. Report and recommendations on masonry conservation and protection. Prepared for Cork CountyCouncil (unpublished).

Ashurst, J. and Burns, C. (2000). Guildford Castle Arch. Siteinvestigation and repair exemplars for conservation of sandstoneand chalk. Prepared for Guildford Borough Council(unpublished).

Ashurst, J., Woolfitt, C. and Abrey, G. (2000). GuildfordCastle Keep. Report on the condition of the masonry with recommendations for a future repair and conservationstrategy. Prepared for Guildford Borough Council(unpublished).

Ashurst, J., Woolfitt, C. and Abrey, G. (2000). ClarendonPalace. Proposals for masonry consolidation. Prepared for aprivate client (unpublished).

Ashurst, J., Burns, C. and Hanna, S. (2002). CharnelHouse, Spitalfield. Description of proposed repair, con-servation and protection. Prepared for English Heritage(unpublished).

Swallow, P., Dallas, R., Jackson, S. and Watt, D. (2004).Measurement and Recording of Historic Buildings. DonheadPublishing.

photographic illustrations. The report shouldclearly and concisely summarise any identifieddefects using numbered paragraphs for ease of reference. The report should contain thefollowing sections. The report recommenda-tions should include a summary of costs foreach recommended phase. Four copies of thebound report should be submitted togetherwith one digital copy in Adobe pdf format.Photographic images should be provided asTIFF files to a 300dpi resolution.

1.0 Report Summary1.1 Schedule of the Structures included

in the Survey1.2 Description of the Structures1.3 Construction and Materials1.4 Inaccessible Parts1.5 Summary of General Condition1.6 Recommendations for Further

Investigation1.7 Recommendations for Further

Specialist Advice

2.0 Description of Defects – Structures2.1 Masonry Walls2.2 Floors2.3 Surfaces Finishes2.4 Protective Structures/Coverings2.5 Past Repairs

3.0 Description of Defects – The Site3.1 Landscape3.2 Invasive Plant Growth3.3 Site Drainage3.4 Visitor Impact

4.0 Recommendations4.1 For Immediate Action4.2 For Completion within Two Years4.3 For Completion within Five Years4.4 For Completion within Ten Years4.5 Monitoring Work4.6 Adequacy of Routine Maintenance

5.0 Schedule of Defects

6.0 Photographic Illustrations

7.0 Annotated Survey Drawings

Ch03-H6429.qxd 10/14/06 3:21 PM Page 80

Viles, H., Groves, C. and Wood, C. (2002). Soft WallCapping Experiments, English Heritage Research Trans-actions, Volume 2. Stone.

Watts, D. and Swallow, P. (1996). Surveying HistoricBuildings. Donhead Publishing.

Woolfitt, C. and Burns, C. (2000). St Michael’s ChurchTower, Gloucester. Report on salt contamination of the masonry

with recommendations on remedial measures. Prepared forGloucester City Council (unpublished).

Woolfitt, C., Ashurst, J. and Stewart, J. (2002). BeauportPark Roman Bath House. Appraisal of conservation options.Prepared for Beauport Park Archaeological Trust(unpublished).

Condition surveys of masonry ruins 81

Ch03-H6429.qxd 10/14/06 3:21 PM Page 81

Ch04-H6429.qxd 10/17/06 2:40 PM Page 82

We don’t believe in ‘restoration’. We have no cogni-sance of that word … If we had attempted to carry out‘restoration’ instead of spending the few thousands perannum which we have spent, we should have spenthundreds of thousands and ruined the historic characterof the monuments.

(Sir Frank Baines, Office of Works, 19211)

The living, historic building must be repaired tokeep it habitable and secure, so that even whenminimum works are carried out there are alwaysaspects of restoration involved. The ruin is different;its partial destruction and the reasons for thatdestruction are part of its story, to be conserved. Onan untouched site, the conservation team are ‘first atthe scene of the crime’. The exact way walls arefound and the arrangement of fallen material areimportant to record and to preserve if the story isnot to be altered for future generations. Even sitesonce consolidated can still, to the observant eye,contain evidence not previously noticed or under-stood, evidence which can be secured and madelegible for the first time. The study and conserva-tion of ruins is truly a specialised discipline and art.

In what is now the United Kingdom, an Act ofParliament in 1882 established, for the first time,some legal protection for its important ruins, describedas ‘ancient monuments’. Although these were initiallyprimarily prehistoric monuments, the scope was soonto increase. Most importantly, the Act was the begin-ning of an Inspectorate of Ancient Monuments,whose duty was to report on the condition of

monuments and to advise on the best methods ofpreserving them. An initially slow advance of aware-ness and concern was significantly changed with theappointment of Charles Peers as Inspector in 1910,10 years after the death of the first Inspector, GeneralPitt-Rivers. A one-time architectural editor of theVictoria County Histories, he contributed much tothe first inventory of the English Royal Commissionon Historic Monuments, began a process of system-atic recording and reporting, and established a spe-cialist works division for the repair and maintenanceof monuments under the architect Frank Baines.Most importantly, Peers was concerned with estab-lishing specific common standards for the mainten-ance of monuments in State care. In particular:

… maintenance must avoid, as far as possible, anythingwhich can be considered in the nature of restoration, to donothing which could impair the archaeological interest ofthe monuments and to confine themselves rigorously tosuch works as may be necessary to ensure their stability,to accentuate their interest and to perpetuate their exis-tence in the form in which they have come down to us.2

In legislative terms, a philosophy of ‘preserve asfound’ had formally and officially arrived. True, itwas not new and had been advocated since at leastthe middle of the nineteenth century. For instance,in 1856, Philip Hardwick, architect of the EustonArch, reported to the Office of Works:

In repair of any old structure the first object to be gainedis to arrest the progress of decay without altering in anyway the character or features of the building. Therestoration of an ancient fabric, without bearing inmind this rule, usually ends in its destruction as a workof interest and study. There is nothing that requiresmore judicious skill on the part of the architect than thetreatment of a ruined building in this respect and in thefirst place I would recommend, at any rate, a partialremoval of the ivy that has grown over the walls. Themischief that creepers do whose roots have the power ofpenetrating walls cannot be exaggerated … The wallsshould then be carefully examined, loose stones be

83

Chapter 4

Philosophy, technology and craft

John Ashurst and Colin Burns

Opposite page Glastonbury. The 12th century north portal of Glastonbury Abbey, UK, illustrates the survival ofimportant sculptural detail in the context of a ruin and the par-ticular care that is needed in recording, condition monitoring, andcarrying out periodic treatment. The orders of the portal still have evidence of polychrome. Soluble salts (mainly chlorides andnitrates), are present in the joints, and there are fissured gypsumcrusts on much of the detail. Periodic poulticing and reversiblelime mortar repairs and crack fillings form the principal mainte-nance interventions.

Ch04-H6429.qxd 10/17/06 2:40 PM Page 83

fixed in their places and settlements stopped. Where thecoping stones remain in situ they should be firmly secured,and when they are destroyed, as is generally the case,the upper stones should be set in their places where theyare found and means taken to prevent water resting on

the top of the wall and soaking into it. Wherever largeapertures exist or where wrought masonry such as win-dow heads etc. have fallen out, they may be restored toprevent further dilapidation, but, in general, it is notdesirable to make any restoration of work which is

84 Conservation of Ruins

Figure 4.1 The west front of Tintern Abbey c. 1860. This view is typical of the ‘romantic ruin’ which caught the imaginationof Wordsworth and other poets. The heavy ivy mantles conceal the potentially disastrous development of several major structural prob-lems, including the collapse of the south wall of the nave.

Ch04-H6429.qxd 10/17/06 2:40 PM Page 84

merely decayed and not likely soon to become loose, fallout or otherwise injure the rest of the fabric.

One hundred and fifty years later, English Heritagestill seek to follow the same guidelines.

But the pioneering work of the Office of Workswas often the subject of considerable criticism andacrimony. Entrenched romantics, defenders of the‘ivy-mantled tower’, resented the heavy hand of offi-cialdom and, at least in some cases, believed thatarchitects and stonemasons of the right calibre coulddevise solutions and produce results in a far moretraditional and sympathetic way than an Office ofWorks engineer. Much of the opposition to thework being carried out at some of the first sites suchas Tintern Abbey was based on a confidence bred ofsound training and experience in the repair of trad-itional buildings. But the Office of Works’ innovativeuse of concrete and steel to ‘preserve as found’ was,in many cases, the only way to retain broken struc-tures in perilous conditions, and history has largelyvindicated the action of its pioneer architects, engin-eers and masons. There is little doubt that withouttheir ingenuity much of what survives today wouldhave been lost; moreover, their achievements wereremarkable in being largely undetectable on com-pletion. Where criticism can sometimes be justlymade is in matters of detail, and then only with thebenefit of hindsight. We know, now, that masonry isnot well served by deep-tamping and grouting incement-based material and that concrete pouredagainst the tails of ancient stones can create stress anddamage to the fabric it was intended to save. In truthit can be said, however, that we have learnt morefrom the experience of the old Office of Works thanthey might have learned from us, three-quarters of acentury later.

A study of the conservation of the Cistercian Abbeyat Tintern, one of the earliest sites to benefit frommajor ‘secret’ structural intervention, is informativeand illuminating of the determination of a fledglinggovernment body to implement a philosophy ofpreservation without restoration, and of the ingenu-ity and imagination of the engineers and architects ofthe time.

Tintern Abbey is picturesquely set in the woodedWye valley of South Wales, built over a period ofsome 50 years, commencing in 1269. Following dis-solution in 1535 it was, as was usual, stripped of itslead roof covering shortly afterwards, thus beginningthe slow process of decay and eventual collapse of itsroof, vault and tower, and the mantling of its walls in ivy. The romantic appeal of Tintern was much

enhanced by artists and writers of the eighteenth andnineteenth centuries, and it was this legacy whichseemed, to critics of the Office of Works (and therewere many) in the early twentieth century, to be soneedlessly and carelessly degraded.

William Woodward wrote to the Daily Express inJuly 1921:

It is acknowledged that Tintern was the loveliest of ourruined abbeys, and so it is upon this particular ruin thatthe Office of Works has bestowed its benign influence.It has not been satisfied by the unnecessary strippingthe walls of their ivy and wild roses, but it has intro-duced its favourite steel and concrete work as if it werecomplying with a London County Council DangerousStructures Act.

But the ivy canopies were not only concealing butcontributing to the further demise of the ruinedbuildings. Frank Baines was very positive on thesubject and is famously quoted as saying:

There is no more pernicious weed in the country than ivy.I once used to go about with a small saw, and wheneverI saw ivy I cut its throat.3

One of the first structural analysts of the substantialruins of Tintern at the time of the First World Warwas William Harvey, whose studies of Tintern,Rievaulx, Westminster and St Paul’s Cathedral werepublished by the Architectural Press in 1925,4 advo-cating the essential practice of knowing the wholebuilding to understand its movements and the rea-son for distortion and fracturing. Two major areasof concern were identified at Tintern, once the ivywas removed. The first was a progressive westwardmovement of the north chancel wall, towards thegreat arch of the missing tower and the overhangingbroken end of the north arcade of the nave (Figure4.2). Local repairs were not able to contain thiswestwards movement, as the north-west pier distortedand developed a pattern of fine stress cracks. Thedrift of its masonry piers in the chancel to the westcould only be restrained by the installation of thereinforced wall head beams shown in Figure 4.3. Thecorbelled masonry of the nave arcade could only besupported by the installation of the steel ledgersshown in Figure 4.4b.

The second major potential collapse was of thesouth wall of the nave. There it was found that thehead of the wall, at its centre point, had a lean to the north of just over half a metre. The instability of the wall was confirmed by cracking patterns. Twooptions to correct the problem were considered:either to replace temporary timber shoring on the

Philosophy, technology and craft 85

Ch04-H6429.qxd 10/17/06 2:40 PM Page 85

north side erected by the Office of Works, withmasonry buttresses, or to devise a method of tyingback the head of the walls. This second option wasselected both for reasons of avoiding visual intrusionin the nave and through fears of possible settlementof massive buttresses which would exacerbate theproblem.

The proposal to tie back the wall head was madedistinctly more feasible by the presence of a southaisle which once had a single pitch roof. Replacementof this roof, whose line was clearly evident at east andwest, would enable a system of reinforcement to beintroduced. A lattice girder was installed to restrainthe nave walls and bolted through the nave wall with-out attempting to correct the distortion. The latticegirder was finally covered with oak rafters and tile-stones, leaving the soffit exposed. A secondary oper-ation involved the substituting of the heavy timbershores with brick masonry supports to enable theshattered masonry of some of the piers to bestrengthened by cutting out and inserting steel stan-chions within the core of the nave piers; the steel wassubsequently concealed by replacing original stones,or new stones where the originals had been shat-tered, and the brick supports removed.

These were the engineering works that so enragedWilliam Woodward and others in the 1920s, but illus-trate the ingenuity and care which were taken to

transform a dangerous structure into a stable ruin. Acertain pride developed based on the ability of archi-tects, engineers and masons to execute major andminor works that were subsequently not easilydetectable. Other major sites that received earlystructural attention and general masonry consolida-tion were the abbeys of Jedburgh, Furness, Rievaulx,Whitby, Byland and Netley, and the castles ofCaernarvon, Kirkby Muxloe and Goodrich. It wason such illustrious sites as these that the ‘AncientMonuments’ team of professionals and craftsmen cuttheir teeth and developed considerable expertise.Undoubtedly there was, and remained, a criticalbenefit in accumulative experience of the group andits continuity between and after the two world wars.While adverse criticism may be levelled, sometimesjustly, against directly employed specialist worksteams, there is little doubt that they have a distinctadvantage over contractors in becoming familiar withtheir historic sites over many years and in knowingthe techniques and standards required. In the absenceof any such in-house team of expertise, the provisionof adequate specialist training for architects, survey-ors, archaeologists, engineers and craft techniciansbecomes even more important. This subject isaddressed in Chapter 8. Based on review and studyof the many pioneering works in monument con-solidation, which were practical interpretations of

86 Conservation of Ruins

Figure 4.2 William Harvey’s drawing of the north chancel wall showing the drift of the masonry to the west.

Ch04-H6429.qxd 10/17/06 2:40 PM Page 86

Philosophy, technology and craft 87

Figure 4.3a William Harvey’s elevation and plan showing the proposed installation of reinforced concrete wall head beam linkedto a ring beam at the head of the tower.

Figure 4.3b Reinforcement of the corbelled masonry of the broken nave arcade.

Ch04-H6429.qxd 10/17/06 2:40 PM Page 87

conservation philosophy and which, at a majorstructural level, are illustrated in Figures 4.2– 4.4,certain disciplines and methods have been developedin the approach to the ruin sites which can now bedescribed.

Context and definitions

The most often repeated phrase in historic fabricconservation must be ‘conserve as found with min-imum intervention’.

‘Conserving as found’ is, of course, a philosophywhose implementation is governed, at least in part,by the nature and condition of the site, but it shouldinfluence every decision and remain as the ideal goal.In particular, essential conserving works should neverintroduce speculative restoration, or damage or alterevidence of the original buildings, or conceal thecause and character of their past deterioration andcollapse.

‘Minimum intervention’ is the other familiarguiding principle for conservators of ruins, as forconservation of more complete historic buildings.Unfortunately, fundamental as the principle is, ‘min-imum intervention’ cannot always mean doing verylittle, and a virtue should not be made of it wheremore serious intervention is actually needed. Largelyworthless, low-key interventions are really onlyplacebos, and may be illustrated by, for instance, thetamping and pointing of fractures without analysingthe cause of fracturing, or installing an anchor withina crack or a bulging wall when what is needed is aprogramme of recording, taking down and rebuild-ing ‘as found’.

Difficulties arise in two common ways. The firstmay be illustrated by a scholarly, theoretical demandthat everything should be ‘conserved as found, withminimum intervention’, which is partly or largelyignorant of the materials or construction and thedynamics of an impending collapse. The second may

88 Conservation of Ruins

Figure 4.4a Tintern Abbey - North west pier showing timbershoring under broken nave arcade. This overhanging masonry wasrepaired in the manner shown in Figure 4.4b.

Figure 4.4b

Ch04-H6429.qxd 10/17/06 2:41 PM Page 88

be illustrated by an ignorance of any real belief inconservation principles, coupled with preconceivedideas of how standard building repair solutions willresolve the problem. The combination of both atti-tudes, which again is not uncommon, is inevitablydamaging for the site where they meet.

Research into, and monitoring of, conditions foundon ruin sites are often desirable and are sometimesessential. The benefit of a multi-disciplined team withcontinuity of experience is that information is collec-tive and the risk of unnecessary duplication is avoided;but the individuality of ruin sites is such that there isalways likely to be an element of investigation andtreatment trial, most commonly in the design of mor-tars and often in the monitoring of fractures.

Structural archaeology

The informed, visual examination of any structure,but particularly an historic ruin, will usually enablesome, and perhaps a great deal, of its building his-tory to be deduced. This kind of examination wasdescribed by the late Patrick Faulkner as ‘structuralarchaeology’.5 The process is multi-disciplinary, and inthe first stages architect, surveyor, engineer, archae-ologist, historian and materials scientist may all beinvolved. In the later stages the ‘conservation tech-nicians’, those who must unpick, clean, consolidateand stabilise, are always also involved; in fact, theyare often the first to see anything not immediatelyexposed on the surfaces. This is one of the manyreasons why their role is so important and so demand-ing of training. They are in a position both to revealand illuminate or to destroy.

Structural archaeology is quite distinct from struc-tural analysis, which is based on a study of the struc-tural content and condition as described in Chapter 2;its evidence is final and incontrovertible, overridingeven archival record. Typical features occurring andto be looked for in the ruined structure may be listedas follows:

● Straight vertical joints● Toothed joints● Random joints● Straight horizontal joints● Inserted openings● Shadow lines indicative of the removal or decay

of a feature● Surface cavities such as putlog holes or lost fixings● Assembly marks● Changes in wall thickness

● Changes in construction type● Changes in materials.

The last category may be immediately obvious butmore often is rather subtle in character, especially in the case of mortar or plaster. Long exposure to,and experience of, the materials can become veryimportant if evidence is not to be unwittinglydestroyed. In some countries, especially, for instance,those which formed part of the Roman empire, mor-tar (used as lumps of aggregate), stone, brick and tilewere extensively salvaged and reused. Areas of salvagedmaterial may crop up randomly in post-Roman con-struction, indicative of periods of demolition andspasmodic delivery, and some may be recycled morethan once.6 Accurate survey plotting of properlyidentified materials is an important aspect of struc-tural archaeology.

Temporary supports and protection

A condition survey, or even a more basic, prelimin-ary survey, will identify parts of a building and itssite which are at risk and which may present imme-diate dangers. In this category might be, for instance,seriously leaning walls, new or spreading fractures,bulging facework with open joints, displaced stonesat high level or major landslips. Conditions of thiskind often require immediate intervention both tosupport, contain and protect the ruin from furtherloss, and to protect visitors, legitimate or not, frominjury and possible loss of life. Work of this kind willalso be required on sites in poor condition whichare unlikely to be consolidated and conserved formany years, and, within the context of a current con-servation programme, areas which could be lost orcause injury to contract personnel.

In order to design and place such support and pro-tective temporary structures, a thorough understand-ing of such ruined buildings and their condition is essential. A heavy-handed and ignorant approachcould cause collapse of large areas of masonry andpossible loss of life of those carrying out the works.Typical temporary support and protection works areillustrated in Figures 4.5– 4.9.

On some sites, removal of vegetation is required inorder to inspect the masonry and make some assess-ment of its condition. This operation requires morecare and understanding than is generally appreciated,and should in any case be preceded by considerationof the ecological impact removal will entail (seeChapter 6).

Philosophy, technology and craft 89

Ch04-H6429.qxd 10/17/06 2:41 PM Page 89

Figure 4.5 Installation of temporary timber supports in the form of plates, props and wedges and synthetic rope net over vegeta-tion and loose wall head, weighted with sand bags.

Ch04-H6429.qxd 10/17/06 2:41 PM Page 90

Philosophy, technology and craft 91

Figure 4.6 Small lancet window largely unconnected to its originalmasonry has been provided with corset plates bolted through the open-ing to provide temporary stability.

Figure 4.7 Leaning and fractured wall provided with simple temporary buttressing of concrete blocks, and ringed with securityfencing. Myross Church, Ireland.

Ch04-H6429.qxd 10/17/06 2:41 PM Page 91

92 Conservation of Ruins

Figure 4.8 Temporary support of high leaning wall in theform of board facings and flying shores.

Figure 4.9 Temporary protection and insulation of masonry against rain and frost and temporary support works, County Cork,Ireland.

Ch04-H6429.qxd 10/17/06 2:41 PM Page 92

Removal of the foliage and thin, easily accessiblestems with shears can usually enable a condition assess-ment to be made of the masonry without trying tomove heavy growth. Well-developed plants such asmature ivy (Hedera helix) are often found to be clasp-ing and supporting unstable areas of masonry, so thatpremature or injudicious removal can result in localcollapse and injury. Where trees have establishedthemselves in the masonry, the usual approach is tocut them back to within 600 mm of the buildingface; however, consideration must always be given toeffects that the release of the applied loading mayhave on the wall as the weight of the tree is removed.To avoid local collapses it may be necessary to installsome temporary support to vulnerable areas beforetrees are cut.

A common practice in removing ivy is to cut outa metre section of the plant close to the ground toallow the plant to die on the wall and to poison theroot by forming a frill girdle and applying a paste ofammonium sulphamate. There is no reason why thispractice should not be followed unless a long periodof time is going to elapse before clearance and con-solidation of the wall can take place. If there are considerable delays, the dying plant may no longer beable to support unstable, overhanging masonry andmay penetrate the structure at higher level in order toseek out the nutrients it has been denied at groundlevel, leading to further disruption, displacement andstress within the wall. In these situations the plantshould not be cut at ground level until a work pro-gramme can proceed.

Wall tops (Figure 4.10)

Where walls still stand to their original height, theexposed and untouched wall tops of a ruin are oftena rich source of information. Evidence of corbels orcorbel tables, wall plates, tie beams, water outlets andeven roof coverings may be present within a matrixof loose masonry and vegetation. Probably nowhereare structural archaeology and stability found in suchan intimate and fragile relationship. Uninformed wall clearance and consolidation not only consignimportant information to oblivion, but can alsoconserve and present the surviving masonry in quitemisleading ways.

Damaged wall tops, where significant amounts ofmasonry have fallen, are less likely to contain so muchinformation, although some of the elements listedabove may still be in the accumulations of stone anddebris at the floor of the wall. Even in these circum-

stances, however, the same cautious, archaeologicalapproach must be adopted during survey, site clear-ance and conservation processes. Broken wall headsmay still be indicative of original, complete forms,such as crenellations, gables or towers.

Walls that have been reduced to low levels, stand-ing only a metre or less above present ground levels,often appear to have very little evidence indeed oftheir original scale and form. Some sections may bemissing altogether, or may only survive as foundationlevels below the existing soil or sand. Careful record-ing, study and structural archaeology are still vital if the last pieces of information about the buildingare not to be obliterated or misrepresented by con-solidation. In particular, evidence of door openings,buttresses, straight joints indicative of alterations oradditions, plaster or tile fragments, changes in mater-ials or construction methods may still survive andmust be protected and made as legible as possible bythe consolidation process. Maintaining the characterof the masonry construction is vital; the size, shapeand relationship of core to facework must reflect the‘as found’ condition. Very-low-lying walls are par-ticularly vulnerable, in some contexts, to flooding,frost damage, foot traffic, vegetation and stone rob-bing (Figure 4.11).

All categories of wall may, of course, have beenpartly or comprehensively conserved in the past. Pre-treated sites of this kind can present particular prob-lems, relating, for instance, to the use of cement-basedmortar in joints and cappings, the modification ofprofiles to shed water and speculative (or accurate)areas of reconstruction. One of the most commonproblems is the deterioration of original work imme-diately below cement-rich wall cappings and thedetachment of areas of facework pointed in cement-rich mortar (Figures 4.12– 4.19). Only rarely dodetailed records of such work survive even if theywere ever made. The recording of past interventions,and of new ones, must become a part of the site’sarchive, securely stored and easily retrieved. The‘unpicking’ of previous work, where of poor ordamaging quality, and reconsolidation of the origi-nal construction is a common requirement.

The approach and methods for consolidating pre-viously untouched wall heads is suggested as follows.Where present, vegetation should be removed, aspreviously described. Where there is an intention to reinstate a ‘soft’ or natural capping to a wall head,the soil, root mats and small plants can be set aside andkept in suitable conditions for re-laying. Enough mustbe removed to a level where structural and archaeo-logical assessments and recording can be carried out.

Philosophy, technology and craft 93

Ch04-H6429.qxd 10/17/06 2:41 PM Page 93

94 Conservation of Ruins

Figure 4.10a Ruin profiles. Broken wall heads.

Ch04-H6429.qxd 10/17/06 2:41 PM Page 94

Philosophy, technology and craft 95

Figure 4.10b Broken wall heads in masonry and core.

Ch04-H6429.qxd 10/17/06 2:41 PM Page 95

96 Conservation of Ruins

Figure 4.10c End profiles and overhangs.

Ch04-H6429.qxd 10/17/06 2:41 PM Page 96

Philosophy, technology and craft 97

Figure 4.11 Treatments of low-lying walls.

Ch04-H6429.qxd 10/17/06 2:41 PM Page 97

98 Conservation of Ruins

Figure 4.12 Wall head treatment.

Figure 4.13 Cement-based mortar wall capping and wall profilecombining to concentrate water run-off in one area with subsequent decayof wall face. Kenilworth Castle.

Ch04-H6429.qxd 10/17/06 2:41 PM Page 98

Philosophy, technology and craft 99

Figure 4.14 Early form of cement-based mortar and flint capping in large surface areas. These attempts to throw water off the wallhead have the undesired side effect of taking water into the core through cross-cracking, where it remains trapped. Visually the corework is too far forward. Old Sarum.

Figure 4.15 Low-lying walls such as this are very vulnerable to frost damage in cold climates and to disruption by visitors anywhere.These walls are ideal candidates for soft capping, following consolidation. Note how hard capping has been placed over unconsolidatedcore with disastrous results as the capped zone lifts and cracks. Thornton Abbey.

Ch04-H6429.qxd 10/17/06 2:41 PM Page 99

100 Conservation of Ruins

Figure 4.17 Most of this wall lies below original floor levels, with only a few stone facings showing above ground. The fragile core hasbeen covered with geotextile membrane and sand, then set with unmortared limestone scalpings. The result is a free-draining protection whichallows the wall line to be clearly read. Loose, large stones discourage visitors from walking on the walls and a more comfortable board walkis provided immediately adjacent to the wall. (see Figure 4.11, C2)

Figure 4.16 Core facework, especially that exposed at wall heads,and even buried core are particularly susceptible to binder dissolutionand migration in very wet conditions, especially at low temperatures(see Appendix). The design of replacement mortar for these conditionsis clearly important. Non-hydraulic or weakly hydraulic mortars aretoo vulnerable and may never carbonate satisfactorily in persistentlywet conditions. Moderately or even eminently hydraulic lime may beneeded. But if the original material is too weak for such binders a weakmortar with soil and turf capping should be used. Face core work atCastle Acre Castle.

Ch04-H6429.qxd 10/17/06 2:41 PM Page 100

Philosophy, technology and craft 101

Figure 4.18 First stage clearance of ruinous wall head showing removal of vegetation and the stratification layers which confront aconservation technician.

Figure 4.19 Later stage of wall head clearance clearly showing thetop courses of the wall and the twice-holed tilestones lying in the loosedebris; this was the first evidence seen of the original roof covering. Theconservation team needed to record, lift off, consolidate and reinstate asmuch as possible lying in its original position.

Ch04-H6429.qxd 10/17/06 2:42 PM Page 101

Recording should consist of photographs at all stagesof progress and should make use of planning framesin preparation for consolidation.

Planning frames are used to record the positions ofeach stone forming the faces of the wall and thearrangement of exposed core, the aim being toenable the masonry to be put back in exactly thesame positions as found. Carried out correctly, theconsolidation work will not confuse interpretationof the structure in the future. The consolidationwork will thus include any fractures, distortions orleaning and avoid the mistake of ‘correcting’ or‘restoring’.

The planning frames are shown in use in Figures4.20 and 4.21. The outline and locations of eachstone are drawn with indelible markers onto theplastic film, and each one is numbered. As the loosestones are lifted from the walls they are cleaned by abristle brushing and identified by a number corres-ponding to the number in the planning frame. Withthe exception of its uppermost course, this number ismarked on the top bed of the stone. The markingsystem should make use of waterproof markers orpaint, all of which, except the top course, will behidden within the wall when rebuilt. The top course

can be marked on the bottom bed. The marking sys-tem enables the stones to be replaced in their ori-ginal positions. When the loose, marked stones aretaken down they are stacked neatly on the scaffold,ready for rebuilding. As the process of cleaning off,marking, lifting down and stacking proceeds, rootsand soil within the walls are removed. Substantialroots are normally followed down into the wall byunpicking masonry until they no longer present aproblem, but not all traces of root need to beremoved. Fine roots can remain buried within thewall where, without light, they are unlikely to grow.The extent to which a wall head is taken downdepends on a number of factors, including the sizeand arrangement of the masonry units, condition ofthe original mortars, extent of root invasion and dis-placement of masonry. As always, experience isessential to decision-making. The exposed wall headis prepared for resetting face stones and core bybrushing down and, if available, removing small,loose material with an industrial vacuum cleaner,followed by washing with clean water. Rebuildingproceeds using a well-designed bedding mortar (see‘Mortar’, p. 133). The position and alignment ofeach stone are checked with the planning frame and

102 Conservation of Ruins

Figure 4.20 The planning frame is shown at the battered angleof the wall top connected to the scaffold tube. Temporary supports inthe form of plate and props is shown bottom left.

Ch04-H6429.qxd 10/17/06 2:42 PM Page 102

any profiles that were made during dismantling,until the work has been raised to its original posi-tion. There is a general acceptance that the finishedwall head can be modified from the original ‘asfound’ position to eliminate the risk of rainwater‘ponding’, providing that this does not affect or alterany archaeological features that exist within themasonry (Figures 4.22– 4.25). If, however, it isintended to reinstate root mats, soil and plants, theponding issue is not as relevant. On occasion, newsoil and seeds representative of the site’s naturalecology are installed to provide a ‘soft top’ whichacts as a benign sponge-like covering. The benefitsof such a capping can be seen on many ‘natural’sites. English Heritage found this of sufficient signif-icance to carry out research into the beneficialeffects of ‘soft tops’ as opposed to traditional hardcappings7 (Figures 4.26 – 4.32).

Broken wall ends and core facework

Collapsed or destroyed sections of wall leave a var-iety of conditions requiring conservation treatment.

In the common, composite wall the core filling isexposed and the facing stones that encase it are vulnerable to detachment. The original cause ofdamage can often be read in the broken profile: subsidence, stone robbing, loss of restraints orcounterforts, failures of arches, lintels and buttresses,deliberate partial demolition, mining, artillery fire,high explosives, all leave particular signatures which,for the most part, should remain as legible after con-solidation as before.

The term ‘core facework’ is often used todescribe situations where the facing masonry hasbeen robbed or lost and the core of the wall is nowexposed as a ‘face’ (Figure 4.34). Broken compositewall ends always involve ‘core facework’, but thestone facings are often lost from large areas of wallextending back from the break, or quite independ-ently of it. Stone robbing from the accessible lowercourses and subsequent collapse of some of theupper courses is a common cause of loss. ‘Core face-work’ is thus a very important element in masonryconservation.

Inspection of the exposed core, especially whenthe original facing was of coursed ashlar, will often

Philosophy, technology and craft 103

Figure 4.21 Planning frames shown in position for recording wall tops. The frames will need to be capable of repositioning inexactly the same position during the rebuilding process. Note, left, tilestone consolidated in the position found on the wall head.

Ch04-H6429.qxd 10/17/06 2:42 PM Page 103

104 Conservation of Ruins

Figure 4.22

Figure 4.23

Figure 4.24

Figure 4.25

Consolidated walls showing reinstatement of all fractures, distortions and displacements as found. This work, carried out by the CorkCounty Council conservation technicians illustrates the highest standards of work which can be achieved in this field.

Ch04-H6429.qxd 10/17/06 2:42 PM Page 104

Philosophy, technology and craft 105

Figure 4.26 Perfect protection for this roofless ruin is provided by a mature mat of turf and wild flowers. This natural covering canhardly be improved on, and if the masonry below is stable, should be left alone.

Figure 4.27 Another example of natural wall cover, this time on relatively weak, partly earthy core. The cover provides the ideal capping for any weak core which is not suitable as a weathering surface. Butrint,Albania

Ch04-H6429.qxd 10/17/06 2:42 PM Page 105

106 Conservation of Ruins

Figure 4.29 Following consolidation of this broken wall head, alayer of humus and turf is in the process of being laid to act as thenew weathering surface; the variety of grass and the composition ofthe bedding material should follow specialist recommendations andthe species should be natural to the area.

Figure 4.28 Walls built in clay mortar should not have cement or even lime-based mortar introduced as part of a consolidationprocess. Biodegradable net is used here to secure the loose wall heads after excavation, pegged with long plastic anchors deep into thecore. In this wet area, grass and plants native to the site soon take over the wall tops again.

Ch04-H6429.qxd 10/17/06 2:42 PM Page 106

Philosophy, technology and craft 107

Figure 4.30 Rushen Abbey. The Chapter House cleared of brambles and deep roots.

Figure 4.31 The Chapter House vault consolidated and prepared with a hydraulic lime-based screed.

Ch04-H6429.qxd 10/17/06 2:42 PM Page 107

108 Conservation of Ruins

Figure 4.32 The Chapter House vault covered with humus and turf taken from the site.

reveal the imprint of the ‘tails’ of the facings, whichwere rough-backed and unworked. In this type ofwalling, core was raised with the stone ashlars inregular heights so that even when the ashlars havebeen lost it is possible to read the course heights andeven the individual block sizes (Figure 4.34 – 4.36).Other kinds of lost facing, such as Roman reticulateconstruction, may similarly be recorded in core.Impressions of facings are sometimes all that remainsas evidence of their existence, and the preservationof the lime core becomes a matter of great import-ance. Any rebuilding needs to retain the appearanceof the original, even when it is distinguished from itby some identifying characteristic (see ‘Mortar’).The recreation of core of this type and its conserva-tion are highly demanding of interpretative andpractical skills.

The profiles of broken wall ends generally fallinto three categories. The first is largely vertical,and may occur, for instance, at a straight joint orwhere a gable wall had been very inadequatelybonded to the return walls. The second is ramped,or stepped back, often the pattern of progressive

collapse, and sometimes achieving reasonable stabil-ity. The third is overhanging, a potentially danger-ous situation commonly resulting from the collapseof a large window head, or a vault, leaving high-levelmasonry in a cantilevered position.

Undertaking the consolidation work of masonry inthese reduced circumstances requires a proper under-standing of the way stones can be corbelled out andcounterbalanced in dry masonry. Mortar should neverbe relied on to achieve stability as a substitute for thisunderstanding. In situations where balance cannot bereached, structural assistance can be provided byincorporating non-ferrous metals in the form ofrestraining cramps, dowels, corbel bars or column andplate supports (Figures 4.37–4.41).

Fractures

Fractures are part of the ruin’s history. Their causesare many and varied, as discussed in Chapter 2, andare often indicative of the manner in which thebuilding failed or was destroyed.

Ch04-H6429.qxd 10/17/06 2:42 PM Page 108

Philosophy, technology and craft 109

Figure 4.33 Characteristics of different kinds of core in ruined contexts.

Ch04-H6429.qxd 10/17/06 2:42 PM Page 109

110 Conservation of Ruins

Figure 4.35 Detail of core showing the tail impressions of missing stones, with a few surviving ashlars bottom left. This evidenceneeds careful ‘as found’ consolidation to avoid losing or distorting the record. Clarendon Palace.

Figure 4.34 Almost all facework has been lost from his medieval composite wall. Only the core provides a record of the stone cours-ing and other features such as a column and vault springing line. Such core needs careful treatment; in particular, the wall heads mustnot be so consolidated that they become water-shedding. Either lime-mortared core or a ‘soft top’ of vegetation should be used.Waverley Abbey.

Ch04-H6429.qxd 10/17/06 2:42 PM Page 110

Philosophy, technology and craft 111

Figure 4.36 Consolidation work completed to a very high ‘as found’ standard with corbelled arch rings and corbelled out core.Complete stability has been achieved through the use of judicious masonry techniques and materials without any engineering device.Mourne Abbey.

Figure 4.37 Stainless steel torsion bars introduced at the springing line of a broken vault, anchored into the core with pattressplates, to prevent the vaults spreading, fracturing and failing. Sheriff Hutton Castle.

Ch04-H6429.qxd 10/17/06 2:42 PM Page 111

112 Conservation of Ruins

Figure 4.38 Consolidation of overhanging masonry with long restraining cramps set into core work at Byland Abbey.

Figure 4.39 View of overhanging high level masonry supportedby restraining cramps at Nunney Castle.

Ch04-H6429.qxd 10/17/06 2:42 PM Page 112

Some fractures are stable, and no further move-ment is likely to take place provided a maintenanceplan is in place and is acted upon. Typically, somefractures are partly filled with debris. Live or suspectlive fractures will usually require some form ofmonitoring in order to understand the causes ofmovement and to enable the correct mitigating pro-cedures to be designed and installed. These mayinvolve some underpinning, or underpinning andbridging areas of subsidence, and may sometimesrequire the insertion of wall-head beams or ringbeams of tile or lime concrete (Figure 4.42). Morecommonly, large fractures such as those occurring afew metres from a wall end, with displacement onone side of the fracture, may require physical stitch-ing across them; this is achieved by removing face-work and core to form slots across the fracture at

intervals. The slots are used to receive suitablyshaped long stones, or non-ferrous metal bars withturned-down ends or stainless steel threaded bars setin resin dovetails, or lime concrete stitches. Allstitches are intended to prevent further movementin the future. The type of stitch needs to be selectedfor particular conditions on site. For instance, if thecore of a composite wall is found to be rather poorquality, it may be necessary to extend the stitch somedistance either side of the fracture and to lock it wellin two directions into the core (see Figure 4.43). Ifthe core is well made and in good condition, the useof bars or even stones may be quite adequate. Theinstallation of these stitches is followed by replace-ment of the facing stones in their original positions.Proprietary stitching systems incorporating a bar anda sock that are grouted in situ with a cementitious or

Philosophy, technology and craft 113

Figure 4.40 Pattress plates and anchors used to tie back overhanging core work at Sheriff Hutton Castle.

Ch04-H6429.qxd 10/17/06 2:42 PM Page 113

114 Conservation of Ruins

Figure 4.41 Structural interventions in masonry ruins.

Ch04-H6429.qxd 10/17/06 2:42 PM Page 114

Philosoph

y, technology an

d craft115

Figure 4.42 Installation of ring beam.

Ch04-H6429.qxd 10/17/06 2:42 PM Page 115

116 Conservation of Ruins

Figure 4.43 Fracture stitching systems.

Ch04-H6429.qxd 10/17/06 2:43 PM Page 116

Philosophy, technology and craft 117

Figure 4.44 Distortion of this medieval arcade is due to multiple causes including loss of restraints and counter-forts during ruination.Most seriously, the low wall on the left of the picture below the twisted cluster of columns is badly fractured. Only the central shaft ismaking contact with the wall and the arch springing.

resin grout to form a locking profile with the wallcore are an ideal solution in certain wall conditions;however, when the wall core is poorly constructedtheir benefit can be questionable (Figures 4.44 and 4.45).

Whether the fracture is fine or wide, it is import-ant to pack and tamp or grout them with lime mor-tar to prevent further degradation of the wall coreby denying water access. Grout and mortar shouldbe kept back from the face to a sufficient depth to create a shadow line within the old fracture, sothat the overall appearance is unchanged after theweakness has been resolved within the core of the wall.

Voids in walls

Long-term exposure of wall heads, especially wherefractures are present, can result in the creation ofvoids within the core of the wall. Such voids are not limited to ruins, but are particularly common inroofless structures and may house tenants such asbats, birds or snakes (see Chapter 6), who will require

consideration before any remedial work is com-menced. In the first decades of conservation workon ancient monuments in Britain, these voids werefilled with cement grout (liquid mortar) introducedby a gravity feed system (Figures 4.46 and 4.47).The principles used were sound and the stabilityachieved in many cases undisputed, but unfortu-nately the choice of material sometimes contributednew problems without completely resolving theoriginal ones. Unmodified cement grouts have poormobility and create cold, impermeable zones withinthe lime-built construction where condensation canoccur, encouraging frost damage in cold climates,and can deposit new soluble salts in the masonry.

In occupied buildings, the discomfort and incon-venience of water penetrating to the internal sur-faces of walls is most likely to draw attention to thepresence of channels and voids within the wall. Inthe ruined structure dark patches persisting aroundjoints in the drying out period after heavy rain,water running from joints or out of exposed coreand white patches of redeposited lime washed out ofcore are all common indicators of internal cavities.In serious cases of prolonged washing out, bulging

Ch04-H6429.qxd 10/17/06 2:43 PM Page 117

118 Conservation of Ruins

Figure 4.45 Detail of base of column cluster seen in Figure 4.44 showing the distorted and fractured support wall. Temporarysupports of the arcade are required to enable the wall to be recorded, taken down and rebuilt in hydraulic lime mortar. Stitching of suchpoor construction is inadvisable because of lack of adequate anchorage.

Figure 4.46 Traditional gravity grouting at Fountains Abbeyshowing the grout pan in its cradle on top of a scaffold. The grout solidsare being stirred to keep them in suspension before releasing a plug whichwill allow the grout to rise from the bottom of the voided wall.

Ch04-H6429.qxd 10/17/06 2:43 PM Page 118

of facework may be observed. The severity of suchbulging may mean taking down and rebuilding thedetached area, but if the situation is not too advancedit may still be resolved by grouting, and on occasionthe combination of face pinning and grouting canbe employed.

Attempts to correct the excessive movement ofwater in and out of the wall are, unfortunately,often in the form of pointing up cracks and jointswith impervious, cement-based mortar. This prac-tice commonly exacerbates the problem by failingto exclude water, because of the habit of the mortarto shrink and crack, and by inhibiting its evapora-tion and encouraging entrapment (see ‘Mortar’). Inthe rectification of voided core problems, it is ofparamount importance that such mortars are removed,unless such removal causes unacceptable damage tothe structure.

Void patterns within walls are difficult to deter-mine accurately by survey. The distribution systemfor invasive water within a thick wall core can bevery complex. In spite of this, entry and exit pointscan be observed and should be recorded. A simpleprocess of sounding the wall faces with a hammer

will indicate some of the void locations close to theface, and the removal of a face stone in a suspectarea will be even more informative. More sophisti-cated systems such as using gamma or X-ray orultrasonic testing are sometimes advocated, but thetime and cost and, especially, the potential benefitsshould be carefully considered against their truevalue. In all remedial works procedures the simplestmeans possible to achieve the required result shouldbe selected.

In some situations voids may be apparent fol-lowing the removal of degraded or inappropriatemortar pointing, especially at perpendicular joints.On occasion it is advisable to remove a number offace stones within an elevation, in order to get a bet-ter indication of the extent of voiding within a wall.

To further establish voids at greater depths and todetermine their extent and direction, water can befed into the wall using a hosepipe. Flushing withwater in this manner has a number of benefits. Itwill escape the core from either face and indicatesthe bottoms of tracks or voids within the wall.These are marked as grout injection points. Loosedust and debris is flushed from the wall during this

Philosophy, technology and craft 119

Figure 4.47 At the base of the wall this illustration shows grout emerging from one of the escape holes provided, confirming therise of grout behind the face stones. The blocks here are shown levelled with oak pegs and the joints plugged, in the traditional waywith tarred rope.

Ch04-H6429.qxd 10/17/06 2:43 PM Page 119

operation and the core is well wetted, ready for thegrouting process.

The entire wall or walls are tested in this manner.Any large areas of masonry not showing signs ofleaking during the process can be deep drilled throughjoints on a grid system of 0.5 m vertically, 1.0 mhorizontally, and staggered in order to connect withlong voids which will act as both grout injection andproving holes during the works.

All marked water escape points are fitted withplastic tubes set into the wall that are of a diameterto accept the grout injection nozzles. Repointing ofthe wall or walls can now take place and in doing sothe plastic tubes are fixed into the masonry.

Grout is always introduced from the base of a wall,not from the top. This important practice is to avoidblocking through air locking and to prevent finedebris working down and closing up the voids. Forthis reason, it is sensible to plan repointing at openjoints from the bottom upwards, so that the mortarcan gain enough strength to contain the grout with-out leakage. In some circumstances the open jointscan be plugged with foam backer rod or some alter-native packing and repointed after grouting.

Introduction of grout is ideally carried out using a simple diaphragm pump which works by

pushing and pulling the operating lever (Figures4.48– 4.49).

A pressure gauge is fitted to the pump and this,during pumping, should hardly register, as intro-duction of grout into the wall needs to allow for thegrout to spread slowly and horizontally along thewall, rather than creating a vertical head of groutlocally at the injection point and then allowing it tospread along the voids within the wall.

The lift heights for grouting will vary on buildings.Large granite ashlars with a fine joint system could be raised 1.5–2.0m in one day. Alternatively, smallstones in a weak mortar should not be raised above0.5m without the risk of hydrostatic pressure movingfaces away from the core. Decisions on height ofgrout per day can only be taken on site and must bebased on extensive previous experience.

If possible, each lift of grout introduced to a wallshould be left for one day before resuming grouting.This is in order to give the grout time to dewaterand stabilise before more grout is added to the wall.Grout continues in this manner until the head of thewall is reached. At this stage it is advisable to apply ahead of grout to the upper proving holes, to com-pensate for the reduction in volume of grout due tode-watering within the voids. Quantities of grout

120 Conservation of Ruins

Figure 4.48 The simple diaphragm pump which has largely replaced gravity grouting of masonry walls.

Ch04-H6429.qxd 10/17/06 2:43 PM Page 120

taken up at each injection point should be recordedto provide an indication of the volumes filled.

On completion of grouting and after a period ofthree to four days, the plastic sleeves can beremoved and the injection points can be deeptamped and pointed.

Stone replacement

Within the philosophical context already described itis unusual to find any substantial replacements of newstone. All stones, in whatever condition and espe-cially any that have to be replaced, must be recordedand evaluated. All types need to be petrographicallyidentified and provenanced as closely as possible,and archaeological evidence such as lifting tenons,quarry-working marks, tooling, identification marksand mortices must be recorded. When different typesof stone have been used in construction, identifica-tion may indicate important changes in the historyof the building or, for instance, the use of salvagematerial from other sites.6 Where replacement isnecessary, to support or protect historic material atrisk, the rule of ‘like with like’ is generally thought

to be appropriate. In many cases this can amount tono more than geological compatibility, becauseoriginal sources of stone are often no longer avail-able. Matching colour, grain size and texture arethought to be important in the repair of anymasonry buildings, but in the conservation of old,weathered masonry the overriding objective mustbe to so modify the situation in the wall that its lifeexpectancy is significantly increased.

Some general points on the selection of appropri-ate material may be made. The stone should be ofthe same type as the original, and of the same over-all size and character, achieved through cutting anddressing techniques. Other characteristics are moreproblematical. Even when a replacement stone isnear to identical with the original stone it will bedifferent by reason of its unweathered state; its sur-face, at least, is going to be more resistant to weather-ing and decay agencies. Bedded and grouted intothe old masonry, even in appropriate mortars, thenew work is commonly much sounder than the oldand may initially cause additional local stress to thefabric it is intended to assist. Admittedly, this is onlylikely to be the case when the old masonry is in verypoor condition, but such situations are not unusual

Philosophy, technology and craft 121

Figure 4.49 Masonry wall showing grout nozzles installed. These can be simply coupled to the grout feed hose.

Ch04-H6429.qxd 10/17/06 2:43 PM Page 121

122 Conservation of Ruins

Figure 4.50 Grouting masonry walls.

Ch04-H6429.qxd 10/17/06 2:43 PM Page 122

in ruin conservation. With these concerns in mind,alternatives to stone replacement are sometimesspecified, and these are described below.

The requirement for new stone is usually identifiedduring the condition inspection and becomes incor-porated in a schedule of repairs. Regardless of irregu-lar arrises or damages, new stone should be scheduledgiving large enough dimensions (length onface � depth on bed � height – L � B � H) toallow for dressing back to the final sizes required. Inmany countries new stone is now supplied four or sixsides sawn as standard (Figure 4.51); such blockswould have been very expensive to produce in cen-turies past, when it is usual to find only the face andshort-return dimensions worked square, with theback or tail of the stone irregular as quarried.Replacements should normally be 100 or 150mm onbed, and sometimes longer, depending on their func-tions, but the face dimensions (L and H) should matchthose of the lost stone as closely as possible and, mostimportantly, should be set to the original face line onthe building (Figures 4.52 and 4.53). In weatheredand decayed masonry, this means that the new stonewill project, often forming a ledge on the top bed and

creating a shadow line under its bottom bed. In spiteof this, there should be no deviation from this rule orthe evidence of the original face line and its profileswill be lost, and the authors of future replacementsdenied essential information.

Projecting stones of this kind do not need con-spicuous mortar frames, and especially not mortarfillets applied to the top bed as a ‘weathering’(Figure 4.54). Mortar bedding and pointing shouldfollow the weathered profile of the masonry, so thatjoints never increase in thickness over the originalwidth and are not enlarged to fill out local damages.On the top bed, the stone may be given a very slightweathering and a pencil-rounded front arris to assistthe discharge of water from the face (Figure 4.53).Stones should be set into well washed, cleaned cav-ities on a full bed of mortar (see ‘Mortars’). The topbed joint should be filled with ‘dry-pack’ mortar(the bedding mortar with a low water ratio). Thiscrumbly material can be firmly and tightly packedusing a tamping iron, to within 20 –30 mm of theface, and later pointed. Unless dry packing is usedthere will be a tendency for the top mortar bed toshrink, leaving the stone above unsupported.

Philosophy, technology and craft 123

Figure 4.51 Uncomfortable machine cut replacement stone in an eighteenth century context of quarry-dressed stones.

Ch04-H6429.qxd 10/17/06 2:43 PM Page 123

124 Conservation of Ruins

Figure 4.53 This replacement stone has been set in a damaged medieval entrance arch still used by vehicular traffic. The stone isthe correct chamfered profile taken from the head of the arch and is placed in its correct line in the jamb. Although the new stone proj-ects from the weathered masonry no mortar weatherings are used; instead the stone has a very slight fall on its top bed and a pencil-round arris. Providing the bedding mortar is deep and well packed this stone will shed water effectively. Guildford, Surrey, UK.

Figure 4.52 This section of Roman cornice has been prepared from templates made from a complete stone found in excavation. It is set in the wall to fill a gap and to show the original architectural line and detail. Beth Shean Israel.

Ch04-H6429.qxd 10/17/06 2:43 PM Page 124

Replacement stone should always be identifiable,and there is a tradition of incising the date of place-ment on new stone. In some situations stone replace-ment within ruins may be structurally necessary anda stylistic difference may be made to differentiatenew from old. Examples of this approach are shownat Battle Abbey (Figure 4.55) and Furness Abbey(Figure 4.56). In both cases a structural solution hasbeen provided with the ‘correct’ stone, but stonewhich has not been moulded to imitate the original,deliberately staying short of any accusation of restor-ation. It can be argued, in the case of the Furnessillustration, that some ghosting of the vertical rolland hollow moulding would have been an aestheticgain; certainly, the course lines of the blocks shouldhave been carried through.

In cases where severely decayed masonry is inneed of local replacement, an alternative to wholeblock indenting may be the use of tiles. The Societyfor the Protection of Ancient Buildings in Englandhas for decades recommended the use of coursed

clay tiles for philosophical reasons, in both hydrauliclime and cement and lime. The argument for thisapproach is that structural support can be intro-duced in a way that does not compromise the truth,even if the tile repairs were rendered, as they oftenwere. An example of such a repair is shown inFigure 4.57, at Guildford Castle, carried out in1914. A more elaborate example, including full archrings, is shown used at Wolvesey Castle, Winchester(Figure 4.58).

There are, however, some situations where the useof tiles, clay or stone, may be the most suitable andsuccessful replacement option, quite apart from thephilosophical issues of honesty in repair. Tile slipsmay, for instance, be introduced with less loss oforiginal material, in the repair of decayed vault ribs,performing perfectly well in compression within thearch thrust of which they will become a part. Orwithin a very weak, cavernously decayed contextsuch as the poorly lithified limestone of Herod’sNorthern Palace at Masada, they may be almost

Philosophy, technology and craft 125

Figure 4.54 New sawn stones are rather more comfortable in a setting of squared ashlars but suffer from arrises which are too sharpand bedding which is out of line. There is also far too much mortar on the top bed, placed in an attempt to provide a weathering. Thisshould be compared with 4.20. New mortar has an unnatural, flat face.

Ch04-H6429.qxd 10/17/06 2:43 PM Page 125

the only option, as described in Chapter 10.2. Theimportance of this technique is primarily in its com-patibility with the ancient fabric. Porous, permeabletiles of clay or weathered stone set in porous, per-meable mortars are receptive to water vapour move-ment and the passage of salts in solution; they do notcreate new crises for the beleaguered walls in whichthey are set and can, in later years, be replaced. Unlikenew stone or brick they can be expected to performin a truly sacrificial role for the benefit of the oldwork they are trying to sustain. In setting tiles intoa cavity created by the removal of decay, beddingmortar is placed on the upper face of the top tile andthe joint below is dry-packed with a tamping ironto ensure that the soft mortar is pushed up into theirregular roof of the cavity.

Stone repairs

The retention, rather than the replacement, of thestones or bricks in a ruin should be an obviouschoice. Old techniques of repairing stones included

the ‘tinning’ of open fractures by running in liquidcement, joining detached fragments with shellac orclasping elements such as mullions and tracery withcopper tape. Minimum replacement is frequentlycoupled with techniques of filling small lacunae withmortar (‘dental repairs’), or with small pieces ofstone or tile within the boundaries of an old stone(‘piecing-in’), or of drilling and stitching fracturedstones. The design of appropriate mortar fills mustfollow the general principles set out under ‘mortarspecification for joints’, but in the repair context itis even more crucial to have good water vapour permeability and moduli of elasticity in addition togood texture and good, stable colour in both wetand dry conditions. Dental repairs, like stone repairs,should always be sacrificial and records of their com-position must be retained so that future repair mate-rial can be repeated or modified.

The technique of repair, preceded by photo-graphic recording of the conditions, is to cut awaythe decay with small points or chisels, or even aspatula, scraping back to a sound surface and form-ing slight undercuts around the perimeter of the

126 Conservation of Ruins

Figure 4.55 Philosophy in place at Battle Abbey, Sussex. In the 1920s the left hand window head and masonry on each sidewere rebuilt. To distinguish the rebuild from the original, seen on right, the stones were roughly shaped voussoirs and jambs whichrecreate the scale and design of the original but remain permanently distinguishable from it. This illustrates a typical Society for theProtection of Ancient Buildings approach of the time.

Ch04-H6429.qxd 10/17/06 2:43 PM Page 126

repair, to avoid feather-edging and to help to ‘lock’the repair into the host material. Following prepara-tion of the repair area it should be washed and ster-ilised, ideally by a small steam-pencil or by fine

water sprays and a biocide. What is required is afirm surface, free of dust and debris and of micro-organisms. Before the repair is placed, a final stageof spray-wetting will be needed, especially in hot,

Philosophy, technology and craft 127

Figure 4.56 Philosophy in place at Furness Abbey. The missing outer orders of the arcade pier have been replaced in a similar redsandstone which provides the necessary structural support for the arch but which is visually rather unsuccessful. The new line of thepier face is too far forward, and has no articulation representing the base and cap. In addition, the course lines of the new stone do notrun through to match the original coursing. Some shallow vertical channelling echoing the original roll and hollow moulding wouldhave made it a much better intervention, whilst still remaining an obvious intervention.

Ch04-H6429.qxd 10/17/06 2:43 PM Page 127

dry and/or windy conditions. Unless there is areservoir of moisture in the repair zone, the stone orbrick will draw too much water from the mortarwhen it is placed, with subsequent shrinkage.Drying shrinkage is the most common cause of fail-ure in mortar repair, either due to this ‘de-watering’by the background or to inadequate curing in theright conditions (see ‘Mortar’).

Following careful placing and packing of the mor-tar, which is either achieved in one layer (shallow

repairs) or two or three, each layer being well com-pacted to the earlier one while it is still damp (‘green’),wet packs of material such as cotton wool are placedover the repair and intermittent misting with water,usually from hand-held sprays, continued over threeto seven days to ensure slow curing.

Fractures in individual stones often require amethod of stitching. The use of adhesives alone isnot particularly recommended, unless the repair isvery small, and should never be used on interfaces

128 Conservation of Ruins

Figure 4.57 Philosophy in place at Guildford Castle. The 1914 period clay tile replacements for decayed stones were once ren-dered. These repairs were and are unmistakable interventions, which is exactly what was intended.

Ch04-H6429.qxd 10/17/06 2:43 PM Page 128

Philosophy, technology and craft 129

Figure 4.58 Philosophy in place at Wolvesey Castle in Winchester. Missing stones of the arch have been replaced with clay tilerings; although an effective piece of consolidation the completeness of the tile ring could be misleading, suggesting that this might orig-inally have been a tile arch.

exceeding 10mm2 as they form barriers to watermovement and can encourage local build-ups of salts.Stitching involves drilling across the fracture, blowingout the debris with a drinking straw or rubber ‘puffer’,flushing out with water and a suitably sized bottlebrush, and grouting in a ‘stitch’, pre-cut and first fitteddry. Micro-stitching of this kind is best carried outwith twisted strands of copper wire (two or threestrands can be twisted together using a hand or powerdrill and then cut to size). Slightly larger stitching canbe carried out using purpose-made ceramic pins or T-bars, which have the benefit of being highly compati-ble with porous stones or ceramic. Very fine stitchingcan be executed with carbon-fibre pins. In most cases,stitches can be satisfactorily grouted in hydraulic lime.

Mortar

Where ancient ruined masonry is mortared the mor-tar may be based on lime, soil or gypsum, or on somecombination of these three. If a modern artificialcement is present, usually a type of Portland cement,

in pre-1850 buildings, it belongs almost withoutexception to previous and inappropriate programmesof remedial work. Reference has already been madeto some of the cement-generated problems experi-enced by conservators in the first half of the twenti-eth century. Most prominent among these arecracking of both joints and stones or bricks, lifting ofconsolidated wall heads, increased decay rates tostone, plaster, earth walls or mosaics caused by accel-erated wetting and drying of salt contaminated water,and increased incidence of frost damage in cold, wetclimates. Simply put, there is an inherent and fatalincompatibility between cement and lime-mortaredconstruction, which no amount of theorising ormodification will eliminate (Figures 4.59– 4.62).

There is a significant body of material availableon historic mortars and their replication.8 In thecontext of ruined buildings which are to be con-served there is perhaps more justification for mortarstudy than might be the case with complete, roofedand protected buildings. The old mortar, whetherin joints, exposed core work or applied as a plaster,is as much a part of the fabric as bricks and stones,

Ch04-H6429.qxd 10/17/06 2:43 PM Page 129

130 Conservation of Ruins

Figure 4.60 The volcanic crater of Santorini (Thera). The ash from this famous volcano has been important since classical timesas a setting additive (pozzolana) for lime mortar and concrete.

Figure 4.59 Mature lime putty which has been aged for three years exhibiting the right consistency for use as mortar. Bryn Gilby’slime production, South Wales.

Ch04-H6429.qxd 10/17/06 2:44 PM Page 130

Philosophy, technology and craft 131

Figure 4.61 This deposit of pozzolana near Tivoli shows the typical range of colours found in volcanic ash. This pozzolana hasbeen used extensively since the Roman period. The most reactive material, mixed with lime and water was used very extensively forengineering works.

and is equally at risk; moreover, mortar can containimportant information about the technology andmaterials of the time of its composition and place-ment (Figure 4.62). A study of provenanced mortarsamples is an important part of recording the historyof a ruined building. The composite wall, alreadydescribed, consisting of two masonry skins enclos-ing a core of stone and mortar, is the most common,traditional form of load-bearing wall, but variationsin construction are very numerous and these vari-ations have a profound effect on how walls behavewhen they are broken and exposed to the weather.

For instance, a wall in which the facings are bed-ded in good mortar and are well integrated into asoundly coursed and compacted core can withstandthe trauma of partial destruction remarkably well.But if only the facings are set in good mortar and thecore is of inferior material such as clay, then exposurethrough partial collapse or destruction will make thewhole wall very vulnerable indeed. An importantaspect of conserving composite walls with weak coresis that the facing joints must be very well maintainedusing an appropriate mortar to tamp and point wherenecessary; cement-based mortar must again beexcluded altogether, as it will significantly inhibit the

drying out of the wall following wet periods whileallowing water in through movement and shrinkagegaps. Incorrect use of impervious mortar can bringout the rapid collapse of such construction.

Both clay- and gypsum-built masonry could be,and usually was, protected with lime-mortared facingsor lime plaster. Without these original means of pro-tection or a suitable replacement, walls will fail. No‘anti-restoration’ philosophy should be used to denyessential protection to the walls of ruined structures,although it may, of course, sometimes dictate the useof a cover building (see Chapter 5) rather than replace-ment of plaster; but the risks to exposed cores mustbe understood by the decision-makers.

‘Appropriate’ mortars for ruined masonry arewide ranging in their detail, because of the tendencyto use aggregates that are local to each site. Never-theless, it is possible and important to make some gen-eral rules and classifications for mortars, plasters andgrouts applicable almost anywhere. The steps to speci-fication decision-making may be set out as follows:

● Make a visual inspection of the mortars on site;look for individual characteristics of colour, textureand weathering, and for differences; where

Ch04-H6429.qxd 10/17/06 2:44 PM Page 131

132 Conservation of Ruins

Figure 4.63 Exposed core of Hadrian’s Wall with its wall head screed intact. Loss of face stones requires careful consolidation ofmaterials not designed for weathering.

Figure 4.62 Roman mortar at Pevensey, Sussex, England showing the use of artificial pozzolan in the form of powdered brickor tile blended with large brick aggregate and lime. This mortar is extremely durable and has survived a marine environment for 2000years.

Ch04-H6429.qxd 10/17/06 2:44 PM Page 132

possible, identify earlier interventions; look forand record areas of failure or apparent risk andareas of decaying stone or bricks.

● Take samples of unweathered mortar for recordand analysis; this is much simpler matter fromwall cores than from joints, but the aim is toremove samples that have not been significantlyaltered. Each sample should be kept in a sealablebag or jar clearly and indelibly labelled with thename of the site, the location of the site and adescription of the mortar sample, preferably sup-ported by a photographic reference and a recordof the date and who took the sample.

● Design a mortar that will protect the masonrywithout creating new problems and that will bevisually harmonious with the other mortars onsite. This should take account of the originalaggregates used and recorded from samples, butanalysis should not be used as the basis of a newspecification, which is for a mortar whose role isto perform alongside weathered and alteredstones, bricks or earth. The condition of the old masonry must always be the first considera-tion, the role of the mortar the second and theexposure of the mortar the third.

● Prepare trial batches of mortars and look at themin the context of the site. Prepare method state-ments for the preparation of the remedial mor-tars using the site conditions to ‘fine-tune’ theway the mortar is treated and finished. Whencompleted, these trials and the mortar specifica-tion should become a part of the permanentrecord of the site and are essential for future conservation and maintenance. Without suchrecords no useful lessons can be learnt in thefuture.

Decisions need to be made on how new mortarshould look. The traditional ‘like with like’ approach,although visually satisfying, may need some adjust-ment if the new work is to be distinguishable fromthe old. The last stage of well-executed joint filling isto tamp or wash the mortar face to match the wea-thered texture of old surviving mortar, or it may beprofiled to match an original profile. This is skilledwork which is to be encouraged. But some ‘tagging’device, such as the inclusion of a distinguishingnon-prejudicial addition to the aggregate, may beconsidered proper to enable replacement mortar tobe distinguished in the future. Although there areprecedents for a ‘conservation house style’ such as aparticular kind of washed grit finish, this is far fromsatisfactory when used indiscriminately over a wide

range of different sites, and a more discreet methodof identification is recommended.

Critical to the success of mortar, mortar repair orplaster repair is the curing process. Whatever mortar isused it will almost certainly fail if it dries too quicklyfor a proper carbonation process to take place. Thefirst essential is to make sure that the backing for mor-tar or plaster is made adequately damp. In practicalterms this means that enough water will have beenapplied to the surface to avoid any significant suctionon the new material. The surface should not glistenwith water but it should refuse to take any more.Once the new mortar has been placed it needs to bescreened, ideally with plastic film that retains humid-ity better than any open textured material. Whenworking on scaffolds the construction of curingscreens is a very useful way of maintaining the desir-able conditions. These screens are typically 2m highand 1m wide, formed of 15mm � 25mm batten,and faced on one side with plastic film and on theother side with hessian (burlap). The hessian-facedside can be well wetted with sprays and placed close tothe wall, allowing some ventilation. A series of screenscan be joined together using a simple hook and eyesystem, and screens can be simply secured to scaffold-ing. If a plastic sheet is used alone it should be rein-forced and fitted with reinforced eyelets to avoidtearing and to provide secure anchorage against windlift. Screens are normally used as overnight protectionbut can be used during the working day by movingthem to the back of the workspace to protect againstsun or drying wind. During the day intermittent finespraying of mortar surfaces is recommended to keepthem in a slightly damp condition over a period of7–10 days. Without this initial care a great deal of timeand effort will be wasted, as the mortar will eithershrink and crack or will carbonate rapidly on the sur-face, sealing mortar behind which will never gain ade-quate strength.

Replacement mortar materials

Placing new mortar into ancient walls is a seriousresponsibility. Failure to recognise and accept theresponsibility through ignorance, insensibility ormistaken ideas related to cost-cutting is always paidfor by the historic fabric. Decades of capping thebroken and open wall heads of ruins, filling theirjoints and voids in cement-based mortar and grouthave already caused too much damage. The researchand field work on this subject have been carried out.The responsibility of the conservator is now to use

Philosophy, technology and craft 133

Ch04-H6429.qxd 10/17/06 2:44 PM Page 133

materials that are wholly compatible with lime-,earth- or gypsum-based mortar and plaster, andwhich are ultimately sacrificial.

Non-hydraulic lime (‘air lime’) and hydraulic lime(‘water lime’) with pozzolans such as ceramic powderto promote set and react with available free lime arethe usual binder materials for replacement mortars.Gypsum mortars are relatively rare outside thosecountries with hot, dry climates. Sand and other nat-ural stone aggregates, including porous types, brokenbrick fragments, charcoal and slag, are commonfiller materials.

A comparison of hydraulic and non-hydraulic limeproducts and production is provided in Appendix 1.The range of conditions and exposures worldwide is almost limitless, so that it may seem rather ambitiousto make recommendations on mortar mixes. Never-theless, although combinations, adjustments and mod-ifications may be infinite, certain parameters illustratedby typical mixes can be set with some confidence.Two mortar categories are proposed in Tables 4.1 and4.2. The first, Type A, is based on a non-hydrauliclime in the form of putty, with a pozzolan additive toprovide a weak hydraulic set. Three pozzolans are sug-gested, one wood ash and the other crushed ceramictile or brick, and the third one a metakaolin. True poz-zolan could also be included but variations in reactiv-ity are so wide that to do so is not helpful. The purposeof adding pozzolan, following an ancient traditionwhich survives to the present day, is to provide a rela-tively weak hydraulic set. The weakest of these wasoften achieved by reaction of some of the lime in thekiln with the ash or slag from the fuel used in the com-bustion process. The second category, Type B, is basedon natural hydraulic lime using the European stan-dards to describe them as NHL2 (approximating ‘fee-bly hydraulic’), NHL3.5 (approximating ‘moderatelyhydraulic’) and NHL5 (approximating ‘eminentlyhydraulic’). In one case the addition of a pozzolan is

suggested to react with some of the free lime presentafter the hydraulic set has taken place.

Description of mortar constituents

● Lime putty. This should be putty prepared fromquicklime stored in an airtight tub or under waterfor a minimum of six months. Aged putties wellin excess of one year old are particularly desirablefor the weaker mixes. The putty must be in a stiff,plastic state when it is gauged, to avoid inaccur-acies when batching. A stiff putty yields signifi-cantly more lime than the same volume of a loose,wet putty. As a guide for practice, a cut columnof putty 50 mm � 50 mm and 150 mm highshould be able to stand for five minutes withoutany appreciable lean or slump.

● Aggregate – hard, angular. This describes a clean,sharp grit-sand, well graded to suit the appearanceof the mortar being matched.

● Aggregate – rough, porous. This describes aggregatewith a pore structure that will assist carbonationof the mortar and improve its resistance to saltcrystallisation and to freeze–thaw damage. Typic-ally, this would be broken, graded limestone orbrick, but could include particles of slag and otherporous material.

● Pozzolan – metakaolin. This product may not beavailable in every country, but is a useful material.China clay fired at approximately 800°C producesmaterial that will react rapidly with calciumhydroxide to provide a hydraulic set. Strengthgains continue over quite a long period. Quantitiesin excess of one-tenth of the lime binder are notrecommended.

● Pozzolan – ceramic. Following Roman tradition,this pozzolan is typically a low-fired brick or tile powder fired at relatively low temperatures

134 Conservation of Ruins

Table 4.1 Mortar type ‘A’ – lime putty and pozzolan

Mix designation

A1 A2 A3

Mature lime putty 1.0 1.0 1Aggregate – hard, angular 1.5 1.0 1.0Aggregate – rough, porous 1.5 1.5 1.5Aggregate – metakaolin – 1/10Aggregate – ceramic – 1.0Aggregate – wood ash 1.0

A1 � weakest; A3 � strongest

Table 4.2 Mortar type ‘B’ – hydraulic lime

Mix designation

B1 B2 B3

NHL2 1.0 – –NHL3.5 – 1.0 –NHL5 – – 1Aggregate – hard angular 1.5 1.0 1.0Aggregate – rough porous 1.0 1.0 1.0Aggregate – ceramic – – 0.5

B1 � weakest; B3 � strongest

Ch04-H6429.qxd 10/17/06 2:44 PM Page 134

(c. 1000°C) ground to a fine powder (passing a75-micron sieve). Grinding to provide fresh bro-ken surfaces can be useful. Proportions are nor-mally 1:1 with the binder.

● Pozzolan – wood ash. The weakest of the poz-zolans is a difficult material to quantify, and likeall additives must be subject to preliminary trials.The great advantage is that ash is universallyavailable. Great care should be taken in using anyother forms of fuel ash with unknown solublesalt contents and unknown reactivity.

● Natural hydraulic limes – NHL2, NHL3.5 andNHL5. Natural hydraulic limes are becomingincreasingly available, with France being the cur-rent major supplier. The classification is important.In general, it is best to avoid a classification ofNHL2, NHL3.5 or NHL5 suffixed with a ‘Z’,unless the Z additive is known. For historic workavoid any material simply classified as HL. Allhydraulic lime mixes should be first blended dryand allowed to stand after being mixed with water.An NHL2 should be left for at least 24 hours afterwet mixing; an NHL5 should be left for at least12 hours. The wet mixes should be protectedfrom rain and sun, and remixed before use.

The mortars in Tables 4.1 and 4.2 are arrangedaccording to their strength; thus, the weakest mortar isA1 and the strongest is B3. The weakest mortar able toperform the intended function without creating newproblems for historic fabric should always be selected.

Grout materials

Non-hydraulic lime (‘air lime’) and hydraulic limes(‘water limes’) in combination with pozzolans such aspulverised fuel ash (pfa) or fine powdered ceramicwith suspension aids such as bentonite are the usualsolids used in grouting. Although, in the past, cementwas extensively and almost exclusively used, it shouldnow be eliminated from grouts for historic masonry.Some mix proportions are shown in Figure 4.50.

Unmortared walls (Figures 4.64 and 4.65)

Many examples of unmortared masonry survive froma wide range of cultures, time and geographical distribution. These may be highly sophisticated orvery primitive, but all required skill and experience

Philosophy, technology and craft 135

Figure 4.64 Trei’r Ceiri. Unmortared, roughly split slate walls of iron age date in Wales. The sophistication of this masonry liesnot in the dressing of the stones but in the way in which they are assembled, each stone acting as a structural component and sittingcomfortably within the wall. Such walls could be packed with earth and turf to make them water and wind proof, but should never bemortared in any consolidation work.

Ch04-H6429.qxd 10/17/06 2:44 PM Page 135

to construct, whether water-washed boulders at TelDan, irregularly split slate slabs at Trei’r Ceiri, care-fully fitted polygonal stones at Cuzco (Figure 4.66) orthe seamless ashlar of classical Greece. The principalthreats to such construction, depending on location,are stone robbing, seismic movement, subsidence andacts of war. Not being mortar dependent at all, theyare often extremely durable and stable. The contrastbetween dry-built and mortared construction is par-ticularly interesting in wet, cold climates; there is lit-tle that water movement (aside from scouring at thewall base) can do to unmortared walls, and freezingpresents few problems because of the free-drainingnature of the construction. Some dry-built construc-tion was packed with earth to keep out wind andrain, but these materials in such a context are non-structural and usually lost through time and weather-ing. Some were also plastered with clay, lime- orgypsum-based plasters.

The most important and perhaps obvious point tomake in conservation work is that mortar and groutmust never be introduced. Such interference withthe natural wetting and drying rhythms in the wallwill be damaging and may result in localised col-lapse, quite apart from falsifying the evidence. If

locally bulging or leaning wall sections require help,they must be carefully recorded and marked beforetaking down and rebuilding using the planningframe. Iron cramps run in lead and bronze crampswere both used in dry-built ashlar. Occasionally,these need replacing in phosphor bronze or stainlesssteel, with preference given to bronze alloy wherethe installations are likely to be seen. If new stonesare introduced into ashlar the work must carefullymatch the precision of the original; a slip-bed oflime putty or clay slurry will be needed to ease theblock into position, but this has no mortar functionand must not appear on the surface.

Earth walls

Earth walls have a very significant place in the historyof building, and in many parts of the world earthtraditions are still alive and the associated technolo-gies are still well understood. Ironically, it is in thoseparts of the world where modern technology ismost advanced and accessible that traditional con-struction such as earth is least understood and isoften badly treated. Happily, there are some notable

136 Conservation of Ruins

Figure 4.65 Massive, unmortared stones as Cuzco illustrate some of the most accurately worked masonry seen anywhere, and vir-tually indestructible except through severe seismic activity, deliberate demolition or artillery fire.

Ch04-H6429.qxd 10/17/06 2:44 PM Page 136

exceptions and there has been a revival of interestsin use of earth for new constructions.

Continuity in earth building may be found incountries such as Afghanistan, Iran, Saudi Arabia,the Yemen, South America and the south-west USA,India, Africa and China, and it is from such areasthat lessons on behaviour, repair and conservation ofearth walls can be best learnt. Where suitable earthexists it has been used for construction, and for allbuilding types. One of the most impressive early usesis in the form of the banks and ditches of the greatCeltic oppida, although it may be argued that theseare not ‘walls’ in the traditional sense. Nevertheless,earth has a longer history in defensive works thandoes any other material, absorbing impact and shockfrom modern artillery as effectively as it resistedmissiles from Roman and medieval siege engines(Figure 4.67). Although mud-brick masonry couldeasily be breached by the swinging ram, earth andturf walls absorbed the shock very effectively. Earth‘ruins’ include not only hill forts but a worldwidearray of artillery forts from the seventeenth to thenineteenth centuries and the trench defences of twoworld wars (Figure 4.68).9

In more traditional usage, clay is the single mostimportant constituent in earth walls, as an adhesive,

Philosophy, technology and craft 137

Figure 4.67 The Medieval earth motte of OkehamptonCastle, UK, showing earth slippage after heavy rain, exacerbatedby burrowing rabbits. Turf repairs are appropriate, cutting into themound and laying turfs as bonded blocks with staggered joints.Synthetic rope land mesh can be pegged across the repair until thegrass is established.

Figure 4.66 Masonry of water-washed boulders at Tel Dan, Northern Israel. Upper courses rebuilt.

Ch04-H6429.qxd 10/17/06 2:44 PM Page 137

binding agent. Clay-poor earths need to be modifiedby the addition of clay from another source; earthvery rich in clay and therefore prone to crackingneeds to be balanced with a filler such as sharp sand,small angular stones and stress distributors such aschopped straw. The expansion and contraction of awell-balanced earth wall provides a useful degree ofstructural flexibility, but in general it must be remem-bered that earth walls are strong in compression andweak in tension. Construction methods includecasting in moulds to produce bricks and blocks andramming, with or without shuttering.10

The vulnerability of earth construction is at itsgreatest when damage and partial ruination haveoccurred (Figure 4.69). In wet climates such asnorthern Europe, earth walls can only survive whena water-resistant plinth and a water-shedding roofwith a wide overhang and a slurry or plaster wallcovering are maintained in good condition. Damageand neglect, especially at the wall head, quickly leadto disintegration and collapse. In drier climates, thedisintegration process takes longer but may be exacer-bated by wind-blown sand, and will inevitably andeventually take place without adequate protection.Unlike fired clay, capillary rise in walls of mud brick

is low and the damage resulting from rising dampand deposition of soluble salts is relatively small.11

Excavated earth structures are often found inexcellent condition, but rapid deterioration will fol-low exposure unless appropriate countermeasures aretaken. Cover buildings (see Chapter 5) and screens toprovide protection from direct rain and wind, anddrainage channels to divert water away from earthwalls are sometimes used, especially for important andextensive earth building complexes. More low-keyprotection can be provided by roof canopies for individual walls, but these must have wide (at least600mm) overhangs and catchments at the base of thewall to divert water run-off and avoid splash-back.Soft plasters or slurries of mud or stone dust and limeputty can be used to protect wall faces. Wall headscan be protected with soil-lime caps. A mix of clay-rich earth, natural hydraulic lime, sand and choppedstraw or fibre (8:1:1) can be used as a structural repair,as capping slabs and even as plaster. The soil needs to be left under water for a few days before addingthe other constituents.10 These materials have goodreversibility, especially mud, and are easily renewable.Where losses have caused, or threatened to cause,instability, as often occurs near wall bases subject to

138 Conservation of Ruins

Figure 4.68 The use of earth and turf on the late nineteenth century Fort Brockhurst, part of the Palmerston Defences of theNaval dockyards of Portsmouth. The meticulously trimmed profiles quickly become wilder in appearance as grass gains height and wildflowers become established. Repairs are made in block bonded grass sods.

Ch04-H6429.qxd 10/17/06 2:44 PM Page 138

water erosion and salt damage, earth walls are mostsuitably repaired by cutting out the degraded areaand indenting new earth blocks. These blocks can bemade by ramming a suitable earth mixture into woodmoulds. Small quantities of hydraulic lime (e.g. 10per cent by volume) can be added to help bind theblock together, and chopped straw or synthetic fibrecan be added to improve its mechanical properties.The mixture must be well compacted into the mouldsand allowed to dry slowly. This curing period is bestcarried out under wet sheets of geotextile over aperiod of up to seven days, before de-moulding andbeing allowed to dry naturally, protected from rainand direct sun. Wall heads may also be capped withnew modified earth blocks or plastered with earth or,as a temporary protective measure, covered with geo-textile sacks half filled with sand. Rammed earth con-struction can be repaired in this way, as well as blockconstruction. The homogeneous nature of rammedearth makes it difficult or impossible to repair with arammed mix. In both forms of earth construction theblocks should harmonise in colour and texture, butcan be easily identified as repairs.

Wood and metal

The conservation of wood- and metal-framed build-ings is not discussed in this book, primarily becausetheir conservation is a separate specialist subject, butalso because the wood or metal ‘ruin’ normallyrequires re-roofing and recladding if it is to survive forany length of time. The dismantling, re-erection,renewal, replacement and restoration that are nor-mally needed belong more to the field of historicbuilding repair and conservation than to the conser-vation of ruins.

Wood and metal elements within ruins are in arather different category and often form a small butintegral and important part of their story. Woodoften survives well in waterlogged conditions or invery dry conditions. Thus, the medieval oak andelm piling of the Byward Tower at the Tower ofLondon (Figure 4.70) remained largely intact in themud of the river Thames, and sections of Herod’stimber scaffolding can still be seen in the walls ofMasada and, at the same site, the date-palm lacing ofSilva’s earth and rock siege ramp. In between such

Philosophy, technology and craft 139

Figure 4.69 The use of a cement rich plaster applied to earth walls is seen here in dramatic failure mode. Cracking of the plasteroccurred within 6 months and failure within one year. During its lifetime it held water against the ancient earth wall causing soften-ing and significant losses for the first time in many centuries.

Ch04-H6429.qxd 10/17/06 2:44 PM Page 139

140 Conservation of Ruins

Figure 4.70 Medieval timber piling, Byward Tower, Tower of London. Plants and pile-heads remained sound until the waterlevel dropped, exposing the critical zone below the masonry to drying, wetting/drying cycles and decay. Settlement and facturing ofthe masonry followed, requiring dry-packed mortar to make the load bearing connection between piles and wall base. Casework: SaraFerraby. Drawn by John Ashurst.

extremes, without preservative treatment, wooddoes not normally do well in the ruin context.Fragments of beam ends, wall plates and lacings,door and window frames, panel fixings and evensculpture, such as the angel on Francis Bacon’s six-teenth century gatehouse at Old Gorhambury, maylast a few hundred years. The recording of these

relatively fugitive elements is very important, andthey may be consolidated in situ.

Wood elements such as lintels over door or win-dow openings sometimes survive in a sound enoughcondition to provide dating information throughdendrochronology or, more usually, in a form whichis degraded by fungal and insect attack but which can

Ch04-H6429.qxd 10/17/06 2:44 PM Page 140

be consolidated using, for instance, epoxy or acrylicresin, modified to suit each particular situation. Suchtreatment is ideally carried out after removing thewood from the masonry in which it is set, subse-quently replacing it on lead spacers to allow air cir-culation. To achieve this, some first-stage hardeningwith brush-applied resin may be necessary. If thewood has an applied finish such as limewash, carehas to be taken to protect the finish from staining. Insitu flooding or grouting of surviving wood withinthe wall is an extremely hazardous operation andshould normally be avoided because of the difficul-ties in controlling migration of the resin to sur-rounding materials.11–14

Metals often survive well in the form of wroughtiron dog cramps, restraint fixings for facings, pintles,brackets and tie bars, and sometimes as sections ofrailings or even complete gates, and may need littletreatment. In later buildings there may be survivalsof cast iron beams which, in the present context,may be more vulnerable and may require effectivecleaning and painting. Some classical sites have beenseriously damaged by bronze cramps being dug outof masonry walls. Lead may be found in rainwateroutlets through walls, in chases as flashings for lostroofs, as cover flashings on copings and cornices, asjoggles or grouts around iron fixings, as glazingcame and occasionally as sculptural elements.

Where corrosion of iron is taking place to theextent that stone is being damaged, the iron will needto be cleaned and stabilised where exposed or partlyexposed. Typically, this involves rubbing down withsilicon-carbide wool, washing and drying, and the useof a zinc-rich primer followed by a micaceous ironoxide before painting. Extensive damage to masonryfrom corroding iron cramps may indicate that the useof impressed current cathodic protection (ICCP) maybe justified as a means of halting corrosion.14

Plaster

Plaster often survives in ruins, sometimes to the extentthat it still has a protective role for the masonry, some-times only as small coatings of gesso on architecturalmoulding, sometimes as the last indication of a dec-orative scheme, coloured or polished; its value indating a structure or in indicating the original char-acter of the building or a room within it is oftenconsiderable (Figure 4.71). Plaster bedding maysometimes be found for wall mosaics or other fac-ings. The impressions of the lost finishes may be theonly indication surviving of the original scheme.

Philosophy, technology and craft 141

Figure 4.71 Polished Herodian plaster. Only a small per-centage of plaster survives within a white cement frame which hadbeen mistakenly used to hold the plaster in position. At the topof the picture only the cement frame survives.

Figure 4.72 Finished consolidation work on decorative frag-ments of eighteenth century plaster which involved the removal ofcement mortar fillets and patches and the substitution of limeputty and ceramic fills. The plaster was cleaned of organic growthusing a small hand-held steam gun and was treated with a shel-ter coat of lime, marble dust and casein.

Ch04-H6429.qxd 10/17/06 2:44 PM Page 141

Accurate survey and recording is always impor-tant, and should not be delayed indefinitely, espe-cially where there are signs of detachment. All plasterthat was originally internal is at risk once a roof islost, and even external plasters are in danger wherebroken edges have been created during the processof ruination. The most vulnerable plasters in thecontext of a ruin are those based on clay-earth (mudundercoats or full plasters) and those based on gyp-sum, especially in wet climates. Both are readilydegraded in water and suffer surface softening andattrition followed by detachment, often soon afterexposure if they are not protected by paint or lime-wash. Well-carbonated lime plasters, non-hydraulicas well as hydraulic, can have surprising tenacity anddurability, and natural cement and artificial cement

stuccos commonly only fail due to cracking,detachment and freezing of trapped water, althoughthese failures may be exacerbated by a history of sol-uble salt crystallisation.

In the context of the ruin, conservation activityincludes the installation of small roof covers attachedto the wall to throw water clear of the plaster(Figure 4.74), removal of organic soil with biocideand small steam guns, removal of any impermeablecement-based mortar edge fillets or patches, flushingand grouting detachments and fractures, and installinglime mortar edge fillets and fills in lacunae (Figure4.75). In some situations, because of the good tensilestrength and flexibility of haired lime plaster, it is pos-sible to carefully ease back a detaching plaster faceonto a cleaned and lime slurried wall. Plaster groutspecifications are provided in Appendix 1.3.

The replacement of areas of plaster, sometimes inthe form of easily distinguishable undercoats, issometimes advisable around a surviving ‘island’ oforiginal plaster on the wall. These new plaster areascan help provide support and can act sacrificially (ifproperly designed, with good water vapour per-meability) for the benefit of the old plaster. Weak sur-faces can sometimes be consolidated with multipleapplications of lime water and, where appropriate,protected with finely screened limewash, gaugedwith a small percentage of casein.

In common with other surfaces not originallydesigned for external weathering, internal plastersurfaces must be regularly monitored to keep trackof their condition.

Floors

Solid floors exposed by the loss of roofs are chal-lenged in the same way as wall heads and internalwall surfaces; they were not intended to be wea-thering surfaces. The most vulnerable are those oframmed earth, with or without a plaster finish.These are very quickly destroyed by rain and theroot systems of plants, although evidence sometimessurvives close to the protected base of walls or wherethe floor was covered with fallen debris. Floors ofthis kind, after recording, must be covered if they areto be retained in dry, ventilated conditions. Evenwhen the floor finish is missing there may be layers ofcompacted material below, indicative of the originalfloor level and even of the missing finish type. Oncerecorded these compacted layers normally need tobe protected by back-filling.

Lime, ash and gypsum composition floors can be almost as vulnerable.14 Low-fired, ceramic tiles,

142 Conservation of Ruins

Figure 4.73 Plaster survival in dry conditions. Multi coat plas-ter at Paestum. Plasters in these conditions can become detachedthrough the activity of soluble salts migrating in the wall, especiallyafter excavation. Detachments may need to be grouted with weakhydraulic lime and broken edges closed up with weak hydraulic limemortar, carefully cured. Regular inspection of these important plas-ters is essential and replacement of protective mortar fillets may beneeded from time to time.

Ch04-H6429.qxd 10/17/06 2:44 PM Page 142

especially those which were subjected to heat as inoven floors, or to excessive wear, can also be easilydestroyed and need to be provided with covers. Well-fired brick or tile and stone slabs or cobbles are themost durable finishes and may, with judicious point-ing in hydraulic lime and sand, lifting and rebeddingwhere necessary to avoid hollows where pondingcan take place, weather well in exposed contexts.All floors need to be inspected regularly for signs ofdeterioration. One of the problems may be unusuallevels of wear by numerous visitors. Rerouting maybe necessary and some areas may need to be pro-tected altogether from foot traffic even if exposed toview (see Chapter 9).15

Floors such as Roman or Byzantine mosaic, ormedieval floor tiles, present particular problems inthe context of ruins. They may have been damaged byfallen masonry, roof tiles or timber and may survivein localised areas with unsupported edges, becomingloose through exposure to weather. They are vulner-able to plant growth and organic soiling and saltdeposits, and to hollows developing in the supporting

base, leading to subsidence and water collection.They are, perhaps more than any other artefact onthe ruin site, at risk from souvenir hunters. Unfortu-nately, many of these floors have been badly treatedby uninformed custodians, and both mosaics andtiles have been grouted and even bedded in strongcement-based mortar to try to secure them. In cold,wet zones this treatment can have disastrous effectson clay floor tiles, and on ceramic and limestonetesserae, with the ancient fabric acting sacrificiallyto the mortar; similarly, in sites where soluble saltsmigrate to the floor surface, ceramic, limestone andmarble will again suffer casualties while the mortarsurvives.10

Bedding, framing and grouting mortar must havegood water vapour permeability. A mortar such aslime putty:sand:ceramic powder in the portions 1:3:1,or weak hydraulic lime (NHL2) and limestoneaggregate (1:2.5) have the right kind of characteristics,but even weaker mortars may be suitable dependingon circumstances. Surface protection such as geo-textile and half-filled sandbags of geotextile and

Philosophy, technology and craft 143

Figure 4.74 Plaster survival in wet conditions. Decorative plaster at this level, seen at Hardwick Old Hall, is particularly susceptibleto damage by water and colonisation by organic growth. In the absence of a roof, protection is provided by small, timber board projectionsof 300 –450 mm, covered with lead. The upturn of the lead against the wall must be into a carefully formed wall chase, secured withstainless steel screws and washers. Maintenance is essential, including the use of thin lime washes.

Ch04-H6429.qxd 10/17/06 2:45 PM Page 143

sand covers may be needed on insecure sites, and oncold sites ventilated and insulated box covers areneeded for the winter, a role once filled on somesites by layers of cut bracken. Organic ‘blankets’ ofthis traditional kind, although often effective againstfrost, can cause staining and invite investigation byhumans and animals (see Chapter 5 for details onprotective covers).

Some experimental work in flood-treating weakclay tiles and stamped and slip-filled medieval tiles hasbeen carried out with catalysed silane consolidant.The areas of tile were first enclosed by a low upstandwall of lime mortar standing about 75mm above the

floor surface. The areas were cleaned, dried for someweeks under ventilated covers, and then surfacewarmed and dried with hot air before flooding andallowing the floor to absorb the low-viscosity consol-idant, achieving enhanced resistance to freeze–thawdamage. While such a treatment cannot be describedas reversible, it is not ‘permanent’ either, and mayneed retreatment, which can safely be renewed aftera minimum period of one year.

Conservators on site

Walls and floors of ruined structures may themselvesbe fragile as in the case of earth construction, andare not infrequently associated with and intimatelyconnected to fragile survival, such as plaster, paint,tile, mosaic, wood, metal and glass. Architecturalmoulding and sculpture can be added to this list.Although the in situ conservation of these importantsurfaces is properly the work of conservators specif-ically trained in their care, there is often a ‘grey zone’in ruined buildings where fragmentary survivals areneglected or mistreated. Yet these survivals are oftenvery important indeed to the understanding of thecharacter and chronology of a site, and the ‘conser-vation technicians’ working on the stabilisation andconservation of the walls need to be able to recog-nise them and to protect them, until conservators canget to the site (see Figure 4.74).10

144 Conservation of Ruins

Figure 4.75 The conservation work required on Bacon’s latesixteenth century entrance porch included mortar repairs, stainlesssteel and ceramic stitches to hold edge bedded columns together,conservation and replication of Roman marble, consolidation andsurface treatment of a range of decorative stones and consolidationof heavily decayed wood sculpture.

Figure 4.76 An unusual reversible wall capping system seenon the so-called ‘Temple of Saturn’ in the Forum of Rome, whichis designed to protect the archaeology of the wall head. This is amulti-layer lime-pozzolana plaster which is designed to providea weathering surface but which can easily be broken off in thefuture without damage to the original substrate.

Ch04-H6429.qxd 10/17/06 2:45 PM Page 144

Philosophy, technology and craft 145

Summary

This chapter has shown the combination of technol-ogy and craft being used in the service of conserva-tion and in the context of a philosophy of minimumintervention to achieve maximum retention of his-toric fabric. The objective is to be able to look at aruin and know that it is an ‘authentic survival’ fromits period or periods, with the ‘non-authentic’ parts,necessary for that survival, clearly defined. Amongstbuildings, the ruin can be unique in this way becausethere is no practical reason or necessity to restore it, as Frank Baines was at pains to point out at thebeginning.1

Who can carry out this work, and how such people can be found or trained, is the subject ofanother chapter.

Notes and references

1. Baines, F. (1923). Preservation of ancient monumentsand historic buildings. RIBA Journal.

2. Peers, C. (1931). The treatment of old buildings. RIBAJournal.

3. Baines, F. (1924). From an address to the NorthernPolytechnic Department on the Preservation of AncientMonuments and Historic Buildings, 3 December.

4. Harvey, W. (1925). The Preservation of St Paul’sCathedral and Other Famous Buildings: A Text Book onthe New Science of Conservation. The Architectural Press.

5. Faulkner, P. (1989). Notes on Structural Archaeology(unpublished).

6. Eaton, T. (2000). Plundering the Past – Roman Stoneworkin Britain. Tempus.

7. Viles, H., Groves, C. and Wood, C. (2002). Soft wallcapping experiments. English Heritage Research Transac-tions, Volume II.

8. Eaton, T. (2000). Plundering the Past – Roman Stoneworkin Britain. Tempus.

9. See, for instance, Harrison, R. (1999). Earth. EnglishHeritage Research Transactions, Volume III.

10. Pearson, G. T. (1992). Conservation of Clay and ChalkBuildings. Donhead.

11. Ibid.12. Shalom, A. Excavation and Conservation on Archaeological

Sites. Archaeological Conservation Centre, Sede BokerAcademy, Negev Highlands.

13. Notes from Harrison, H. (2006). Conservation ofPolychrome Wood.

14. Martin, W. and Blackney, K. (1998). The applicationof cathodic protection to historic buildings. EnglishHeritage Research Transactions, Volume I.

15. Fawcett, J. (2001). Historic Floors – Their Care andConservation. Butterworth-Heinemann.

Ch04-H6429.qxd 10/17/06 2:45 PM Page 145

Open-sided shelters protecting the bath house at Beit She’an, Israel.

Ch05-H6429.qxd 10/14/06 3:32 PM Page 146

Introduction

Attitudes to the protection of ruined monuments havealtered radically over the past century, in the wake ofthe international conservation movement and inter-national conservation charters, and with statutoryprotection of ancient monuments introduced in manycountries. It has been common practice in manyplaces to leave architectural remains on archaeologi-cal sites exposed with minimal or no interventionafter excavation, once the valuable data and portableartefacts have been extracted. Experience has shown,however, that exposure without protection or inter-vention generally has disastrous consequences forbuilding fabric and that the natural forces, whichquickly set to work, are almost always destructive tosome degree and in some form.

As a minimum, if other measures are deemedinappropriate or resources are limited, recently excav-ated ruins should be reburied, or back-filled, to usethe term normally employed in an archaeologicalcontext. For a number of reasons, including limitedresources in some cases, purpose-built shelters orenclosures, which would both provide protectionand allow the ruins to be permanently on display, aregenerally reserved for the most important sites, ofnational and international significance. Such sitestypically feature decorative architectural elements,such as mosaics, which can attract sufficient numbersof visitors for the site to be sustainable.

Ruins are diverse in materials, size, form and con-text. This chapter sets out methods and materials forprotecting ruins of various types, from ruins standingto some height and masonry shells to low-lying walls,and their associated architectural detail and decor-ation, and outlines criteria for their use. Potential pro-tective measures, including reconstruction, reburial,

open shelters and permanent enclosure buildings, aredescribed with examples drawn from historic andcurrent practice. This chapter also touches on othercrucial issues: condition survey, interpretation and pre-sentation of sites, and conservation principles, particu-larly authenticity and significance.

The number of ruined sites formally recognisedas being of international importance by inscriptionon UNESCO’s list of World Heritage Sites growsannually. At a national level, archaeological excav-ations continue to reveal new sites, many with ruinedstructures, which require some form of protection,and often masonry consolidation if they are to beexposed to the weather. It is not an exaggeration tostate that need far exceeds available resources for pro-tection and maintenance of ruins, even in the mostaffluent nations. It has been reported, for instance,that the total budget currently required for protec-tion and treatment of the ruins of Pompeii in Italyexceeds the present annual budget by a factor of 10.1

Consequently, it is essential to define and apply theterm ‘preventive conservation’ as broadly as possi-ble. The concept of preventive conservation is well-known in objects conservation but little used in thecontext of ruins. Essentially, preventive conserva-tion denotes an approach whose primary objectiveis to ensure the long-term physical survival of his-toric fabric; other objectives, relating, for example,to presentation and interpretation, are consideredsecondary. In general, preventive conservation entailsmodification of the ruin’s environment by measuressuch as reburial and shelters, and the role of remedialwork is minimised. However, reconstruction canmodify the environment of a ruin, locally or on alarger scale, to secure the survival of vulnerable fab-ric. When used is special circumstances, to meet spe-cific conservation-based objectives, reconstruction

147

Chapter 5

Preventive conservation of ruins: reconstruction,reburial and enclosure

Catherine Woolfitt

Ch05-H6429.qxd 10/14/06 3:32 PM Page 147

or reinstatement of missing elements has a role inpreventive conservation. Proposals for any form ofprotection or intervention must be founded onrespect for the essential values and integrity of a siteand its structures, and seek to ensure that these arenot compromised. In most cases, however, proposalsthat require permanent construction work on a largeand multi-layered site will inevitably have someadverse impact. In these situations any negative aspectsmust carefully be weighed against the long-termbenefits of a scheme.

The statutory framework

In England and Wales, ruins may fall within the classification of either a scheduled ancient monu-ment or a listed building, or may be classed as both.There is considerable overlap between these two cat-egories of statutory protection and both are verybroadly defined. Virtually any alteration or additionto a scheduled ancient monument requires sched-uled monument consent. Depending on the statusof the ruin, either listed building consent or sched-uled monument consent will be required for protect-ive measures. If the ruin is both scheduled and listed,only scheduled monument consent will be required,to avoid duplication, and planning consent may alsobe required, depending on the nature of the work.2

This statutory framework is, however, set to change.The government has indicated its intention to inte-grate the existing separate control systems and vari-ous forms of statutory designation.

At present in England, English Heritage imple-ments controls over work to scheduled ancientmonuments, on behalf of central government; localplanning authorities administer control of work tolisted buildings (listed building consent), and con-sult with English Heritage and other organisations,as required and especially on grade I and II* listedbuildings. The principal general guidance docu-ments are Planning Policy Guidance (PPG) 15, ‘TheHistoric Environment’, and PPG 16, ‘Archaeologyand Planning’. Underpinning these policies andother guidance documents issued periodically byEnglish Heritage are various international charters.

The Venice Charter of 1964 was fundamental andset out the key definitions and principles to beapplied in ‘conservation’ and ‘restoration’ of monu-ments. The definitions of terms such as restorationand reconstruction have evolved since then. Two ofthe most recent charters address the specific issues ofauthenticity and reconstruction: the Riga Charter

of 2000 ‘On Authenticity and Historical Recon-struction in Relationship to Cultural Heritage’ andthe ‘Nara Document on Authenticity’ of 1994. It is worth setting out the definitions provided byEnglish Heritage in 2001 in the ‘English HeritagePolicy Statement on Restoration, Reconstruction andSpeculative Recreation of Archaeological SitesIncluding Ruins’, which are adopted from the BurraCharter of 1999:

● Restoration – returning the existing fabric of aplace to a known earlier state by removing accre-tions or by reassembling existing componentswithout the introduction of new material.

● Reconstruction – returning a place to a knownearlier state; distinguished from restoration bythe introduction of new material into the fabric.

● Recreation – speculative creation of a presumedearlier state on the basis of surviving evidencefrom that place and other sites, and on deductionsdrawn from that evidence using new materials.

This English Heritage policy document includes thefollowing important principles: that restoration andreconstruction should be approached with cautionand never be carried out on a speculative basis, andthat only minimum conservation work necessary forlong-term survival should be done. These are keyprinciples which guide the implementation of workto ruins in the UK and elsewhere. It should be noted,however, that it is almost impossible in practice tocarry out ‘restoration’ work to a ruin, however min-imal in scope, without introducing some new mater-ial. Reassembly of rubble and some types of ashlarmasonry will, for example, necessarily entail intro-duction of new mortar. Most masonry conservationactivities discussed in the other chapters of this bookinvolve the introduction of new materials, mainlythose based on lime. Usage and implicit definitionsof the words restoration and reconstruction varyquite substantially in conservation literature and evenmore widely in the ‘heritage’ industry generally.Confusion and imprecision in the language of con-servation and restoration is a problem, which some-times hinders the progress of proposals for preventiveconservation. It is not uncommon for proposals to berejected on the basis of the use of the word recon-struction or restoration, when the same interventioncouched in terms such as consolidation or reinstate-ment might find acceptance.

It is important to recognise that some of the issuessurrounding protective measures, such as visual oraesthetic impact, can be subjective, and that the prin-ciples and policies set out in various charters and

148 Conservation of Ruins

Ch05-H6429.qxd 10/14/06 3:32 PM Page 148

Preventive conservation of ruins: reconstruction, reburial and enclosure 149

guidelines, like the terms reconstruction and restor-ation, can often be interpreted in more than one way.Consequently, opinions may diverge substantiallywhen policies must be translated into firm proposalsfor protective measures and actual implementation ofwork on site. This is the case particularly in the con-text of proposals for reconstruction and enclosure,which can substantially alter the appearance of ruinsand their settings.

Reconstruction

Should ‘reconstruction’ even be considered as ‘pre-ventive conservation’? This is potentially a divisive andcontroversial issue. To include it may risk abuse byzealous restorers, but to exclude it denies the legiti-mate role illustrated in the case work provided. Thetest, of course, must be a rigorous assessment of themotivation and justification for its use.

The success or failure of any scheme of recon-struction must be judged in its local, regional andnational contexts. The kind of reconstruction workcarried out by the Canadian federal government atthe site of the town and Fortress of Louisbourg inCape Breton, Nova Scotia, begun in the 1960s,which entailed complete rebuilding of a section ofthe eighteenth century French fortifications and

settlement on the original ruined masonry remains,is alien in the British context, where there is a trad-ition of conservation and historic rejection ofreconstruction and restoration. In Canada, however,this work was conceived as an act of preservation,motivated by a combination of cultural and socio-economic factors: the need to stimulate an econom-ically depressed and isolated region of the country,where the impact of the collapse in the coal miningindustry was sorely felt, and the growth of a nationalheritage preservation movement. The reconstruc-tion is an interesting example of how federal gov-ernment policy and intervention at several levels,including in this case the economy and tourism, canimpact directly on a ruined heritage site. The subjectof the Rand Royal Commission of 1959 was theeconomy, and in particular the coal industry, but itsreport extended to cultural resources and it con-cluded: ‘That site [Louisbourg] marks a salient occa-sion in the transplantation of a civilization significantto the history of Canada; and to allow it to sink intoruin and obliteration would be a grave loss to thecivilizing interests of this country.’3 Based on exten-sive archival research in Canada, France and England,and on extensive archaeological investigation of thesite, the reconstruction involved faithful replication oforiginal eighteenth century structures, generallyexecuted in the same materials and constructed on

Figure 5.1 View of the reconstructed section of the Fortress of Louisbourg in Cape Breton, Nova Scotia, Canada (photograph: G.Abrey).

Ch05-H6429.qxd 10/14/06 3:32 PM Page 149

the remains of the original masonry. The reconstruc-tion attracts many visitors who would not otherwisevisit the site, which is located in a remote part ofNova Scotia. In combination with the interpretivemeasures, which include costumed animation, char-acters in historic costume enacting scenarios andinteriors furnished in the style of the period, it pro-vides a vivid picture of life in the eighteenth centuryFrench settlement.

There is always scope for criticism of this approachin terms of authenticity and the scale of physicalintervention, but in this case, where reconstructionrelied on thorough research rather than speculationand the forms of many of the buildings, especiallythe public ones, could be established by a combin-ation of archaeological investigation and documen-tary research, the benefits of reconstruction wereconsidered to outweigh such concerns. The recon-struction has brought tangible educational benefitsfor visitors and extended the life of the site, beyondthat of many excavated sites, where the nature of thelow-lying masonry remains is such that they will notattract many visitors, other than those with a spe-cialist or informed interest. If the impact of theFortress Louisbourg reconstruction were measuredagainst the various international charters, the assess-ment would vary depending on which one isapplied. The charters differ in the strands of conser-vation philosophy, ethics or values that are empha-sised. Judged by the terms of the Burra Charter andthe English Heritage policy statement on restor-ation and reconstruction, the work at Louisbourgmight be criticised as bordering on recreation. Ifconsidered by the terms of the Nara Document,with its emphasis on the cultural context of authen-ticity, the conclusion might be more favourable,allowing for factors specific to the Canadian con-text, such as the comparative scarcity of eighteenthcentury architecture standing above ground and theimportance of the site as the strongest fort on theAtlantic coast of North America at that time.

Other recent examples of reconstruction discussedbelow are much more limited in scope and typicallymotivated by a combination of factors. An importantpoint is that the aim of reconstruction can be, entirelyor partly, to ensure the preservation of ruins, throughnot only physical interventions but also the widerbenefits brought by these interventions, which caninclude raising the profile of a site in a positive way,increasing accessibility, and enhancing visitors’ experi-ence and understanding of sites and their history. Theobjectives in reconstruction can extend far beyond thephysical preservation of ruins. Fortress Louisbourg isan extreme example in the sense that it is at one end

of the spectrum of ruins reconstruction – completerebuilding of entire structures, albeit of only a sectionof the site.

This extent of reconstruction is unusual on anarchaeological site. More typical in the context ofancient sites is the re-erection of original masonry,with or without the introduction of new material toreplace missing elements. This has long been practisedon Mediterranean and Near Eastern sites and is gen-erally referred to as anastylosis. Traditionally, masonryunits which have fallen for whatever reason, earth-quake, erosion or otherwise, are re-erected after excavation and recording. Well-known examplesinclude the Treasury of the Athenians and othermonuments at Delphi, in Greece, the Library ofCelsus at Ephesus in Turkey and vertical elements ofthe Northern Palace at Masada, Israel (see Figure5.27 – view of Ephesus). Columns are favouritesubjects for this form of reconstruction since theydeliver an immediate visual impact, their verticalitydefining space on sites where masonry remains areoften otherwise low in height. The aim, in manycases, has been as much visual and interpretive asexplicitly for the physical preservation of the ruinedfabric of the site.

When to reconstruct or reinstate

It is difficult to specify precisely when reconstructionis appropriate, since any proposals for such work mustbe tailored to the particular conditions and needs ofindividual sites and contexts, but there are some gen-eral guiding principles. As a very general rule, theolder the ruins, the more potential problems andcomplexities may be expected in attempting to carryout authentic reconstruction, or reinstatement of lostelements. The extent of documentation, drawingsand written accounts to inform reconstruction worktapers off from the present through the past and intoprehistory, where only physical evidence of struc-tures and the material culture survives. For this reasonand others, reconstruction of ancient ruins typicallyentails some degree of speculation and should only becarried out in special circumstances, to meet specificconservation-based objectives.

However, the age of a ruined monument is onlyone aspect of its significance. The historic signifi-cance of the ruined sites of the Second World War,which are comparatively recent, is undeniable.Oradour in France, site of a terrible massacre anddestruction of an entire town, and the Cathedral ofSt Michael in Coventry, destroyed by bombing in1940, and its counterpart, the Kaiser WilhelmGedachtniskirche in Berlin, are important examples

150 Conservation of Ruins

Ch05-H6429.qxd 10/14/06 3:32 PM Page 150

Preventive conservation of ruins: reconstruction, reburial and enclosure 151

(see Figure I.3, Introduction chapter for a view ofOradour). In the case of these sites, reconstructionwas considered inappropriate. Their significance liesin their ruined condition, which is meant to capturethe moment of their destruction; they are to be left‘frozen in time’ as reminders of the horrors of war.The ongoing challenge at these sites, as at any ruinwhich has lost its roof, is to ensure the preservationof the fabric and prevent deterioration with minimalintervention.

It is easy to find fault with early attempts atreconstruction of ancient ruins, but it must beacknowledged that much has been learned frompast mistakes. The reconstruction of parts of theBronze Age Minoan Palace of Knossos on Creteunder the direction of Arthur Evans in the earlytwentieth century illustrates two principal issues,which have been addressed by later conservationcharters: lack of authenticity and speculative work(Figure 5.2). Criticism of the Knossos reconstruction

Figure 5.2 Light well in the ‘Throne Room’ at the Minoan Palace of Knossos on Crete, early twentieth century reconstruction byArthur Evans (photograph: C. Woolfitt).

Ch05-H6429.qxd 10/14/06 3:32 PM Page 151

152 Conservation of Ruins

has focused on the use of materials alien to Minoanarchitecture (such as reinforced concrete) and thesometimes scant evidence for quite extensive recon-struction, including wall paintings. In the 1950s theAmerican School of Classics at Athens carried outthe complete reconstruction of the second centuryBC Stoa of Attalos at the site of the ancientAthenian Agora, building on the surviving founda-tions, and incorporating sections of the original,mainly at the south end.4 The new stoa providesaccommodation for the Agora museum and store,and for a conservation laboratory and offices for theAgora excavations (Figure 5.3). Although the newmaterials and design followed the original, as far asthese could be determined from the archaeologicalremains and from nineteenth century photographs,there are some variations, for example in the mod-ern terrazzo floor, which is quite different in char-acter from the original, a section of which waspreserved in the 1950s. Both the Knossos and Stoaof Attalos reconstructions might equally bedescribed as recreations by the definitions of theseterms set out above. The new stoa is a large struc-ture and, inevitably, as the only complete classicalbuilding in the vicinity standing to a height of two

storeys above ground level, it dominates the site ofthe Agora. It provides welcome shade in an other-wise exposed site during hot weather, but has nev-ertheless attracted criticism due to its impact on theoriginal ruins and its scale and completeness in thecontext of the surrounding low-lying ruins.5

Dismantling and reconstruction of ancient ruinsis sometimes necessary to rectify the failure of past interventions. Corrosion of ferrous fixings inashlar masonry is a common problem and one thatafflicted the ruined monuments on the Acropolis inAthens (Figure 5.4). The current, extensive pro-gramme of work on the Acropolis entails localisedreconstruction – dismantling of ashlar masonry,removal of the ferrous fixings and other defectiverepairs installed in past reconstruction work – as wellas some introduction of new stone to fill lacunae andreplace missing blocks. The general approach andscale of reconstruction work contrasts markedly withthe treatment of the Stoa of Attalos (Figure 5.3),although, in fairness, the two schemes of work areseparated by several decades, during which period theinternational conservation movement grew. Sculptureis removed to a museum environment and replacedwith replicas; the threat posed by the corrosive

Figure 5.3 View of the reconstructed Stoa of Attalos in the Athenian Agora, Greece (photograph: C. Woolfitt).

Ch05-H6429.qxd 10/14/06 3:32 PM Page 152

Athenian environment is considered too great to riskongoing exposure of the remaining sculpture.

The Parthenon, in particular, is a good example ofpast reconstruction work and its unfortunate conse-quences. The partial destruction of the Parthenon bythe famous explosion of 1687 created a ruin much lesscomplete than the one currently on display; the longwalls were largely destroyed, leaving mainly the westand east ends of the temple standing.6 Prior to theexplosion the structure had been adapted for use as aChristian church and a mosque. Nineteenth centurywork on the Acropolis included stripping away all evi-dence of accretions later than the fifth century BC.Work on the Parthenon extended into the first halfof the twentieth century under the engineer NikalaosBalanos, who published an account in Les Monumentsde L’Acropole: relèvement et conservation (1938). Thiswork has been criticised for a number of reasons, forthe lack of accuracy and authenticity, since little effortwas made to reinstate the marble blocks in their orig-inal positions, and for inappropriate materials – the iron fixings used, instead of iron set in lead asdone originally. The later fixings subsequently oxi-dised, splitting and cracking the marble. UNESCO

produced a report in 1970 addressing these prob-lems and the threat from the corrosive urban envi-ronment, the result of which was the formation inthe mid-1970s of a new committee to supervise theconservation and restoration of all monuments onthe Acropolis site. Work on the Parthenon includesdismantling and reconstruction with detailed record-ing; stones are individually recorded, lifted andrepositioned, the iron fixings removed and replacedwith titanium substitutes. The Athena Nike andErechtheion temples have received similar treatment.Recent assessment of the work on the Acropolishighlights the painstaking detail of the work, butalso a tendency to focus on the fifth century remainsto the exclusion of subsequent periods, a trendwhich began in the nineteenth century.7

The issue of authenticity can be complex whendiscussing ruins that have been subject to frequentrebuilding and repair in the past. As Mary Beardwrites of the Colosseum:

It is a well-known axiom among archaeologists that themore famous a monument is … the more likely it is tohave been restored, rebuilt, and more or less imaginatively,

Preventive conservation of ruins: reconstruction, reburial and enclosure 153

Figure 5.4 The Erechtheion on the Acropolis, Athens, Greece, one of the monuments subject to the ongoing programme of conser-vation work (photograph: C. Woolfitt).

Ch05-H6429.qxd 10/14/06 3:32 PM Page 153

reconstructed. There is an inverse correlation, in otherwords, between fame and ‘authenticity’ in the strictestsense.8

Recent examples from Israel illustrate the use ofreconstruction on a small scale and with specific con-servation-based objectives – to restore structuralintegrity and protect against erosion and loss. TheNorthern Palace at Masada, built by King Herod inthe first century BC, is a remarkable feat of engineer-ing; its structures on three terraces cling to steepprecipices. On completion, lime plasters protected theearth and gypsum bedding mortars and undercoatsagainst weather. Since excavation in the 1960s thesite’s vulnerability has been realised, and study andrecording has revealed the sometimes precarious con-dition of the masonry, the causes of which includedthe proximity to the salt-laden Dead Sea, infrequentbut torrential rainfall, and the nature of the rock for-mation on which the masonry was erected.9 Thedecision was taken to reinstate sections of missingmasonry to stabilise surviving fragmentary masonryremains. The broken vault of the bath house has beencompleted, both to protect what survived and to pre-vent further damage to the plaster lining of the bath,

which had been damaged by stones thrown or fallenfrom the viewing platform above (see Chapter 10).Eroded and missing sections of the tholos (middleplatform) have been repaired or reconstructed toprotect the wall core. One factor in the decision toreconstruct was the inaccessibility of the site, whichmakes scaffolding very difficult and expensive, andprevents routine maintenance. The recent work atMasada is discussed further in Chapter 10.

Vandalism can be a problem at remote sites. Aninteresting example is the Nabataean site ofMamshit, in the Negev desert of Israel. Here a teamof Italian conservators from the Centro di Conser-vazione Archeologica (CCA) carried out recordingand conservation of the mosaic pavement in thewest Byzantine church.10 At the end of the workthe mosaic was smashed overnight and much dam-age done to sections of detail. The decision wasmade to restore the mosaic, dislodged tesserae wereretrieved and, using the records, which fortunatelyhad been produced before conservation work hadcommenced, the damaged sections were reassem-bled remotely in Italy and sent back to the site forreinstatement (Figure 5.5).

154 Conservation of Ruins

Figure 5.5 Reinstatement of the vandalised mosaic pavement of the west Byzantine Church at Mamshit in Israel (photograph: AsiShalom).

Ch05-H6429.qxd 10/14/06 3:32 PM Page 154

Reconstruction of part of a ruined monument issometimes carried out to permit or facilitate its par-ticular use. Seats and steps in ancient Greek andRoman theatres are often reinstated, either partially orcompletely, to provide access for modern perform-ances. This has occurred, for example, at the theatresof Epidaurus (Sanctuary of Asklepios, mainly in the1950s and 1960s) and Athens (Odeion of HerodesAtticus) in Greece, and more recently at Caesarea andBeit She’an in Israel (Figure 5.6). In the case ofCaesarea this involved very substantial reconstructionand introduction of new concrete elements to supportupper levels of seats (Figure 5.7). One principle ofreconstruction on archaeological sites is that newwork should be visually distinguishable from the ori-ginal. The pristine condition of new ashlar stoneworkoften contrasts strongly with the weathered original,but this initial contrast may become less obvious withweathering. Seating in a different material would bemore readily obvious as a modern insertion. A sectionof new seats at the amphitheatre of Beit Guvrin inIsrael has, for example, been erected in timber on ametal frame.

In raising masonry walls the original work issometimes differentiated from the new by a lineapplied to the face of the masonry joint forming thisinterface. Such markings can be aesthetically unsatis-factory, for example when carried out in a materialsuch as black paint (Figure 5.8) over comparativelywide rubble masonry joints. A more aestheticallypleasing and durable alternative for use in rubblemasonry is the incorporation of small stone or tile‘nails’ incorporated or driven into the bedding mor-tar to delineate the new work from the original.

Although it is sometimes difficult to draw a hardline between the two types of ruin or ruin context –historic and archaeological – reconstruction of his-toric ruins is, in general, likely to be less complex andproblematic. In some contexts, for example historiclandscapes and gardens where ruined structures havefallen into disrepair and ruin, repair and reconstructionis the only viable option without losing importantarchitectural elements within the historic landscape.The repair and localised reconstruction of the ruinedgarden walls (listed grade II) at Lauderdale House,Waterlow Park, Highgate, London, completed in

Preventive conservation of ruins: reconstruction, reburial and enclosure 155

Figure 5.6 Reconstructed section of the theatre of Beit She’an in Israel (photograph: C. Woolfitt).

Ch05-H6429.qxd 10/14/06 3:32 PM Page 155

2004, is an example of reconstruction in the contextof a historic garden. The terraced brick walls werebuilt as part of the landscaped gardens for the six-teenth century house and adapted and altered oversubsequent centuries. Work to the ruined walls waspart of a larger scheme to restore the historic land-scape and enhance visitor use and awareness of thepark; the Heritage Lottery Fund supported thescheme undertaken by the London Borough ofCamden. The garden retaining walls had become soovergrown by plants that they were barely visible.Large sections of the walls had collapsed or beeninvaded by roots of woody species. Initial surveywork included clearance of as much growth as pos-sible, identification of brick dimensions and types toclassify the walls and to produce new bricks, whichwere made by hand by Bulmer Brickworks, tomatch the physical and visual properties of the ori-ginals.11 Accompanying this work was archaeologi-cal analysis of the original brick details, copings,mouldings at the base of the walls and evidence fororiginal iron railings. These original details were

recorded and drawn and formed the basis for recon-struction work (see Figures 3.9 and 3.10).

Re-roofing and reinstatement of internalstructures

Re-roofing and reinstatement of internal floor struc-tures are classed here under the heading ‘Recon-struction’, although in some respects they equallywell fit under the heading of ‘Protective enclosuresand shelters’. Where a ruin comprises a masonryshell standing to sufficient height that the originalroof and floor levels are legible, re-roofing and reinstatement of floors may be a viable option. Suchmeasures bring a number of benefits, including pro-tection of internal masonry and other features fromweather, protection of wall heads (depending on theform of the roof ), improved access to more parts ofthe structure for maintenance and associated inter-pretive benefits of defining internal spaces. Proposalsmust be based on buildings’ archaeology – studyand interpretation of the structure. Evidence for the

156 Conservation of Ruins

Figure 5.7 New seats and supporting structure installed at the theatre of Caesarea in Israel (photograph: C. Woolfitt).

Ch05-H6429.qxd 10/14/06 3:33 PM Page 156

original roof level is typically in the form ofmasonry offsets or other features (cuttings) whichprovided support for a timber roof structure. Rain-water outlets through masonry walls are anotherform of evidence for roofs set behind parapet walls.Both offsets and sockets for timbers may be evi-dence for floor levels, as well as the level of openingsin walls above ground level. It should be noted,however, that in ruined buildings of multiple phases

of reuse and rebuilding or adaptation, the ‘original’roof or floor levels may be unclear or the levels mayhave changed.

As a class of ancient monument, the tower is aform that lends itself to re-roofing and installationof new floors/stairs, provided, of course, that thecondition of the masonry is adequate to support theroof and these interventions would bring other justi-fiable benefits. A programme of repair, conservation

Preventive conservation of ruins: reconstruction, reburial and enclosure 157

Figure 5.8 At Masada in Israel a black line through masonry joints is used to delineate rebuilt masonry from the original (photograph:J. Ashurst).

Ch05-H6429.qxd 10/14/06 3:33 PM Page 157

and investigation of the masonry of the Normangreat tower of c. 1100 at Guildford Castle in 2003led to the discovery of two early Norman construc-tion phases and confirmation of the earliest rooflevel (see Chapter 10). Proposals were adapted toinclude the installation of a new roof and floor atprincipal (first floor) level. Evidence for the originalroof level and crenellated parapet was found in thecourse of repair work; this included infilled embras-ures, the line between the original parapet and theraised section of masonry above defined across largesections of all external elevations by a fine white lineof plaster. Study of the masonry also revealed chan-nels through one masonry wall for drainage of rain-water from the roof. The new roof was designed tomake use of these channels, with large lead chutesprojecting to throw rainwater clear of the building(see Figures 10.2 and 10.13 in Chapter 10 – view ofnew roof at Guildford Castle and view before instal-lation of roof, with damp environment and abun-dant organic growth on internal walls).

The rationale for re-roofing at Guildford was basedon two main premises: evidence for the earliest rooflevel and the benefits for the condition of the tower.The interior of Guildford’s tower had suffered fromabundant organic growth and a generally damp envi-ronment; the wall heads had been covered in a screed,formed with falls which directed rainwater into,rather than outside, the tower. The damp envir-onment caused early decay of the oak viewing galleryand ground-level access stair, within 10 years of theirinstallation in 1989, and created an unpleasant envir-onment, exacerbated by nesting pigeons and theirguano. The great tower closed to visitors in 1998due to health and safety concerns. Re-roofing and anew floor offered the opportunity to improve theinternal environment dramatically, to provide accessto the entire principal floor level, including a garder-obe chamber discovered in the course of work, andgave access to the upper sections of the walls above thelevel of the new roof for routine maintenance, mainlyremoval of plant growth from the wall head, since anumber of harness points were installed, as well as fix-ings for a ladder. The design of the new roof and floormakes no attempt to recreate the Norman construc-tion. The roof construction is of prefabricated soft-wood, covered with lead, and the soffit (ceiling) isboarded internally with ventilation gaps. The floorand access stair are of steel with oak boards and bothare independent of the historic fabric.

More contemporary designs and materials aresometimes used for new roofs. At Rochester Castle anew tensile fabric roof has been installed over the

forebuilding to the great tower. The glass roofinstalled over the ruined remains of the medievalJuval Castle (section of the ruin adjacent to the keep)in Alto Adige, in Italy, was designed to preserve thewalls from further decay and to make the internalspace available for various uses, such as sculptureexhibitions.12 In a sense it is a shelter rather than aform of reconstruction, but is mentioned here as acontrast to the Guildford Castle re-roofing, wheretraditional material, lead, was employed for roofcover. The roof design at Juval Castle employs a min-imal supporting structure of small section steel beams(I-beams) and tension rods. The roof structure isfixed to the masonry at only a few points and extendsbeyond the wall heads between 250 and 400mm,with gaps between the often irregular profile of thewalls and the new roof. The roof cover is of 16mmlaminated (toughened) safety glass and consequentlythe roof appears almost to float over the ruin.

Reconstruction/reinstatement – aspects ofplanning

The following aspects of conservation planning needto be addressed in the context of proposals for recon-structing all or a substantial section of a site, althoughtheir relevance will vary, depending on the nature ofthe site. These will also apply for other protectivemeasures, reburial and sheltering or enclosure.

● Defining significance. The aspects of a site whichconstitute its significance need to be identifiedand explicitly stated. The need to establish signifi-cance is recognised in various guidance docu-ments and charters. English Heritage’s InformedConservation: Understanding historic buildings andtheir landscapes for conservation (2001) by KateClark addresses this issue in detail.

● Multi-phase sites. Many ancient sites have developedand been adapted for different uses over centuries.The issue of which phase of construction or useto interpret can be an important consideration.

● Justification/rationale. The reasons for carrying outreconstruction work should be explicitly stated,and may be manifold, including any combin-ation of the following (and others): condition ofthe fabric and need to prevent deterioration orvandalism, enabling ongoing maintenance of a ruin,significance, rectifying past interventions whichare defective or promote decay, and a whole rangeof other factors such as socio-economic consid-erations, which will be unique to a site in its localand national context. Reconstruction should be

158 Conservation of Ruins

Ch05-H6429.qxd 10/14/06 3:33 PM Page 158

justifiable mainly on the basis of the long-termcondition of the ruin, minimising risks to its fab-ric, and the benefits the proposed reconstructionbrings for the physical remains. However, otherissues, such as those of interpretation, presenta-tion and access, often play a part and all factorsmust be considered together.

● Research and understanding/interpreting a site. Thispoint is linked to the first one, of understandingand defining significance. Reconstruction cannotbe carried out without a thorough understandingof the culture that produced the original monu-ment or building. Reconstruction will almostinvariably entail interpretation of the ruins, insome respect, and must be based on sound know-ledge and understanding of the historical and/orarchaeological evidence.

● Recording and drawn/photographic survey work.Recording of existing remains is essential, if this hasnot been carried out previously, and usually con-tributes substantially to understanding of a site andto developing project proposals. The record pro-duced is important for a number of reasons, notleast so that the extent of new work can be deter-mined in future. The scope of work will dependvery much on the nature of the ruin and its detail,as well as the extent of past records in the case ofexcavated sites, but should normally include acombination of written, drawn and photographicrecords. Most drawings, and a proportion of pho-tographic records in the UK, are now produceddigitally for ease of editing and of combining andoverlaying different types of data. The followingguidance documents on survey work are useful:Understanding Historic Buildings: A guide to goodrecording practice (English Heritage, 2006); MetricSurvey Specification for English Heritage (2000); andThe Presentation of Historic Building Survey in CAID,also by English Heritage.

● Condition survey work (see Chapter 3). Allied torecording and measured and photographic sur-vey is condition survey work. Condition surveywork must be recognised as a distinct activity andprocess, from measured, drawn or photographicsurvey, although the two can sometimes be car-ried out together, depending on the skills andexperience of the surveyor. Condition surveynormally employs the graphic representationsproduced by drawn/photographic survey workand may entail the addition of further data ontothe digital files. Proposals for reconstruction orother protective measures must be based onsound understanding of the physical condition of

the ruined fabric. It is essential that survey workbe carried out by specialists who have detailedknowledge of the building techniques and mater-ials originally employed, and the methods andmaterials currently available for implementingrepair and conservation work.

● Archaeological investigation/buildings archaeology. Provi-sion must be made for recording any archaeologi-cal features that might be uncovered in the process of reconstruction work. In England suchrecording is often a condition of scheduled monu-ment consent. A scope of work and methodologyshould be produced in advance and recording mayneed to proceed in stages, both at the outsetbefore work commences and in tandem withreconstruction work on site, where new featuresare uncovered.

● Authenticity. Are the form, materials and detailsof the original structures sufficiently establishedfrom the ruined remains and from any docu-mentary evidence to provide a sound basis for an authentic reconstruction? Speculative recon-struction is to be avoided. It is possible, however,for the design of new structural elements, such asroofs and floors, to be blatantly contemporary, toavoid any confusion of the original with new.

● Reversibility and minimal impact on original fabric. Theprinciples of reversibility and minimal interventionare fundamental in conservation. It should be pos-sible to remove later insertions and sections of newwork, and the extent of alteration to original fab-ric should be kept to the absolute minimum nec-essary to secure its stability. In practice, some typesof work, such as the introduction of new structuralelements, will necessitate some alteration of origi-nal fabric/masonry, either fixings or installation offoundations. When designing new structural ele-ments, whether in the context of reconstruction orfor sheltering or enclosure of sites, the intentionshould always be to minimise their impact.

● Environmental impact. There is a significant over-lap in many cases between the cultural or builtheritage and natural heritage sites. Ruins are oftenhome to numerous species of plants and animalsand form part of important natural environments.In many countries there is joint curation of nat-ural and cultural environments, with organisa-tions such as Parks Canada, National ParksService in the USA, and the Israel Nature andNational Parks Protection Authority (INNPPA).It is important that any proposals consider theimpact on the environment as a whole (seeChapter 6).

Preventive conservation of ruins: reconstruction, reburial and enclosure 159

Ch05-H6429.qxd 10/14/06 3:33 PM Page 159

● Resources and sustainability. The necessary resourceswill depend on the scope and nature of recon-struction proposed. Are the resources available toexecute the work and to involve specialists fromthe various disciplines whose input will be essen-tial? Have these resources been secured for thefuture? It is rare for any body, apart from centralgovernments, to be able to commit the resourcesnecessary over a sustained period for large-scalereconstruction work, for example of the extentand duration discussed above at the Fortress ofLouisbourg.

● Multi-disciplinary input. It is essential that suitablyexperienced specialists be assembled to plan, over-see and execute the work. For a medium- to large-scale reconstruction the following disciplines areusually necessary: archaeologist, researcher (whomay be an archaeologist or historian), architect/surveyor, engineer, craftspeople (masonry, joinery,blacksmiths), conservators, and possibly specialistsin design, display and interpretation. All membersof the team should be experienced in work onruined sites, with knowledge of the relevant periodof history/archaeology, of the building techniquesemployed in the original construction and of thematerials appropriate to carry out the work on site.It is essential for success that these various special-ists work together and in the case of work overlong periods they should all be based at or near thesite, at least for substantial blocks of time, so thatdecisions can be made jointly as work progresses.

● Planning/project management. Some group or indi-vidual must be responsible for overall coordination,assembling the necessary expertise, programming,budgets and practical execution of the work. In thecontext of the construction industry in the UK, aplanning supervisor must be designated to beresponsible for site health and safety.

Reconstruction/resinstatement – aspects ofimplementation (execution of site work)

● Specification and selection of materials. It is some-times not entirely straightforward to apply simpleconservation principles, couched in terms suchas ‘like for like’ replacement or ‘new materials tomatch originals’. These principles may need tobe further defined or interpreted, to provide suf-ficient guidance in the selection and specificationof materials. In the case of stone the issue of suit-able replacement is relatively straightforward,provided the original source or type of stone isstill available. Matching original bricks, at least intheir visual and physical characteristics, is also

often achievable. In the case of mortars and plas-ters, however, the matter is sometimes morecomplex. It is more realistic to seek a compatiblematerial than what could be strictly termed a‘matching’ material. Analysis and replication ofhistoric mortars has received attention in recentyears and the range of available lime binders hasincreased, with classification set out in the stan-dard BS EN-459 Building Lime (2001, parts 1 and2). In many cases it should be possible for a suit-ably experienced specialist in the conservation ofruins to identify the physical properties of theoriginal mortars on the basis of visual analysis andsimple tests, without recourse to chemical orother analyses, and to specify a visually and phys-ically compatible mortar. In some instances, itmay be necessary to use a mortar with differentproperties from the original, to meet certain per-formance requirements.

● Implementation – quality of work. No amount ofplanning or other professional work will com-pensate for poor-quality work on site. It is essen-tial that those carrying out site work be trainedand experienced in all aspects of the work, fromthe original construction methods and materials(so that they can detect any significant previouslyundetected features of the ruined fabric) to theparticular techniques and materials to be employedin new work.

● Recording during dismantling. Techniques formasonry consolidation and dismantling are discus-sed elsewhere in this volume. It is essential thatrecording work accompany any dismantling andthat appropriate labelling and cross-referencingto drawings or photographs be carried out so thatmasonry or other elements can be reinstated intheir original positions.

Reconstruction – summary

It is difficult for the word reconstruction to shed itspast associations with schemes of rebuilding work,which were sometimes speculative, and unsympa-thetic in scale and materials to the original ruin. Thisis unfortunate, for reconstruction (or reinstatement, ifthis term carries less negative connotations) has a roleto play in preventive conservation, on a limited scaleand in certain circumstances. Where ruins sufferaccelerated rates of erosion and loss after exposure,reinstatement or restoration of missing elements, suchas plaster, may be appropriate as a protective measure.Re-plastering has been used very successfully for theprotection of rubble masonry at a number of impor-tant historic buildings in England, notably at the early

160 Conservation of Ruins

Ch05-H6429.qxd 10/14/06 3:33 PM Page 160

churches of St Mary’s at Iffley near Oxford and atBosham in West Sussex. Where fabric is structurallyunstable and has lost its integrity through degradationof constituent elements, whether corework or face-work or both in the case of masonry, or where thereis a risk of collapse and loss, reconstruction or rein-statement may be the best option.

Reburial

Reburial is the most basic, low-tech and, in general,the most effective protective measure, a practicecommonly known in archaeology as back-filling. It isalso the most cost-effective in the long term since,apart from the initial expense of the reburial process,it reduces the need for subsequent site maintenance.Where necessary, it will permit land to be returned toother uses, whilst protecting the buried remains. Thefeasibility of reburial will depend on a number of fac-tors. It should be a relatively straightforward optionfor recently excavated sites, since in most cases thesoil and other fill material removed in the process ofexcavation will be suitable for this purpose. In othercircumstances, where ruined monuments stand to aconsiderable height, or have never been buried, it maynot be possible. Partial reburial (leaving the uppersections of walls exposed) and reburial of selected

elements (notably of mosaic pavements), has beencarried out at a number of sites. An advantage of par-tial reburial is that the building’s plan form remainslegible. In current practice, reburial typically incorp-orates a membrane of geotextile over surfaces to beburied, often as a horizon marker to delineate thearchaeological deposits from the fill materials. Anintermediate layer of sand or other material is some-times used and then the soil fill. However, recentevaluation of past reburials has highlighted problemswith the use of geotextiles in the context of coveringsensitive surfaces, such as mosaic pavements. Reburialshould be the minimal measure anticipated as a post-excavation activity in planning the excavation of siteswhere ruined architectural remains are likely to befound. Reburial will not necessarily obviate the needfor consolidation or treatment of remains. No pre-ventive conservation measure is entirely maintenancefree, and even reburied sites require monitoring andcontrol of vegetation, to prevent damage by plantswith potentially disruptive root systems.

The consequences of leaving ruined sites exposedwithout any protective measures or even minimalmaintenance to remove invasive plants and theirdamaging root systems are depressingly familiar.The vulnerability of various materials and agents ofdeterioration are discussed further at the end of thechapter, but several illustrations (Figures 5.9–5.12)

Preventive conservation of ruins: reconstruction, reburial and enclosure 161

Figure 5.9 Section of ancient opus sectile pavement suffering gradual loss from visitor traffic and exposure; imprints of missingstones are visible (photograph: C. Woolfitt).

Ch05-H6429.qxd 10/14/06 3:33 PM Page 161

from ancient sites in the eastern Mediterranean areincluded here to highlight the problems.

When to rebury

Reburial may be the most appropriate protectivemeasure in the following very general circumstances:

● When the resources necessary to implementother measures – either essential conservation,

repair and maintenance necessary for long-termexposure or protection by cover building – areunavailable. This may be the case at sites of lesserinterest or significance, where visitor numberswill be insufficient for the site to function as avisitor attraction.

● As a temporary measure while decisions can bemade regarding more permanent solutions, suchas protective shelters or enclosures.

162 Conservation of Ruins

Figure 5.10 Wall plaster, lined out in imitation of ashlar, with detachment caused by the combined effects of vegetation and exposureto weather (photograph: C. Woolfitt).

Ch05-H6429.qxd 10/14/06 3:33 PM Page 162

Preventive conservation of ruins: reconstruction, reburial and enclosure 163

Figure 5.11 A neglected shelter and ancient site lacking maintenance, where vegetation grows uncontrolled (photograph: C.Woolfitt).

Figure 5.12 Exposed Byzantine mosaic pavement, with the pattern of water ponding and saturation reflected in the organic growth(photograph: C. Woolfitt).

Ch05-H6429.qxd 10/14/06 3:33 PM Page 163

164 Conservation of Ruins

● When the ruined fabric, in general, is particularlyvulnerable to exposure. Earthen ruins or masonrywith earth as a principal component are, for example, particularly vulnerable, especially inmore aggressive environments.

● Where sites are situated in isolated locations andinspection and maintenance is therefore difficult,or where there is a risk of vandalism, isolated sitestending to be easier targets.

● When particular vulnerable elements, such asmosaics, need to be selectively protected.

● When damage by frost is a primary concern,reburial is the only permanent measure (apartfrom enclosure with adequate environmentalcontrol) that will effectively protect surfaces, pro-vided remains are reburied to an adequate depth.(Note: The agents of deterioration therefore needto be established in advance of any proposals.Condition survey work is discussed further at theend of this chapter and also in Chapter 3.)

The buried environment

Reburial generally provides a more stable environ-ment than exposure to weather. Prior to excavation,soils or other fill materials are in intimate contactwith building surfaces, which may consist ofmasonry, with finishes of plaster or paint, or of tim-ber. Although problems can sometimes occur at thesurface–fill interface, such as precipitation of hardand insoluble minerals through percolation of mois-ture and soluble material through soils, this closecontact with the fill normally has a protective effect,provided conditions remain stable. Certainly forinorganic building materials, stone, ceramic, earth,lime mortars and plasters, the buried environment ismore benign than the weather with its combinedeffects of daily and seasonal cycles, of wetting anddrying, and heating and cooling. The surprisinglyvibrant appearance of freshly excavated wall paint-ings and plaster of the Roman period, from bothwarmer and drier climates and wetter and colderones, at sites across the former Roman empire is tes-tament to the durability of these materials in a rangeof buried environments. Unfortunately, paint andplaster finishes are among the most vulnerableelements of a ruin once they are exposed. In theBritish climate, exposed surfaces of more vulnerablematerials, plasters and paint, whether of earth orlime based, may need protection in the course ofexcavation. Past excavation reports of Roman sitesin Britain have occasionally noted the red mud thatresults during unprotected excavation, where plasters

containing crushed tile (opus signinum) survive. Insuch cases there is clearly a need for protection dur-ing excavation, as well as after.

For inorganic or porous building materials, thespecific soil conditions, such as moisture levels andpH (acidity/alkalinity), are less critical than fororganic materials. Organic materials, such as timber,behave quite differently and are much more sensi-tive to varying soil conditions. It is common, in theUK at least, to find only traces of timber structuresduring the course of excavations; timber elementsof early structures are typically visible as discol-oration in the soil. In certain conditions, however,timber can be well preserved. There are two generaltypes of buried environment that favour timberpreservation: (1) waterlogged or saturated depositsthat typically consist of soils of low moisture permea-bility (such as clays) and low levels of oxygen,known as anaerobic or anoxic environments, and(2) arid conditions. The condition of waterloggedtimbers presents a particular challenge in terms ofconservation; the timbers must either be kept satur-ated or treated, to avoid drying out and collapse ofthe timber microstructure, the cell walls, whichresults in shrinkage and deformation of the timber.Treatment of waterlogged artefacts normally involvesimpregnation with polyethylene glycol (PEG) byimmersion and subsequent freeze-drying.

Temporary protective measures during excavation

Exposure of building fabric by excavation alters theequilibrium that has been reached over centuries inthe buried environment and can be traumatic forsome materials, depending on environmental condi-tions. In some cases protective measures need to betaken during excavation, to avoid loss and deterior-ation. Moisture content at the surface of the structurewill change quite rapidly with exposure depend-ing on the nature of the material and the externalenvironment. Drying occurs at the surface, and ifthis occurs too rapidly, damage can result to somematerials, especially to mortars and plasters based onearth or weak lime binders. With drying, soluble saltsare often mobilised and migrate to surfaces wherethey can cause either insoluble, hard deposits, in com-bination with remaining soil, or characteristic pittingand friability. The effects of soluble salts may not beevident until some time after excavation. Soluble saltdamage occurred at the site of Masada in Israel afterexcavation and resulted in the subsequent decision todetach wall paintings from the masonry substrates and

Ch05-H6429.qxd 10/14/06 3:33 PM Page 164

Preventive conservation of ruins: reconstruction, reburial and enclosure 165

Figure 5.13 Detail of wall painting on the lower terrace at the Northern Palace, Masada in Israel, with pitting to the lower sectionfrom soluble salts (photograph: C. Woolfitt).

mount them independently so that they were isolatedfrom the source of salts (Figure 5.13).

Pre-excavation planning should anticipate thetypes of materials that might be uncovered and theirpotential vulnerability so that protective measurescan be implemented at an early stage during excav-ation. In the case of decorative surfaces, such as wallpaintings and earth plasters, it may be necessary toemploy measures to slow rapid drying and associ-ated problems of salt and insoluble deposits. These

can include leaving a layer of protective soil on vul-nerable surfaces after excavation to allow this tofunction as the drying zone into which potentiallyharmful salts can migrate. The advice of a conserva-tor specialising in the conservation of archaeologicalremains in situ should be sought when vulnerabledecorative surfaces are found. Treatments that mightbe appropriate for detached decoration (wall paint-ings, mosaics) in a museum context are often unsuit-able for in situ treatment, due largely to the differences

Ch05-H6429.qxd 10/14/06 3:33 PM Page 165

in environmental conditions. This is particularly trueof long-term as opposed to temporary measures.The problem of applying materials and techniquesapplicable in a museum/objects context directly on asite is discussed further in the section below on‘Protective enclosures and shelters’.

The problem of excavating waterlogged timbersand the need to maintain their saturated condition isa familiar one in the UK. Measures to keep timbersdamp on site include the use of plastic (polyethyl-ene) covers and intermittent water spraying toensure an adequate moisture content in both the soilmatrix and the timbers themselves. Where existinggroundwater levels are relatively high, as typicallyoccurs on waterlogged sites, this is helpful in main-taining the required moisture levels.

The in situ conservation of remains of the Romanamphitheatre in London, within the basement of theGuildhall, is an interesting example of how ruinscan be protected in the course of urban redevelop-ment and construction work, and creatively inter-preted.13 Remains of the amphitheatre walls, composedof Kentish ragstone and tile, were uncovered during

excavations in 1988 and designated a scheduledancient monument (Figure 5.14). Designs for thenew structure, the Guildhall Art Gallery, were con-sequently modified and adapted to accommodatethe Roman remains and to ensure their protectionwhilst two new basement levels were formed belowthe level of the amphitheatre. Considerable engin-eering work was required to support the Romanremains in situ, by underpinning and strategicallylocating the piles to support the new structurearound the ancient remains.

The amphitheatre walls were protected in twophases during the long construction process. First, forthe piling operation carried out from a suspendedsteel deck above the amphitheatre, the remains wereboxed in with plywood, with a layer of thick poly-thene protecting the masonry surfaces and the voidbetween the masonry and plywood box filled withexpanding sprayed foam. In preparation for the second construction phase, of underpinning, theremains were boxed in with concrete block. Prior tocommencing the second phase, the entire area wasdried out and the environment within the plywood

166 Conservation of Ruins

Figure 5.14 View of protected remains of the Roman amphitheatre in the course of redevelopment at the Guildhall, London (pho-tograph courtesy of Museum of London Archaeology Service).

Ch05-H6429.qxd 10/14/06 3:33 PM Page 166

Preventive conservation of ruins: reconstruction, reburial and enclosure 167

enclosures monitored to prevent rapid drying, whichmight cause cracking.

The amphitheatre walls were underpinned usingneedles and a new concrete slab was formed beneaththe remains, connected to the main floor slab. Onceambient relative humidity had stabilised to 50 percent relative humidity, the masonry remains wereuncovered gradually over a period of 15 weeks, withregular monitoring of masonry condition. No deteri-oration was observed and the remains are now dis-played and interpreted. The display includes timberelements of the amphitheatre, which were removedfrom site for conservation and subsequently reinstated.Ruins displayed in such urban basement settings areoften drab and uninspiring, but in this case consider-able effort has been made to give an imaginativeimpression of the amphitheatre’s original function andform, using dramatic lighting, projection and sound(Figure 5.15).

Materials which may be useful in the tempor-ary protection of ruins against the weather during

excavation or against physical damage in the courseof construction work include:

● Geotextiles. Various types are available and may beused for various purposes, as barriers against soil-ing, as ‘horizon markers’ to separate archaeo-logical deposits from added fill, or to containcushioning/fill materials. Available under a rangeof trade names in the UK, such as Terram™ andTerralys™, these may be either of non-woven (needle-punched or heat-bonded) fibres or woven,and are composed of polymers such as polyethyl-ene and polypropylene. Geotextiles are designedfor civil engineering purposes, for example toretain particulates whilst allowing transmission ofwater within soils. Lapped joints between geo-textiles can be sewn or heat bonded in the case of thermoplastic materials. Recent research haslooked at geotextiles used extensively at theinterface between excavated remains and back-filled soil and as membranes to facilitate future

Figure 5.15 The remains of the Roman amphitheatre in London displayed in the basement of the Guildhall (photograph courtesyof Museum of London Archaeology Service).

Ch05-H6429.qxd 10/14/06 3:33 PM Page 167

excavation. In general, non-woven, needle-punched geotextiles have been found to have bet-ter water permeability characteristics. Examinationof re-excavated sites has found damage from geo-textiles adhering to architectural surfaces, throughthe precipitation of minerals at the surface–geotextile interface. Geotextiles should be per-meable to water, depending on the intended use and proximity to vulnerable surfaces, but thereare variations in water transmission characteristicsdepending on the geotextile type and properties,such as grade, mass per unit of area.

● Plastic sheet and tarpaulins. Waterproof covers(transparent, translucent or opaque), typicallycomposed of polyethylene sheet, are available invarious grades (heavier grades are better to avoidpunctures and other damage), for walls and otherarchitectural elements, which can be used aloneor in conjunction with quilts or other materials.Prefabricated tarpaulins (also of polyethylene) areuseful since they are prefabricated with eyeletsand reinforced hems, making them easier tosecure in position. Opaque covers may be prefer-able to cover surfaces that are exposed to light, todiscourage organic growth, especially in dampconditions.

● Padded or insulated quilts. These may be useful forprotection against frost if designed specifically for this purpose. Those designed and available for the curing of concrete may be appropriate.Industrial fabric suppliers can produce these tovarious materials and performance specifications,including the use of a range of synthetic or syn-thetic and natural fibre blends, with fill/waddingof synthetic (for example, polyester, acrylic, poly-propylene, viscose) or natural fibres (wool, whichis now used in insulating houses, offers goodinsulating properties).

● Geo-mesh. Synthetic (plastic) mesh of various sizesand types, such as those used in soil reinforce-ment; may be useful for securing covers.

● Plywood sheet. Various grades and thicknesses areavailable; marine grade plywood may be useful inwaterlogged contexts.

● Semi-rigid plastic ‘corrugated’ sheet. An example isCorex™, which has twin walls and is available invarious forms, varying in the degree of flexibil-ity; useful for protecting surfaces where rigidplywood is awkward, due to the greater flexibil-ity of plastic sheet and ease of cutting/forming torequired shapes.

● Foam and other synthetic packaging/cushioning mater-ials. Various foam products are commercially

available in sheet, pellet or spray form. Sheets andlaminates come in various forms, varying in thick-ness and flexibility; these are typically composedof polyethylene or polyurethane. Expanding sprayfoam, of the kind used for insulating buildings,which is normally of polyurethane, may be useful,but care must be taken to isolate surfaces beforeapplication. Bubble Wrap™ is a commerciallyavailable lightweight polyethylene packaging mater-ial, with cells filled with air, that can be useful forcushioning, as an alternative to heavier materials,when used in rolls, provided it is wrapped andprotected from direct weathering.

● Sand. Normally used in bags for ease of removal.Natural fibre bags will deteriorate quite rapidlywith exposure to weather and damp conditions.Synthetic fibre bags (such as nylon) should be usedinstead, although these will also degrade withlengthy exposure in an external environment.

● Vermiculite/perlite. These materials have been usedrecently in the context of protecting vulnerablesurfaces, such as plaster detail, on archaeologicalsites.14,15 They are naturally occurring minerals,which expand on heating to many times theiroriginal size, to form lightweight, highly absorbentparticles. They are widely used in horticultureand the construction industry for their insulatingproperties.

● Earth- and lime-based materials. These are used assacrificial or protective plasters, with various aggre-gates (sand, crushed brick and limestone) andfillers. They may be useful in protecting masonry,as well as decorative surfaces. Advice on appropri-ate applications and mixes should be sought fromspecialists in the in situ conservation of ruinedstructures and their finishes.

Reburied waterlogged sites: experience to date

There is comparatively little published informationon the subject of the reburial of ruins in the UK.However, recent initiatives, principally by theMuseum of London Archaeology Service (MoLAS),supported by English Heritage and the University ofBradford, have resulted in very useful review andpublication of reburial methods and materials, partic-ularly in the context of waterlogged sites.16 There area few waterlogged sites in the UK where ruins havebeen reburied with the intention of periodic excav-ation to monitor their condition. The Sweet Track, a section of the Neolithic trackway that crosses theSomerset Levels, is preserved in Shapwick Heath

168 Conservation of Ruins

Ch05-H6429.qxd 10/14/06 3:33 PM Page 168

Preventive conservation of ruins: reconstruction, reburial and enclosure 169

Figure 5.16 Sketch of temporary protective measures for specific conditions (sketch by Prof. John Ashurst).

Ch05-H6429.qxd 10/14/06 3:33 PM Page 169

170 Conservation of Ruins

Figure 5.17 Sketch of temporary protective measures for specific conditions (sketch by Prof. John Ashurst).

Ch05-H6429.qxd 10/14/06 3:33 PM Page 170

Nature Reserve. Sustained efforts to maintain the sat-urated environment and ensure the stability of thereburied timbers have included the creation of abund, pumping of water and control of vegetation.The trackway condition has also been monitored byre-excavation of small sections and detailed analysisof the timbers and of the buried environment.17 FlagFen near Peterborough is another early waterloggedsite, but in this case a section of the Bronze Age tim-ber causeway has been uncovered and protectedunder a cover building, with the moisture content ofthe timbers maintained by regular water spraying, thewater containing silver ions to inhibit biologicalactivity. Corfield comments that this is not considereda permanent solution and at some point in the futurethe site will be back-filled.18

The Rose Theatre, in Southwark, London, is oneof the few sites in the UK that has been published,the process of its reburial described in detail and thesite subject to ongoing monitoring.18,19 Built towardsthe end of the sixteenth century, the Rose Theatrewas discovered in 1989 during preliminary investiga-tion of the site, in advance of redevelopment. Upondiscovery of the theatre remains, a temporary roofwas built to permit excavation and public viewing.The site attracted much public attention, not leastfrom prominent actors, and the preservation of thesite was eventually secured by negotiation with thedevelopers. The agreed scheme involved retainingthe remains in situ within the basement of the newstructure on the site and redesigning the foundationsto avoid damage to the theatre remains. Temporaryprotection in the course of archaeological excavationand investigation included maintaining the dampcondition of the clay matrix in which the theatreremains were imbedded, with water sprays and coversto prevent drying out.

Initially, it was envisaged that covering the theatreremains, as described below, would be temporary,lasting only a few years, until later excavation andconservation could take place, but the site remainscovered and under water. Once the decision to reburythe remains had been made, various materials wereconsidered for use in this process. Selection criteriaincluded that these be chemically inert to minimisetheir effect on the reburial environment and deposits.The reburial process, as described by Corfield, com-prised the following:

● A cover of non-woven geotextile (Terram™), laidin sheets, with depressions below filled with sandto form a level surface. Joins between sheets weresealed with a weak 1:6 lime and sand mortar.

Subsequent reassessment recommends that heatsealing (‘heat welding’) or sealing tape may havebeen better than mortar for use at these joints.

● A layer of clean Buckland silica sand, free of con-taminants such as soluble salts, carbonates and ironoxide, was then applied to a minimum depth of300mm over the remains. The sand was pumpedthrough a flexible hosepipe to minimise use ofwheelbarrows.

● The sand was saturated with mains water, withoutany purification, and leaky horticultural hosepipewas laid at 1500-mm intervals for subsequentintroduction of water; these pipes were in turncovered with an additional layer of approximately12mm of soft sand blinding.

● Plastic (polyethylene sheeting) covered the sandlayers, and over this was laid a 50-mm weak con-crete screed.

● Monitoring points were incorporated in thereburial strata so that the following could bechecked: moisture content of soil and sand, waterlevel (groundwater with contribution from leakypipes), water quality (pH, redox potential, dis-solved oxygen and temperature – as an indicatorof biological or chemical activity).

As levels vary within the site, a pool of water hasformed. Small sondages have been made to replacethe soil moisture cells and to check the condition ofthe clay matrix and the timber, and these have beenfound to be stable. The criteria for selection of sand inthe reburial process at the Rose Theatre were carefullyconsidered and published separately.20

Parameters to be monitored in the context ofwaterlogged reburied sites include moisture contentof the deposits and the quality of the water in thedeposits. Research and evaluation of past reburial hasfound that relevant water quality parameters are:temperature, pH, dissolved oxygen content, redoxpotential and electrical conductivity.21 The type andquantity of micro-organisms that can cause decom-position of timber is another variable. In general, onthe basis of experience and ongoing monitoring atsites such as the Rose Theatre and the Sweet Track,it seems that reburial of waterlogged sites can be suc-cessful provided the conditions that favour preserva-tion of the timber can be maintained.

Protection of decorative elements

Ruined remains incorporating significant decorativedetail, such as decorative plasterwork, wall paintingsand mosaic, tile or other pavements, are particularly

Preventive conservation of ruins: reconstruction, reburial and enclosure 171

Ch05-H6429.qxd 10/14/06 3:33 PM Page 171

172 Conservation of Ruins

vulnerable to weather and deterioration, and forthis, and other reasons, tend to receive more atten-tion than masonry ruins that have lost their decora-tive finishes. There is published experience of thereburial of mosaics, in particular, due to the effortsof the International Committee for the Conserva-tion of Mosaics (ICCM), which hosts an inter-national conference on a triennial basis and publishesthe papers presented, and to joint initiatives of theGetty Conservation Institute and ICCROM, amongstother organisations, which have led to the very usefulrecent publication of a Special Issue on Site Reburialin the journal The Conservation and Management of Arch-aeological Sites (CMAS).22 The MoLAS and CMASvolumes provide the most extensive accounts ofexperience of past reburials to date.

In the UK, the example of the Orpheus mosaic atWoodchester Roman villa is often cited. Uncoveredin the late eighteenth century, the mosaic was sub-sequently reburied and uncovered at intervals subse-quently, most recently in the 1970s, attracting largenumbers of visitors. Decorative floors, such asmosaics, make relatively easy subjects for reburial, atleast in terms of the practicality of physically cover-ing the remains. This approach was adopted for the

recently excavated Roman mosaic at Lopen inSomerset (Figure 5.18). In this instance, the mosaicwas reburied after recording and consolidation offragile edges. Reburial included the following: a coverof soil directly on the mosaic surface, a layer ofTerram™ geotextile, more soil, strategically placedconcrete slabs and finally a cover layer of soil, formedinto a slight mound.23 The same process was used forreburial at the Roman villa site at nearby Dinnington.At Chedworth, Roman villa mosaics not protected bythe existing cover buildings have also been reburied.A cover layer of gravel has been used for protectionagainst burrowing rodents and vegetation.24

Recent reassessment of the condition of reburiedmosaics has provided useful information regardingsuitable methods and materials. Standard practicehas entailed the use of a geotextile or plastic (poly-thene) sheet as a barrier between the mosaic and thesoil or fill. Recent experience has shown, however,that there are problems associated with the use ofsuch membranes, particularly when they are imper-meable to water vapour.25 They can create problemsat the mosaic–fill interface, by trapping moisture,with related microbial interactions, localised pHvariations and the formation of mineral precipitates

Figure 5.18 View of the excavated Roman mosaic at Lopen in Somerset, prior to reburial (photograph: G. Abrey).

Ch05-H6429.qxd 10/14/06 3:33 PM Page 172

on mosaic surfaces. If mosaics are not covered tosufficient depth, vegetation and root systems canalso cause damage, even where geotextiles are used.Sand and clay pellets have also been used directlyover mosaic surfaces in the past but neither is idealfor this purpose. Experience has shown that fillshould be in intimate contact with the mosaic sur-face, in the way that soil provided protection priorto excavation. Fill of sand or clay pellets will havelarge pores and voids at the interface with themosaic. Soil is preferable as a fill material in directcontact with a mosaic. If sand is to be used it shouldbe free of contaminants which cause staining and ofsoluble salts. Any cover or fill material should bechemically inert and its pH compatible with themosaic; the lime mortars used in mosaics are alkaline,so acidic fills should be avoided.

At the site of Horvat Minim (Khirbet al-Minya)in Israel, where Umayyad period mosaics of theeighth century AD were covered, from the mosaicsurface to the top, with black plastic mesh, non-woven geotextile, volcanic pellets and then sand,recent uncovering and evaluation has found thatsubstantial vegetation had grown after a period ofonly four years’ reburial, causing damage to mosaics

and detachment of the tessellatum (the surface layercontaining the decorative image, composed oftesserae and lime).26 This illustrates the need forroutine inspection and maintenance of reburiedsites to ensure vegetation cannot cause damage. Italso illustrates the need to create a sufficiently deepprotective layer so that any vegetation and root sys-tems are confined to the upper surface of the pro-tective cover, above the sensitive ancient surfaces.

Recent work at the Neolithic site of Catalhöyökin Turkey involved the development of materialsand techniques, including the use of mock-ups, forthe temporary protection of freshly excavated earthenwalls and murals.14 This work by Matero and Mossillustrates an analytical approach to a particular formof deterioration in specific site conditions, with theuse of materials analysis and trial tests/simulationsto determine the best methods and materials for in situ protection. Ongoing excavation at Catalhöyök,which was first excavated in the 1960s, has uncoveredstructures of mud brick with wall plaster, modelledreliefs and wall paintings. Past experience had shownthat exposure to the environment by excavation was problematic for the earthen building materials.Rapid drying normally occurred very soon after

Preventive conservation of ruins: reconstruction, reburial and enclosure 173

Figure 5.19 Section of mosaic pavement at Horvat Minim in Israel covered with geotextile, pozzolanic pellets and sand, whichwere found to be ineffective in protecting surfaces from vegetation (photograph: G. Abrey).

Ch05-H6429.qxd 10/14/06 3:33 PM Page 173

174 Conservation of Ruins

exposure, with resulting cracking and breakdown ofsurfaces. The thickness of surface finishes, up to 100layers, was another factor in deterioration. Some min-imal pressure directly against surfaces helped keepthem under compression and maintained the bond tothe wall substrate during the drying period immedi-ately after excavation. Efforts had been made to slowthe drying process by erection of shelter structuresduring excavation and between seasons, but other flex-ible and easy-to-use methods were necessary to slowthe drying rate of the plastered mud-brick-structures.Vermiculite and perlite, both materials of mineral ori-gin, formed by heating and consequent expansion,were identified as suitable lightweight and non-abrasive fillers, for use at the drying interface. Thesematerials were held in place against the wall face withthe following system: a perforated rigid retaining‘wall’, held in place by sandbags, and water-repellent(but moisture-permeable) geotextile, which con-tained the fill and extended up to the wall head anddown, under the sandbags.

There is very little reliable information and guid-ance for the protection of decorated, plastered andpainted wall surfaces prior to reburial. The use of fine

synthetic polyester fabrics such as Holytex™ hasbeen considered, along with sacrificial lime-basedplasters, which have been tested at the Hippodromeat Caesarea as removable protective coatings in anexposed marine environment.15,27 At Caesarea suchplasters were found to prevent alteration of the orig-inal surfaces and to be removable without damage tothe underlying plaster. This research included the useof various aggregate and fillers, including pozzolansand coloured fibres as visible markers to distinguishapplied plaster layers. In the light of recent experiencein the conservation of mosaics, it seems advisable toapproach the use of geotextiles and other synthetictextiles in direct contact with any decorative surfacevery cautiously. The use of protective earth or weaklime (non-hydraulic or high calcium lime) plasterswould, however, seem to be viable options as pro-tective measures in preparation for reburial. Anysystem should be tested on a small area of the surfaceto be protected, to assess properties such as adhe-sion, ease of removal, any residual staining and otherconsequences.

Recent work at the ancient site of Zeugma inTurkey, founded in the fourth century BC, provides

Figure 5.20 View of the Hippodrome at Caesarea in Israel, a site of recent testing of sacrificial lime plasters for protection of original plaster surfaces in a severely exposed marine environment (photograph: C. Woolfitt).

Ch05-H6429.qxd 10/14/06 3:33 PM Page 174

an interesting example of reburial in unusual circum-stances. Approximately one-third of the site was sub-merged in 2000 by construction of a hydroelectricdam and subsequent flooding, a controversial event,which has been widely reported. Emergency excav-ation in advance of attempts to commence in situ con-servation measures had, unfortunately, resulted in thedetachment of substantial quantities of mosaics andwall paintings in less than ideal conditions. Measuresimplemented to protect exceptionally fine mosaicpavements and other archaeological remains in situincluded reburial, and have been published by Nardiand others who carried out the work.28 Specific pro-tective and preventive measures in the reburial processwere: application of lime washes and hydraulic limemortars to mosaic surfaces in preparation for reburial,necessary consolidation (as opposed to ‘restoration’ ofstructures) and barriers to protect buried remainsagainst displacement by waves of water. The use ofmortars to protect mosaic and wall painting surfacesis of particular interest, especially since comparativelylittle work of this kind has been reported. The limemixture was composed of hydraulic lime (Lafarge),lime, brick powder and crushed stone in proportionsof 0.5:0.5:1.5:0.5 or a 1:2 ratio of binder to aggre-gate/filler. It was applied to a thickness of 20mm towall paintings and 50mm to mosaics. Hydraulic limemixes will gain strength under water and it would beinteresting to investigate in the future how difficultthe removal of such a mix proves to be. The strengthand adhesion of the mortar might be tempered by theintermediate layer of limewash, which was intendedto facilitate future removal, and by the high propor-tion of fines (crushed brick and stone) in the mortar.Additional measures have been required to maintainprotection of buried structures along the zone of the new shoreline at Zeugma, where erosion hadoccurred; these included depositing bags (biodegrad-able) filled with pebbles and gravel and sufficientcement to hold the aggregate in place.

Reburial systems in arid climates

The descriptions of reburial procedures and assess-ment at the World Heritage Site of Chaco Canyonin New Mexico by Ford and others in the CMASSpecial Issue on Site Reburial are particularly detailedand provide useful information on the treatment ofmasonry incorporating timber members in an aridclimate. The motivation for reburial and the methodsadopted are summarised here in some detail, sincethey illustrate very well an analytical approach tofinding a suitable methodology for the particular

site conditions.29 The ruined structures of ChacoCanyon belong to the ninth to twelfth centuriesAD, stand to considerable height, and are built ofstone bonded with earth mortar, with imbeddedtimber members and earth plasters. The rationalefor partial reburial of selected structures included:the need to address visible and accelerated deteri-oration of the ruins; to prevent the loss of fabric andauthenticity which has occurred through mainte-nance cycles; a desire to allow walls and structures toremain legible; and the need to equalise fill levels andpressures in adjacent rooms where one room wasopen to some height and the adjacent room infilled.In the case of one of the great houses, Chetro Ketl,the imbedded timber elements used for ceilings/floors and lintels to openings were of particular con-cern and the reburial system was designed to ensuretheir preservation and to maintain the timbers at amoisture content not exceeding 15 per cent byweight in the reburial environment to prevent rot byfungal growth and termites. Although the climate isgenerally dry, two sources of moisture were identi-fied: snowmelt and rainwater. The reburial systemneeded to cope with periodic wetting of the fill andprevent water penetration into imbedded timbers.The special measures adopted to cope with precipi-tation were essentially:

● Forming compacted and graded/sloping surfacesincorporating a central drain which fed throughburied PVC pipes to a drainage trench externalto the structure.

● Inclusion of an impermeable geotextile mem-brane below the surface fill to prevent absorptionof snowmelt water, which otherwise was foundto penetrate to a depth of approximately 1 m.

The reburial sequence included the following:

1 A permeable geotextile horizon marker at thebottom, on top of any existing fill or archaeology.

2 Bulk fill of local soil (compacted every 300 mmwith weighted drum roller and hand-held steelplate tamper; a skid loader and conveyor systemwas used to bring the fill material into the indi-vidual rooms).

3 Protruding surviving timbers were wrapped ingeotextile (various types depending on context).

4 PVC drainage system.5 Impermeable membrane (Tuff-Ply)™, with an

erosion control membrane on top of this(Enkamat™ – nylon 3-D webbed matting).

6 Top layer of surface soil fill (200 –500 mm deep).

Preventive conservation of ruins: reconstruction, reburial and enclosure 175

Ch05-H6429.qxd 10/14/06 3:33 PM Page 175

The reburied area of Chetro Ketl remains closed tovisitors but can be viewed from vantage points.Monitoring points were installed through the depthof the fill, at 300-mm intervals, during reburial sothat moisture contents can be monitored on anongoing basis. Subsequent evaluation of the reburialfocused largely on the moisture content of the soilfill and of the buried timbers. One positive result ofthe reburial measures was a reduction in the erosionat the base of walls standing above ground level,apparently due to the combined effects of reducedmoisture content of fill, the membrane and drainagesystem. Problems highlighted by evaluation includedthat some discontinuities in membranes occurred(punctures in membrane and incompletely sealed orpoorly overlapped junctions) and were problemat-ical, and also that soil moisture contents of 15 percent by weight were insufficient to prevent deterior-ation of timber by fungi and termites.

Factors to consider in reburial

Depending on the complexities and scale of the ruinsto be reburied, it may be necessary to assemble amulti-disciplinary team, including potentially the dis-ciplines of geology, soil science, civil engineering andlandscape architecture. Primary issues and variables tobe considered in any proposals for reburial, especiallyfor sites that have always been exposed or have beenexposed for some time, include the following:

● Condition survey and options appraisal. Conditionsurvey and appraisal is essential to determine thenature of the constituent elements of the fabric,their vulnerability to various agents of decay, andpatterns of deterioration which have developedand may be anticipated in future, depending onhow the site environment is altered. The issue ofcondition survey is discussed further at the end ofthis chapter and in Chapter 3.

● Landscape design, height and morphology of remains andstability of reburial. The height and form of ruinswill determine to a considerable extent the finalform of the reburied site/monument. Methods ofreburial should anticipate the final appearance ofthe reburied site and how ruined remains can beinterpreted. Drainage of the site needs to be con-sidered, with levels planned to avoid water trapsand areas of ponding, in larger schemes of reburial.Reinforcement of soil infill may be necessary insome cases, for example where slopes are formed.Final finishing with topsoil, seeding or plantingshould also be considered, where appropriate.

● Reburial or cover material. In practice the best fillmaterial is often that which was removed in theprocess of excavation. Any fill should be stableand chemically similar to the original burialmaterial. Extremes of pH should be avoided asthis affects dissolution and redeposition of min-eral processes. If sand is used it should be free ofstaining iron oxides, calcareous or other materialwhich could be dissolved and redeposited on sur-faces.20,30 The soil matrix of the ruined remainsand reburial medium should be of similar poros-ity and permeability to minimise the risk of min-eral deposits forming at interfaces between theruined remains and the fill, and to ensure uni-form drainage of water. Ideally, the buried envir-onment should differ as little as possible from theenvironment of the ruin prior to exposure. Thisis particularly important for waterlogged ruins.The following properties should be compatible:soil characteristics and typology, such as particlesizes (relative proportions of sand, silt and clay)and pore structure, groundwater levels and mois-ture content, pH and redox potential.31

● Reburial process. Experience has shown that, ingeneral, fill materials should be in intimate contactwith surfaces, to avoid problems at the interfacewith architectural surfaces. Fills need to be com-pacted. A layer of topsoil which supports manage-able plant growth has a protective function inpreventing weathering and erosion of the coverlayer. This may be difficult to achieve in drier cli-mates, where the level of clay in soil could be apositive factor, possibly enhancing cohesion andimproving protection.

● Depth of cover. Cover must be sufficient to create aprotective zone over the buried surfaces, to bufferagainst changes in temperature and moisture con-tent and to ensure vegetation remains in the uppersurface layer, posing no threat to buried remains.The depth of cover required will depend on theparticular site, materials to be protected and theagents of deterioration, which pose a threat,whether these consist of vegetation, weather, ther-mal or moisture changes, animals, or humans.

● Maintenance. Sites must be monitored and the fre-quency of routine inspections will depend on thenature of the site and the system of cover. Allreburied sites need some maintenance to controlvegetation. Where sites are reburied entirely andto adequate depth, and where land is suitable forpasture, introduction of grazing animals, sheep,cattle or goats, may be an environmentally friendlyway of controlling vegetation.

176 Conservation of Ruins

Ch05-H6429.qxd 10/14/06 3:33 PM Page 176

Preventive conservation of ruins: reconstruction, reburial and enclosure 177

Protective enclosures and shelters

The terms protective enclosure and shelter are usedhere to describe structures that provide, respect-ively, complete enclosure or partial cover, the lattertypically in the form of a roof, open to varyingextent at the sides. These may be of a temporarynature, constructed to provide shelter in the shortterm, for example during excavation or whilst proposals for more permanent protection can bedeveloped. More frequently they are permanentstructures. The idea of such protective structures isnot new; a number of sites in England were pro-tected in this way in the nineteenth century, prom-inent examples including the Roman villas of Bignorin West Sussex and Chedworth in Gloucestershire,where structures were built for the protection ofexposed mosaics. As a class of monument, inEngland at least, the Roman villa tends to receive

protection of this form more often than others, duein large part to the significant and vulnerable archi-tectural detail, such as mosaics and decorative orpainted plaster, which often survives.

Early enclosure buildings such as those atChedworth and Bignor are in traditional style andmaterials and, in general, have the appearance of agri-cultural buildings. Those at Chedworth are builtupon the existing Roman walls and have timber-clad walls and stone-covered roofs. At Bignor theyare in the form of rubble stone buildings withthatched roofs. The Chedworth cover buildings pro-tect mosaics and other remains of rooms, mainly inone wing of the villa, and openings in the south walls,either doors or windows, provide access for viewingthe remains. The nineteenth century Bignor shelterswere comparatively small in scale, designed to encloseindividual rooms and mosaics. The current, morerecent display building incorporates some of these

Figure 5.21 View of nineteenth century enclosure buildings over the remains of a wing of the Roman villa at Chedworth (photo-graph: C. Woolfitt).

Ch05-H6429.qxd 10/14/06 3:34 PM Page 177

pre-existing enclosures and provides access to a largerarea of the Roman villa, permitting visitor circulation.

Current design of such protective structures tendsto make use of modern construction materials andtechnology, incorporating, for example, textilemembrane covers (under tension), translucent ortransparent polymeric (plastic – polycarbonate oracrylic) cover for roofs and cladding to walls, andlightweight steel or aluminium frames for the mainstructure. Space frames, or three-dimensional frameswith characteristic lattice-like structures, are increas-ingly adopted since they can span large areas, requir-ing relatively few central supports, be prefabricatedoff site, and erected in a comparatively short time.Probably the most famous examples of the spaceframe in England are the geodesic domes built to house the Eden Project in Cornwall. Covers tosuch structures are typically of plastic sheet (Perspexor other transparent or translucent plastics) or ofsynthetic textiles, under tension, which are nor-mally translucent to some extent and coated withpolymers for enhanced water repellency – to be‘self-cleaning’.

In current practice shelter designs tend to be con-sciously modern, functional and distinct from theruins they cover; with some exceptions, they tendnot to relate or make reference to the ruin and itsconstruction, design or materials. The use of trad-itional masonry construction for shelters is, in gen-eral, avoided. The principal reasons are apparently:the expense and slow rate of construction, comparedto modern methods, the risk of confusing newmasonry with existing, and the lack of transparencyand light of solid masonry structures, in comparisonto the translucent or transparent effects that are pos-sible with other construction methods and materials.

Past experience of protective structures

Understanding of the effects of enclosing ruinedstructures has evolved through revisiting historicshelters erected over the past hundred years andmore. In the process it has been possible to identifyand rectify some problems with past approaches. On the other hand, some problems persist, such asthe perennial one in wetter climates of groundwater

178 Conservation of Ruins

Figure 5.22 View of wall paintings at the Northern Palace at Masada in their display cases.

Ch05-H6429.qxd 10/14/06 3:34 PM Page 178

causing organic growth and associated problems ondecorative surfaces. It is clear that a holistic approachis necessary in shelter design and that the entireenvironment of the ruin must be understood so thatthe new environment created within the structureand its impact on the fabric can be anticipated.Recent research has emphasized the importance ofenvironmental factors, that these need to be under-stood, and that modelling can assist in producingdesigns for shelters and enclosures.32

Recent review of protective structures built inSicily in the mid-twentieth century by Stanley-Priceand Jokilehto has highlighted a number of attitudesand practices that have evolved since that datethrough experience of problems encountered at thesesites and others.33 At The Roman Villa del Casale atPiazza Armerina the protective structure was erectedin 1957– 60 with walkways installed on top of theoriginal walls, for viewing the mosaic pavements.This consisted of a lightweight steel frame clad intransparent plastic sheeting. The focus was clearly onthe mosaics, to the exclusion of the masonry elem-ents of the site. A principal disadvantage has been theenvironmental impact – the ‘greenhouse effect’ – aswell as the need for regular renewal of the cladding.At the site of Gela mud brick masonry was encased inglass panels (one metre square) fixed flush to the sur-face, and held in place with aluminium fixings drilledthrough the face. Problems here have included thevisual impact, both of the reflective surfaces and thedisfiguring moisture and organic growth, the devel-opment of an undesirable microclimate behind theglass, and the failure of the aluminium fixings, withopenings appearing between glass panels. Finally, at thetheatre of Heraclea Minoa plastic (Plexiglas) coverswere installed over the seats, replicating their forms,and requiring some alteration and cutting of originalstone to fix these. Again, the problem of a micro-climate below the plastic developed, as well as deteri-oration of the plastic itself.

The wall paintings of the Northern Palace atMasada provide another illustration of the problemof using glass in proximity to ruined surfaces, with-out ventilation. At Masada the frescoes have beendetached and remounted on new support layers andmetal frames; they are now displayed behind unven-tilated glass cases. The use of museum-based displaytechniques, materials and treatments in the contextof an exposed archaeological site presents problems.The wall paintings at Masada exposed to the heat ofthe sun for the longest period have suffered theworst; these exhibit localised cracking and detach-ment of the painted surface layer from the new

supports. In summary, these examples from Sicilyand Israel illustrate the following points:

● Proposals should be based on a holistic view ofthe site and individual elements should not besacrificed or ignored for the benefit of others. A balance must be struck in presenting thoseaspects of the site perceived to be of most generalinterest and protection of the site as an integratedwhole.

● Protective glass or plastic surfaces must not beplaced in close proximity to original surfaceswhere microclimates can develop. Lack of venti-lation exacerbates the problem. Even when thesematerials are used over larger areas this can be aproblem if there is inadequate ventilation (green-house effect). One problem is visual; such glassand plastic surfaces, especially in close range tobuilding surfaces, tend to be obscured with dust,organic growth or condensation. They tend totrap moisture and create differential thermal andmoisture levels (internal/external).

● Alteration and damage to original masonry, forexample by fixings to accommodate new struc-tures, should be avoided as far as possible.

● Detachment of original decorative finishes (suchas mosaic pavements and wall paintings) shouldbe avoided as far as possible. Where such elem-ents are detached, displaying them in situ, with-out adequate protection from the sun andweather, using techniques such as glass displaycases in an external environment, is problematic.

Shelters built in the latter half of the twentieth cen-tury, particularly those over large ruined sites, havetended to be industrial in nature and appearance. Theshelter at the Bronze Age site of Akrotiri, on theGreek island of Santorini, consisting of a Dexionframe, which is soon to be superseded (constructionof a new enclosure is in progress at present), is anexample of this. At Akrotiri the shelter extends overthe entire excavated area of the site and the struc-tural remains stand to more than one storey, so thatthe shelter is necessarily large. The new structure isintended to be more environmentally friendly thanthe one it replaces, with roofs designed to be less con-spicuous in the landscape. Shelters which rely on con-crete construction, such as the 1960s concrete framedshelter over the Early Bronze Age House of Tiles atLerna in Greece, also tend to be industrial in appear-ance. At least the architecture of the cover buildings,in such cases, is purely functional and does not com-pete with the archaeological remains for attention.

Preventive conservation of ruins: reconstruction, reburial and enclosure 179

Ch05-H6429.qxd 10/14/06 3:34 PM Page 179

Proposals to shelter the important mosaic of theByzantine synagogue at Ein Gedi in Israel, with itsinscription relating to the production of perfume,were debated before the current tent-like structurewas built in the mid-1990s. It consists of metal postsand cables securing a tensile fabric cover, whichextends down to provide additional protection at thesides. As for any substantial structure of this kind, con-crete foundations anchors were required and somearchaeology was sacrificed. In contrast with the formof the Ein Gedi Shelter is that over the Bronze Agegate of Tel Dan in Israel, whose arched form divertswater away from the vulnerable mud brick structure.It consists of a metal space frame covered with plasticsheet. The Israel Antiquities Authority erected thestructure in the 1990s and carried out limited consoli-dation and support for the mud brick at the same time.

The cover building over an entire residential block(insula) at the ancient city of Ephesus in Turkey pro-vides a good illustration of the application of contem-porary structural design to the problem of protectingruined remains over a very large area. There areextensive and remarkably intact and complete remainsof wall paintings, mosaics and decorative stone (opus

sectile) pavements. Designed and constructed underthe aegis of the Austrian Archaeological Institute, theshelter was completed at the end of 1999.34 The shel-ter is remarkable not only for its scale – it covers amassive area of approximately 4000m2 – but also asone of the few examples where an account of thedesign has been published. Previous shelters over thesite, built in the 1980s, were deemed unsuitable forvarious reasons and a new design developed. The newshelter was engineered to meet specific environmentalrequirements and the internal environment modelledby computer simulation, taking into account variablesof temperature, air exchange/air flow, relative humid-ity, condensation and light.

The stepped roof profile of the new shelter fol-lows the topography of the site and the terraces ofthe original structures. The support structure is alightweight steel frame, with a tensioned fabric roofcover and polycarbonate cover for the sides, whichare louvred for ventilation. The overall visual effectinternally is light and there is no need for artificiallight (see Figures 5.27 and 5.28). The outlines of theruined buildings remain legible to some extent fromthe exterior. The materials and design were selected

180 Conservation of Ruins

Figure 5.23 View of the Bronze Age site of Akrotiri on the Greek island of Santorini in 1987; a new protective enclosure build-ing is under construction (photograph: C. Woolfitt).

Ch05-H6429.qxd 10/14/06 3:34 PM Page 180

for maximum surface reflectance to minimise solargain and prevent increase of the internal tempera-ture. The roof cover (PTFE–fibreglass membrane)is translucent but also reflects solar radiation. Thesides are enclosed and covered with polycarbonate(Lexan™) ‘louvres’ for ventilation. The louvres areopaque on the south side of the building, whichreceives most sun, and transparent elsewhere. TheEphesus shelter, in effect, creates an in situ museumwhere visitors can comfortably circulate and viewthe architectural remains, complete with mosaicpavements and wall paintings.

At Cleeve Abbey, a site in the care of EnglishHeritage, a tent-like cover has recently been erectedto protect an important medieval tile pavement.The structure consists of a simple metal frame covered with a translucent tension membrane cover,with openings that can be closed in the same way asthose of a large tent. The cover structure, which isreminiscent of a marquee, unavoidably has a visual

impact in the context of the medieval building infront of which it stands, but has the advantage ofbeing comparatively easily dismantled.

Another recent and interesting example in Englandis the enclosure building over the west range of theRoman town house in Dorchester in Dorset, whichcombines contemporary and traditional elements.Here the design of the cover building, and the roofprofiles, give some impression of the volume andform of the Roman building. The projecting eaveshelp prevent solar gain through the glass elevations.Purbeck stones used for the roof cover have beenformed to replicate the Roman originals found dur-ing excavation. The plate glass that encloses the ele-vations is fixed to the structure’s tubular metal framewith ventilation gaps between the frame and glass,and hinging of some panels for additional ventila-tion when required.

Although none of the protective structures men-tioned so far feature active environmental control

Preventive conservation of ruins: reconstruction, reburial and enclosure 181

Figure 5.24 View of the tent-like shelter over the site of the Byzantine synagogue at Ein Gedi in Israel (photograph: OritBortnik).

Ch05-H6429.qxd 10/14/06 3:34 PM Page 181

182 Conservation of Ruins

Figure 5.25 Detail of anchor for the Ein Gedi shelter shown in Figure 5.24 (photograph: Orit Bortnik).

Figure 5.26 Protective shelter at Tel Dan in Israel (photograph: J. Ashurst).

Ch05-H6429.qxd 10/14/06 3:34 PM Page 182

measures, to regulate temperature or humidity, thedesign and selection of materials will affect theinternal environment of enclosed structures, in whatmight be termed a ‘passive’ way. Materials whichreflect solar radiation, for example, reduce solar gainand moderate internal temperature gain so that theinterior is somewhat cooler than the exterior duringhot weather. Gaps between materials which formthe walls, either as louvres or in plates in the examplesnoted above, likewise provide ‘passive’ ventilation.In effect, however, the environment within suchbuildings will not differ substantially from the exter-nal environment. Consequently, any environmentalconditions, such as frost or damp with relatedorganic growth, which might be damaging, will notnecessarily be eliminated within such enclosurebuildings.

A common problem for ruins enclosed withinshelters is rising damp and associated organicgrowth and soluble salt migration. Groundwater isdrawn through the fabric to drying surfaces, wallfaces and floors, and signs of moisture movement,often with associated deterioration, manifest them-selves, which can be particularly disfiguring andpotentially damaging for decorative surfaces such as

plaster and mosaics. Surfaces typically appear greenor dark (black) from organic growth, which caninclude fungi, commonly known as moulds. Wettingand drying and salt crystallisation can adversely affectstone, lime plaster and brick, resulting in friable andweakened surfaces. Figures 5.32 and 5.33 illustratethis situation. In this case Roman remains have beenprotected under an ad hoc shelter, intended to betemporary, at a site where groundwater levels andother environmental factors contribute to ongoingdecay of masonry surfaces.

The enclosure building over the remains of thenorth wing of Fishbourne Roman Palace in WestSussex was built in parallel with the later stages of excavations in the late 1960s.35 Problems withgroundwater and the condition of the mosaicsprompted lifting and relaying of some mosaics atthat early stage; others were lifted and relaid subse-quently on impervious membranes in the 1980s.Current modernisation of the 1960s structure, oftimber, aluminium and glass, is being carried out aspart of a wider programme of upgrading of inter-pretation facilities at the site, supported by the Heri-tage Lottery Fund. Work to the enclosure buildingincludes improvements to lighting and internal

Preventive conservation of ruins: reconstruction, reburial and enclosure 183

Figure 5.27 View of the new enclosure of an ancient city block of Ephesus, with the reconstructed façade of the Library of Celsusnearby (photograph courtesy of the Austrian Archaeological Institute).

Ch05-H6429.qxd 10/14/06 3:34 PM Page 183

walkways, and the installation of double glazing andan external colonnade to reduce solar gain throughthe south elevation.

The example of Fishbourne illustrates the generalpoint that, where high groundwater levels are a par-ticular problem, construction of an enclosure build-ing will not in itself resolve this situation. Experienceat other sites of a similar type in England, at Ched-worth, Bignor and Brading Roman villas, proves thesame point. Staining and organic growth are visible on

some mosaic pavements and wall surfaces at Ched-worth Roman villa, and monitoring of external andinternal conditions is ongoing.36 At Brading Romanvilla on the Isle of Wight groundwater levels, coupledwith heavy rainfall, resulted in flooding of the sitetwice in the 1990s and progressive deterioration ofthe mosaics occurred under a corrugated iron coverbuilding. Extensive survey and recording work,including the use of ground penetrating radar, led tothe decision to install a drainage trench to prevent

184 Conservation of Ruins

Figure 5.28 Interior of the new enclosure at Ephesus, with translucent roof and wall cover (photograph courtesy of the AustrianArchaeological Institute).

Ch05-H6429.qxd 10/14/06 3:34 PM Page 184

Preventive conservation of ruins: reconstruction, reburial and enclosure 185

Figure 5.29 View of the tent-like shelter structure over tile pavement at Cleeve Abbey (photograph: J. Ashurst).

Figure 5.30 Internal view within the shelter at Cleeve Abbey (photograph: J. Ashurst).

Ch05-H6429.qxd 10/14/06 3:34 PM Page 185

186 Conservation of Ruins

Figure 5.31 The recent protective building over the west range of the Roman Town House in Dorchester (photograph: C. Woolfitt).

Figure 5.32 Temporary shelter over Roman remains situated in a natural depression in the landscape (photograph: C. Woolfitt).

Ch05-H6429.qxd 10/14/06 3:34 PM Page 186

recurrence of flooding and alteration to the coverbuilding’s rainwater disposal system, as well as tophased conservation work.37 However, a new enclos-ure building and interpretation centre has since beenbuilt at Brading, with the support of the HeritageLottery Fund; the building is mainly of timber, with a‘green’ roof. The visual impact of the Brading coverbuilding is more ‘architectural’ than, for example, thatof the recent cover building at Ephesus, and the arti-ficially lit interior at Brading contrasts with the natur-ally lit interiors created where translucent covers, forexample of tensile membranes, are used. An aim ofthe design at Brading was, however, to avoid the ther-mal fluctuations caused by natural light.

Design briefs, environmental and other considerations

A design brief or performance specification forarchitects, structural engineers and others who willbe responsible for the final design of the structure is

essential, to guide the design process and achievethe objectives established by initial site assessmentand survey. This should set out the significance,context, essential history and archaeology of the sitein summary form, with reference to more detaileddocumentation. The brief should relate the essentialvalues and significance of the site and stress howthese must underpin the shelter or enclosure design.It should set out which elements of the site are vul-nerable and the particular environmental factorsthat play a key role in the deterioration of the site asa whole and in its various constituent parts.

The planning process can be broken down intoseveral parts and there may be more, depending onthe nature of the site:

1 Condition assessment and survey. Survey and inves-tigation of the nature of the ruined fabric. Thissubject is addressed in detail in Chapter 3.

2 Environmental assessment and investigation. Collec-tion of data regarding all aspects of the site’s envir-onment. Condition survey and environmental

Preventive conservation of ruins: reconstruction, reburial and enclosure 187

Figure 5.33 Detail of typical condition of masonry remains within the shelter shown in Figure 5.32, with damp conditions, deteriorating and friable surfaces supporting organic growth (photograph: C. Woolfitt).

Ch05-H6429.qxd 10/14/06 3:34 PM Page 187

188 Conservation of Ruins

assessment are often carried out in tandem.Monitoring may be necessary and may includesome or all of the factors outlined below. Toobtain a complete picture of an environment,monitoring should take place over a long periodand durations of more than a year are typical sothat seasonal variations can be determined. Thelarge amounts of data gathered require interpret-ation and study to yield meaningful results thatcan be used to inform conservation proposals.Translating the results of monitoring into prac-tical measures is perhaps the most challengingaspect of the process.

3 Options appraisal. Appraisal of potential/preven-tive measures, where the full range of options is to be considered: reburial, remedial work (whetherreinstatement or consolidation), or protectivestructures. The impact of each on the ruin mustbe anticipated in advance.

4 Building function. As well as functioning to protectsites, large structures must also sometimes accom-modate large numbers of visitors and function insome cases as a visitor centre and kind of sitemuseum. Interpretation, access and circulation ofvisitors need to be considered.

Although environmental control and monitoringare not addressed in detail in this chapter, the fol-lowing environmental factors are important in the context of designing protective enclosures andshelters:

● Rainfall. Both annual averages and seasonal vari-ations need to be considered. Whilst rainfall in aridor desert climates is rare, it can have catastrophicconsequences, since it often occurs without warn-ing and in large quantities. Rainwater managementand disposal and potential impact on masonryremains are considerations. Some materials are

Figure 5.34 General view of the south elevation of the enclosure building at Fishbourne Roman Palace, in the process of moderni-sation and upgrading (photograph: C. Woolfitt).

Ch05-H6429.qxd 10/14/06 3:34 PM Page 188

Preventive conservation of ruins: reconstruction, reburial and enclosure 189

inherently more vulnerable to the action of rain-water and wetting and drying cycles than others.Earth mortars and plasters are, for example, morevulnerable than those based on lime, with high-calcium lime mortars in turn more vulnerable thanhydraulic limes.

● Rainwater management. Condition survey shouldinclude study of the pattern of rainwater run-off:the way rainwater is shed from the ruin, satur-ation points and collection/ponding areas and vul-nerability of these, and potential for improvementby protective measures. Understanding of existingpatterns of rainwater run-off may help guidedesign of a shelter or other protective measures.

● Temperature. Thermal fluctuations need to beconsidered. Both air temperatures and surfacetemperatures may be significant, depending onthe nature of the remains and the site. Extremesof temperature can be problematic, causing, for

example, localised greenhouse effects in enclosed,unventilated environments subject to direct sunand frost damage to porous materials, with char-acteristic shattering and spalling of surfaces, inconditions of high moisture content and lowtemperature. Internal environments can, in the-ory, be controlled by heating and ventilation sys-tems, but the practicalities of introducing suchsystems with radiators, fans and associated pipesand other fittings may be prohibitive, not least interms of cost. This is sometimes achievable forruins in the context of urban redevelopments,which are contained within new buildings and inrare cases isolated from the ground.

● Wind. This relates to the provision of ventilationand, at exposed sites, can contribute to erosion ofsurfaces. Wind loading is obviously an importantconsideration in the design of shelters at exposedsites.

Figure 5.35 Detail within the enclosure building at Fishbourne, with groundwater ponding on the mosaic surface and causing stain-ing (photograph: C. Woolfitt).

Ch05-H6429.qxd 10/14/06 3:34 PM Page 189

● Light. The source of light needs to be considered.In general, it is easier to design shelters that makeuse of natural light. The popularity of membranecovers for shelters is due in part to their ability totransmit some light, obviating the need to intro-duce artificial light. The orientation of any pro-posed building relative to incident sunlight maybe an important consideration.

● Ventilation. Lack of ventilation within an enclosedstructure can result in undesirable effects, espe-cially in combination with transparent covers,which transmit direct sunlight.

● Relative humidity is a function of temperature andmoisture content in the air. Unless environmentalcontrols are introduced, the internal relative hum-idity of a protective enclosure normally closely fol-lows that of the exterior. In situations whereenclosed ruined remains have elevated moisturecontents, however, the internal relative humiditycould potentially be higher. In certain conditions(at dew point) condensation will occur, withadverse effects on surfaces in some cases.

● Local flora and fauna. The nature of any flora andfauna that have colonised the ruins, and theirimpact. Burrowing animals, which could poten-tially pose a problem in the UK, include rats,badgers, moles, rabbits and foxes.38 Birds may neston ruins and their droppings (guano) cause soilingand contamination of surfaces, as well as contain-ing seeds that can grow on ruins. Feral pigeons aretypically a problem in urban areas, where ruinsstanding to some height provide ideal nesting andperching places. They pose a health hazard to people in addition to other problems, and enclo-sure of ruins colonised by pigeons will requiremeasures to exclude their access; openings mayneed to be screened.

● Site topography, geology and hydrology. The natureof the local geology, composition of soil andunderlying strata is important in understandinghow water is absorbed into the building fabric,particularly at sites where groundwater levels arehigh and rising damp plays a significant role indeterioration.

● Salts. These may be present as part of original fab-ric or introduced from the local environment, byrising damp or carried by wind and rain. Sulphateskins or crust will often develop on the surfaces oflimestones and lime mortar in polluted environ-ments, through the conversion of calcium carbon-ate to calcium sulphate. Sulphates are common inthe surfaces of other materials as contamination orsoiling deposited in polluted environments.

Other factors to be considered are:

● Visual impact. The impact of a new structure onthe site must be considered. It is impossible for anew structure in a ruined context to have novisual impact. As far as possible, however, thenew structure should be subservient to the ruin.

● Security. Is there a risk of vandalism and can thestructure be made secure against intruders?

● Reversibility is always desirable, but is rarely com-pletely achievable when erecting large structuresover ruined sites, where foundations, howeverminimal, are a necessity.

● Wide consultation and publication. This will ensurethat those who have an interest in the site, atwhatever level, as local residents or as specialists inthe field, can contribute or at least be informed of the process of developing schemes for sites.Information can be made widely available on theInternet. A good example is the current proposalto build shelters over the Hagar Qim and MnajdraTemples on Malta, details of which have beenmade available online.39

● Materials and design of proposed structure. As discussedbriefly above, selection of materials and design hasan influence on the internal environment.

● Foundations for structure. The issue of minimisingimpact on the ruined structures and archaeo-logical deposits has been addressed above.

● Vulnerability of original ruins. Survey and assessmentof fabric is covered in more detail in Chapter 3,but this point is repeated here to reinforce theimportance of understanding the materials whichcomprise the ruined fabric. An understanding ofthe vulnerability of the ruin as a whole and of itsconstituent parts is essential. It is often sufficientto characterise materials such as stone and mor-tar by visual examination and comparison to ref-erence samples, although recourse to analysis(petrographic/microscopical or chemical) may benecessary.

● Cost and sustainability. Budgets for schemes toprotect sites are often very limited. Design shouldaim for maximum cost-effectiveness and durabil-ity, although some elements, such as roof covers,may have a shorter life and require renewal.

● Evaluation. Ongoing evaluation of performanceand condition is important for understanding theeffectiveness of protective structures in varyingconditions. Recent research by the Getty Con-servation Institute has emphasised this point andentailed some practical testing of the efficacy ofan experimental hexashelter, using control sam-ples located both inside and outside the shelter.40

190 Conservation of Ruins

Ch05-H6429.qxd 10/14/06 3:34 PM Page 190

● Organic growth. The potential for organic growth,on a micro and macro scale within the shelter,should be considered. Enclosure or shelter of aruin will not necessarily prevent the growth ofeither. Provided the essentials for such growth(water, light, suitable food/growing medium)are present, organic growth is likely to persist andwill, in some cases, need to be managed.

Ruins sheltered within other buildings

In the context of urban site redevelopment, theenclosure and in situ conservation of ruins withinother buildings has sometimes been unavoidable.The following is a small selection of examples:

● An early and prominent example is the Romanbath complex in Bath, where the Great Bath is the focal point of the nineteenth century redevelopment.

● The London amphitheatre within the GuildhallArt Gallery, discussed above under ‘Reburial’.

● Sections of the Roman city walls in the City ofLondon.

● 50 –54 High Street, Guildford – remains of anearly medieval chamber, now located in thebasement of a bookshop.

● The fourteenth century Charnel House at Spital-fields, London.

● Billingsgate Roman Bath House in London.

Environmental problems in these contexts oftenrelate to high groundwater levels, high moisture con-tent in the ruins, and associated problems of mobil-isation of soluble salts and organic growth on surfaces.Other problems are visual and interpretive. It is oftendifficult to provide an adequate setting for ruins dueto constraints of space and construction within a newbuilding superimposed over the ruins. Views of theruins are often obscured by new structures, making itdifficult to appreciate their plan and form.

Survey work and appraisal of protectiveoptions

Although the subject of survey and options appraisalhas been left to the end of the chapter, it should beone of the first steps in the development of any proposals for preventive conservation. Survey and site assessment are the essential foundations of anyscheme for medium- to long-term protective meas-ures, without which the whole edifice of the plannedintervention is likely to founder.41 There are inherent

and subtle distinctions between condition surveywork in the context of protective measures of thekind discussed in this chapter and survey of ruins gen-erally, as addressed in Chapter 3. Both address thecondition of the fabric, but survey for the purposes ofprotective measures must be, in some respects, widerin scope. It must extend to an appraisal of potentialprotective options, anticipating the physical impacteach optional approach would have on the ruinedfabric.

Inadequate or incomplete survey work leading toill-advised schemes of preventive or other conserva-tion work will manifest itself eventually, often inlater, unforeseen need for additional maintenanceor repair work and associated costs. Although surveymay highlight as many potential risks and problemsas benefits of a proposed scheme of preventive con-servation, at least these can then be addressed, andmaintenance and monitoring regimes designed tocope with anticipated problems.

Acknowledgements

The author gratefully acknowledges the assistanceof the following: Graham Abrey and Professor JohnAshurst of Ingram Consultancy Ltd, John Stewart ofEnglish Heritage, Asi Shalom, and Sophie Jacksonand Nick Bateman of the Museum of LondonArchaeology Service.

Notes and references

1. Slayman, A. L. (1997). Archaeology, Magazine of theArchaeological Institute of America, 50(6). Abstractavailable online: http://www.archaeology.org/9711/abstracts/pompeii2.html. The poor condition of the ruined remains of Pompeii and Herculaneum hasbeen widely reported; see, for example, Dr Salvatore Ciro Nappo, ‘Pompeii: its discoveryand preservation’ at http://www.bbc.co.uk/history/ancien/romans/pompeii_rediscovery_shtmland http://www.channel4.com/history/microsites/P/pompeii.

2. Mynors, C. (1999). Listed Buildings, ConservationAreas and Monuments, 3rd edition, pp. 79–88,343–353. Sweet & Maxwell, London.

3. MacLean, T. (1995). Louisbourg Heritage: From Ruinsto Reconstruction, p. 21, citing the Rand RoyalCommission Report of 1959. University College ofCape Breton Press, Sydney, Nova Scotia. This bookprovides an excellent summary of the philosophy,

Preventive conservation of ruins: reconstruction, reburial and enclosure 191

Ch05-H6429.qxd 10/14/06 3:34 PM Page 191

research, planning and interdisciplinary research thatunderpinned the reconstruction.

4. Thompson, H. A. (1992). The Stoa of Attalos II inAthens, Excavations of the Athenian Agora PictureBook No. 2.

5. See, for example, Schmidt, H. (1999). The impossi-bility of resurrecting the past: reconstructions onarchaeological excavation sites. Conservation andManagement of Archaeological Sites, 3(1/2), 61– 68; andBinder, J. (1994). Review of Athens. The AncientHeritage and the Historic Cityscape in a ModernMetropolis. The Archaeological Society at Athens. InThe Bryn Mawr Classical Review, 97.9.12, athttp://ccat.sas.upenn.edu/bmcr/1997/97.9.12.html.

6. Beard, M. (2002). The Parthenon. Profile Books,London. Chapter 4, ‘From Ruins to Reconstruc-tion’, pp. 83–115, provides a very good outline ofthe treatment of the building from the explosion of1687 through to the commencement of the currentprogramme of work. Balanos (1938) wrote his ownaccount of the reconstruction in the first half of thetwentieth century: Les Monuments de l’Acropole:relèvement et conservation, Paris. For a more detailedaccount of the current work on the Acropolis mon-uments generally, see: Economakis, R. (ed.) (1994).Acropolis Restoration: the CCAM Interventions.Academy Editions, London.

7. Jokilehto, J. (2003). Fifth International Meeting forthe Restoration of the Acropolis Monuments (4 – 6October 2002), Conference Report. Conservation andManagement of Archaeological Sites, 6(2), 112–116.

8. Beard, M. (2005). The Colosseum, p. 122. ProfileBooks, London.

9. Ashurst, J. and Woolfitt, C. (1999). Proposals for thePreservation and Conservation of the NorthernPalace, Masada, April, prepared for the Israel Natureand National Parks Protection Authority (unpub-lished report).

10. Zizola, C. (1999). The conservation and restorationof the mosaic floor of the Byzantine Church(Western) in the Nabataean town of Mamshit in theNegev desert. Proceedings of the VIIth TriennialInternational Meeting on the Conservation of Mosaics.ICCM, Arles.

11. Ingram Consultancy (Graham Abrey and Prof. JohnAshurst) (2000). Terraced garden walls, WaterlowPark, Highgate: Report on the condition of the brickterraced garden walls with recommendations forrepair, conservation and reinstatement. Unpublishedreport, prepared for London Borough of Camden,November.

12. Schittich, C. et al. (1999). Glass Construction Manual(P. Green and G. Sööäffker, trans.), pp. 298–299.Birkhäuser, Berlin.

13. For accounts of the amphitheatre’s conservation, see:Ganiaris, H. and Bateman, N. (2004). From arena to art gallery: the preservation of London’s Roman

amphitheatre in situ. In Preserving Archaeological Remains InSitu (T. Nixon, ed.), Proceedings of the 2ndConference, 12–14 September 2001, pp. 198–201.Museum of London Archaeology Service and EnglishHeritage. Bateman, N., Cowan, C. and Wroe-Brown,R. (in preparation). London’s Roman amphitheatre:excavations at the Guildhall 1985–1999. MoLASMonograph Series.

14. Matero, F. and Moss, E. (2004). Temporary site pro-tection for earthen walls and murals at Catalhöyök,Turkey. Conservation and Management of ArchaeologicalSites, Special Issue on Site Reburial, 213–228.

15. Tibensky, K. (2000). Application of a protectiveplaster layer for in-situ preservation of exposedarchaeological wall paintings at the Hippodrome,Caesarea, Israel at http://www.ukic.org/stonewp/sawpsect2.html, Abstracts of research submitted onthe Courtauld Institute of Art MA in the Conser-vation of Wall Paintings, Summer 2000, undertakenin collaboration with the Israel AntiquitiesAuthority and sponsored by English Heritage.

16. Corfield, M., Hinton, P., Nixon, T. and Pollard, M.(eds) (1998). Preserving Archaeological Remains In Situ,Proceedings of the Conference 1–3 April 1996.Museum of London Archaeology Service and theUniversity of Bradford. Nixon, T. (ed.) (2004).Preserving Archaeological Remains In Situ (PARIS 2),Proceedings of the 2nd Conference, 12–14September 2001. Museum of London ArchaeologyService.

17. Brunning, R. et al. (2000). Saving the Sweet Track:the in situ preservation of a Neolithic wooden track-way. Conservation and Management of ArchaeologicalSites, 4(1), 3 –20.

18. Corfield, M. (1998). Saving the Rose Theatre:England’s first managed and monitored reburial. InPreserving Archaeological Remains In Situ (M. Corfield,P. Hinton, T. Nixon and M. Pollard, eds),Proceedings of the Conference, 1–3 April 1996, pp. 305–314. Museum of London ArchaeologyService and the University of Bradford.

19. Ashurst, J., Balaam, N. and Foley, K. (1989). TheRose Theatre. Conservation Bulletin, pp. 9–10.English Heritage, London.

20. Canti, M. and Davis, M. (1999). Tests and guidelinesfor the suitability of sands to be used in archaeologi-cal site reburial. Journal of Archaeological Science, 26,775–781.

21. Caple, C. (1998). Parameters for monitoring anoxicenvironments. In Preserving Archaeological Remains In Situ (M. Corfield, P. Hinton, T. Nixon and M. Pollard, eds), Proceedings of the Conference,1–3 April 1996, pp. 113–123. Museum of LondonArchaeology Service and the University of Bradford.Davis, M. (1998). In situ monitoring of wet archaeo-logical environments: a review of available monitor-ing technologies. Idem, pp. 21–25.

192 Conservation of Ruins

Ch05-H6429.qxd 10/14/06 3:34 PM Page 192

22. Stanley-Price, N. et al. (2004). Conservation andManagement of Archaeological Sites, 6(3/4), SpecialIssue on Site Reburial, Selected Papers from the col-loquium, ‘Reburial of Archaeological Sites’, SantaFe, NM, USA, 17–21 March 2003.

23. Croft, R. (2005). Somerset County Archaeologist.Personal communication, 19 December.

24. Reference to the reburial of mosaics at Lopen andChedworth from Stewart, J. (2004). Conservation of archaeological mosaic pavements by means ofreburial. Conservation and Management of ArchaeologicalSites, 6(3/4), 237–246, Special Issue on Site Reburial,N. Stanley-Price et al. (eds), Selected Papers from the colloquium, ‘Reburial of Archaeological Sites’,Santa Fe, NM, USA, 17–21 March 2003.

25. Stewart, J. (2004). Conservation of archaeologicalmosaic pavements by means of reburial. Conservationand Management of Archaeological Sites, 6(3/4), 237–246.

26. Neguer, J. (2004). Reburial and protective coveringof ancient mosaic pavements. Conservation andManagement of Archaeological Sites, Special Issue onSite Reburial, 247–258.

27. Burch, R. and Agnew, N. (2004). Conceptual designfor field testing reburial of wall plasters and mosaicpavements. Conservation and Management of Archaeolog-ical Sites, 347–362.

28. Nardi, R. and Schneider, K. (2004). Zeugma archaeo-logical programme 2000: the conservation manage-ment programme. In Preserving Archaeological RemainsIn Situ (T. Nixon, ed.), Proceedings of the 2ndConference, 12–14 September 2001, pp. 157–167,198–201. Museum of London Archaeology Serviceand English Heritage.

29. Ford, D. et al. (2004). Chaco Canyon Reburial Pro-gramme. Conservation and Management of ArchaeologicalSites, Special Issue on Site Reburial, 177–202.

30. Caple, C. (2004). Towards a benign reburial context:the chemistry of the burial environment. Conservationand Management of Archaeological Sites, Special Issueon Site Reburial, 155–166.

31. Pollard, M. (1998). The chemical nature of the bur-ial environment. In Preserving Archaeological RemainsIn Situ, 1996 Conference, pp. 60 – 65. MoLAS.

32. Aslan, Z. (2001). Designing protective structures at archaeological sites: criteria and environmentaldesign methodology for a proposed structure at Lot’s

Basilica, Jordan. Conservation and Management ofArchaeological Sites, 5(1/2), 73–85. Aslan, Z. (1997).Protective structures for the conservation and pre-sentation of archaeological sites. Journal of Conser-vation and Museum Studies, no. 3, November, onlineat http://www.jcms.ucl.ac.uk.

33. Stanley-Price, N. and Jokilehto, J. (2001). The deci-sion to shelter archaeological sites: three case-studiesfrom Sicily. Conservation and Management of Archaeo-logical Sites, Special Issue on Protective Shelters,5(1/2), 19–34.

34. Krinzinger, F. (ed.) (2000). A Roof for Ephesos: TheShelter for Terrace House 2. Austrian ArchaeologicalInstitute, Vienna (in three languages – German,English and Turkish).

35. Cunliffe, B. (1999). Fishbourne Roman Palace. TempusPublishing, Great Britain.

36. Stewart, J., Julien, S. and Staniforth, S. (2004). Anintegrated monitoring strategy at Chedworth Romanvilla (Gloucestershire). In PARIS 2, pp. 179–187.Museum of London Archaeology Service, London.

37. Edwards, C. et al. (2003). The investigation and con-servation of 4th century AD mosaics at BradingRoman Villa, Isle of Wight, England. Mosaics Make aSite: The Conservation In Situ of Mosaics on Archaeo-logical Sites, Proceedings of the VIth InternationalCommittee for the Conservation of Mosaics, pp. 101–110.

38. Dunwell, A. J. and Trout, R. C. (1999). BurrowingAnimals and Archaeology. Historic Scotland, Tech-nical Advice Note 16, Research and EducationDivision.

39. Lino Bianco and Associates (with Heritage Malta)(2004). Hagar Qim and Mnajdra Temples Conservationand Interpretation Projecti, December, available onlinevia www.heritagemalta.org.

40. Agnew, N. (2001). Methodology, conservation cri-teria and performance evaluation for archaeologicalsite shelters. Conservation and Management of Archaeo-logical Sites, Special Issue on Protective Shelters,5(1/2), 7–18.

41. The need for survey to understand the condition ofa site is recognised in various publications and guid-ance documents. See Clark, K. (2001). InformedConservation: Understanding historic buildings and theirlandscapes for conservation. English Heritage.

Preventive conservation of ruins: reconstruction, reburial and enclosure 193

Ch05-H6429.qxd 10/14/06 3:34 PM Page 193

Herbert Railton’s (1857–1910) illustration of Thomas Hood’s ‘The Haunted House’ (Lawrence and Buller, 1896) captures almostbetter than any photograph the reversion of a building in a ruinous condition to a natural site (reproduced with permission fromBlackburn Museum).

Ch06-H6429.qxd 10/17/06 2:34 PM Page 194

… and thorns shall come up in its fortified towers, nettlesand thistles in its fortified cities; it shall also be a haunt ofjackals and an abode of ostriches and the desert creaturesshall meet with the wolves, the long-haired goat also shallcry to its kind; … the night monster shall settle there andshall find for herself a resting place. The tree snake shallmake its nest and lay eggs there and it will hatch andgather them under its protection … the hawks shall begathered there, every one with its kind…

(Isaiah 34, v. 13–15, c. 700 BC)

‘Ecology’ is invented to convey the idea of the study of animals and plants in relation to their habit and habitats … we take, then, this word from the Greek(‘oikos’ – home and ‘logos’ – science) to mean ‘the studyof the household of nature’.

(Paul Colinvaux, Introduction to Ecology, JohnWiley, USA/Canada, 1973)

Introduction

Unchallenged, the natural world soon asserts controlover the works of humankind. No longer buildings,not yet wholly a natural landscape, ruins provide aspecialised environment which plays host to a widerange of flora and fauna. In most cases this is astraightforward matter of the local populations mov-ing back in, processes familiar to all who haveobserved a neglected demolition site, but in others theparticular combinations of stones, bricks and mortarand the ways in which masonry may decay and col-lapse attract plants and other wildlife not previouslyindigenous to the locality.

Ruins which are remote and have little contact withvisitors and little or no maintenance revert surpris-ingly quickly to a natural and untamed state, and may

become sites with a diverse ecology of considerableinterest. In the processes of survey, recording, excavat-ing, stabilising and conserving, it is easy to ignore theimportance of the site’s natural assets and to overlookthe need to protect its natural environment. In theearly decades of interest in the conservation of ruins,one of the greatest problems was the extensive groundand wall cover, and a practice of total clearance ofvegetation was established with the object of provid-ing a formal, park-like setting for the ruin in its place. In the UK, considerable research and site trialswere directed towards achieving long-term control oforganic growth on historic walls (Figure 6.1), anobjective which is now seen to be very much at oddswith the interest in ruin site ecology.

Any practical and professional approach must con-sider an action plan for the analysis of the site’s ecol-ogy, its structural stability, masonry consolidation,fabric conservation and long-term management ofthe complete site, without affecting its ecology andinherent ‘romantic’ quality. To this end it is necessaryto identify the professional skills required and toengage suitably experienced professional advisers,skilled craftsmen and operatives to work in collabora-tion to achieve the desired outcomes of the conserva-tion project and promote the longevity of the site asfound and the continuity of its natural life.

Detailed survey, investigations, site trials and theinstallation of exemplars are necessary means by whichall aspects of the site are fully understood, risk miti-gated and the most appropriate repair conservationmethods specified. Such understanding will be furtherdeveloped through discussion and debate with allindividuals involved in a design team, contractor teamand through consultation with the appropriate statu-tory authorities, local groups and amenity societies,where these exist.

195

Chapter 6

The ecology of ruin sites

Sara Ferraby

Ch06-H6429.qxd 10/17/06 2:34 PM Page 195

Ecology and making safe

Ruins are ‘unsafe’ places. Even following full consoli-dation they usually retain some potentially dangerouselements, but in the case of virgin or long neglectedsites the hazards may be considerable and not alwayseasy to identify, especially where there is extensivevegetation cover and large areas of fallen masonry.Endeavouring to make the site safe for the initial sur-veys which need to be carried out is fraught withchallenges, but is a very important preliminary todetailed investigation work. The measures involvedare likely to include setting up secure perimeter fenc-ing around the site with warning signage and alarms,access controls, temporary propping and netting, andsometimes limited areas of access scaffolding. In mostcases this work will need to be carried out in consul-tation with relevant statutory authorities and can formpart of a preliminary site set-up and ‘enabling works’programme. These works should be factored into theearly cost exercises.

Although no works or close examination otherthan these preliminary ones should be carried out atthese early stages, the conservation team, includingits ecologist, should have the opportunity to visit the site as soon as possible and make first-stageassessments.

The first danger to the ruin and its site is often atthe preliminary site investigation stage. For example,because thick surface growth may obscure the wallsurfaces, severely inhibiting any extensive conditionsurvey or graphic record-making, it is often deemednecessary to remove major plant growth, includingthat which is well anchored into the masonry. Thiswell-intentioned but ill-informed site clearance canhave catastrophic consequences in terms of safety, lossof historic fabric and the ecology of the site. Dangersto masonry of overzealous root removal have beendescribed in Chapter 4. The dangers to species of floraand fauna are emphasised here and in the followingchapter on submerged ruins. The aesthetic loss in cre-ating a sterile environment is also considerable. For all

196 Conservation of Ruins

Figure 6.1 Biocide trials at Tintern Abbey in 1972, carried out by the Ancient Monuments Division and the Building ResearchStation. The objective was to compare different treatments against untreated controls, to identify the most effective and persistent mate-rials to keep wall tops free of organic growth.

Ch06-H6429.qxd 10/17/06 2:34 PM Page 196

these reasons, virgin or neglected sites must always bethe subject of a biological survey to identify all speciesand to see how they interrelate and integrate with theruined buildings and the site.

The biological survey

The illustrations of a small selection of diverse sites(Figures 6.2–6.4) serve to emphasise, if emphasis isneeded, how important the natural environment is tothe character of the ruin site, quite apart from itsimportance as a habitat for largely hidden species ofwildlife. The ecologist is therefore to be welcomed asthe newest and essential member of the traditional‘conservation team’. While the primary concernremains the conservation of the fabric and the archae-ology of the ruin and its site, this must never excludethe recognition and care of the natural heritage whichhas been established across its boundaries.

There are inevitable conflicts of interest at timeswhen elements such as leaning walls, decaying treestumps in masonry and voids in walls which provideideal habitats for species of flora or fauna constitutethreats to stability. Excavation by mammals such asrabbits, foxes or badgers (a protected species in the

UK) may add to the dangers and are always poten-tially destructive to archaeology.

The biological survey needs to identify and assessthe significance of the species present on the site, andto make recommendations on what can safely beremoved and what needs to be retained and protected.The survey obviously needs to be carried out by asuitably qualified experienced individual (the ecolo-gist), who should remain as an advisory member ofthe conservation team throughout a programme ofworks and the specification of maintenance regimes.In this way, through regular consultation, there shoulddevelop sound and practical implementation of pro-posals for holistic conservation of the site.

In practical terms the biological survey will pro-vide detailed information on all species identified onsite, and on prior inhabitation; it is essential to thepreparation of contract documentation and informa-tion for conservation works and for long-term man-agement of the site.

Effective planning and programming, the basis ofthe ecological assessment, will mitigate risk of delayonce work has commenced on site. Stoppages anddelays will be minimised as far as possible by the identification of certain species at survey stage. Forinstance, respect of breeding seasons will avoid having

The ecology of ruin sites 197

Figure 6.2 Pevensey Castle and the Marsh; wetlands habitat. The design of conservation works need to be planned in such a waythat the natural life of the site is respected and impacts on it are minimised.

Ch06-H6429.qxd 10/17/06 2:34 PM Page 197

to make special provisions to encourage species toreturn to the site on completion of works.

Early meeting on site between the ecologist andarchitect or surveyor will focus on the nature ofmasonry and other materials present, and samples ofstones, mortar and soil may be taken, for instance, todetermine pH conditions affecting the selection of thesite by particular species of flora.

A well-colonised site may take up to 80 years todevelop. Thus, as with historic fabric, once this is lostor destroyed it is impossible to recreate. Recording ofall species and roost sites and sampling of speciesshould also be carried out. Such sampling may ensurethat colonies are maintained and traditional localspecies are cultivated and reintroduced to the site. Itshould be established, as part of the survey, whatdamage is being caused to vulnerable masonry andwhat structural damage is attributed to uncontrolledgrowth. Protections should be applied to vulnerablecarvings, mouldings and details at immediate risk ofcollapse or loss.

Further specialist advice should also be providedwhere specific unknown species are found, so that thecorrect approach to their protection and prolongation

is followed. An environmental impact assessmentshould be produced to identify the impact of pro-posed repair works on the natural habitats and species,and to determine the extent and effect of removal of,for instance, old trunks or ivy canopies from rubblewalling and the disturbance of roost sites. The bio-logical survey will set out the significance and prove-nance of each species and the risks of undertakingworks on their future.

The biological survey will sometimes extendbeyond the ‘natural state’ of the ruin itself to adjacentand associated gardens, park or woodland. Any majorproposals such as the reculturing of historic plantingschemes and the removal of inappropriate species willalso need to be the subject of environmental impactassessment.

Treatment of flora

Historic sites with ruins are often of particular eco-logical interest, because heavily weathered stones and mortars and the common exposures of large areas of lime-rich core provide particularly suitable

198 Conservation of Ruins

Figure 6.3 Biodiversity at Butrint, Albania. A balance has to be found between the lush flora, the natural habitat and/or foodof insects, snails and reptiles, and the survey, recording and conservation of the ruins.

Ch06-H6429.qxd 10/17/06 2:34 PM Page 198

environments for a wide variety of plants (Figures 6.5and 6.6). The archaeology of the stones may have anunusual bearing on plant colonies when, for instance,siliceous stones are transported to sites in limestoneregions and become host to lichens and other plantsnot native to the region. Similarly, sandstone copingson brick or limestone walls may support species dis-tinctly different from each other. Walls, generally, arenot hospitable to many plants because of the lack ofsoil and water, sometimes coupled with extreme

exposures, but these unpromising conditions some-times lead to the development of a specialised florawhich can withstand long periods without water andextremes of temperature. Vertical surfaces, in particu-lar, may sometimes support particularly interestingplants.

Weathered surfaces, wall tops, ledges and softjoints provide an ideal environment for a variety ofvegetation, mosses and lichens. Different species willoccur in each wall zone according to local climatic

The ecology of ruin sites 199

Figure 6.4 Early spring flowers at Beth Shean, Israel, thriving on previously excavated ground, are important to the biodiversityof the site and need monitoring and protection.

Ch06-H6429.qxd 10/17/06 2:34 PM Page 199

200 Conservation of Ruins

Figure 6.5 Plants thriving on the lime core and sloping surfaces of collapsed walls at Butrint, Albania. On such an extensive site,zones such as these may be left in their ‘natural’ condition without loss or detriment to the monument.

Figure 6.6 Wall cover at Jervaulx Abbey, UK, including wild roses, is an undeniable asset to the site, but needs to be controlledto allow adequate stabilisation and masonry maintenance to be carried out.

Ch06-H6429.qxd 10/17/06 2:35 PM Page 200

conditions and microclimate, water run-off, sun-light, pore structures, alkalinity and acidity. Themild, wet climate is a major factor for the rich diver-sity of wildlife found on UK sites, but this situationmay well alter with climate changes, with fewercolonies inhabiting sites and perhaps some speciesdying out, so it is even more important that theexisting flora is recorded and retained.

Many types of plants are prevalent in masonry wallsof traditional construction as their root stems pene-trate through the soft mortar seeking the voids withinthe core and the nutrients inherent in the alkaline oracidic conditions of the masonry substrate. Changesin patterns of colonization occurred from the late1800s following the introduction of Portland cementto the construction industry, which resulted in fewersoft, lime-rich mortars. Hence, virgin ruin sites oftenprovide ideal environments for a variety of lime-loving traditional species of plants, ferns, mosses andlichens. Flora reflects local conditions and species witha variety of garden, aquatic, wetland and marinespecies occurring according to the location of the siteand method of seed dispersal.

Woody growth and roots affect the stability of thestructure and must be assessed prior to removal.Assessment should consider the importance and sig-nificance of the growth, its maturity and age, as wellas considering the impact of its removal upon thestructure. Removal of woody specimens may causethe collapse and loss of historic fabric where embed-ded in the structure or where roots are earth-bound;removal could cause settlement or dislocation ofmasonry walls. Assessment may require localised‘opening up’ to determine the extent of root growth,supporting openings and shoring of overhangs, eitheras a temporary measure during investigations andrepair and as a permanent management solution usinganchors, ties and grout–stitch–pin consolidationtechniques (see Chapter 4).

The common sight of ivy-clad ruins presents aproblem in assessing condition of the stoneworkbeneath and, by removal of luxuriant cover, the char-acter of the ruin will be jeopardised. It is necessary toremove the damaging major woody stems where

possible by cutting back to the main trunk andremoving the minor stems carefully by hand. Largerroots should be left in situ where their removal wouldcause too much damage. Common ivy and otherclimbers and creepers which can cause damage to softmasonry should be carefully removed or controlled.However, it is likely that these heavy ivy mantles canalso provide protection for the vulnerable masonryfrom accelerated weathering, processes of decay andfrost damage, as well as wildlife habitats, so someretention should be considered as part of the biologi-cal assessment and long-term management of the site.

Pesticides and herbicides should only be used as alast resort for removing plants and only after specialistadvice is sought. Due to the tough stems of someplants, such as rhododendron and buddleia, chemicaltreatments are often used, as manual removal couldcause more damage to the masonry fabric. Chemicalcontrol methods should only be undertaken followingbiological survey and, once the species are known,should be restricted to use on species of little botani-cal interest or which are likely to cause damage. Theuse of pesticides should be controlled and appropriatemeasures taken for the control of run-off or errantspray so that it does not come into contact with otherspecies or watercourses.

Nature can sometimes be harnessed to protectancient sites. For instance, a more benign form of theRoman use of quickset thorn hedges in defensiveditches can be utilised in a ‘natural ruin’ to increasesecurity, with brambles, blackthorn and nettles beingintroduced to provide ‘soft’ security of remote sites.Mature planting of this kind can be very effectiveagainst illegal access and vandalism, as opposed to hav-ing harsh ‘hard’ security measures surrounding thesite, such as perimeter fencing, warning notices andsteel gates.

Treatment of fauna*

The biological survey, thoroughly carried out, willreveal a great deal of information about the currentand past occupancies of a ruin site from occurrences

The ecology of ruin sites 201

*There is an increasing awareness of the importance of the environment to wildlife fauna as effects of climate change are becoming more

widely known. For instance, the plight of polar bears and seals associated with the loss of sea ice as the northern ice cover retreats is well

publicised and of national concern, but there are many other threats to the planet’s animals and not only those which were, or are, being

hunted to extinction, but those for whom there is simply no more room. ‘The bigger the animals, the more conflicts there are with

humans over territory. There are just too many people,’ the Israeli INNP has said of the limited return of leopards of the Judean desert.

Visitors and leopards are not often in direct contact, but the visitors scare away natural food sources such as ibex and rabbits. Although

there are few ruin sites in polar bear territory and many in the leopards’, the point is that successful survival is always a delicate balance

and there are always competitive elements, even when the context is shrunk, as now, to the microcosm of the single site. Here, too, com-

plex societies, almost unnoticed, can experience crises or face local extinction through ignorant intervention. Ed.

Ch06-H6429.qxd 10/17/06 2:35 PM Page 201

and patterns of guano, droppings, skeletal remains,excavations from burrows, shed skins, hair and feath-ers. The presence of protected species will almost cer-tainly restrict works at certain periods and exclusionfrom some zones of the site, requiring careful plan-ning. For instance, English Nature recommends abuffer zone between the entrance to badger sets andbuilding activities, suggesting that light machineryshould not be used closer than 20 metres to theentrances and that heavy machinery should only beused at distances exceeding 30 metres. The intrusionof the conservation team’s work and manner inwhich it is carried out should not be allowed to putany protected species at risk. Survival of species caneither be threatened or enhanced by informed andcareful treatment.

In the UK, all birds are protected during the nest-ing season. English Nature encourages vegetationmanagement outside the bird breeding season(February to July), and woodland and shrubland man-agement between October and February. The avoid-ance of nesting and roosting periods often presents aconflict with repair needs since these generally fall insummer, when conditions are favourable to conserva-tion works using traditional materials such as limeputty-based mortar. However, such works can also bemanaged in winter periods, with appropriate solu-tions such as heating and double sheeting to scaffolds,hessian protections and the like, and care of newlyplaced mortars to ensure they are not significantlyaffected by cold and damp conditions.

It is also possible that, following consultation withthe relevant Statutory Nature Conservation Organisa-tions (SNCOs), some minor non-disruptive surveyworks or enabling works and site set-up can be under-taken during these periods if they are of no detrimentor risk to the wildlife.

Information from the biological survey is vital inthe preparation and discussion of applications forstatutory consents and relevant nature conservationconsents. In general, statutory bodies are fully awareof the implications of delay to project works and willadvise the best method of resolving delays caused bythe presence or unexpected appearance of certainspecies on site and assist with the appropriate removalor control techniques. They will also advise, in collab-oration with the project ecologist and design team, onhabitat creation and risk control whilst maintainingthe site in a natural but managed state.

Without the commissioning of a biological survey,the discovery of the presence of bats is a commoncause for delays in conservation work. In the UKthere are 16 species and all are protected, as are their

roost sites, and works must be halted as soon as theyare identified; works should also be avoided duringthe roosting and breeding season, which generallyoccurs during May to September. Once bats areidentified it is necessary to halt any works and to con-sult a specialist organisation or SNCO such as EnglishNature (EN), so that their presence can be recordedby an officer of EN and they can be temporarilyremoved from the site during the works if necessary.Once works are complete, they can be reintroducedonto the site as long as the conditions are maintainedfor their inhabitation (Figure 6.7).

In fact, conditions can often be enhanced by theproject works, by the provision of nesting boxes forbirds of prey, such as owls, bat boxes and unob-structed flight paths as part of the works contract andexclusion of the public from certain vulnerable areasof the site.

Another situation which sometimes needs to beaddressed and resolved is the presence on site of bur-rowing animals such as moles, rabbits and badgers(Figure 6.9). These creatures create voids under-ground in the development of their habitats, and theseindiscriminately excavated voids can cause the under-mining, settlement and partial collapse of masonrywalls and destruction of earthworks. Selective soilgrouting of rabbit warrens in earthworks, once thepopulation has moved out, is a stabilising conservationtechnique which is sometimes useful and appropriate.Badgers are a protected species under the provisions ofthe Wildlife Act 1981 and the Protection of BadgersAct, but these burrowing animals can be humanelycontrolled under the guidance of the SNCO. Theirexistence should be encouraged as they are rare andbeautiful creatures which are now under the addedthreat of culling due to a disputed risk of their trans-mitting tuberculosis to cattle. Conditions can gener-ally be improved via the works for the animals andfauna, and built into the ongoing management policyfor the site.

Voided walls and weathered surfaces provide idealbasking places and refuges for a variety of animals,insects and reptiles. Their presence on site will beidentified in the biological survey and if possible thedeep-tamping and filling of voids to masonry wallsshould be minimised or avoided to ensure these habi-tats are maintained. At the very least the voids shouldbe inspected as far as possible prior to filling or con-solidation to ensure that the animals are not trappedwithin. A high concentration of guano from bats andbirds can be of detriment to the building fabric as theacid content can accelerate decay and deterioration ofthe masonry surfaces. This can be mitigated by the

202 Conservation of Ruins

Ch06-H6429.qxd 10/17/06 2:35 PM Page 202

The ecology of ruin sites 203

Figure 6.7 The late fifteenth/early sixteenth century brick precinct wall of a monastery, with its moat, now generally dry but sea-sonally wet, showing settlement fractures with brick underpins, mortar deterioration and luxuriant ivy growth. The wall is host to batsand masonry bees, sometimes to owls, and frogs, slow worms and newts are sometime inhabitants of the moat. The ConservationManagement Plan includes recommendations for the management and maintenance of the site which must embrace and balance the preser-vation needs of the historic fabric and the needs of the natural inhabitants and their environment.

Figure 6.8 Flooded area of hypocaust, Butrint, now home to terrapins, requires draining if soluble salt damage to pilae is to beaddressed. Alternative flooded zones with less sensitive fabric can be used for relocation.

Ch06-H6429.qxd 10/17/06 2:35 PM Page 203

introduction of timber guards or baffles to protect themasonry under the areas of congregation and by the provision of fine mesh to mouldings and carvingsto prevent damage.

As part of the habitat creation and long-term eco-logical management of the site, provisions can beintroduced such as piles of dead and decaying wood;composting and bare soil provide habitats and refugesfor a variety of species.

Treatment of wall tops

Wall tops often support coarse grasses, mosses andwoody weed growth, mainly of local species whichhave formed an organic mat over the years. Tradition-ally, it was common to remove all traces of this natu-ral ‘soft capping’ and replace it with a hard capping of mortar following consolidation and repair of themasonry to parapet walls and sky-facing surfaces(Figure 6.10).

A more modern approach following the survey andprior to the masonry repairs is to carefully take up anyexisting natural growth covering the wall tops, toexpose the condition of the wall below, extent of rootgrowth and damage to the substrate. The precise loca-tions of any planting should be recorded and the turfor planting should be retained on site in appropriateconditions to keep it alive, for later re-instatement.

The masonry from where the turf or planting isremoved should be carefully recorded with photogra-phy and photogrammetry, if funds allow, in additionto sketches and textual descriptions. Any stone fallsshould be recorded and retained on site for replace-ment during the repair works, and any loose or unsta-ble masonry should be taken down to sound masonryand the wall top rebuilt. Damaging main root sectionsshould be cut out and removed where possible or poi-soned and left in situ to avoid major disturbance to thestructure (see Chapter 4).

Following consolidation and rebuilding of theoriginal profiles, the ecologist should be able tomake recommendations on installing soft capping of

204 Conservation of Ruins

Figure 6.9 Underground engineering works by one of the UK’s protected species, the badger, can become a problem for buildingsand earthworks.

Ch06-H6429.qxd 10/17/06 2:35 PM Page 204

the wall tops, including existing ‘natural’, local andcontrived species. The contrived species are thosewhich are newly introduced to the site but may be types which previously flourished. It is prudentto take seed samples from any existing specimenswhen they are removed prior to repair works and are intended to be reinstated within the walltop. This ensures that the seeds can be germinated

either off site or in suitable conditions on site andexisting species can be cultivated for these and otherlocations.

Following consolidation and surface repair, thewall tops can be covered with a separating membraneof geotextile to prevent the migration of fines fromthe soil layer, which in turn is covered with turf or thesalvage root mat if possible. The turf will contain the

The ecology of ruin sites 205

Figure 6.10 Wall tops at Tintern Abbey showing formation of grass and bryophytes in the foreground and biocide-treated sur-faces beyond.

Ch06-H6429.qxd 10/17/06 2:35 PM Page 205

206 Conservation of Ruins

Figure 6.11 Site clearance and maintenance by grazing-1. Goats were brought onto the site of Fort Southwick above Portsmouthon the Portsdown Hill to reduce the thick cover of brambles and buddleia growing above the precipitous walls of the dry moat.

Figure 6.12 Site clearance and maintenance by grazing-2. Sheep grazing the site of Henry II’s palace of Clarendon aboveSalisbury, were introduced to exercise some control of low level vegetation growing on and over low lying, partly excavated masonryremains on the site.

Ch06-H6429.qxd 10/17/06 2:35 PM Page 206

new seedlings, seeds and any salvaged species retainedon site for replanting.

Procurement options

At planning stage, an appraisal of all feasible optionswill have to be considered according to phasing of theworks in terms of priority, limitations of the site andfunding available. All options for phasing the workswill have to be costed so that the best approach can beundertaken within the given constraints of cost, qual-ity and time, and to ensure that the ecological impacthas been adequately considered and assessed in under-taking the options appraisal.

So that expensive preliminaries and site costs arenot incurred when site activity is limited by decision-making, exploratory trials and during breeding sea-sons, it may be possible that several minor works ordirect works packages can be set up to undertake thenecessary enabling works. Enabling works packagescould include provision or improvement of site accessroads to enable contractors’ vehicles to get to the site,direct procurement of site accommodation and safetyelements such as temporary supports. Some of theinitial site clearance could be carried out, if properlysupervised, under a minor works contract to reducemain contractor overheads and avoid taking valuablefunds away from the repair works.

Minor works contracts could also be used for theprocurement of site trials and exemplars, undertakenby a suitably skilled conservation contractor and inreducing the length of the main contract period.Trials and exemplars, such as for tamping, pointingand soft capping, are also needed well in advance ofthe tender to develop and fine-tune the specification,and provide valuable quality, cost and programmeinformation.

Competitive bids for the main contract shouldonly be invited from suitably skilled craftsmen andcontractors with previous experience in similar sitesand of building ruins. Unless these are known fromprevious projects or trusted word of mouth, refer-ences and examples of work should be sought and,if necessary, interviews should be conducted withshort-listed companies at which the site foremanshould be in attendance so the contractor candemonstrate the ability to undertake the works (seeChapter 8).

Pre-tender site visits should be arranged, accompa-nied, so that the contractor is aware of the complexi-ties of the site, which may be considerable. Becauseeverything is seen and questions can be asked, these

visits significantly reduce the risk of the contractormisunderstanding the scope and quality of worksrequired. In the context of this chapter it is essentialthat the contracting team is fully aware of the ecolog-ical sensitivity of the site and understands the reasonsfor respecting it and its implications.

Risk can be further mitigated by the careful andcomplete preparation of preliminaries and contractdocumentation illustrating the site constraints, restric-tions and implications of the work on the surroundinglandscape and ecological system. A ‘tight’, well-defined specification and drawings will ensure that thework is carried out correctly and in the first instance ispriced correctly so there are no surprises on site; anyunknowns can be included as provisional sums items.Any time periods for attendances by members of thedesign team and statutory authorities should also bebuilt in for programming and pricing purposes.

The importance of effective site supervision by acompetent site foreman, who fully understands therequirements of the specification, the complexities ofthe site and its constraints, and is knowledgeableenough to stop work if new factors are discovered,cannot be overemphasised. The contractor and fore-man must be able to work in full cooperation withthe professional team and other contractors on site,including liaison with directly procured contractors.

According to the duration of the contract, regularsite progress meetings should be held with the con-tractor and the design team, including the ecologist,where appropriate and necessary. Regular site visitsby the lead consultant should also be undertaken toreview progress and approve samples and trials, andto instruct the contractor.

The Conservation Management Plan

A Conservation Management Plan should include adetailed description of the site and its significance,assess all issues relevant to its conservation andlongevity, and provide a plan for the prioritisationand implementation of these issues. In particular, inthe context of this chapter, the plan and any revisionto it must consider the biodiversity of the site and itswildlife, as well as the historic fabric; specifically, itmust consider how best to protect and enhance theseassets, and the ability to which they can sustainchange in the future.

It is important that all stakeholders have an inputinto the contents of the plan as well as the localcommunity. This includes all those professionals andcraftspeople involved in the conservation project,

The ecology of ruin sites 207

Ch06-H6429.qxd 10/17/06 2:35 PM Page 207

statutory authorities, amenity societies, and localresidents and ‘friends’ groups.

The plan is intended to include a survey of the siteand its architectural, archaeological and historical significance, the characteristics of the natural envi-ronment, any original planting schemes, detail regard-ing its statutory listing and controls, site restrictions,financial information, and recommendations for themanagement and maintenance of the site. This willinclude information on restrictions upon works, suchas those due to breeding patterns, and the ongoingmonitoring and inspection and how this should bestbe implemented. The plan should also incorporatethe findings and recommendations of the biologicalsurvey and assessment, detailing all species identifiedon the site and the requirements for their ongoingconservation and protection.

The ecology of the site must be incorporated intomanagement considerations within the plan, includ-ing procedures for the encouragement of biodiversityand habitat creation, as well as ensuring that existingspecies are recorded, monitored, retained and pre-served. This should also link into local and nationalpolicies for ecological control and conservation, and the recommendations of any local BiodiversityAction Plans.

Visitor access

Priorities of the management plan will include theconservation of the cultural heritage, habitat creationand maintenance of existing species and habitats, aswell as health, safety and security measures to ensurethat visitors to the site enjoy a safe, accessible andsecure environment in which to enjoy both its builtand natural assets.

There can be a conflict between the longevity andprotection of the site and its assets and allowing accessby the public (see Chapter 9). With visitors come theinevitable clutter of car parks, cafes, shops, ticketkiosks, litter bins and wayfinding signage, whichaffects the character and aesthetic of the site and itsvistas. However, these sites represent national historyand heritage, and there is an obligation to promotethem as an educational tool for all members of thecommunity; visitors also provide vital revenue toensure their ongoing care. To this end, a balance mustbe struck between the needs of the visitors and thoseof the site. The site should always remain the priorityand it should not be compromised by the visitors’needs or the need for commercial gain.

Following the provisions of the Disability Discrim-ination Act (DDA), there is also a responsibility placedon the owners of any property to improve access forall, including wheelchair access. There is perceivedconflict between the historic and natural environ-ment in implementing the requirements of the DDA,especially in terms of implementing physical changesto enable access. This comprises sufficiently wideopenings, ramps, lifts and other such facilities toenable unaided access to the site by wheelchair usersand those with physical disabilities. However, there isa test of reasonableness to be applied to this, and theprotection of the buildings and their natural settingmust remain the priority. This ‘conflict’ is often mit-igated by the provision of web-based virtual realitytours and information sites accessible via heritagecentres or tourist information offices that are notrequired to be on the site itself.

Ongoing management

This outline approach ensures that a detailed recordis maintained of the species existing on the site priorto works and also immediately following completionof the works, especially where reintroduction of tra-ditional local species has been implemented on thebasis of site findings and local environment and cli-mate. As part of the longer-term management of thesite it is essential that this biological survey is a livedocument updated at regular intervals, such as thequinquennial inspections. This means that ongoinginvestigation and survey should be carried out inorder to maintain a record of all species as a naturalconservation record in accordance with the site’sConservation (Management) Plan.

The ongoing management of the site will be aprocess informed by the ecological survey findingsand recommendations. The elements will be includedwithin the Conservation Plan and will include secu-rity, structural survey, health and safety issues, ongoingsurvey and condition inspection to promote thelongevity of the site and its ecology. It is not necessar-ily the case that wildlife will thrive where the site istotally abandoned, so a management procedure is verynecessary to ensure the long-term future of the site.Management policy will also comprise site security,access for the public, accessibility, and wayfinding andinterpretative signage. Quinquennial fabric conditionsurveys should be undertaken with findings costed,prioritised and fed back into the maintenance andrepair programmes.

208 Conservation of Ruins

Ch06-H6429.qxd 10/17/06 2:35 PM Page 208

In terms of ongoing management and survey of thenatural heritage, it is important that inspections arecarried out regularly and a vegetation control systemis built into the regular maintenance routine, withdamaging vegetation removed or selectively con-trolled. Individual species should be checked for con-tinued breeding and use of the site. This is especiallyinformative and important following the disruption ofmajor repair works, as some species may not returnand their numbers must be calculated. Also, wheretraditional local species have been reintroduced tosites, it is important to record population levels tomonitor the success of the project and the ongoingsignificance of the site as a whole, as well as a bench-mark for future projects and national statistics.

But it is important that the ruin site becomeslargely self-sufficient. The need for ongoing fundingfor surveys and inspections following repair workswill not be welcomed by clients and funding bodies.The self-sufficient but managed site conserves andpromotes its ecology, and establishes and controlsaccess to the site by the public.

An economic and effective management resourcemay well be the local community groups, volun-teers, friends groups and local residents. They maybe trained, under strict supervision and by example, to undertake regular inspection, monitoring andrestricted control of vegetation and site managementfollowing exemplars of the level and extent of anyworks. While the integrity of the historic and natu-ral heritage must not be jeopardised or compro-mised by this approach, it can encourage people totake responsibility through a sense of ownership andinvolvement. Local groups can provide an enormoussecurity benefit and any unusual activities, patternsof loss or other problems can be reported promptly.

Summary

Ruin sites often provide ideal habitats for a diversewildlife. The presence of many different species is auseful indicator of climate and conditions, and siteswhich have been largely undisturbed for decades orcenturies can provide valuable historical informationon past changes. Rare species of flora and fauna maybe present, some of which may be protected by law.

Ecology helps to identify and understand the naturalenvironment of the ruin, which enhances its culturaland aesthetic value, and helps to plan for its future.

Any approach to conserving the ruin should antic-ipate and resolve potential conflict between stabilisingand conserving the buildings and preserving their nat-ural environment. Understanding and appreciatingthe value of both before any work plan is finalised andimplemented will go a long way to avoiding damag-ing interventions to either.

The biological survey, carried out by the ecologist,is an essential tool for developing a plan of work injust the same way as structural, archaeological andcondition surveys; it should therefore be carried outas part of an integrated approach, and its recommen-dations incorporated within the works and linked tothe current and long-term management of the site.

A word of warning seems appropriate at a time(and there will always be such times) when strainedbudgets are causing managers to look for all possiblesavings on maintaining the heritage of ruins. Chapter9 makes reference to policies described, euphemisti-cally, as ‘managed decline’ and ‘benign neglect’. Thegrowing awareness of an interest in the natural envi-ronment can sometimes be exploited by those whoneed to justify budget cuts on essential maintenanceto historic fabric. Such misplaced ideas and abusesmasquerading as a ‘return to nature’ should always bechallenged. In conclusion, the approach to conserv-ing a ruin and its site must be holistic, encompassingan understanding in its ecological as well as its archae-ological, architectural and historical significance. Byadopting this approach it is possible for the built andnatural heritage to be managed in conjunction, sothat the site and its inhabitants can be sustained inharmony.

Further reading

Darlington, A. (1981). Ecology of Walls, HeinemannEducational Books, London.

Gilbert, O. (1992). Rooted in Stone – The Natural Flore ofUrban Walls, Department of Landscape Architecture,Sheffield University, English Nature.

Meech, H. (ed.) (2001). Wildlife and Buildings, TechnicalGuidance for Architects, Builders, Building Managers andOther. National Trust.

The ecology of ruin sites 209

Ch06-H6429.qxd 10/17/06 2:35 PM Page 209

Figure 6.13 The ruin site: typical examples of conflicts of interest to be resolved.

Examples Description Building conservation Ecological conservation

Superficial damage by certain species of If damage is taking place to important detail the Crustose (crust forming), foliose (leafy) and fruc-

crustose lichen is caused by acid secretions careful and selective removal of algae, fungi or tose (shrubby) lichens are interesting, attractive

and growth of cells within stone pores. lichen becomes necessary, using a combination and ancient species commonly found on old

Some algae and fungi also secrete organic of steam pencil, gentle mechanical processes and masonry structures, the most important habitat

acids, especially oxalic acid. Thin surface biocides. If surfaces are not threatened but joints for saxicolous lichens. Some species are unusual.

scaling, surface bleaching, blistering and need to be filled or repairs carried out extreme They are important pollution monitors and use-

erosion pits can occur as a result on lime- care needs to be taken to avoid wet lime contact ful indicators of the acidity/alkalinity of the sub-

stones, marble and calcareous sandstones, with growth which is to be retained. Any biocide strate. Some can be of considerable age and are

but can also attack silica and cause etching treatment needs to be carefully controlled to objects of scientific study. Species need specialist

of granite. These conditions cause damage avoid run-off onto areas outside the treatment identification to determine significance and

to shallow tooled surfaces, surfaces with zone and any contamination of water courses. inform approach. Care should be taken to pro-

small-scale detail and low relief, incised There are cost implications involved in this tect them and preserve their habitats, avoiding

letters, masons marks, polished finishes conservation approach. unnecessary cleaning.

and plaster. Churchyards and ruin sites

often provide ideal habitats.

Ruin walls provide demanding conditions The careful removal of wall cover is necessary to Wall flora is a distinctive and attractive feature of

creating a specialised flora, some rooted in ascertain condition, to record the masonry and ruin sites, regionally diverse and indicative of

soil at the wall base and some growing on to schedule repair and conservation works. The different masonry types, exposures and pollution

the wall faces and wall heads. Woody weeds subsequent, programmed removal of ivy and other levels. The recording and preservation of wall

such as ivy, buddleia, red valerian and wall invasive, woody plants is needed to carry out con- colonising species is an important aspect of the

flower can cause varying amounts of disrup- solidation of the ruin. Even if soft wall capping is site’s value and conservation. Wall flora is impor-

tion of masonry, cracking and loosening adopted it is usually necessary to carefully record tant to insects such as bees and butterflies.

mortar and jacking and displacing stones and remove mats of vegetation for later reinstalla- Disruption and removal of dense foliage, often

and bricks, especially at wall head level tion. Voids within the wall need to be grouted or untouched for years, catastrophically disturbs the

and at broken wall ends. Luxuriant packed with mortar and open joints to be deep- wildlife it supports and may inhibit or preclude

canopies of growth and voids within the tamped and pointed. future growth; some insects, reptiles and small

wall provide habitats for a wide range of mammals may leave the site altogether.

wildlife.

SURFACE GROWTH

WALL COVER

Ch06-H6429.qxd 10/17/06 2:35 PM Page 210

Many sites were taken over by woodland Major structural and archaeological damage can be The loss of woodland, especially ancient wood-

before becoming subjects of national caused by mature tree roots growing on or near land, is always to be resisted, and if essential for

interest. During centuries of neglect some walls. Above ground the tree has often become archaeology or consolidation must be limited in

trees grew on standing or collapsed sections integral with the masonry fabric so that its removal scale and scope, exclude some particular species

of masonry and their roots moved down to is impossible without destroying the wall. Cutting and be planned for the right time of year to

break up floors of lime, tile or mosaic and back the tree to the wall face is the only way to cause minimum disruption to wildlife. Even lim-

seek out old water courses. Architectural prevent further growth and destruction by penetra- ited removal is potentially damaging by modify-

features within the wall were often obscured tion and leverage, after which it must be main- ing habitats and the landscape value of the site.

or broken up; the effects of wind on high tained in its reduced condition. Growth control Methods such as pollarding to reduce root

trees further weakened the walls on which methods on mature trees on archaeologically growth may be acceptable.

they stood and falling trees can demolish sensitive areas such as pollarding are necessary to

substantial sections of masonry. reduce root growth and are part of the ongoing

site management.

Previously excavated areas such as founda- Avoidance of subsurface damage to archaeology is Conditions of dereliction often support a rich

tion trenches and raised mounds or banks often a major concern, as is any undermining of bio-diversity of plants and wildlife. Existing

are attractive to burrowing animals such as fragile walls above ground. The extent of under- habitats, especially for protected species, need to

rabbits, foxes and badgers. Burrows and sets ground voids caused by burrowing animals is be preserved. Intrusive conservation works can

can be well established and extensive and difficult to ascertain; vacated sets and burrows may disrupt established habitats and the site may be

can undermine foundations, causing insta- need to be filled by soil grouting. Site clearance vacated to the detriment of the species; where

bility and even structural failure. Damage under archaeological supervision to provide access protected and rare species are involved such as

can also be caused to vulnerable plaster or to walls and floor levels and to record, salvage and the Great Crested Newt this is a serious matter.

mosaic floors, to burials and to archaeolog- identify fallen material is standard practice. Fallen, The disturbance of habitats and breeding zones

ical stratification. Piles of fallen masonry overgrown masonry on water courses such as protected by law, especially during breeding sea-

can provide excellent habitats for a range medieval drains, wharfs and bridges require similar sons may constitute a criminal offence, as does

of insects and reptiles; overgrown water highly invasive practices to properly record, the injuring or killing of reptiles and/or amphib-

courses with collapsed masonry provide reinstate and consolidate. ians. It is important to understand, respect and

ideal soft-bank conditions for voles and preserve the conditions in which these creatures

other aquatic and amphibian life; long can thrive, such as food sources and living con-

undisturbed and overgrown areas may be ditions. Specialist ecological advice must always

well established zones occupied by slow be sought before any proposed works are put

worms or snakes, frogs, toads and newts. in hand.

Resolution of conflicts begins with statements of significance and bringing together the condition survey of the building fabric, describing structure and materials, and the Biological survey,

providing a species list for the flora and fauna of the site.

Ferraby/Ashurst

SPECIAL HABITATS

TREES

Ch06-H6429.qxd 10/17/06 2:35 PM Page 211

The extensive ruins of Caesarea are located on the western edge of modern Israel and lie partly under the coastal waters of theMediterranean sea. Herod’s city lies over an earlier Phoenician port, traditionally founded by Straton. Underwater survey has formeda significant element of the investigation and recording of the site over many years. Survey and excavation are carried by the centre forMaritime Studies, University of Haifa.

Ch07-H6429.qxd 10/14/06 3:38 PM Page 212

Introduction

Nel tempo, e con l’acqua, tutto muta. (In time and withwater, everything changes.)

(Leonardo da Vinci)

One of the results of the historic use of the coastand rivers for the exploitation of natural resources,trade and communications has been the developmentof towns, villages, individual buildings, monuments,structures and complexes along the coastlines of theworld. This pattern of historic settlement of coastal

regions is seen internationally and reflected in modernpopulation distributions – 50 per cent of the popula-tion of the industrialised world lives within onekilometre of the coast.1 This legacy of archaeologicalmonuments and historic buildings in close proximityto the coast ranges from the earliest tombs and ritualcomplexes to the wealth of medieval towns, fortifica-tions and ecclesiastical settlements, through to theincreasing diversity of post-medieval and twentiethcentury cultural heritage. The coast is not an immov-able or constant boundary, and changes shape over awide range of timespans. The tides rise and fall daily,storm events can cause sudden dramatic alteration,and over longer periods the processes of erosion anddeposition cause shorelines to change shape and pos-ition. This has led to the phenomenon of historic har-bours becoming landlocked, and other buildings andstructures gradually sinking beneath the waves. Theencroachment of the sea on the land and the inunda-tion and submergence of historic buildings poses ahost of new challenging conservation issues.

Considering the conservation of a submerged orsubmerging ruin is a complex task. The sea presents anaggressive, powerful environment, a salt-rich solutionpopulated by a wide range of complex biologicalorganisms seeking surfaces to colonise. And the sea ismobile, moving both landward and seaward, under-mining, burying, abrading and corrading. There is noestablished ‘best practice’, no specialised generic tech-niques to draw on and very little previous work todraw comparison with. Instead, there are a range ofissues which must be considered in addition to thosefamiliar to architectural conservation, and a range ofassessment, recording, monitoring and repair tech-niques which must be moulded, shaped and adaptedto address site-specific needs.

213

Chapter 7

Submerged ruins

Jason Bolton

Figure 7.1 Map c. 1843 overlain with digital aerial photo c.1999 of Bray, on the soft glacial tills of the east coast of Ireland,showing extent of coastal loss (aerial photo courtesy of GearoidO’Riain, Compass Infomatics).

Ch07-H6429.qxd 10/14/06 3:38 PM Page 213

Evaluation of the marine environment

Nature of the coast

One of the first challenges is to understand theprocesses of coastline change and what we mean by‘the coast’ itself. The coast is most often defined asthe place where the land meets the sea. However, theidentification of where the sea stops and the landbegins is a matter of some debate. The debatebecomes increasingly complex in coastal systems suchas coastal plains, mudflats, mangrove swamps and saltmarshes, where the extent of the inter-tidal and theimmediately supra-tidal is not clear. Common map-ping practice is to use the edge of vegetation cover asthe coastline, as it often indicates the furthest extentof high water. Historically, the mean high tide markhas been used as a convenient boundary to mark thecoastline. However, the high tide mark is not animmovable datum point. The line fluctuates with thedaily and annual cycle of tides, and over longer time-frames as the shoreline itself undergoes change throughprocesses of erosion and accretion, and with changes

in land and sea levels. Although in popular terminol-ogy the term coastline is frequently used, in practicethe coast has width and depth as well as length, and inrecent years it has become more common interna-tionally to refer to a ‘coastal zone’.

There are no clearly defined and universallyaccepted boundaries to the coastal zone. The manygovernments, institutions and other bodies involvedwith research and management of the world’s coast-lines operate on a wide variety of scales, using differ-ent boundaries for different purposes. Increasingly,definitions of the coastal zone are moving away froma spatial definition, to a broad description in line withCarter’s2 definition of the coast as ‘that space in whichterrestrial environments influence marine (or lacus-trine) environments and vice versa’. Many definitionsof the coastal zone do not contain physical limits andpurposely leave the parameters open. Where the landis relatively flat, the coastal zone may extend somedistance landward, and where the sea meets a cliff faceor other steep surface, the coastal zone may be con-fined to a relatively narrow band. Within this broad

214 Conservation of Ruins

Figure 7.2 This railway at Bray, Co. Wicklow on the eroding east coast of Ireland, was abandoned c. 1917, but stretches under-water for more than 2 km, with submerged traces of two martello towers, a gate lodge, fishermans cottages and a submerged forest over6000 years old.

Ch07-H6429.qxd 10/14/06 3:38 PM Page 214

definition, it is possible to break the coastal zone intoa number of generic units, the parameters of whichmay vary from site to site, and each of which posesparticular challenges to monuments:

● The sub-littoral or sub-tidal area – extending fromthe mean low spring tide water mark seaward

● The littoral or inter-tidal area – extending from themean low spring tide water mark to the meanhigh spring tide water mark

● The supra-littoral area (spray zone) and adjoiningcoastal land – extending landward from the meanhigh spring tide water mark.

A ruined monument may be entirely, partially oroccasionally submerged, depending on its locationwithin each of these zones. These zones may alsomove either landward or seaward due to both naturaland anthropogenic factors, and consequently a ruinedstructure may ‘pass’ from one zone to the next dur-ing a process of emergence or submergence. The keycharacteristic of these zones is the amount of availablesea water which can impact on a building surface.Coasts are defined in a number of different ways fordifferent purposes, but at the simplest level are eitheraggrading (advancing seaward), stable (no currentsignificant change) or eroding where the shoreline isretreating.

Coastal erosion – causes and processes

Coastal erosion can be defined as the landwardmovement of a shoreline resulting from a loss of sedi-mentary or rocky substrate from the inter-tidal andforeshore zones. The process can be damaging tomonuments in a number of ways – commonly under-mining the foundations of a building, and allowingthe direct impact of wave, spray and the marine envir-onment on building surfaces as a prelude to inunda-tion. Coastal erosion is the result of a combination ofa number of factors, including changes in relativesea level, the intensity of wave action, tidal amplitude,the frequency of storm events, patterns and alter-ations to sediment distribution along the coastline,and the composition of the shoreline. Coastal erosioncan be reduced or accelerated by natural and artifi-cial changes to sediment distribution, such as alter-ations resulting from land reclamation works andmineral/aggregate extraction. The process of coastalerosion tends to arise from a combination of causalfactors, and the relative importance of these factorschanges according to local variables.

The rate and severity of coastal erosion is alsocontrolled by the nature of the shoreline – most

commonly divided into ‘soft’ (sandy dunes, glacial till)and ‘hard’ (rocky sea cliffs, man-made sea walls, etc.).The shoreline type is a key factor in estimating sus-ceptibility to coastal erosion and consequent risk to amonument. However, at the small scale applicable tothe consideration of levels of current and possiblefuture deterioration of a coastal monument, large-scale surveys can underestimate the amount of dam-age occurring at small scale and need to be criticallyevaluated in assessing potential risk to a site. Publishedlarge-scale studies of coastal erosion tend to break thecoastline up into coastal cells, rating each in terms ofshoreline type and use, risk factors and an average rateof loss. At the small scale applicable to a coastal monu-ment, greater variation is apparent. Local factors suchas the durability of the monument itself influence ero-sion. The construction of hard coastal protectionworks has often led to accelerated rates of erosion atthe edge of these works,3 and this same phenomenoncan be seen at some coastal sites where a durable stonemasonry structure focuses the effects of coastal erosionat the edges or other vulnerable point.

All shorelines are subject to change, and even aseemingly robust rocky sea cliff is undergoing minorerosive processes such as sub-aerial scarp recession,weathering along mineralised joints, abrasion andcorrasion (particularly adjacent to cobble/gravelbeaches), notching and undercutting on platform/cliff junctions, and exploitation of sedimentary bed-ding and areas of structural weaknesses which lead toretreat of the cliff face. Low cliffs composed of softsediments can experience gradual attrition leading torecession rates of 0.5–1.0 metres per annum, as wellas sudden dramatic losses associated with storms.Historical shoreline changes on coastlines composedof soft sediments show that the pattern is not one ofsimple continual retreat, but of alternating periods oferosion, collapse, sediment build-up and then ero-sion again. Sandy shorelines are often in a continualstate of flux, which can be extremely damaging tobuildings located close to the inter-tidal zone.

Changes in sea level and potential impact of current climate change models for coastal heritage

Coastal buildings are also affected by changes in sealevel. The level at which the sea stands relative tothe land around the world’s coastline is determinedby a number of factors. Global mean sea level is ultim-ately determined (after Beniston and Tol4) by:

● The amount of water in the ocean● The temperature of that water

Submerged ruins 215

Ch07-H6429.qxd 10/14/06 3:38 PM Page 215

● The volume of water stored in the Antarctic andGreenland ice sheets

● The volume of water stored in non-polar glaciers● The volume of water stored in natural and artifi-

cial inland catchments, lakes and reservoirs.

Global mean sea level is affected by the balance ofevaporation and precipitation produced by thehydrological cycle, the effects of gravity within theearth–moon–sun system, winds, atmospheric pres-sure fluctuations, and also on the extent and config-uration of the crustal depressions which contain theworlds oceans.3 Sea level is not constant, and fluctu-ates over a range of timescales, from diurnal oscilla-tion with the tides to fluctuations over geologicaltime through tectonic and eustatic movements (or acombination of the two). Tidal fluctuations alsovary in direction, duration, height and speed due tolocal factors such as coastline morphology, bathym-etry and weather conditions. Despite the naturalfluctuations in sea level outlined above, mean sealevel has historically been used as a constant datum,and is still used in practice to the present day.

There is currently worldwide concern about thepossible impacts of predicted models of climate changeand resultant sea-level rise resulting from increasingconcentrations of greenhouse gases and otherprocesses (commonly known as global warming).Increasingly, climate change scenarios are being usedto postulate the impacts arising from possibleincreases in global mean sea level, and the possibilityof increased incidences of storms and flooding, lead-ing to potential impacts on ecosystems and humancoastal infrastructure. Current studies on climatechange4 tend to concentrate on ascertaining the rateat which mean sea level may rise, estimated atbetween 14 and 80 cm, with a mid-range estimateof about 0.5 m, and increased levels in the frequencyand severity of precipitation and storm events. How-ever, it is the resultant changes in tidal amplitude,especially ascending levels of the highest tides, thatmay be of most relevance to the built heritage alongthe coastline. The maximum extent of the tidesmust also be considered in the understanding of thepossible impacts of increased levels of storminesspredicted for the twenty-first century. Storm surgescaused by winds and atmospheric pressure changescan result in a temporary rise in sea level of up toseveral metres on a lee shore, and the production ofsignificantly high-energy waves can result in dramaticloss to land and to buildings. The scenarios take abroad global and continental scope; however, localimpacts of global warming are difficult to predict

with any certainty, and both regional and localchanges could differ substantially from the globalmean value. The impact of climate change on coast-lines is unlikely to be uniform, and influencing fac-tors include shoreline type, topography and localvariables. However, certain coastal types such astidal deltas, low-lying coastal plains, beaches, islands(including barrier islands), coastal wetlands andestuaries may face greater risk due to their physicalcharacteristics.

At the small scale of survey relevant to the consid-eration of ruined monuments, consideration of theshoreline type and consequent susceptibility to shore-line alteration may be a much more important indi-cator of risk than a rise in sea level per se. Inundationalone does not necessarily lead to significant deterior-ation of monuments on the coast. Many sites such asharbours and coastal fortifications were intended tobe partially immersed. It is the factors associated withsea-level rise that have the potential to cause damageto ruined monuments – increased wave and stormactivity, increased coastal erosion, and changes in cli-mate and weathering parameters. And these associ-ated factors may be controlled by local variables suchas shoreline type, local and regional longshore andoffshore sediment transportation processes, fetch andexposure to wave energy.

Techniques of recording and monitoring

The scope of assessment

The initial task is to determine the necessary level ofscale(s) of recording that are necessary to understandthe condition of the ruined structure and the levelof intervention required to conserve it. There arefour broad scales of evaluation:

1 Coastline assessment. Geomorphological studyidentifying the shoreline type, tidal range, degreeof exposure of the coast to wave and storm action,local sediment transport patterns, and an assess-ment of historical and current coastal erosion andsea-level change.

2 Assessment of the shoreline or seabed immediately asso-ciated with the ruin. Type, nature and durability of the substrate, coastal erosion or depositionalenvironment.

3 General assessment of the building. Survey of theextent of the building, noting design, materials,condition, range, type and level of colonisationby marine organisms, and identifying areas ofvulnerability.

216 Conservation of Ruins

Ch07-H6429.qxd 10/14/06 3:38 PM Page 216

4 Detailed assessment of areas of vulnerability. Forexample, detailed assessments of local undermin-ing, wall movement and other structural issues,areas of severe stone deterioration, etc.

The initial coastal assessment should comprise a desk-top review of relevant literature, cartography, aerialphotography, and previous coastal environmental anderosion studies (where available). However, much ofthe existing literature base is composed of wide-scalestudies for coastal management purposes and whileproviding a good overview of coastal processes in anarea, are generally not applicable to the relatively smallscale of survey required for the conservation of aruined monument. For the majority of sites, usefulinformation is unlikely to already exist and must begathered through site-specific research, survey, analy-sis and evaluation.

The assessment of a small section of coast, orcoastal cell, is vital to understand the coastal processesthat have led to the submergence of the ruin, and willhave a strong bearing on the feasibility of practicalconservation measures. The durability of the sub-strate and its resistance to erosion and undermining isoften the prime determinant of the longevity of asubmerging building.

This task becomes much more challenging thansimilar assessment and evaluation requirements onterrestrial sites. Though the ruin may require thesame amount of investigative work, obtaining thenecessary information can be a complex and haz-ardous undertaking. Working conditions associatedwith submerged and partially submerged ruins

require thorough planning and adaptation to chan-ging site conditions. In the inter-tidal area, the ruinmay only be accessible for a few hours per day. Forsome sites only exposed on certain low spring tides,these may only be dry for a few hours per year.

Practical on-site assessment

On-site assessment comprises three main areas: a geo-morphological study of the coastal cell, an inter-tidalsurvey of the ruin and an underwater survey of theruin.

The geomorphological assessment should ascertain thenature, type, present condition and vulnerabilities ofa defined section of coastline, and should ideally bedone twice – once in the spring and once in theautumn for comparison. Different types of coastlinerequire different evaluation techniques, as many ofthe decay forms are specific to different coastal types.For example, evidence of a wave-cut escarpment atthe toe of a dune or embryo dunes could suggesteither recent storm damage or a lull in continuingerosion. Glacial till cliffs require different questionsto be asked, as different types of slippage, vegetationcover or the position and nature of the toe of the cliffcould indicate one or a combination of drainage,storm or continual erosion problems.

The inter-tidal survey generally uses standard land-based techniques with some adjustments for the wetconditions and the limited amount of time availablebetween tides. Midsummer is the best survey seasonas both low tide periods can be worked; however,continuous working in the inter-tidal area is not

Submerged ruins 217

Table 7.1 Typical large-scale problems found for some coastal cell types

Coast type Description Typical problems

Sand dunes Accumulations of wind-blown sand, usually as a Vegetation damageseries of ridges Storm damage

Blow-out

Sand cliff Cliffs of sand/gravel, either glacial deposits or Storm damageovergrown relic dunes Continuous erosion

Glacial till cliffs An incohesive conglomerate normally formed Drainage problemof sand, gravel and boulders ‘floating’ in a poorly Storm attackbound clay matrix, normally deposited by Recent slipglacial action Continuous erosion

Storm beach Gravel/shingle ridge or barrier which protects the Ridge active from wave activitybackshore from storm attack Storm damage

Wash-over by sea

Buildings Monuments, seawalls, rock revetments, timber/ Wave reflection and longshore drift rock groynes, etc. leading to beach lowering and undermining

Ch07-H6429.qxd 10/14/06 3:38 PM Page 217

possible. Winter offers the poorest working condi-tions with few daylight hours, cold and wet condi-tions, but may return more valuable information asthe monument can be assessed before, during andafter a storm event. The main constraint is the condi-tion of the foreshore. Deep layers of thick, stickymud may impede movement, access for a hoist maynot be possible, equipment must usually be broughton site and erected each day, and special safety con-siderations and measures may need to be undertaken.Careful planning can maximise the time available onsite; however, inter-tidal surveying is usually merelyawkward rather than difficult. A greater amount ofrecording tends to be carried out in the upper reachesof the tide due to the greater window of time avail-able. However, this can be compensated for by allow-ing an overlap with the underwater survey.

Underwater survey is a specialised activity, withmany site-specific limitations including wave activity,tidal movements, water temperature and through-water visibility. Underwater visibility is normally themost important factor in determining the quality andaccuracy of underwater survey, and is a factor that canchange dramatically from day to day and hour to hour.Underwater visibility may range from nil to greaterthan 20 metres depending on water depth, waterquality, light penetration, time of year, tidal condi-tions, turbidity, marine growth and especially theamount of particulate matter suspended in the water.The working time of a diver is limited by depth andpressure and the availability of air (though this can be extended by use of surface demand diving). Theworking conditions may be challenging, but under-water survey is normally essential to determine thecondition of the monument and to plan an effectiveconservation strategy.

The purpose of underwater surveying for the con-servation of a monument is to record a sufficientamount of accurate, quality information to deter-mine the condition of the structure, and to plan andspecify necessary repairs. The type of survey is nor-mally a combination of on-site visual assessment,survey drawing (generally a two-dimensional planwith supporting descriptions and measurements) andphotographic survey. A video record of the site canalso provide additional contextual information assupplementary information. Basic low-tech surveytechniques can achieve a high level of accuracy onunderwater sites. Many of the techniques5 and spe-cialised underwater surveying software were developedfor recording shipwrecks, but are equally applicableto the complex, almost organic shapes characteristicof ruined structures.

Photography is one of the most useful underwaterrecording techniques, though commonly limited bypoor visibility, low light levels and the refractive indexof water (1.33). It is usually necessary to use wide-angle lenses (with consequent distortion) rangingfrom 15 to 20 mm in all but the clearest water. Lowlight levels can be treated with artificial light sources,and poor visibility can be compensated by choosingan optimum dive time and good diving techniques toprevent disturbing sediments on the seabed or on themonument. Underwater visibility is unlikely to allowan entire structure or large sections of it to be photo-graphed. As ruined structures tend to present large flatareas of masonry surface, photomosaics of overlappingphotographs can be very effective. A photomosaic canbe quickly created using a photo-tower with 50 percent overlap between shots (obtaining a scale), andafter digital matching and correction can provide ahigh, cost-effective degree of detail to complementand corroborate the drawn survey.

There are a wide range of geophysical and remotesensing equipment and techniques available whichare commonly used for mapping and interpretingsubmerged archaeological resources. The quality andaccuracy of the information returned are continu-ously improving, and can be very valuable in inter-preting the nature of the seabed and the extent and/ordistribution of submerged structures. However, themajority of these techniques are currently of limiteduse for the consideration of the conservation of theseruins. The exceptions are remotely operated vehicles(ROVs), which allow for long periods of visual (videoand still photography) monitoring and limited sam-pling. Other specialised applications include the use ofunderwater metal detectors to locate iron cramps andother fittings.

Decay diagnosis of a submergingmonument

Evaluating risk to submerged masonry structures

The evaluation of deterioration and risk to a sub-merged ruin is a combination of established architec-tural decay diagnostic techniques,6,7 natural stoneweathering and coastal erosion and geomorphologicalstudies,8,9 supported by standard drawn, photographicand video recording techniques. Established labora-tory techniques can also be used to address particularissues. Petrography is particularly valuable in evaluat-ing stone and mortars, while some techniques such

218 Conservation of Ruins

Ch07-H6429.qxd 10/14/06 3:38 PM Page 218

as electron microscopy (SEM) tend to be limited bythe presence of abundant marine salts and marineorganisms characteristic of submerged stone andmasonry.

The buildings, complexes and sites recorded inthe archaeological record are composed of a varietyof building materials such as stone, earth, timber andother organic materials, and man-made materialssuch as mortars and burnt clay products. Timber andother organic materials can survive in good condi-tion in submerged, boggy and other waterloggedsites, and submerged ruins may incorporate a certainamount of timber (e.g. structural members, piles,etc.). Metals, especially iron, can also be found per-forming both decorative and functional require-ments. The deterioration of waterlogged wood10,11

and the corrosion of metals12,13 in marine environ-ments is a well-researched area. The majority of sub-merged ruins are likely to be composed of morerobust materials, such as stone.

Stone monuments present a particularly interestingfield of study as they tend to be good survivors, withdifferent architectonic forms often from overlappinghistorical periods used for a variety of social and cul-tural purposes. The term ‘stone’ covers a group ofmaterials of highly variable strength, durability andappearance. Yet, throughout history and continuingto the present day, stone has been chosen as a high-quality, durability material intended often for import-ant and prestigious constructions. The deteriorationof a stone building can be considered as a combina-tion of environmental conditions, building failuresand stone failures – most notably the surface alterationof stones.

The deterioration of a submerged or partially sub-merged ruin is often due to a combination of manyfactors, including mechanical wave erosion, dailywet–dry tidal cycling, salt weathering, bioerosion andother biological influences, frost and related mech-anisms, and alterations in beach levels and shorelinemorphology. The stone and mortar surfaces compris-ing the monument are also susceptible to a wide rangeof decay processes, normally determined by evalu-ation of visual indicators of decay forms supported bylaboratory analyses. Submerging ruins present furthercomplexities as the upper (dry) sections of the struc-ture may show similar decay forms to comparablebuildings inland, while submerging sections mayshow radically different forms due to underwaterprocesses of stone decay and deterioration, varyingsignificantly from processes encountered in urban andunpolluted inland environments. Pointing, beddingand rendering lime mortars common to historic

buildings are particularly susceptible to dissolutionand survive poorly in marine contexts. Dry joints mayrange from local cavities to substantial loss, leading to subsidence and/or partial collapse of sections ofmasonry wall. Dry joints are common at the base ofthe wall, where sand and other particulate matter areconcentrated as water-borne abrasives. Incipient dryjoints may also be exploited by a wide range of marineorganisms which tend to enlarge the voids. It shouldbe noted that in a marine context a dry joint mayextend >1 metre in depth into the wall core. The wallcore itself may also contain a substantial amount ofvoids through dissolution and may require substantialgrouting.

The structure and individual materials of a sub-merging monument may then be susceptible to awide range of terrestrial and marine-specific decayforms and processes. In addition to the alteration anddeterioration of submerging stone surfaces14 andmortars, marine-specific decay forms may includeundermining, wave action, abrasion and corrasion,colonisation by marine organisms and the action ofmarine salts.

Undermining

The undermining and collapse of built structureslocated on the coast is brought about predominantlyby coastal processes acting upon the underlyinggeology, rather than primarily on the fabric of themonument. For example, the east coast of Irelandfeatures long stretches of sandy cliffs which experi-ence constant loss of material through wind erosionand wave erosion at every high tide period. The baseof the sandy cliffs is often fronted by a highly mobilecobble beach, causing mechanical erosion throughabrasion to the toe of the cliffs combining withwave action, sub-aerial processes and storm events,resulting in sudden failures of sections of the cliffface. The level of erosion is stabilised by the rede-position of this material during tidal movements.However, longshore sediment transport processesultimately remove this material offshore, resultingin further collapses. As the protective head of col-lapsed detritus is gradually removed offshore bylocal sediment transport processes, the cycle of ero-sion is renewed. The process of erosion and deposi-tion results in both the encroachment of the seaonto the land and fluctuating beach levels. Therecan therefore be both vertical and horizontal alter-ations to the character of a beach area. Changes tothe morphology of the shoreline result in a numberof destructive processes threatening monuments,

Submerged ruins 219

Ch07-H6429.qxd 10/14/06 3:38 PM Page 219

220 Conservation of Ruins

Figure 7.4 Erosion is now beginning to undermine the corners of the tower, with the cobble beach corrading the cills of the principalhistoric stone entranceway.

Figure 7.3 Ballinaskelligs Castle, a medieval tower house now situated on a very vulnerable narrow sandy isthmus on the south-east coast of Ireland.

Ch07-H6429.qxd 10/14/06 3:38 PM Page 220

including undermining, abrasion and corrasion, and the exposure of previously buried areas to dailywet–dry cycling through tidal movements. Theprocess of undermining commonly leads to theexposure of the shallow foundations typical of his-toric buildings and the formation of structuralcracks, which tend to develop rapidly and lead tothe partial collapse of sections of the monument.

Wave action, abrasion and corrasion

The degree of exposure, severity and type of waveaction is an important factor in assessing a coastalmonument. Almost all shore erosion can beexplained by the action of different types of waves.Gravity acts as the main force to bring sea water toequilibrium. Waves are generated by either periodic(e.g. the sun and the moon influence tides) or non-periodic (wind) disturbances of the water surface.Wave development is dependent on three factors:wind speed, wind duration and the distance overwhich the wind travels (the fetch). Ocean coastlineswill therefore normally experience waves of muchhigher energy than a small sea, channel or shelteredbay. Storm waves tend to be steep, short-lived and

irregular; however, once these waves move awayfrom the storm area they naturally sort into swellwaves of regular height, length and period, whichlose little energy before reaching the coast. Oncenearing the shore and shallow water, the waves maythen experience a series of transformations gov-erned by the reducing water depth (which causeswaves to become steeper as they approach the shore,with narrow crests and flatter troughs) and depthcontours (leading to variations in the height of break-ing waves and currents). Eventually, the water is soshallow the waves over-steepen and break, resultingin a swash and backwash of sea water, which results inchanges in the beach profile.

Evaluation of shore morphology and the type ofwave action impacting in the vicinity of a submergedor submerging ruin allows the informed considera-tion of the potential seasonal or longer-term changesand pressures, and a better understanding of theprocesses of deterioration. Wave action will abrade amasonry surface both by direct impact and by abra-sion from sand particles suspended in the water, com-monly leading to the rounding and polishing of thesurface of the stone units, and removal of mortarfrom the joints which disrupts the wall fabric, leading

Submerged ruins 221

Figure 7.5 Subsidence of the corner of this 19th century granite harbour due to extensive dry jointing and undermining.

Ch07-H6429.qxd 10/14/06 3:38 PM Page 221

to settlement and collapse. At the base of the wall, themasonry may show significant rounding and etchingby the corrasion of gravel, cobbles and boulders act-ing against the base of the structure by wave action.This generally occurs in a narrow band extendingfrom the base of the wall to a height of 100 –300mm.Underwater inspection of the base of a submergedruin will often show one elevation experiencing sig-nificantly greater rates and severity of deterioration –normally aligned with the prevailing winds and openfetch of the sea. Grooves can also develop in certainareas according to the topography of the buildingsurface and the seabed in the immediate area.

Further stresses are also caused by wave quarrying –believed by many researchers8 to be the dominantform of erosive mechanism on many rock coasts.Submerged ruins can be considered artificial rockcoasts and are subject to many of the same processes of

deterioration as coastal rocky cliffs. Quarrying occursin a narrow band extending just below the still waterlevel up the wave crest, causing shock pressures of thebreaking wave, water hammer and air compression injoints. Masonry blocks can be dislodged as a result ofthe pockets of air trapped along joint, stone beddingplanes and other vulnerable areas as waves breakagainst the building. The process is cyclical as eachwave brings sudden pressure and sudden release, andbecomes a particularly effective erosive techniquewhen sand particles are contained in the water, form-ing a highly abrasive solution. These processes aremost damaging during the winter months when wavestrength is highest, and most damaging when thewave front or bore is parallel with the building eleva-tion, reducing the amount of wave energy that isdeflected along the building elevation if the wavestrikes at an angle.

222 Conservation of Ruins

Figure 7.6 Vertical zonation showing transition from marine to terrestrial species.

Ch07-H6429.qxd 10/14/06 3:38 PM Page 222

Marine biological organisms

Biological colonisation is a constant feature of historicbuildings and archaeological monuments,15 and thereis growing research and debate on the impacts (harm-ful and beneficial) of lichen development on stonesurfaces, soft organic capping to wall tops, and therealm of interactions and competing values betweennatural and built heritage. Biological species, bothflora and fauna, exploit building surfaces in a similarmanner to other rocky habitats. The mitigation of harmful biological colonisation on building sur-faces, such as ivy development and bioerosion, is an established area of architectural conservation.However, marine organisms introduce a new worldof complex species competing for habitat in the littoral and sub-littoral areas. A number of factorsdetermine the nature, significance and rate (if this canbe established) of marine bioerosional activity. Marinespecies are distributed in both the vertical and hori-zontal planes, and the distribution of different speciesis controlled by the availability of moisture (local tidalcharacteristics determine periods of inundation andexposure to dessication) and waves, surge and tidal

currents. In general, the width of each organic zoneincreases with increasing wave energy, with widebands of marine organisms found on exposed shoresand an abrupt distinct transition between marine andterrestrial habitats in sheltered sites, where the influ-ence of spray and wave action is greatly reduced.Other factors include salinity levels, pollutants levels,temperature and degree of exposure to sunlight.

Submerged sites may feature a complex environ-ment of floral and faunal species, and the banding anddistribution of marine organisms in the vicinity of asubmerged ruin provides valuable information aboutthe level and severity of exposure. Exposed littoralbuilding surfaces are typically dominated by com-munities of common mussel (Mytilus edulis) and bar-nacles (Semibalenus balaniodes, Chthamalus spp.) withlimpets (Patella spp.) throughout. On exposed sub-merged building surfaces, kelp normally dominates,with an understorey of foliose red or brown sea-weeds forming a dense bed below the main kelpzone. Fucoids also occur in distinct horizontalbands, and a wide stretch of fucoids and seaweedsexposed during low tide indicates potential for

Submerged ruins 223

Figure 7.7 Submerged masonry surfaces can be obscured by extensive marine growth (e.g. the jewel anenome (Corynactis viridis)which may have other heritage values. Courtesy of Rebecca Morris.

Ch07-H6429.qxd 10/14/06 3:38 PM Page 223

224 Conservation of Ruins

Figure 7.9 Erosion of the sandstone bedrock beneath McSwynes Castle by wave action and corrasion by the boulder/cobble beachelement leading to partial collapse of the outer face of masonry.

Figure 7.8 The remains of McSwyne’s Castle, Donegal, located on a narrow eroding isthmus on the Atlantic north-west coast ofIreland.

Ch07-H6429.qxd 10/14/06 3:38 PM Page 224

significant wave action and/or tidal currents. Localanomalies can also be identified by biologicalcolonisation. The replacement of kelp with robustanimal species such as cushion sponges, colonialascidians, bryozoans, anenomes, barnacles and cal-careous tubeworms indicates an area of surge orother strong water movement. The range and typeof marine organisms found on submerged and par-tially submerged ruins can then be used as a rela-tively accurate indicator map of environmentalconditions. However, the presence and activity ofthese marine organisms can also have direct andindirect impacts on submerged masonry.

The effectiveness and zonation of erosive marineorganisms varies according to the nature and dur-ability of the brick or stone masonry substrate. Softerlimestones and siliclastic rocks such as mudstones,siltstones and some sandstones may be very vulner-able to both dissolution and boring organisms. Themost significant organisms are marine bacteria,microflora (e.g. marine and terrestrial algae, lichens)and grazers (which may include a wide range ofspecies including chitons and gastropods – limpetsand periwinkles – echinoids, crabs, starfish and graz-ing fish such as wrasse which mechanically rasp thestone surface). Boring and burrowing organismssuch as crabs and lobsters are very common in sub-

merged open joints, and conger eels of >2 metres inlength can be found colonising the base of harbourwalls and submerged ruins where conditions permit.

A wide variety of green, red and brown algae can be encountered in marine environments, fromChlorophyta (green algae) in the littoral zone,Rhodophyta (red algae) in the lower littoral and sub-littoral zones, and cyanophyta appearing as ablue–green slime in the upper littoral and supra-littoral zones. Algae are physically attached to a build-ing surface and, like their terrestrial counterparts,have associated metabolic processes which can alter astone surface. Some marine algae, such as endolithiccyanophyta, and other microfloral species, such asfungi and lichens, are also effective rock borers. Algaldevelopment is inhibited by grazers, although thesemay also cause a certain amount of disruption (includ-ing the formation of grooves under certain condi-tions) as they mechanically rasp the masonry surfaceto remove the microflora. Lichens tend to dominatethe supra-littoral zones in northern waters, showinga zonation pattern determined by immersion/expos-ure periods. The width/height of lichen bands alsoincreases with increasing exposure, with grey lichens(Ramalina spp.) above yellow lichens (Xanthoria spp.)at the top of the zone to black lichen (Verrucariamaura) at the base.

Submerged ruins 225

Figure 7.10 The inter-tidal area below Carrigaholt Castle, Clare on the west coast of Ireland showing a highly mobile erosivecobble beach. The sub-surface remains of a now-lost gabled house can be seen in the cliff edge, now within 3 metres of the tower.

Ch07-H6429.qxd 10/14/06 3:38 PM Page 225

Boring and burrowing marine organisms mayinclude certain barnacles, polychaete worms, gas-tropods, echinoids (sea urchins), bivalve molluscs andsponges, and may excavate for inhabitation, repro-duction, anchorage or nutrition, and some grazingorganisms use a chemical ‘trail’ to return to a particu-lar location after nightly foraging. These organismsmay have both direct and indirect impacts on stonemasonry. Boring species excavate rocky substratessuch as stone masonry and mortar joints bothmechanically and chemically, and the size of the borevaries with the size of the organism, from 1 to10+mm in diameter. Boring directly removes a sec-tion of the stone surface in a specialised form of hon-eycomb weathering, and contributes to the retreat ofthe stone surface by providing a greater surface areafor other physical and chemical processes. Burrowerstend to excavate softer sediments and excavate at thebase of the wall or may enlarge an already openedmortar joint. They contribute to the undermining ofsubmerged masonry and can penetrate deeply intothe wall where a joint has been opened.

Assessing the rate of marine bioerosion is very dif-ficult, and is affected by population density, the localenvironment, the characteristics of the building

stone and mortar, and the range of species (algal,grazers, borers, etc.) to be considered, balanced withthe repeatability and accuracy of the chosen surveymethod. It should also be noted that some marineorganisms may provide a protective function, protect-ing the underlying masonry from wave action andphysico-chemical attack in the littoral and sub-littoralzones. For example, hand-fired brick found in thesubmerged village of Rosslare Fort in south-eastIreland were found to retain surface features such asgrass marks beneath a shelter coat of red algae,despite 70 years exposure in a high-energy littoralzone, experiencing daily tidal wet–dry cycles, waveaction and abrasion by water-borne sand. A denseorganic coating such as the presence of marine algaemay act as a buffer to incoming waves, and may alsoretain moisture on the building surface and reducethe severity of daily wet–dry cycling in littoralzones.

Marine salts

I observed … that salt exuded from the soil to such anextent as even to injure the pyramids.

(Herodotus)

226 Conservation of Ruins

Figure 7.11 Erosion tends to become focused at the edges of coastal protection works and other masonry surfaces. Here the protec-tive bawn wall of Carrigaholt Castle, recently repaired, is again under threat as erosion tunnels around behind the wall.

Ch07-H6429.qxd 10/14/06 3:38 PM Page 226

The formation, transport and crystallisation of salts inrocks and other porous building materials has beenwidely recognised as one of the primary causes of thedeterioration of historical architecture, archaeologicalmonuments and archaeological objects.16 –20 Salts aresoft, light minerals which are highly susceptible to dis-solution and recrystallisation. They dissolve in water,move in solution and crystallise when water evapor-ation takes place. All circulating waters are slightlyalkaline (pH 7.5–8.4)21 salt solutions, and may con-tain Na+, K+, Ca2+, Mg2+, NH4

+, CO32�, SO4

2�,NO3

� and Cl�. Salts may not always be the originalcause of deterioration, but their presence in conjunc-tion with water and/or moisture may significantlyincrease the deterioration rate of a stone. Charola22

records that the presence of water and/or moisture inthe porous material is as important as the type of saltand the nature, texture, porosity and interior surfaceof the material; and that salts significantly impact onthe weathering of stone, with scaling and granular dis-integration being ubiquitous to all stone types.

Salts have been investigated due to their contribu-tion to the deterioration of a wide range of stonetypes used for the construction of stone monuments.The occurrence, origins, mechanism and effects ofsalts on stone monuments have been a recurringtheme in conferences and research forums for sometime,23 –26 considering the process of damage, individ-ual case studies and occasional conservation treat-ments. Marine aerosol includes a range of particlestermed according to their physical characteristics,such as film drops, jet drops, sea water drops, brinedrops, hydroscopic salt drops, sea-salt nuclei and sea-salt particles. These drops are formed from bubblesbursting in the whitecaps of waves, where a largeamount of air and water are mixed. Marine aerosolsalts are derived from the emission of these minute air-borne drops of sea water creating sea-salt particles by evaporation (mainly Na+, Cl�, Mg2�, SO4

2�).Sodium chloride (NaCl), the most common salt inoceans, can be carried up to 200 miles inland, settlingon the ground and on building surfaces.17 Marine salt-originated damage has been noted by numerousauthors to European cities on the coasts of theMediterranean, the North Sea and the Atlantic coast.Galán et al.27 stated (primarily in the context of lime-stone and marble building stone) that the degradationof built heritage of the Mediterranean region couldbe attributed (in order of importance) to the follow-ing factors:

1 Marine spray activity.2 Industrial and urban pollution (at a local level).

3 Other factors (such as saline rising damp and per-colating waters).

The three main sources of marine salts in the con-text of submerging ruins are sea flooding, risingdamp (both sea water and brine) and marine aerosol(sea spray). Additional sources of marine salts in acoastal monument may include building stone quar-ried from the shoreline, the use of unwashed beachsands as a mortar aggregate and even the use of seawater to mix the mortar. Changing atmosphericcomposition, rainfall, temperature and storm eventswill have an impact on stone deterioration in gen-eral,28 but may have a significant impact on theseverity of marine-related salt damage. Unpollutedcoastal areas with high levels of precipitation maynot exhibit high levels of salt-related weathering, asthe salts are leached from the stonework before theycan accumulate to harmful levels.14 The degree ofdamage caused by marine aerosols is generally con-sidered to be severe;29,30 they are formed when sea-salt particles (Na+, Cl�, Mg2�, SO4

2�) are leftthrough evaporation on the surface of a building ormonument, where they accumulate and penetratethe pore network of building stone and the mortarsof the joints and the wall core.

A monument on the shoreline experiences dailychanges in environment due to the movement ofthe tides – leading to a daily cycle of wetting anddrying episodes, increased periods of wetness ofstone surfaces and the presence of marine salts.Greater levels of salt-related deterioration may thenbe present. However, in regions of high precipita-tion, the continual washing effect of rainwater willhelp in leaching the salts from the masonry.Submerged masonry should then be considered aspotentially heavily salt loaded; the amount anddepth of penetration of salts will be dependent onthe type and nature of the stone involved. If thestone remains submerged, the surface should remainin equilibrium. However, if the stone is beingrecovered, for example the recovery of a carvedstone surface for conservation, the stone mustremain immersed in sea water until proper desalin-ation can be undertaken by a conservator. If thestone is too large for storage tanks, water-soakedabsorbent materials such as hessian drenched withwater at shore intervals can be used as an emergencymeasure during transport to a conservation labora-tory. Desalination is normally undertaken usingcontinuously running or changes of fresh, distilledor deionised water until all salts have been removed –normally confirmed using a conductivity meter.11

Submerged ruins 227

Ch07-H6429.qxd 10/14/06 3:38 PM Page 227

More robust stone types15 may require much lessintervention.

Risk mapping of a submerged monument

A range of conservation issues may then impact on asubmerging ruin. The type, rate and severity of thedecay forms can normally be sorted into vertical andhorizontal zones corresponding with submerged,inter-tidal and spray zones on the shoreline. Mappingthe risks and vulnerabilities in these different zones isthe most effective way of understanding the decay

processes (by mapping decay forms) and planning aconservation strategy. Table 7.2 outlines some of theimpacts to be found.

Protection and conservation

Protection and conservation of a submerging or sub-merged ruin encompasses a wide range of site-specificmeasures comprising protection of the coastline (seeTable 7.3), protection and repair of the monument(which could include repointing, reinstatement of

228 Conservation of Ruins

Table 7.3 A wide range of coastal protection and management options are available to consolidate and protect theshoreline associated with a submerging ruin

Zone Techniques

Submerged Seaweed planting Sand-bypassingBreakwaters

Inter-tidal to submerged Groynes Artificial headlandBeach nourishment Mudflat restorationBeach drainage Silt redistribution

Upper shore to inter-tidal Beach ridge restructuring Sand trap fencingWave barrier fencing Grass seedingDune recontouring Seawalls and revetmentsSand stabilisation Toe protectionArtificial dune ridge building Cliff stabilisationMarram grass planting Land use restrictions

Table 7.2 Typical macro-scale decay processes acting on historic stone masonry at different zones of the shore

Area Type of impact Intensity of damage

U/W Wave action Low to moderateCorrasion and abrasionBiological colonisation (marine sub-littoral)Coastal erosion leading to undermining of structuresFluctuating beach levels leading to undermining of structuresDaily wet–dry cycling

I/T Wave and surf abrasion Moderate to severeCorrasionSea spray (at low tide periods)Increased periods of wetnessBiological colonisation (marine littoral)Erosion of shoreline leading to undermining of structuresWave and surf abrasion

HW Corrasion Moderate to severeSea sprayIncreased periods of wetnessBiological colonisation (terrestrial and marine supra-littoral)

5M Sea spray LowBiological colonisation (terrestrial)

Ch07-H6429.qxd 10/14/06 3:38 PM Page 228

Submerged ruins 229

Figure 7.12 Medieval waterfront merchant’s house at Drogheda on the east coast of Ireland, showing a range of conservationissues, including modern overburden, later repairs, missing and dislodged masonry, and difficulties in interpreting the character of thearchaeological monument.

rebuilding of sections of collapsed masonry, etc.),and ongoing monitoring and maintenance require-ments. Much can be learnt from the experiencesand knowledge base of nature conservation,31 whichhas already developed useful tools for the conservationof vulnerable heritage-rich coasts. Unfortunately,many of the principles of nature conservation, suchas managed retreat, are not applicable to architec-tural conservation, and many of the coastal pro-tection options may significantly detract from thecharacter of the monument. Critical evaluation ofthe available information and innovative solutionsdrawing on a mixture of disciplines are likely tobecome the accepted norm for the conservation ofsubmerging ruins.

Case Study: Medieval waterfrontbuilding, Drogheda, Ireland

This monument appears as the remains of amedieval waterfront merchant’s residence frontingonto the tidal section of the river Boyne on the east coast of Ireland. The structure had continued

in use in different forms and had a modern overbur-den of brick masonry and an iron roof structure,with later annexes in both stone masonry and rein-forced concrete. The main waterside façade of thebuilding retained a number of archaeological features including a water-door and two garderobechutes (toilets) which were designed to be flushedby tidal action.

The original sections of the building showed rela-tively few decay forms. Biological colonisation waslimited by poor water quality and confined to a fewfucoid and crustacean species in the littoral and sub-littoral areas. The base of the wall was disrupted andthe waterside of the building showed a few missingmasonry units, dry jointing and a few dislodged stones.The doorway and garderobes were largely intact.The interior face of the monument was in poor con-dition and required stabilisation. The site had beenarchaeologically excavated and the below-groundstructures were to be preserved in situ.

The conservation strategy for the building was toconsolidate the ruin as a standing archaeological mon-ument for display and appreciation as a public featurewithin a new development. Repairs were planned on

Ch07-H6429.qxd 10/14/06 3:38 PM Page 229

Figure 7.13 Interpretative survey drawing showing stone courses and features of archaeological significance, used as a guide to plan and specify conservation works. Drawing cour-tesy of the Archaeological Diving Company.

Ch07-H6429.qxd 10/14/06 3:38 PM Page 230

a ‘minimum intervention’ basis to stabilise vulnerablesections of masonry, and to allow the still functioningtidally flushed garderobe chutes and the water-door tobe visible to the public. The original mortar wasanalysed, and a new series of mortars were designedusing local sands and different binders to cope withsubmerged areas, inter-tidal areas, general pointingand wall capping. The work encompassed:

● Securing the character of the monument. Controlledremoval of some of the later annexes, the brickmasonry overburden, removal of later repairs inbrick and concrete, and recovery of fallen lime-stone masonry for reuse during conservationworks.

● General conservation works. Stabilisation of vulner-able sections of the wall, pointing and reinstate-ment of limestone masonry wall face wherecollapsed to interior. Analysis of original mortars.

● Submerged conservation works. Comprised reinstate-ment of fallen limestone masonry at the base andsubmerged sections of the monument, andrepointing with separate designed mixes for sub-merged, inter-tidal and ‘dry’ areas.

Case Study: Carrigaholt Castle, Co. Clare

The monument consists of a mid-fifteenth centuryfour-storey tower house with a later bawn wall toseaward. The tower stands on the shoreline at themouth of the river Shannon on the east coast ofIreland. The tower retains a number of featuresincluding an internal spiral staircase, murder hole,crennelations, lime-based wall finishes, dressed stone

doorway and a range of window types. Traces of alarge four-storey house attached to the south of thetower are indicated by protruding roof tiles and dooropenings.

The shoreline consists of a 5 m cliff face (3.5 mhigh siltstone bedrock below 1.5 m soft glacial till).The rocky cliff is friable and deteriorating rapidly,worsened by drainage run-off from the surroundingagricultural pastureland. Corrasion is caused bywater-rolled limestone cobbles, substantially moredurable than the siltstone cliffs. Cliff recession isfunnelled into the formation of shallow caves lead-ing to collapses of sections of the cliff. The founda-tions of a four-storey gabled building and associatedarchaeological deposits are exposed in the erodingcliff face, now standing �3 m from the base of thecastle. The tower itself is in good condition, show-ing only minor decay forms such as biological col-onisation, graffiti and some stone decay.

The main threat to the castle is from coastal ero-sion, and this is not a new phenomenon for the sitewith historical references that ‘Lord Clare trained hisdragoons in front of the castle, on a lawn, long since erodedby the waters of the Shannon’. The castle is also constructed on rocky bedrock, a substrate normallyconsidered stable by coastal erosion studies. This site is also not an isolated example, but one of an increas-ing number of medieval coastal castles such asMcSwynes, Castlecove and Ballinaskeligs which arenow submerging, and a wide range of ecclesiasticalsites and other monuments. There is no simplegeneric solution. ‘Hard’ coastal defences such as seawalls and rock armour often have the knock-on effectof accelerating erosion at the margins and are not per-manent solutions. The process of submergence may

Submerged ruins 231

Figure 7.14 Rosslare Fort at the mouth of Wexford Harbour submerged c. 1927, containing the remains of a quadrangle of brickand timber houses, a lifeboat station, a martello tower and an earthen star-shaped fort.

Ch07-H6429.qxd 10/14/06 3:38 PM Page 231

leave some of these monuments relatively intact.Others such as Rosslare Fort will see entire settlementsdisrupted in situations where conservation is not a fea-sible option, and in some cases it may be necessary todo nothing, and simply to preserve the monument byrecord and commemorate it in some way. The chal-lenge for the future is to preserve what we can, as bestwe can, with the resources currently available.

References

1. Viles, H. and Spencer, T. (1995). Coastal Problems:Geomorphology, ecology and society at the coast. EdwardArnold, London.

2. Carter, R. W. G (1988). Coastal Environments: Anintroduction to the physical, ecological and cultural systemsof coastlines. Academic Press, London.

3. Bird, E. (1992). Submerging Coasts: The effects of risingsea level on coastal environments. John Wiley, Chichester.

4. Beniston, M. and Tol, R. S. J. (eds) (2001). Europe. InInternational Panel on Climate Change: Special Report onThe Regional Impacts of Climate Change An Assessment of Vulnerability (R. T. Watson, M. C. Zinyowera andR. H. Moss, eds). International Panel on ClimateChange, United Nations.

5. Dean, M., Ferrari, B., Oxley, I., Redknap, M. andWatson, K. (eds) (1995). Archaeology Underwater: TheNAS guide to principles and practice. Archetype Publications and Nautical Archaeology Society,Portsmouth.

6. Pavía, S. and Bolton, J. (2001). Stone MonumentsDecay Study 2000: An assessment of the degree of erosionand degradation of a sample of stone monuments inIreland. The Heritage Council, Kilkenny.

7. Fitzner, B. and Heinrichs, K. (2002). Damage diag-nosis on stone monuments – weathering forms,damage categories and damage indices. In Under-standing and Managing Stone Decay (H. A. Viles and R.Prikryl, eds). The Karolinum Press.

8. Trenhaile, A. S. (1987). The Geomorphology of RockCoasts. Clarendon Press, Oxford.

9. Dawson, T. (ed.) (2003). Coastal Archaeology andErosion in Scotland. Historic Scotland, Edinburgh.

10. Oddy, W. A. (ed.) (1975). Problems of the Conservation ofWaterlogged Wood, Maritime Monographs and ReportsNo. 16. National Maritime Museum, Greenwich.

11. Robinson, W. (1998). First Aid for Marine Finds.Archetype Publications and the Nautical ArchaeologySociety, London.

12. North, N. A. (1987). Conservation of metals. InConservation of Marine Archaeological Objects (C. Pearson,ed.). Butterworth-Heinemann, London.

232 Conservation of Ruins

Figure 7.15 Castlecove Castle on the shores of the Ring of Kerry in south-west Ireland. Though protected from the brunt ofAtlantic storms, high tides reach the base of the castle. Increased storminess and rising sea levels may have profound implications for similar coastal ruins.

Ch07-H6429.qxd 10/14/06 3:38 PM Page 232

13. North, N. A. and MacLeod, I. D. (1987). Corrosionof metals. In Conservation of Marine ArchaeologicalObjects (C. Pearson, ed.). Butterworth-Heinemann,London.

14. Bolton, J. (2006, forthcoming). Heritage at Risk: IrishCoastal Stone Monuments. Dublin Institute ofTechnology.

15. Pavía, S. and Bolton, J. (2000). Stone, Brick andMortar: Historical use, decay and conservation of buildingmaterials in Ireland. Wordwell, Bray.

16. Amoroso, G. G. and Fassina, V. (1983). Stone Decayand Conservation: Atmospheric Pollution, Cleaning, Con-solidation and Protection. Elsevier Science, Amsterdam.

17. Winkler, E. M. (1994). Stone in Architecture, Propertiesand Durability. Springer-Verlag, Berlin.

18. Price, C. A. (1996). Stone Conservation: An overviewof current research. The J. Paul Getty Trust, SantaMonica.

19. Rodriguez-Navarro, C. and Doehne, E. (1999). Saltweathering: influence of evaporation rate, supersat-uration and crystallisation pattern. Earth SurfaceProcesses and Landforms, 24, 191–209.

20. Doehne, E. (2002). Salt weathering: a selective review.In Natural Stone, Weathering Phenomena, ConservationStrategies and Case Studies (S. Siegesmund, T. Weiss andA. Vollebrecht, eds), Special Publication No. 205, pp.51–64. Geological Society, London.

21. Florian, M.-L. (1987). The underwater envir-onment. In Conservation of Marine Archaeological Objects (C. Pearson, ed.). Butterworth-Heinemann,London.

22. Charola, A. E. (2000). Salts in the deterioration ofporous materials: an overview. Journal of the AmericanInstitute for Conservation, 39(3, Article 2), 327–343.

23. Delgado-Rodriguez, J. et al. (eds) (1992). SeventhInternational Congress on the Deterioration andConservation of Stone. Laboratorio Nacional deEngenharia Civil, Lisbon.

24. Zezza, F. (ed.) (1996). Origin, Mechanisms and Effects ofSalts on Degradation of Monuments in Marine andContinental Environments. European Commission, Bari.

25. Moropoulou, A. (ed.) (1997). Fourth InternationalSymposium on the Conservation of Monuments in theMediterranean Basin. Technical Chamber of Greece,Rhodes and Athens.

26. Galán, E. and Zezza, F. (eds) (2002). Protection andconservation of the cultural heritage of theMediterranean cities. Proceedings of the 5thInternational Symposium on the Conservation of

Monuments in the Mediterranean Basin, Seville, Spain,5–8 April 2000. Swets & Zeitlinger, Lille.

27. Galán, E., Aires-Barros, L., Christaras, B., Kassoli-Fournaki, A., Fitzner, B. and Zezza, F. (1996).Representative stones from the Sanctuary ofDemeter in Eleusis (Greece), Sta. Marija Ta’Cwerraof Siggiewi (Malta) and Bari (Italy) and Cadiz(Spain) Cathedrals: petrographic characteristics,physical properties and alteration properties. InOrigin, Mechanisms and Effects of Salts on Degradationof Monuments in Marine and Continental Environments(F. Zezza, ed.). European Commission, Bari.

28. Viles, H. (2002). Implications of future climatechange for stone deterioration. In Natural Stone,Weathering Phenomena, Conservation Strategies and CaseStudies (S. Seigesmun, T. Weiss and A. Vollbrecht,eds), Special Publication No. 205, pp. 407– 418.Geological Society, London.

29. Vicente, M. A. (1996). The role of salt crystallisationin the degradation processes of granitic monuments.In Origin, Mechanisms and Effects of Salts on Degradationof Monuments in Marine and Continental Environments(F. Zezza, ed.). European Commission, Bari.

30. Silva, B., Rivas, T., Prieto, B. and Pallares, O. (2002).A methodological approach to evaluate the decay ofgranitic monuments affected by marine aerosol. InProtection and Conservation of the Cultural Heritage of theMediterranean Cities (E. Galán and F. Zezza, eds).Swets & Zeitlinger, Lisse, the Netherlands.

31. Salm, R. V., Clark, J. R. and Siirila, E. (2000). Marineand Coastal Protected Areas: A guide for planners andmanagers. IUCN World Conservation Union,Cambridge.

Further reading

Pearson, C. (ed.) (1987). Conservation of MarineArchaeological Objects. Butterworth-Heinemann,London.

Quelennec, R.-E. (ed.) (1998). Corine Coastal Erosion.European Community, Luxembourg.

Tyson, H. J., Fulford, M. G. and Crutchley, S. (1997).Survey and recording in the intertidal zone. In England’sCoastal Heritage: Archaeological Report 15 (M. Fulford, T. Champion and A. Long, eds). English Heritage,London.

Submerged ruins 233

Ch07-H6429.qxd 10/14/06 3:38 PM Page 233

Training. Training exercises with John Ludlow’s conservation technician team in County Cork, Ireland show, top, the use of the plan-ning frame in marking out stone sizes and positions before taking down and rebuilding and, bottom, the use of profile frames in record-ing twists and distortions in the wall to enable the consolidated work to be built back in exactly the same positions.

Ch08-H6429.qxd 10/14/06 3:40 PM Page 234

Those responsible for the treatment of an ancient building,realising that the contemplative work demands qualifica-tions beyond their knowledge, will doubtless seek advicefrom an architect. It may be thought, having done this,their only remaining duties are to procure the necessaryfunds, and to enter into a building contract so that for afixed sum the recommendation may be carried into effect.

Yet, as can be seen in many an ancient building whichhas been dealt with under these conditions, such a coursedoes not necessarily secure a building from harm.

(The Repair of Ancient Buildings, A. R. Powys, 1929)

Almost a century after Powys wrote his seminal book,ancient buildings, including those surviving as ruins,are still often damaged or degraded in the process ofimplementing conservation work. The truth is thatthe conservation of ancient fabric, and especially theconservation of ruins, is quite outside the usual pro-fessional experience of architects, engineers, survey-ors, building craftspeople and archaeologists. Theymay often believe that they are competent but candeceive themselves and those for whom they provideservices. Most seriously, they will unwittingly play adestructive role in the history of the subject they mayhave set out to protect.

All this is nothing new, as a review of Powys’swork will demonstrate, but there have been changes.Significant numbers of planners, architects and sur-veyors now have first or second degrees in buildingconservation subjects, and work in or as specialistpractices. Specialist conservators, museum or uni-versity trained, may still not be numerous but are nolonger difficult to find in the fields of stone, ceramics,wood, metals and glass. Developments in technologyand in the understanding of traditional materialsscience have made resources available to investigate,analyse and record which, even half a century ago,would have been difficult to imagine.

Against this background of welcome change anddevelopment, it is sometimes hard to believe that his-toric fabric, perhaps especially in the form of ruinedbuildings, still faces substantial risks at the time ofimplementing works.

Directly employed specialists – the‘conservation technicians’

We believe the directly employed labour force has animportant role to play in the repair and maintenance ofour monuments. It contributes a highly skilled and expe-rienced cadre which provides not only the core of spe-cialised skills required for the often delicate work to ourown monuments but also a reference and training sourcefor craftsmen in the private sector. It is also useful in pro-viding a training ground for apprentices (about 10% ofthe force) and technical supervisors whose work is crucial,both to the properties in care programme and to control ofconservation work in the private sector which may befunded by English Heritage.(English Heritage Corporate Plan, 1988–1992)

These acknowledgements by the principal heritageorganisations in the UK of the responsibilities,duties and declaration of policies and intentions hadchanged little since 1911, and thus representedalmost a hundred years of continuity. These initia-tives and models were based, primarily, on a recog-nition of the value of the ‘in-house’ team (Figure8.1) and the benefits to historic sites of a continuityof experience or, as an alternative, on the value of acontractor genuinely dedicated to the conservationof historic fabric training and maintaining a special-ist workforce. A typical structure for an in-houseworkforce based on the ‘ancient monuments model’,with descriptions of responsibilities, is shown inFigures 8.1 and 8.2.

235

Chapter 8

Implementing conservation works on ruins

Sara Ferraby and David Odgers

Ch08-H6429.qxd 10/14/06 3:40 PM Page 235

In the early 1980s, concerns relating to the reduc-tion in numbers of English Heritage’s directlyemployed specialist staff and decline in work standardsled to two major reviews specifically targeting ruinsites in the care of the government. The conclusion of both reviews was a confirmation of decline inresources and standards, and a recommendation that atraining programme should be set up to provide theadditional skills required for professional, craft andtrade personnel to properly care for ruins and theirsites.

English Heritage’s first formal programme of train-ing was launched in 1993 in a specifically designedfacility located in one of its ‘properties in care’, a latenineteenth century artillery fort, Fort Brockhurst, inHampshire. Here, for the first time, masonry ‘ruins’were constructed to recreate many of the conditionsfound in historic sites and many of the problemsencountered in their repair. Significantly, these had tobe built by and under the supervision of the principaltutor, Colin Burns, who had many years of experienceof real conditions on ruin sites. Thus, many common

problems such as broken wall tops and wall ends, frac-tures, detaching facework and voided core were accu-rately simulated and enabled trainees to be givenpractical instruction in remedial works without risksto historic fabric. These ‘ruinettes’ became a keyteaching tool in the training programmes developed atFort Brockhurst.

The directly employed labour force of EnglishHeritage was finally phased out after a life of some 80 years and its place taken by a privatised workforcewho, after a period of five years, had to compete withother contractors to carry out works on historicruined sites. This break in continuity rather reinforcedthan made redundant the need for a training centre, asmany contractors with experience in the repair of his-toric buildings found themselves, for the first time,confronted with new problems in the form of ruinedstructures.

Partly due to organisational changes and new pri-orities the Fort Brockhurst centre closed after fiveyears, although it remained active throughout thistime. English Heritage re-established a new base

236 Conservation of Ruins

Figure 8.1 Organisational Model. John Ashurst and Colin Burns. Reproduced by permission, the Getty Conservation Institute.

Ch08-H6429.qxd 10/14/06 3:40 PM Page 236

Implementing conservation works on ruins 237

Conservation Architect • Is reponsible to the Institute of Monuments for all works on HistoricMonument sites and will make monthly and annual reports on situations andprogress.

• Contributes to planning and policy meetings with the Institute of Monuments.• Organises and coordinates the activities of works teams and contractors and

professional consultants.• Carries out surveys of sites with consultants and is responsible for prioritising

works programmes based on identified needs.• Participates in the interviewing and selection of staff for the Historic

Monuments Conservation team.• Is responsible for the welfare and ongoing training of the Historic Monuments

team, working with consultants as necessary.• Is responsible for ensuring that complete records are made of all work at all

stages and that the records are adequately distributed.• Is responsible at local, national an international levels for communicating and

promoting the work of the conservation team through presentation and publication.

Technical Officer • Has direct responsibility to the Conservation Architect for the implementationof all the works to the required standard.

• Has responsibility under the Conservation Architect for recruitment and training.• Will make annual reports on all site works and forecasts.• Will make monthly reports of activities and progress on all sites.• Will make, keep and circulate records of all site meetings.• Will be responsible for letting and management of all contracts relating to site

works.

Foreman • Has direct responsibility to the Technical Officer for the correct and safe management and execution of all works.

• Will assist the Technical Officer in programming consolidation works and sitemaintenance.

• Will be responsible for requesting and maintaining plant, equipment and materials for the works.

• Will oversee the works and be responsible for the improvement and maintenance of good standards.

• Will maintain a daily works diary.

Working Chargehand • Has direct responsibility to the Foreman for the smooth running of the works.• Is responsible for site safety and welfare.• Will work to instructions issued by the Foreman.• Will be responsible for the training of conservation technicians, especially of

new entrants.• Will provide ongoing training in specialised activities.

Conservation Technician • Will take instructions from the Working Chargehand.• Will carry out basic consolidation of historic monuments and specialised

activities as required under senior supervision and direction.

Labourer • Will be responsible for mixing and transporting mortars to work stations.• Will work generally to support the Conservation Technician’s activities on

the site.• Will maintain the work site in a clean, tidy and safe condition.

Figure 8.2 Job Descriptions. The organisational model as indicated in Figure 8.1 is flexible and adaptable to recession or growth.The middle and higher management levels shown create a slightly ‘top-heavy’ situation and in early stages of development either theTechnical Officer or the Foreman posts could be omitted. As additional works units (Conservation Technician and WorkingChargehand) are added, from six to ten units in number, the full management structure will be needed, especially as historic sites aregeographically widespread.

Ch08-H6429.qxd 10/14/06 3:40 PM Page 237

for training by agreement with Dr David Leigh and the Trustees of the Edward James Foundation at West Dean College. This is some 50 miles east of Fort Brockhurst, where an old dairy building was converted into a training centre and new facili-ties including new ‘ruinettes’ were constructed(Figure 8.3).

The West Dean College inheritance of the EnglishHeritage programme included the training staff fromFort Brockhurst, the two principal tutors forming anessential link through their careers with the old ancientmonuments organisation and other specialist tutors instructural engineering, metals, ecology, paints andarchitectural surfaces.

The tutors developed programmes in ruin consol-idation with specialists in other countries, includingthe training of a directly employed labour force towork on the largely untouched ruin sites in differentlocations. Notable amongst these are Cork in Ireland,under the direction of John Ludlow; the pioneertraining of a similar group in Butrint in Albania,funded by the Getty Conservation Institute, workingwith Reshat Gega; and in Israel, the development of ateam of conservators based at Masada with AsiShalom (Figures 8.4 –8.7).

The first of these two programmes was based on thetradition of ancient monuments training in the UK.The work in Israel, initially for the Israeli Natureand National Parks Authority, was more archaeo-logically orientated. The instigator, Asi Shalom, wenton to publish a manual to encourage and informarchaeological excavators in essential procedures torecord and protect sites in advance of consolidationworks carried out by the architectural/archaeologi-cal conservators. All these training programmes,including a parallel one set up by Historic Scotlandfor its own directly employed labour force, are siteorientated and relate primarily to those who carryout work on ruin sites.

Specialist contractors

It might be thought that conservation work on ruinswas a simple variation on the conservation on any his-toric building, but there are important practical andethical differences which need to be grasped by all theprofessions involved. From a practical point of view, itis often the case that the fabric being conserved wasnever intended as a weathering surface and there are

238 Conservation of Ruins

Figure 8.3 ‘Ruinette’ at West Dean College, Sussex, England, designed by John Ashurst and Colin Burns and built by GerryWilliams and his team. The ruinette incorporates many of the conditions found in the field, such as unstable and voided core work, detach-ing faces, cracked vaults and overhangs. Practitioners can gain experience in consolidation work without risk to historic fabric.

Ch08-H6429.qxd 10/14/06 3:40 PM Page 238

Implementing conservation works on ruins 239

also greater challenges ethically in trying to ensurethat preservation and presentation do not becomemutually exclusive.

Whether directly employed staff or specialist con-tractors are involved, good communication and anhonest appraisal of the role of each contributor to theproject are at the heart of any successful project.Depending on the ownership of the site, the source offunding and the vagaries of the client, there are goingto be a number of professionals involved; it shouldnever be forgotten that the contractor needs to be oneof those professionals. Often, they are the last appoint-ment made, but this should not preclude them frombeing fully briefed and included in any decisions thatrelate to the project. Often, in the planning andimplementation of any works it is useful to include thecontractor at initial concept and design stage, as theycan have much to contribute from their knowledgeand experience acquired on other projects, not least interms of access, enabling works, phasing and pro-gramming. It is unfortunate that they are usually onlybrought in at the ‘final’ stages of a project once thespecification and scope of works have been agreedrather than to input knowledge into the trials andinvestigations stage.

Once a decision has been taken to implementworks on any ruin site it is beholden on the client toensure that their appointed professionals have boththe technical knowledge and experience required tooversee the project. All too frequently, this may notbe the case and these professionals rely on the con-tractor to provide the expertise. This rarely resultsin a fruitful relationship and it is therefore essentialthat there is someone appointed to the client teamwho understands all aspects of the work.

Unless the relevant skills are available ‘in-house’the client will need to appoint a consultant team todeliver the project, depending on the size, scope andvalue of the works. These consultants will generallyinclude a project manager, architect and/or buildingsurveyor also acting as contract administrator, quan-tity surveyor and structural engineer. On larger andmore complex projects this team may also comprisean ecologist, services engineer and even a historicinteriors specialist, amongst others.

The appointment of the specialist consultant team is as important as that of the contractor and should be as scrupulous. The process of appointment shouldinclude references and prior knowledge, site referencevisits and interviews to ensure that the professionalsare suitably knowledgeable and experienced. Often,client organisations secure the resources of these professionals via formal framework contracts whereby

rates are agreed against certain services. This has thebenefit of ensuring that there is a long-term relation-ship developed between the client and the consultant,and the consultants become more familiar with thebuildings and properties in their care and their repairconsiderations. The team should be able to collaborateto achieve the desired outcomes of the project and tocommunicate effectively with the contractor beforeand during the works to achieve best quality.

A ‘tight’, well-defined and detailed specificationand tender package will ensure that the work is car-ried out correctly and in the first instance is pricedcorrectly so there are no surprises on site; anyunknowns can be included as provisional sums items.Any restrictions, site constraints and time periods forattendances by members of the design team and statu-tory authorities should also be built in for program-ming and pricing purposes.

The tender documents are almost always assumedto be the crucial administrative tool that drives theproject; this should indeed be the case, but only if it isa well-informed and clearly written document thatconveys the full scope of the intended works. One ofthe main problems with conservation works on stand-ing buildings (ruins or otherwise) is that, until fullaccess is obtained, it is impossible to be precise aboutthe extent of the works. This is sometimes used as anexcuse to provide a tender that is woefully short ofinformation and thus requires the contractor to takeall financial risks; a project built upon such stonyground can never be a success.

It is essential therefore that the methodology isestablished prior to tender; this means undertak-ing small-scale trials and exemplars to reduce theunknowns and therefore risk, as far as practicable andpossible, in terms of time, cost and quality. The impor-tance of this part of the project cannot be underesti-mated. It need not be an expensive undertaking but ithas big benefits to the project, enabling a detailed spec-ification to be written and also allowing potential con-tractors to see what needs to be achieved in terms ofquality of workmanship. In addition, it allows theclient to be realistic in their perception of what theycan expect at the end of a project and it will ensure amore accurate assessment of cost and programme.

Once the specification is written and drawings pro-duced, tender documentation can be drawn up. Thespecification must be a clear and concise documentthat identifies quantities and establishes a transparentway of measuring variations. Trials should havehelped significantly towards establishing those quanti-ties but there may still be elements that cannot bemeasured. In such cases it is not the contractor that

Ch08-H6429.qxd 10/14/06 3:40 PM Page 239

240 Conservation of Ruins

Figure 8.4 Site training with Asi Shalom’s conservator team on the Byzantine Church at Masada. Stabilisation of weak surfacesand consolidation of wall heads.

Figure 8.5 Site training on the ‘Venetian’ House, Butrint, Albania. First-stage site recording and assessment.

Ch08-H6429.qxd 10/14/06 3:40 PM Page 240

Implementing conservation works on ruins 241

should be expected to estimate but rather the client’srepresentative (usually a quantity surveyor or projectmanager), who establishes parameters for dealing withsuch imprecision. This may be by allowing for anhourly rate for the works or by allocating a provisionalsum which may or may not be expended during thecontract.

Tenders for a main contract should be invited fromsuitably skilled craftsmen and contractors with previ-ous experience in similar sites and of historic build-ings. Unless these are well known from previousprojects or trusted word of mouth, references andexamples of work must be sought and, if necessary,interviews should be conducted with short-listedcompanies. The site foreman should be in attendanceat this interview so the contractor can properlydemonstrate his ability to undertake the works. Pre-tender site visits should be arranged, accompanied, sothat the contractor is aware of the complexities of thesite. Although some authorities restrict this open ten-dering where all contractors are in attendance, thebenefits are such that risk can be reduced from thecontractor fully understanding the scope of works andquestions can be asked on site and communicated toall on the tender list.

The choice of contractors who are to be invited totender is a very crucial part of the process. Work onany historic structure requires a contractor to displaya variety of skills, a depth of experience and a soundtechnical knowledge, as well as less tangible criterialike approach and attitude. Work on ruins tends to beless commonplace than work on roofed historicbuildings and it is therefore even more crucial thatthese requirements are fulfilled. Regulations may existthat require a certain number of tenderers, but thisnumber should be guided by the more importantconsideration of a known and proven ability to carryout the work. It is not appropriate for contractorswho do not have the right experience to be includedon the tender list merely to make up the requirednumbers. If they end up submitting the lowest tenderthe client or his representative is usually bound toaccept this, so the project is set to fail from the outsetwith obvious risk to the historic fabric.

This is the general failing of many public sectororganisations and local authorities which are boundby strict procurement procedures for the appointmentof contractors. These procedures include governmentprocedures such as Official Journal of the EuropeanUnion (OJEU) publication, financial checks, securityvetting, knowledge of previous works undertaken forthe organisation or other local authorities and on thebasis of approved contractors lists. Quality and skill are

compromised by the need to appoint on the basis oflowest cost. These procedures are archaic and have noconsideration for the conservation of the historic fab-ric. Tender lists often comprise contractors from an‘approved list’ who have little or no experience ofwork on historic buildings and have been entered onthe list because of success on previous general con-struction projects and refurbishments using modernmaterials and construction techniques, and because oftheir financial standing. There is a clear risk to historicbuildings as there will be little understanding of tradi-tional materials and methods of construction and, forinstance, cement will creep into the specification,especially if the professionals involved are lacking inexperience and knowledge.

Although most tender preliminaries state that thecontract will not be let on least cost alone, it is oftenwhat happens and least cost seldom represents bestquality. The only way quality can be assured andrisk mitigated is by the carefully compiled tenderlist. Tenderers should be of similar size, experienceand skill, so that the tender will be truly a fair exer-cise and tender prices will reflect this relationship;only then will the tender evaluation process be trulyone of quality judged on the basis of cost, time andquality.

There is also a need for the enlightened technicalofficers from local authorities and public organisationsto educate those in authority who are able to makedecisions on procurement methods, in order that theseold-fashioned approaches to tendering building worksare made more flexible. This requires such measures assingle tender or negotiated tender to specialist firms forcertain works where specific skills or experience arerequired. This is preferable to inviting tenders from thespecialist firm with a number of others selected solelyto make up the numbers but without the relevantexperience for the works in hand. This creates a diffi-cult situation as the desired tenderer will seldom besuccessful or lowest tenderers, so there will be a periodof negotiation with the decision-makers to approvethe appointment at a higher level in order to justifypublic spend and increased contract sum.

Another problem affecting the quality of the ten-der and the work itself is the lack of sufficient pro-fessional and technical knowledge amongst clientin-house teams. This translates into poorly prepareddocumentation or insufficient brief to the consultantteam, which in turn makes for problems once theworks are on site as the specification will not con-sider all the client’s requirements. This risk will betransferred into additional cost once the project ison site and omissions are identified.

Ch08-H6429.qxd 10/14/06 3:40 PM Page 241

242 Conservation of Ruins

Figure 8.6 The distorted and failing arch of a medieval flying buttress has been temporarily shuttered to its distorted profile. Forit to perform satisfactorily the curvature of the arch needs to be restored but instead a muddled hybrid, partly distorted, partly ‘cor-rected’ has been created resulting in a confused assembly of new and old stones.

Figure 8.7 New stones are simply square blocks sawn six sides with a straight chamfer cut on two faces. Because there is nomasonry involved the blocks still exhibit lash marks from the saw and a parody of tooling has been applied to the faces, even thoughthere is no evidence of tooling on the original stones; the blocks form wedge-shaped joints and the blocks do not even line up. Somejoints are imperfectly filled, and lime stains the surface of the stones.

Lack of experience, confidence, team organisation, masonry skills, supervision and the absence of any trials or exemplars have dam-aging, long term impacts on historic sites; ideally, it should not be possible for work of this quality to be carried out on a national his-toric monument. This situation is never the fault of one individual but of a system which permits it to happen and which may noteven recognise the damage it has done.

Ch08-H6429.qxd 10/14/06 3:40 PM Page 242

In order to ensure the correct choice of contrac-tor, a certain amount of flexibility may be appropri-ate, even perhaps in deciding that one contractordoes not have the ability to carry out all the work and therefore that named subcontractors would berequired. It is the role of the client or their represen-tative to interpret the requirements of the project andto ensure a flexible approach is adopted.

Selection of a contractor for the tender list cannotbe done by simply issuing a pre-qualification ques-tionnaire asking probing questions on relevant skillsand experience, programming and resourcing. Itneeds to be a far more inclusive process and shouldnormally involve a discussion or interview of poten-tial contractors prior to short-listing. This ensuresthat the relevant experience is discussed. All of theclient team should be involved, and the contractorshould be asked to give their view on the nature ofthe works and encouraged to discuss practical andethical issues. This then establishes at an early stagethe spirit of good communication and mutual trustwhich has to play such an important part in the proj-ect as a whole. The proposed site manager shouldalso be invited to attend the interview as well as anypre-contract meetings, as it will provide a forum toensure that they fully understand the complexities ofthe contract.

Crucially also the contractor needs to demonstratean understanding and experience of the specialrequirements for the conservation of ruins. It is notnecessary that all of their site personnel should havehands-on experience of all the techniques required,but it is imperative that there are craftsmen and con-servators on the team who have carried out these tasksand are able to train and educate others during theproject. It is also crucial that all the team have experi-ence in the use of traditional materials to be used, suchas lime putty and hydraulic lime mortars, and that thecontractor is honest about their experience and is will-ing to bring attention to any areas where they lackexperience. This weakness can then be addressed, per-haps by the involvement of a subcontractor.

The pre-tender interview also gives an opportunityto convey how the project would be organised fromthe client’s point of view and to establish how the con-tractor would propose to manage the project. It is notalways sufficient that CVs of key personnel should bepresented. The client needs to be completely confi-dent that the project director will be fully engaged inthe project, and that the site manager and senior crafts-men have the experience and vision to understand the complexities of the project, including historiccontext.

In addition to the necessary skills and experience,the use of correct materials underpins any work onruins. The fact that the ruin has come to its currentstate may be due to inappropriate materials used inthe original construction or, more often, poor sub-sequent maintenance and repair. Any material isonly as good as the person using it, so that training inthe use of the material is essential. Theory and tech-nical background are useful, but it is practical expe-rience that is most important. This can be taught ina formal environment to a certain extent, but is onlyfully learnt by using the material repeatedly in a realsituation. Only through site experience can thenature and working characteristics of any material befully understood and a confident versatility in its usebe acquired.

Another factor in mitigating risk is effective sitesupervision from a competent site foreman, who fullyunderstands the requirements of the specification, thecomplexities of the site, site constraints, and is knowl-edgeable enough to stop work if new elements arediscovered on site and to consult the architect/projectmanager immediately. The contractor and foremanmust be able to work with the professional team andother contractors on site, including liaison withdirectly procured contractors.

This site knowledge is where apprenticeshipschemes can benefit as long as cheap resources arenot used to fund conservation works and delays arenot experienced due to lengthy training periods.Obviously, the importance of any historic buildingis such that it should not be used as a playground forinexperienced craftsmen to develop their skills. Thevery best way is for a contractor to ensure that ateam of people on site are organised so that a lessexperienced individual works alongside somebodywith the requisite skills – an informal, site-based,short-term apprenticeship. The use of lime mortars,for instance, is not overly complex and the necessaryskills can be developed quite quickly as long as thetrainee has the correct attitude to want to learn andthe desire to apply what they have learnt.

The successful implementation of works is not amatter for one individual or for a contractor, butinstead it is a pooling of professional knowledge andskills through mutual respect between everybodyinvolved.

A major problem in all public organisations is theinherent lack of desire to make a decision; this is thelimiting factor in the improvement to existing ten-der procedures. Individuals do not feel sufficientlyempowered to change problems that are contribut-ing to the flaws in many conservation projects.

Implementing conservation works on ruins 243

Ch08-H6429.qxd 10/14/06 3:40 PM Page 243

A lack of decision-making results in a lack of actionand/or loss of the historic fabric by this inaction.

Thus, it is essential that the professionals involvedare suitably experienced and can convey the full scopeof works in the tender documentation. Trials may beundertaken prior to tender to establish the basicmethodology and provide guidance for the tenderprocess. It must also be established that the contractorson the tender list are suitably trained and experiencedin works on historic buildings. The specification mustbe clear and concise to avoid risk and to ensure greatercost certainty.

In order to ensure as far as practicable the (client)requirements of time, cost and quality in any projectworks to historic buildings and sites, a stringent pre-tender process must be developed. In the preliminarystages trials and exemplars can be undertaken in orderthat more information is available on methodology,standards of workmanship, and level and scope ofrepair. As well as providing vital information onmethods and quality, which will be fed into the tech-nical specification, it also provides essential informa-tion on costs and timescales for each element of thework, which gives greater client certainty with regardto budget and programme, as well as aesthetics andquality.

Trials and exemplars will also be necessary as part ofthe statutory approvals process, during which conser-vation officers and EH Inspectors will want to inspecttrials relating to the proposed works such as cleaningtrials, mortar samples, replacement stones and scope ofrepair. This information will feed into the tenderprocess and will ensure that the specification is suffi-ciently detailed and as ‘tight’ as possible to ensure thatthere is greater cost certainty at tender stage, and bidsare therefore realistic and accurate. This will alsomean that provisional sums are not relied upon forunknown elements and all risk is not transferred tothe contractor, with the resultant hike in tender pricesfor vagueness and unknown items.

Another element of ensuring best quality is byallowing suitable timescales for tender periods. Sooften tenders are invited late into the client pro-gramme, so tender periods are reduced to achieve thedesired contract start and completion deadlines.There is inherent risk in shortened tender periods astendering contractors and their subcontractors willnot have adequate time in order to read through andfully understand the requirements of the specificationand undertake site visits to ascertain a best estimate forthe works. Tender periods should be gauged accord-ing to the complexity of the contract, quantity of ten-der documentation and specialist nature of the works

involved, so that the contractor can be offered a suffi-cient period of time to prepare the tender return andsupplementary information required by the tender.This will ensure as far as possible that the tendersreturned are realistic and accurate rather than rushed,and priced accordingly to cover this risk and assump-tions made. In addition, a shorter tender period willresult in a general lack of understanding that willbecome apparent once works are on site. This in turnmay result in a higher percentage of professional feesbeing invoked by the requirement for additionalattendances on site.

The tender list should be compiled from contrac-tors who are sufficiently experienced and knowledge-able in the requirements of the project. Contractorsshould be of similar experience and size so that it isindeed a fair process. Contractor selection should beon the basis of references, site visits, prior knowledge,questionnaires and interviews. This may seem like arigorous process, but it is necessary to ensure bestquality and reduced risk of damage to the building bylack of knowledge and supervision. At pre-contractstage it is important that the CVs of all those involvedare submitted with the tender and these personnelattend all relevant meetings, including the selectionfor tender list. This should include the site foreman,who should be a competent person suitably experi-enced in the requirements of the project and of run-ning sites of similar values and scope. This foremanshould be fully conversant with the specification andshould be able to communicate this to all site person-nel as necessary, as well as any variations as the contract progresses. The foreman should be in atten-dance at all progress meetings to discuss any variationsor logistical issues arising.

Conclusion

Our principal and inter-related policy aims for the prop-erties in our care are: to conserve the fabric of the proper-ties to the highest standard … to maintain, enhance andpromulgate knowledge in its (English Heritage’s) conser-vation works and to set standards for others.

(English Heritage Corporate Plan, 1988–1992, Item 3.1)

A mission statement of this kind, from a key heritageorganisation, underlines the fundamental principlesrelating to the training, implementation and man-agement of conservation works to historic buildingsand sites. As discussed within the chapter, by cre-ation of specialist in-house teams, careful selection ofcontractors, site supervision, ongoing training, and

244 Conservation of Ruins

Ch08-H6429.qxd 10/14/06 3:40 PM Page 244

development of professionals and site personnel,standards can be set for conservation works of thehighest quality to be undertaken on historic sites.But the achievement and maintenance of these stan-dards require expenditure of money and time, notonce but constantly. Without the recognition that

specifically designed training is essential for all per-sonnel involved, from labourer to director, and thatall personnel have an understanding of their respon-sibilities to the historic fabric, successful conser-vation will remain elusive, sometimes fatally so forruins.

Implementing conservation works on ruins 245

Figure 8.8 With no common language, communication on site is the only kind of communication. Colin Burns and Mohammedexchange tobacco, Masada, Israel.

Ch08-H6429.qxd 10/14/06 3:40 PM Page 245

Unwelcome Visitors. Abandoned and neglected sites are always at risk from unwelcome visitors who, in ignorance, show no respect or enjoyment of the ruins. Vandalism in the form of graffiti, dislodging of stones and removal of material from the site is a commonexperience. Photograph Asi Shalom.

Ch09-H6429.qxd 10/14/06 3:44 PM Page 246

This chapter explores the impacts of (human) visitorson ruined sites. It also examines the presentation (dis-play) and interpretation of these sites. Although themain focus is on English practice at historic ruinedsites the principles have a wider resonance.

Tourism and conservation: conflict orharmony?

Tourism of all kinds, whether mass tourism for pleas-ure, business or conference tourism, is one of theworld’s largest industries and is perhaps its largestgrowth industry. Tourism is likely to be here to stayand its sheer scale and associated gross expenditure areof considerable economic importance at national andlocal levels.

Tourist numbers are increasing year on year andever more remote parts of the world, some with par-ticularly fragile and vulnerable remains, are becomingaccessible to large numbers of visitors for the first time.As visitor opportunities increase, so do the complex-ity and variety of threats to visited sites. The challengeposed to those responsible for the protection of sitesand to those with a vested interest in their care is todevelop collaborative management strategies to makethe most of their potential and to anticipate and planto minimise risks.

Long-term strategies must be sustainable. Forinstance, visitor numbers must not be permitted to exceed sustainable levels; profits generated from entrance fees and retail opportunities must bereinvested; fabric, flora and fauna must be protectedand cared for, and educational opportunities raised.

Sustainable tourism

Ruined buildings and structures are unique, irreplace-able resources. All face multiple threats to their

continuing existence and, if their historic value andintegrity are not to diminish with the passing of time,long-term sustainable visitor management strategiesare required. Strategies must maximise the positivebenefits that visitors can bring to sites and mitigate, asfar as practicably possible, negative aspects.

Our heritage of ruins represents a huge legacy ofinformation, craftsmanship, design, energy and mater-ials, and this must be protected against depreciation ifthe labours of our ancestors and the benefits we derivefrom sites are to be preserved. Those charged with thecare of ruined sites must recognise and take account ofenvironmental, social and economic factors whenmaking decisions, and must consider the impacts ofthese factors on the sites and demonstrate account-ability for the consequences of their decisions.

The type and number of people visiting a ruinedmonument should somehow be compatible with itscharacter and needs if a sustainable balance betweentourism and conservation is to be realised. All sites,whatever their type, have a finite capacity to absorbvisitors. Unfortunately, though saturation is undesir-able for both visitors and sites, the tourist market ishighly lucrative and the approach to tourism is toooften demand-orientated rather than supply-led. A supply-led (inward-looking) approach is based onthe desired number of visitors who can comfortablybe absorbed by a site and is always going to be prefer-able to an outward-looking approach, which onlyconsiders what visitors would like or can be persuadedto like. A ‘comfortable’ rather than absolute capacityof sites to absorb visitors should be the basis for every-thing else, such as the marketing policy, visitor facil-ities and interpretation of the site.

When considering the capacity of sites to receivevisitors, their ‘sense of place’ and the impact of vis-itors upon them must be the principal considerations.They should be used intelligently to develop respon-sible proposals if visitor type and numbers are to be

247

Chapter 9

Interpretation and display of ruins and sites

Amanda White

Ch09-H6429.qxd 10/14/06 3:44 PM Page 247

matched with the resource and if future tourismobjectives are to be secured.

Visitors to ruined monuments are to be welcomedand encouraged, but excessive numbers and unwel-come visitor types can have undesirable, sometimesirreversible, effects on their long-term preservation.

Visitor numbers

Ruins may be categorised as attracting many, few orno visitors. Sites visited by the very few or by no vis-itors at all are usually neglected, and are generallyfound in particularly remote, often inhospitable, loca-tions. Monuments can range from little more thanpiles of stones to the substantial remains of what wereonce large and complex buildings or groups of build-ings. The rather inaccessible isolated desert and junglesites of parts of the Middle East and South Americarespectively are examples of rarely visited sites. Theyare perhaps only of interest to national bodies and themost determined of scholars, unofficial archaeologistsand/or looters.

Sites receiving modest numbers of visitors are oftensecluded though relatively more accessible, or theymay have limited visual appeal, or be located in unattractive urban settings. There is commonly littleto see beyond the ruined fabric and they are fre-quently unstaffed and free to enter. Visitors are gener-ally drawn from home markets, with most livingwithin an hour’s travelling distance.

At the other extreme, well-visited sites includeiconic, internationally renowned and well-publicised‘must see’ monuments such as the Colosseum, Italy,the great Pyramids of Egypt and Stonehenge, England.They are located on principal tourist routes, can com-mand substantial entrance fees, and are often supportedby a wealth of visitor facilities and interpretation.

Visitor type

As regards type, visitors may simply be considered asdesirable or undesirable. Desirable visitors comprisecuriosity seekers who perhaps know very little of asite, its past occupants or associated events but areinterested to learn and/or experience more; thosewith a serious interest in studying the physical fab-ric, flora and/or fauna of a site; those who value asite’s ‘sense of place’ and are keen to experience it;those with little or no interest in a site beyond theprestige that comes with attending a function orevent; and those who visit a site purely to takeadvantage of its associated facilities. The latter, ifthey appreciate a ruin resource at all, perhaps value

it merely as a pleasant backdrop to a drink, meal orretail opportunity.

Undesirable visitors include looters and ‘unoffi-cial archaeologists’, especially those equipped withmetal detectors, who want nothing more than totake from monuments for personal gain, and vandalswho want to damage and disfigure as an aspect ofgeneral antisocial behaviour or even for makingpolitical statements.

Visitor impact

Visitors can impact both positively and negatively onruined sites and their environments, and the scale andseverity of impacts will vary according to the type andnumber of visitors. The benefits and risks to neglected,seldom visited sites are both moderate. Whilst physicalimpact is generally negligible, such sites are ofteninfrequently, if at all, inspected or maintained and, assuch, can deteriorate unnoticed. Neglected sites haveno capacity to generate income and there is little, ifany, desire or capital to invest in them.

Sites of low visitor appeal are commonly unstaffedand free to enter. The benefits to the fabric of suchruins are low as there is no or little income-generatingpotential and the risks to the monument can be verygreat; poorly visited sites can attract the unwelcomeattention of vandals, looters and ‘unofficial archaeol-ogists’. The actions of such visitors can go uncheckedfor lengthy periods between inspection cycles. Theknock-on effect is that a lack of care can encouragefurther abuse, as subsequent visitors think it accept-able to follow suit by, for example, adding to existinggraffiti or by taking small archaeological fragments assouvenirs.

Well-visited ruin sites can offer substantial scope interms of their use and thus have huge income-generating potential. Sites can have a wide variety ofuses, including exhibition; education and training;retail, catering and other commercial uses; worshipand/or ritual; functions and events; storage; work-shops and grazing purposes. Heavily or intensely vis-ited sites can result in unacceptable deteriorationand/or damage to vulnerable surfaces, environmentsand habitats. Wear and tear from visitors must not bepermitted to erode the integrity of sites: a sustain-able level and complexity of use must be observedwhereby the risk to fabric, especially to primary fab-ric, and protected flora and fauna is minimal. Whilethe benefit to fabric can be high, this must be balancedagainst the very high risks that large numbers of visitors pose as they challenge and test ruined sites totheir limits.

248 Conservation of Ruins

Ch09-H6429.qxd 10/14/06 3:44 PM Page 248

Exploitation of ruins

More and more site operators are seeking to maximisethe income-generating and educational potential ofruined sites in order to secure their long-term viabil-ity. There can be great scope to improve day visitorbusiness and to exploit other commercial opportun-ities such as weddings, parties, corporate functionsand seminars at many sites. As operators seek out newmarkets and try to improve their existing marketshare, sites are increasingly being developed to pro-vide an array of tempting services and facilities.Though business and financial successes must not bethe key objectives, investment in sites can bring eco-nomic success and provide opportunities for reinvest-ment which might otherwise not be possible. Whilsta degree of investment is welcome it must always becarefully balanced with non-commercial objectives.

Presentation of ruins

It perhaps goes without saying that the appeal of sitesand the expectations of visitors are inextricably linked,and the presentation of physical fabric is, for most, thegreatest draw. Due to their inherent defining nature,that of incompleteness, ruined sites (and their settings),particularly those where substantial parts have beenlost or are masked by fallen masonry and shrouded invegetation, can be confusing to understand. Thedevelopment of sites can be difficult to determine withany certainty. This is particularly the case where docu-mentary evidence is lacking and where similar mater-ials, workmanship and/or architectural styles havebeen used for different phases of work; where build-ings evolved in a complex or protracted manner; orwhere ancient fabric was reworked during construc-tion, alteration or improvement.

So how are ruins to be understood by those thatcare to confront them? There are two ways: the studyof tangible fabric and by reference to written records.Some ‘tidying up’ can often assist a visitor’s under-standing by revealing more of what remains, but it canbe damaging to fabric, upset a site’s delicately balancedecosystem and, at worst, add to confusion by posingmore questions than it answers. Insofar as writtenrecords are concerned, these can sometimes be frag-mentary, if not lost altogether. Our earliest ruinedmonuments, those erected before written accounts,are usually the most difficult to understand.

Those responsible for the preservation of ruins have,therefore, another fundamental objective. In additionto the securing of fabric they must try to make ruins

intelligible to visitors. As our understanding of ruinedstructures can only ever be partial, their physical display will always be problematic. Intelligibility is the prerequisite and a piecemeal approach must beavoided if sites are to be presented in a meaningful and holistic manner.

The objective of presenting a site, ruined or other-wise, must be to portray it in its correct and full documentary and historic context insofar as it isunderstood and possible to do so. Presentation pol-icies must therefore be site specific and take accountof, respect and achieve a balance between all values(emotional, symbolic, cultural, environmental anduse – past and future) attached to or inherent in fab-ric, and clearly define its messages if visitors are tounderstand, learn from and enjoy these sites.

In the UK we have a long history of preserving anddisplaying ruins, and various approaches have beenfollowed. Historically, methods typically came andwent with fashion and as such we come now to a richinheritance of variably treated ruin sites’ fabric. Someapproaches have proved more successful than others inpreserving and rendering fabric intelligible to visitorsand much has been learnt. Whilst some ideas wouldbe considered unethical if adopted at virgin sites today,others currently being debated are perhaps little, ifany, better in terms of the potential for loss.

The objective of physical presentation must, inaddition to being authentic in all respects (design,materials, workmanship and so on), be determined bythe particular nature of a site and its individual setting.These are the most important considerations for thosewho manage sites and they should always be the guid-ing factor.

Picturesque display

The picturesque display of ruined structures, whilst nolonger common, is perhaps the oldest method of presenting ruins. Ruined monuments, much appreci-ated for their time-worn and weathered surfaces, werequite deliberately arranged in their settings during the eighteenth and nineteenth centuries. The object-ive was to create a series of pictures from multipleviewing points, a contrivance which could often be farfrom natural. Natural features were often rearranged toenhance the overall effect of a scheme; hills were raisedor levelled and streams and lakes created as required. Insome cases artificial ruins were constructed as ‘eye-catchers’ and focal points. There was little regard forthe preservation of ruins; they were merely playthingsand no doubt many suffered from selective demolitionto ‘improve’ the romance of their silhouette.

Interpretation and display of ruins and sites 249

Ch09-H6429.qxd 10/14/06 3:44 PM Page 249

Whilst the picturesque landscaped gardens of Stowe,Buckinghamshire and Stourhead, Wiltshire typify thefashion of the day, the ruins of Fountains Abbey inYorkshire dominate what is arguably the most impor-tant eighteenth century water garden to survive inEngland. Though the garden is still much as it wasconceived, it is today presented in a tidied up fashion.Jervaulx Abbey, Fountain’s close neighbour, is one ofonly a handful of ruins to retain the picturesque quali-ties for which it was admired. A thick natural grassthatch and an abundance of wildflowers cover itsruined walls, and seemingly untamed trees, plants andgrasses soften its setting and give the impression of wallsrising from the land as if they were one (Figure 9.2).

Restoration: presentation by wholeness

The presentation of wholeness by restoration – that is,the alteration of a building or part of a building‘which has decayed, been lost or damaged or isthought to have been inappropriately repaired oraltered in the past, the objective of which is to make itconform again to its design or appearance at a previ-ous date’1 – is a long-established means of displayingruins. Though the approach fell from favour in thelate nineteenth century, it is again becoming popularas a means of presentation.

As ruined walls inevitably and exponentially deteri-orate with time, the restoration of ruined monumentsfor beneficial reuse is a much more logical and perhapsunderstandable objective than that of conserving them‘as found’. However, as ‘The accuracy of any restor-ation depends on the extent to which the originaldesign or appearance at a previous date is known, orcan be established’,1 restoration must be carefullyconsidered if it is not to detract from, impact upon orconfuse a structure’s wholeness and message.

Though each case for restoration must be assessedon its own merits, it should perhaps only ever be fol-lowed where monuments are complete enough toallow authentic restoration without unacceptable lossor distortion of evidence or conjecture. It shouldalways be avoided where a ruin’s aesthetic values arereinforced by the scenic value of its existing state andits setting, particularly where they have been a signifi-cant source of artistic inspiration.

Restoration can provide a clear and informativemessage to visitors and can afford other positive benefits, such as providing greater or improved access,improved or new views and an appreciation of original spatial qualities. But it can also be problem-atic, not least selecting the moment in a monument’shistory when restoration should take place. Ruinedmonuments are typically restored to their defining

250 Conservation of Ruins

Figure 9.1 Roche Abbey, Yorkshire in the 1970s showing the use of closely mown grass as a context for the ruins, ‘conserved as found’. This became the presentation house style of the Office of Works and its successors for many decades (photograph:J. Ashurst).

Ch09-H6429.qxd 10/14/06 3:45 PM Page 250

period but, even if this is clear, this can lead to greatdebate and disagreement between even the mosteminent of scholars.2

Restoration always carries the risk of inaccurateinterpretation and can, even when accurately andcarefully carried out, unavoidably confuse originaland contemporary ‘reproduced’ material. It also car-ries the associated consequential risk of significantirreversible archaeological loss or distortion and struc-tural damage which sadly comes with any work on anhistoric structure.

Anastylosis

Anastylosis is the name given to the process of rebuild-ing the remains of collapsed structures in their originalpositions and it is common practice in parts of theworld prone to devastating earthquakes or having suf-fered conflict (Figures 9.4 and 9.5). Elsewhere, anasty-losis is always difficult to justify, but a strong case cansometimes be made for partial rebuilding at sites cater-ing for a broad, often international, audience of mixedvisitor type. Here the re-erection of minimal fabric, afew well chosen significant features, should normally

suffice to provide visitors, particularly those not able orprepared to make the concerted effort required for anunderstanding, with an appreciation of their originalspatial qualities, form and purpose.

Reconstruction

Reconstruction, or the ‘re-establishment of whatoccurred or what existed in the past, on the basis ofdocumentary or physical evidence’,1 can only be jus-tified as a means of presenting ruins if undertaken onthe basis of thorough research of the original. Likeanastylosis, reconstruction is today most commonlyassociated with monuments ruined as a result of con-flict or natural disaster. In reconstruction, ruinedmonuments are reconstructed to their prior existingform and detail in their original location so that theymight fulfil their pre-existing function.

Reconstruction was common in the closingdecades of the nineteenth and early years of thetwentieth centuries (and is now experiencing some-thing of a renaissance). Lost parts of buildings weretypically reconstructed, sometimes completely fordomestic rehabilitation. More commonly, low

Interpretation and display of ruins and sites 251

Figure 9.2 A thick carpet of wild flowers and grasses cap the ruined walls of Jervaulx Abbey (Yorkshire) in a striking picturesquedisplay.

Ch09-H6429.qxd 10/14/06 3:45 PM Page 251

stone walls were typically constructed on originalstone footings and finished using different tech-niques to distinguish between different buildingphases. Muchelney Abbey in Somerset was one ofmany ruined guardianship sites to be treated in thisway; low walls containing some original materialwere constructed on medieval remains, twelfth cen-tury remains were finished with level tops and latermaterial was rough-racked (Figure 9.3).

Reconstruction can be successful if the strength of evidence is good and if appropriately carried out.At Muchelney, the twentieth century treatment ofruined walls oversimplifies the development of thebuildings, which is now known to have been pro-tracted and complex and, to compound matters, theyare no longer considered accurate. The earlier pictur-esque treatment of ruined walls at Jervaulx has perhapsbeen more successful, as carved, moulded and otherdisplaced worked stones were merely stacked alongthe lines of pre-existing walls close to where theywere discovered. Though the practice was unscientific

by modern standards, the randomly stacked dry-stonewalls clearly indicate the past location of missing wallswhilst making no pretence to be anything other thanwhat they are – randomly piled stones.

Special cases for reconstruction can sometimes bemade on safety grounds. Whilst low, ruinous wallscan readily define the plan of a site they can, especiallywhere particularly low, be trip hazards and, wheretaller, hide considerable and hazardous drops. It is notacceptable to ignore such risks to visitor safety and theraising of ruined walls, based on sound archaeologicalresearch and interpreted in a distinguishing manner,can be more aesthetically pleasing than the erection ofa more conventional physical barrier.

Conservation ‘as found’: ruins ‘as evidence’

Conserving ruins ‘as found’ is, at face value, a pro-foundly illogical pursuit. Buildings and structuressurvive by being kept complete – that is, becausethey are not ruins. Even so, ruins are important to us,and there is a long history of valuing, conserving,presenting and enjoying them.

The ‘conserve as found’ approach was common inthe UK from the early twentieth century and waschampioned by the Office of Works and its successorsfor a period of approximately 70 years. During thistime many hundreds of very large and complex vir-gin sites were conserved using what were then largelyexperimental conservation techniques. The approachwas principally concerned with structural matters andarchaeology, and sought to ‘freeze’ masonry at apoint in time in its ‘as found’ condition by revealingas much original fabric as possible (see Chapter 4).Ruined fabric was ‘retrieved’ by the removal of lateradditions, fallen masonry and ‘damaging’ vegetation,and a standard range of consolidation techniques was used to arrest decay. Monuments were set off byclosely mown grass and formal paths so that their pri-mary ‘evidence’ might be displayed to maximumeffect. Though the approach resulted in a high degreeof similarity between sites and an attendant sad air of civic, almost clinical, austerity, it has been highlyinfluential elsewhere in the world and continues toshape contemporary attitudes (Figure 9.1).

Deliberate ruination

An approach of deliberate or planned ruination of siteswas sometimes adopted during the mid-twentiethcentury, where buildings were deemed to have cometo the end of their viable lives and where their cultural values were thought insufficient to justifythe expense of maintenance and reuse. In a period

252 Conservation of Ruins

Figure 9.3 (a) An example of ‘rough racking’, a favouredtreatment by the Ministry of Works (UK) in the first half of thetwentieth century for broken wall ends and heads, used selectivelyat Muchelney Abbey to denote post twelfth century work.

Ch09-H6429.qxd 10/14/06 3:45 PM Page 252

Interpretation and display of ruins and sites 253

Figure 9.4 The excavated site at Beth Shean, Israel showing limestone columns lying on the basalt-paved shopping street, as theyhave been since the town was largely destroyed by earthquake (photograph: J. Ashurst).

Figure 9.3 (b) The use of different forms of masonry consolidation and capping at Muchelney Abbey to distinguish between buildingphases of construction illustrating another early house style of presentation (see page 251).

Ch09-H6429.qxd 10/14/06 3:45 PM Page 253

during which houses were being ‘lost’ at a rate of oneevery two and a half days, an alternative approach wasto record them, then to divest them of their roofs,services, woodwork and other perishable contentsin a misguided bid to reduce maintenance costs.The objectives were to remove all material liable todecay and to leave masonry walls and their openingsintact, and to weather newly exposed wall tops andvoids (such as beam sockets) as required. Followinga serious fire at Witley Court, Worcestershire, in1937, surviving parts of the former EdwardianMansion, having survived calls for demolition in the1960s, were treated in this manner.

Conservation ‘as found’: ‘verdant’ ruins

Whilst much vegetation is still routinely removedfrom ruined walls and their settings are neatly

manicured and vigorously weeded, there is a grow-ing view that many plants may be benign, ratherthan destructive, and that some might even be pro-tective. This view, combined with an increasedunderstanding and valuing of wider ecological issuesand a greater appreciation of a ruin’s ‘sense of place’,has led to a growing interest in the ‘verdant’ or greenapproach to presentation.

A verdant approach manages all facets of a ruinedsite and is still quite rare. It involves the absolute min-imum of fabric conservation, sufficient to make themonument safe and to slow its rate of deterioration,and the divesting of destructive woody growth only.Its principal objective is to preserve, if not enhance,the natural and fragile ecology of a monument andits surroundings. The pioneering approach was suc-cessfully followed at Wigmore Castle, Herefordshire,during the early 1990s following its acquisition bythe state and has generated much interest.

The approach is still relatively embryonic but lessons are already being learned. At Wigmore, theremoval of dense, formerly protective vegetation tofacilitate essential conservation works is, in someplaces, having a deleterious effect on masonry; areasof previously stable but hidden mudstone are dete-riorating, some stones at an alarming rate. On thepositive side, the approach, in striking a balancebetween the ruined fabric and nature, retains thespirit and challenges of the site for those who care toappreciate them. It is significantly less theatrical thanthe picturesque approach but offers, in common withit, a charm and sense of continuity that is sometimesmissing at traditionally presented sites.

Managed decline

Perhaps the most controversial and somewhat sinis-ter approach to presenting ruined structures is that ofmanaged decline, a course of action that allows aruin to safely follow its natural path to destruction.This option involves archaeological recording, moni-toring, control of vegetation, making safe by theprogressive removal of areas of fabric liable to col-lapse or likely to fail and fall in a fragmentary waywith lethal potential.

Whether a ‘letting go and making safe’ policyshould ever take precedence over the preservation ofancient fabric is a delicate point. The adoption of sucha policy, however necessary for economic reasons, hassuch serious ultimate consequences in terms of cul-tural loss that it should only be determined at nationallevel. Its message, were it to be adopted or sanctionedby a state body, would be far reaching and would not

254 Conservation of Ruins

Figure 9.5 Anastylosis at Beth Shean, with re-erectedcolumns recovered from their fallen positions in the street below(but see comments in Chapter 1, page 23, on Tall elementsrepaired with reinforcing rods set in resin).

Ch09-H6429.qxd 10/14/06 3:45 PM Page 254

go unheeded by those who perceive present levels ofpreservation to be unjustified.

Benign neglect

Benign neglect falls somewhere between plannedruination and managed decline insofar as roofedbuildings are ‘allowed’ to decline in a managed way.They are not helped along their way as in plannedruination but the end result is much the same – thatof irretrievable loss. The Defence Estates (the MOD)have recently adopted such an approach, in agree-ment with English Heritage, at selected bomb storesat RAF Scampton.

Replication

Replication offers perhaps the greatest hope for thelong-term survival of our most fragile ruins, whichperhaps would benefit from not being visited at all.Shackleton’s Hut in Antarctica and Easter Island aretwo sites that would undoubtedly be better unvisitedthan be destroyed by tourist development. The use offacsimiles is rare but includes replica sculptures inFlorence and reproduction caves in Altimara, Spainand in Lascaux, France.

Interpretation of messages

As their once completed forms cannot be experi-enced, ruined structures and their true significance canperhaps never be properly understood. Interpretation,whether in the form of official guides and the like orby the transmission of stories, can aid the understand-ing of tangible remains.

Ruined (and non-ruined) historic fabric is physicalhistory and provides, by its very being, actual links tothe past. Ruined fabric is what remains of our ances-tors’ past endeavours, and gives clues to the lives oncelived and to events that took place in and around them.Whilst their study can do much to illuminate history,ruined monuments have great educational potential;lessons in history, art and architecture, societal and cul-tural development and conflict can be explored. But itis not possible to present the whole story of a ruinsolely by reference to the physical remains.

The interpretation of stories provides a means ofconveying more of a monument’s past. It can takemany forms, including: simple printed leaflets; lav-ishly produced illustrated guides and histories; plansshowing phased development and models, tactile orotherwise; graphic panels; exhibitions of relatedartefacts; knowledgeable guides with a command of

multiple languages; audio tours; virtual reality andinteractive television; costumed interpreters, re-enactments of historic events and son et lumière(dramatised spoken history accompanied by spec-tacular lighting effects).

The history of a monument is always best explainedat its site and the provision of interpretation is animportant aspect of managing tourism. Of course, it must be based upon thorough scholarly and accurateresearch and, if it is to be successful, it must inform vis-itors of something worthwhile and add to their under-standing and enjoyment of sites. Though the level andsophistication of interpretation will depend on thebreadth of a site’s appeal and its popularity, at a mini-mum it should explain a building’s pre-ruinous stateand the cause of its ruination. Sites of broad appeal,certainly those of international interest, require partic-ularly careful handling and demand considerableresources if all visitors are to understand their signifi-cance and experience all that they have to offer.

Successful modern approaches to interpretationencompass all phases of a monument’s history andinclude details of its most recent, post-ruinous past,the objective being to provide visitors with the fullestunderstanding of a monument’s story. This is adeparture from the more traditional, quite selectiveapproach in the UK, which focused on a particulartime in the life of the pre-ruined building (typicallyits earliest, defining or grandest phase).

Interpretation is often undeveloped and under-resourced, so that visitors are poorly informed or, atworst, manipulated in a particular direction so that thecomplex nature and messages of a site are missed.Visitors who remain uninformed are often under-standably disappointed with their experience, and maybe frustrated and develop negative attitudes to the siteand its continuing survival, especially those who havetravelled long distances and paid entrance fees.

The same may be the case where interpretation isoverdone. Assailing the visitor with audio-visualfacilities of all kinds can be intrusive to those whosemain interests are archaeological or historical, and tothose who visit sites principally to enjoy and appreci-ate their spirit, sense of place and tranquillity. Clever‘living’ interpretation is perhaps interpretation at itsmost extreme – glamorised and neatly packaged his-tory for mass consumption. The problem of suchpackaging is that, if too heavy-handed, it can becomethe dominant resource, relegating the site to a pleas-ant backdrop and destroying its integrity, insulatingthe visitor from any real sense of the past.

The educational value of many ruined sites is huge,and their interpretation and presentation must be

Interpretation and display of ruins and sites 255

Ch09-H6429.qxd 10/14/06 3:45 PM Page 255

recognised as a responsibility of the custodian to thevisitor rather than a means of drawing greater numbersof visitors to a series of ‘attractions’, which is too oftenthe trigger for providing or improving interpretation.

Visitor services: expectancies andimpacts

In a highly competitive market where visitor expect-ations are high, the provision of a wide range of visitor services is almost a prerequisite. The extentand scope of services is determined by visitor num-bers and type, the ability and appropriateness of a siteto accommodate them, the willingness and ability ofa monument owner or guardian to invest in them,and ultimately of visitors to pay for them.

Access

Access to the location and around ruined sites arequite different matters but can be addressed togetherhere. Whilst entry to and access around ruined sitesshould ideally mirror the original in order that visitorsmight better appreciate them, access has often beenmuch altered since ruination. Though visitors mayoriginally have approached sites along routes designedfor defence or formal drives or landscaped parks, ruins,having been divorced from their surroundings orencroached upon by subsequent development, areoften approached rather abruptly and illogically. Thisis commonly the case for many sites in state guardian-ship, where boundaries were often tightly drawnaround monuments.

Though little can often be done to overcome losses,original approaches can sometimes be successfullyrestored and this should always be the aim wherepossible. Similarly, where gatehouses, successivecourtyards and so forth have disappeared it is alsoimportant that visitors understand and follow theoriginal progression around monuments if they are tobe properly understood and their context maintained.

The disappearance of perishable elements, such as wooden bridges, floors and stairs, can cause bothpractical and intellectual problems. The provision of such items, particularly bridges over moats andditches, is often essential for access and to aid intel-ligibility. Where restored, construction should ideallybe unmistakably modern in design, but of materialssympathetic with what may originally have beenused (Figure 9.6).

Local access to sites from further afield can bemore problematic. Remotely located sites such asDunstanburgh Castle (Figure 9.11) can be difficult

to reach except by the most able and determined.This can benefit fragile sites by protecting themfrom heavy traffic, but as conservation awarenessand, in turn, financial support increase with accessi-bility, limited access can have negative impacts too.

Where there is a need to introduce roads or paths,the aim must always be to guide visitors to and aroundsites by the most sustainable and least interventive andintrusive means. Focal points and pinch points such asgateways and popular routes are particularly sensitiveto wear, and due account must be taken of them if theintegrity of sites is not to be diminished throughdirect erosion.

Access can be altered or modified to benefit thesite by removing pressure from key points or byreducing them to manageable levels. This is achievedeither by altering the pattern of use by re-routingvisitors or by improving the wearing quality of sur-faces. Paths at Hadrian’s Wall had, for years, fol-lowed the line of the wall, and heavy use by walkershad begun to expose and erode its foundations. Theredirection of paths away from sensitive areas has

256 Conservation of Ruins

Figure 9.6 One of two sympathetic, though distinctly mod-ern, oak bridges constructed at Helmsley Castle in Yorkshire.With much timber fabric having long since perished, the use ofoak goes some way to redress the masonry: timber balance.

Ch09-H6429.qxd 10/14/06 3:45 PM Page 256

significantly improved the preservation and settingof the monument.

Facilities and infrastructure

Sites attract visitors and economic opportunities are created by the demand for facilities and infra-structure to cater for them. Visitor facilities areincreasingly a prerequisite at popular ruined sitesand the rise in tourism can put services for visitorsin conflict with the care of sites if not sensitivelyhandled. Where consideration is being given totheir provision, they must be appropriate to, andinfluenced by, their surroundings in terms of design,scale, material and location. New buildings shouldbe soundly constructed and designed for a long life,and be capable of alteration or extension as neces-sary to cater for future needs. Standards of designshould be high and materials should be sustainable,durable and selected to enhance, though not neces-sarily match or be finished in replication of theoriginals.

Facilities should be located in areas of least fragilityand archaeological disturbance kept to an absoluteminimum. They should complement rather than

detract from monuments and should age well andweather comfortably in their settings. The proximityof facilities to historic fabric can be offensive andexcessive; poorly planned, badly designed or insensi-tively located facilities have a seriously adverse impacton the significance of features, ecological characteris-tics and an enjoyment of the site (Figure 9.8).

Where facilities are to be inserted within a mon-ument, new work must respect the significance andsensitive nature of fabric and installations must becarried out in an appropriate and compatible man-ner if fabric loss and the risk of problems occurringat the interface of the old and new are to be avoided.It is important that account be taken of past andintended future use, minimal intervention andreversibility.

The use of uniform or generic corporate facilitiesare often best avoided, no matter how attractivethey might seem in terms of cost. Though the rela-tively ephemeral nature of such accommodationcan be positive, implying a transitory nature, newbuildings must be unique or at least distinctive ifthey are to play their part in the attractiveness of sites;contemporary good design will, after all, be the heritage of tomorrow. On a cautious note, fanciful,

Interpretation and display of ruins and sites 257

Figure 9.7 Helmsley Castle’s new visitor centre was sensitively designed and sited and makes a positive contribution to the his-toric site.

Ch09-H6429.qxd 10/14/06 3:45 PM Page 257

258 Conservation of Ruins

Figure 9.8 The proximity of services, such as portable toilets, to historic fabric can have a seriously adverse effect on enjoyment of a site.

self-conscious buildings can lead to quite unhappyresults.

Servicing sites

Power and lighting along with signage and, in somecases, security measures can be necessary at ruinedsites. Each has a job to do, but each can detract fromthe character of a monument if poorly or inappro-priately designed. It goes without saying that, as for any intervention, the most successful schemesare those which have least interventive and visualimpact on fabric.

Power

Whilst most ruined monuments require very little inthe way of electric power beyond perhaps some basiclighting, modern legislative requirements can beonerous and difficult to meet where visitor facilitiesare provided.

Many ruin sites, particularly those in isolated loca-tions, have no modern power supply (having beenheated by coal or perhaps gas during their pre-ruinousphase) and some have no service provision of any kind

whatsoever. Where mains servicing is required but isprohibitive for reasons of archaeological sensitivity orcost, imaginative responses are needed if today’smandatory standards for human comfort (minimumtemperatures, etc.) and energy efficiency levels are tobe met (Figures 9.9 and 9.10).

When servicing sites, careful thought must begiven to the location of plant and service routes.Modern services, having an expected life of 20 or so years, are transitory when compared to historicfabric, so reversibility and minimal interventionmust dictate the nature of the installation if the special character of sites is to be preserved; no scarsshould be left as and when renewed or replaced, and holes and chases for pipes, cables and ducts, fix-ings and plant bases must be kept to an absoluteminimum.

Service installations can contribute to preventiveconservation by increasing the beneficial use of sites,but can also have a detrimental effect on historicfabric both in terms of physical damage and thedeleterious effect on surfaces, which can result, forinstance, with a sudden change in internal environ-ment. This can be common where ruined monu-ments are reconstructed or restored, and the impacts

Ch09-H6429.qxd 10/14/06 3:45 PM Page 258

Interpretation and display of ruins and sites 259

Figure 9.9 Eight photovoltaic panels are sensitively and reversibly sited on top of the remains of the fourteenth century tower andprovide general power to a small shop and ticket office. The panels replaced a noisy generator, are fully reversible, and meet govern-ment initiatives and green tourism initiatives.

Figure 9.10 Crichton Castle (Midlothian, Scotland) is the first Historic Scotland site to be powered by the sustainable technol-ogy shown above (Figure 9.9).

Ch09-H6429.qxd 10/14/06 3:45 PM Page 259

and benefits of such actions must always be carefullythought through.

Lighting

Good lighting can be welcoming and can alsoenhance security. Ruined spaces in particular need tobe imaginatively and sensitively lit if the beholder is toappreciate something of their former qualities, moreso where such spaces have multi-functional use.

The discreet and careful positioning of lightingcan illuminate parts of a ruined structure that are nolonger accessible and/or would otherwise be diffi-cult to appreciate without doing harm. Elsewhere,imaginative lighting can add interest and intrigue.In terms of effectiveness in internal spaces, schemeswhich attract the eye by echoing the effect of sun-light (or moonlight) are most successful. Externally,low-level up-lighters can have a dramatic effect on abuilding by accentuating the light and shade ofarchitectural detail and its scale. The careful use oflight can also be used to ‘hide’ less favourable orfragile areas by focusing attention elsewhere, andcan also be used to highlight trip and other hazards.Whether floodlighting or special lighting effects(such as son et lumière) are appropriate at ruined sitesfor anything other than temporary, special events isalways debatable.

Signage

Whilst lighting may not be necessary, appropriate or possible at many ruin sites, signage in its variousforms, way-finding and interpretative, is often a prerequisite.

At a minimum, the way to a ruined monumentshould be adequately signed from the road (in theUK, ‘brown signs’ denote monuments of significantinterest) and from footpaths, as necessary, by finger-posts. At the entrance to sites there should be signsadvising contact details in the event of an accident oremergency, or to alert custodians to vandalism, etc.,and giving brief details of the monument’s pre-ruinous form and the cause of its ruination, plus abrief statement about safety. Where payment for entryis required, it is also good practice to display theprice(s) of admission and, for larger or complex sites,a sign displaying an aerial view and a ‘you are here’indicator can also be justified.

Signs, both wayfinding and educational, can enor-mously enhance visitor experience, but only if wellthought out in terms of their design, size, scope,number and location, and if they are well maintained.

Signs should be of an appropriate height so thatthey can be read by all, be consistent in terms ofsymbolisation and the naming of parts (with guidebooks and the like), and should be appropriatelydesigned and located. Inappropriately located ordesigned signage can easily detract from the aes-thetic qualities of a site, and a desire for uniformity(as is the current policy for English Heritage sites)can have both positive and negative affects; uniformsignage can provide quality assurances but, on thedownside, can restrict or undermine the ability ofindividual sites to promote themselves as success-fully as might otherwise be the case.

Security

Human interference at ruin sites has always been amajor agent of destruction, often far greater than thenatural agents of climate and vegetation. Histori-cally, the deliberate levelling and quarrying of siteswas the principal cause of loss, but today they arecommonly protected by law. However, vandalism inthe form of graffiti, the gratuitous destruction ofobjects and looting are modern threats often associ-ated with tourism activities. Some measure of secu-rity is often necessary, and the denser the population,the greater the risk and the greater the requirement.

Casual acts of antisocial behaviour are more oftenthan not a consequence of ignorance and stupiditybut, when deliberately committed for reasons ofpolitical or social unrest or when associated withorganised crime, can be extremely destructive.

The continuous erosion of some sites is certain ifmeasures are not taken to protect them from casualtreasure hunters and opportunist vandals. Security ofmonuments and their associated services generallytake the form of lighting or fencing, but whateverform is employed the means must be appropriate, fitfor the purpose, and carefully designed and located soas not to impact unduly on a site’s significance.

Legislative requirements: health and safetyand disabled access

The ownership of ruins entails many legal responsibil-ities, the most common being related to matters ofhealth, safety and accessibility. In the UK, legislationgoverning both is largely non-prescriptive; standardsare set and an owner or managing authority mustassess what is ‘safe’, ‘suitable’ or ‘reasonable’ for anygiven circumstance. There are no hard and fast rules;for access issues it is a matter of reasonableness and forhealth and safety matters it is one of risk management.

260 Conservation of Ruins

Ch09-H6429.qxd 10/14/06 3:45 PM Page 260

The impact of making safe and providing access onthe presentation and display of a ruin site can begreat. In terms of health and safety, the greater therisk, the greater the impact. In particularly seriouscircumstances, for example where there is a likelyrisk of fatality, access to parts of a site may need to berestricted or the site may have to be closed until suchtime as the risk has been remedied.

A risk assessment which seeks to identify all knownand reasonable anticipated risks identifies worksrequired on health and safety grounds. Whilst com-mon sense should always prevail, owners, anxious toavoid potential legal claims,3 are often precipitate ininstalling safety measures. The challenge lies in identifying ways of overcoming risks to visitors thatdo not erode the enjoyment of the very thing theyhave come to see. The unnecessary use of the ulti-mate irreversible action, that of making safe by takingdown, should of course always be the last option.

Safety and access are thorny issues and often relatedat ruinous sites. Parapet walks, precipitous paths andsteep banks, descaling stone and live plaster are allpotentially dangerous. Floor surfaces may be unevenand dangerous to even the most able of visitors.Whilst a quick-fix option might be to install regula-tion height handrails, dress off historic stone surfacesor to relay an uneven floor or cover it up, the appro-priateness of such actions – in particular, what will begained and at what cost to both the monument andobserver – must always be carefully thought through.In the end, the procedures required to make ‘danger-ous’ sites ‘safe’ may be quite inappropriate. The firstduty of the custodian is security and survival, includ-ing the character, of historic fabric, not the safety ofvisitors. Clearly, the safety of visitors must never beignored, and security fences and ‘Danger – keep out’signs are sometimes the only responsible answer.

Access for disabled visitors can be particularly dif-ficult at ruined sites and imaginative ways must oftenbe developed to overcome them. Many ruinedstructures, particularly castles and fortified houseswhich were designed to keep unwanted visitors atbay, can prove particularly demanding. In the UK,access provision is tested on the grounds of reason-ableness and the alteration of physical fabric is onlyone means of providing it. For instance, a tower ona steep defensive mound can only be reached by asteep ramp of such an incline that it becomesimpracticable for wheelchairs to negotiate, and asteeply inclined ramp of considerable length or achair lift can seriously compromise the integrity of a site. Alternative forms of access, such as improve-ments in intellectual access (written interpretation

and so forth), can be an acceptable, alternativeoption.

Access to and around ruins presents the greatestaccess problems. Access, particularly to remote siteswhere there is no vehicular access (e.g. DunstanburghCastle, England, Figure 9.11), can be difficult at thebest of times and it may not be reasonable in such casesto provide access for all. Whether or not accessimprovements are required is a question of reasonable-ness and, as this is as yet unchallenged in the courts, apragmatic approach must be to consider improve-ments in light of a site’s significance. If a ruined mon-ument is of such archaeological or historic significanceand/or is marketed as a ‘must see’, then it is reasonableto assume that large numbers of visitors will travelfrom afar to see it and that it would be reasonable tocater for disabled visitors accordingly. If disabled visi-tors are prevented from visiting such sites discrimina-tion will be suffered.

In terms of facilities for the disabled, currentEnglish law provides that they must be at least equal tothose provided for non-disabled visitors; discrimina-tion arises if this is not the case. Where, for example,parking and/or toilets are provided for able-bodiedvisitors, then accessible parking and toilets must beprovided for disabled visitors. If there are no facilitieswhatsoever, there is no discrimination.

Maintenance

Maintaining a ruin site in a safe manner is one of themost important responsibilities of an owner whenvisitors are to be admitted. However, whilst all prop-erty is required by law to be maintained to ensurethe health and safety of occupants and visitors, it isstressed again that the principal aim of maintainingruined sites must always be to preserve them, as faras practicable, in their ‘as found’ condition to pro-tect their significance, integrity and setting.Maintenance for health and safety reasons, for pre-sentational purposes or so that they can continue tofulfil their function as a visitor attraction mustalways be secondary.

The complexity and intensity of use of ruin sitesimpacts greatly upon the nature, frequency and tim-ing of maintenance. Infrequently visited sites run therisk of neglect, whilst heavily visited sites or parts ofsites can suffer unacceptable deterioration and damageby attrition. The usage of sites must never be such thatwear and tear from visitors is allowed to erode the fab-ric, ecology or character of monuments or their set-tings. Visitor management and maintenance must be

Interpretation and display of ruins and sites 261

Ch09-H6429.qxd 10/14/06 3:45 PM Page 261

an integral part of a site’s long-term management planand must follow a coordinated and coherent approachif the risk of otherwise avoidable deterioration, loss or,at worst, collapse is to be avoided.

Ruins have no indefinite life. However muchattention is lavished upon them, erosion by naturalagencies cannot be prevented but steps can be takento slow the rate of deterioration. Legally, a failure tomaintain sites appropriately can result, in the UKwhere monuments are listed, in a repairs noticebeing served or compulsory purchase.

The importance of maintenance as a preventivemeasure in slowing deterioration is essential, andeven routine activities must be properly plannedand prioritised. Many regimes are repetitive andinterventionist, and over-maintenance can, where itleads to the loss of fabric, for example in the case ofexcessive repointing, be just as destructive as a lackof maintenance. Maintenance activities have an

undeniable psychological effect on visitors. Neglectedsites or those perceived as such give an impressionthat the site is of no particular importance and thiscan lead to antisocial behaviour. Where sites sufferdeliberate misuse or vandalism, prompt mainte-nance is essential and must always be a priority.

Other visitor types: domestic animalsand livestock

Though this chapter has been concerned with theimpact of human visitors on sites, it is worth saying afew words about the damage that can be caused bydomestic animals and livestock at ruin sites (see alsoChapter 6).

Some sites are particularly vulnerable to theimpact of domestic animals and livestock and, wherethis occurs, it generally results from the ignorance of

262 Conservation of Ruins

Figure 9.11 A significant part of the attraction of some ruin sites is their remoteness and inaccessibility. In these cases it may notbe desirable or reasonable to create intrusive access facilities. Dunstanburgh Castle, England.

Ch09-H6429.qxd 10/14/06 3:45 PM Page 262

owners. Irresponsible dog owners who allow theircharges to run freely and foul sites can severelyreduce the enjoyment of sites by others. Where theyare allowed to foul, a serious health threat is posedand owners are in breach of the Dogs (Fouling ofLand) Act 1996. This Act, where it is enforced, canprove a double-edged sword: the Iron Age hillfort ofOld Sarum in Wiltshire has been particularly popu-lar with dog owners since nearby Salisbury BoroughCouncil began rigorously enforcing the Act in theadjacent city and its parks. Though the excreta ofhorses and other animals does not pose the samehealth hazards as that of dogs, it can be unpleasant forvisitors all the same and owners must be encouragedto take due responsibility.

Livestock grazing can have both positive and neg-ative impacts on the long-term preservation of ruins.Grazing, where it maintains the visibility of monu-ments and deters root-penetrating vegetation such asscrub and bracken growth, can assist the long-termsurvival of sites (see Chapter 6). However, it can bedetrimental. For instance, stocking levels and live-stock type require careful management and the loca-tion of livestock focal points such as troughs needscareful thought if monuments are not to be eroded tobare earth. Erosion or poaching occurs where thegrazing of a site is above the sustainable level for thetype of vegetation or soil. The problem is greater atfocal points and increases during wet periods andduring the winter months.

Summary

There is a long history of valuing and caring forruins. Whatever the cause of ruination, they evokestrong feelings in contemporary society and we valuethem for many reasons. Whether it is their sense ofplace, their tangible link to the past or the secrets and

stories that they hold, we recognise their specialimportance and we want to visit them.

The sensitive and appropriate use of sites must be the best way to preserve sites, and innovative, collaborative and sustainable strategies have to bedeveloped for their long-term management. Con-servation and tourism are in some ways mutuallyexclusive and must be reconcilable. There is nodoubt that tourism depends largely on a pleasantand attractive environment, and that funds gener-ated from site entrance fees can greatly assist conser-vation activities. Tourism is a growing industry andshould be welcomed and harnessed for good; ourheritage of ruins needs visitors to ensure its long-term viability. Conservation and tourism are inex-tricably linked; without visitors the need for thosewho care for ruins will diminish, and the sites willdeteriorate inexorably and will eventually be lost toall but architectural historians and buildings archae-ologists. A balance between the two must be found.Only when harmony between them is achieved willthe future of our ruin monuments be secure.

Notes and references

1. BS 7913 (1998). British Standard Guide to thePrinciples of the Conservation of Historic Buildings, p. 3.

2. The alternative interpretation of the ruined spaceknown as the Tudor Great Hall at Mont OrgueilCastle, Jersey, offered by Dr Warwick Rodwell andProfessor Colin Platt, is a recent case in point andmaterial to reinstatement proposals.

3. In England owners (or guardians) are liable forinjuries to visitors under the Occupiers’ Liability Act1984. A breach or failure to fulfil statutory and legalliabilities can have substantial consequences, particu-larly where matters of safety are concerned, and mayresult in civil or criminal actions being taken.

Interpretation and display of ruins and sites 263

Ch09-H6429.qxd 10/14/06 3:45 PM Page 263

Ch10-H6429.qxd 10/14/06 3:47 PM Page 264

Case Study 1: Guildford Castle, UK

Catherine Woolfitt, John Ashurst and Graham Abrey

The conservation of the tower keep of GuildfordCastle in Surrey illustrates how archaeological investi-gation can inform repair and conservation work on aruin, and conversely how conservation work can aidthe archaeological interpretation of an ancient monu-ment. The tower is the most prominent survival ofGuildford’s Norman castle, standing to a height 15metres above its motte platform (Figure 10.1). Likeother Norman great towers, Guildford Castle’s toweris of massive composite wall construction, with walls3m thick, on average, at ground level. The tower isalmost square in plan, approximately 14.5m by 13m.The date of the tower has never been firmly estab-lished. The earliest written references belong to thereign of Henry II, but the early twelfth century hastraditionally been cited. Prior to commencement ofsurvey and study the original internal arrangement ofthe tower was uncertain. It was clear that there hadbeen a large principal chamber raised above groundlevel, over a smaller ground (or basement) level space.This principal (first floor) chamber had a largeentrance in the west elevation and three large win-dows, one in each of the other three elevations. Incontrast, the ground-level space below had only twovery narrow, small window openings and a smallentrance and, as at other towers of this date, appar-ently functioned as some sort of service or storageroom. It had generally been assumed that there was anadditional (second) floor level due to the presence of a mural chamber in the south-east corner and thecontinuation of a spiral stair in the north-west, but

substantial rebuilding at the top of the tower over the centuries, including the introduction of brick windows in the sixteenth century, had obscured or destroyed much of the earlier construction.

In 1998 Guildford Borough Council, which ownsand operates Guildford Castle’s tower keep as a visitorattraction, was forced to close the tower to the publicdue to concern for visitor health and safety and forthe condition of the tower itself. New access stairs,both internal and external, had been constructed lessthan 10 years previously, in 1989, with an internalviewing gallery at principal (first floor) level, but theoak timbers of these structures had begun to decaydue to the damp internal environment. The towerhad been without a roof since the seventeenth cen-tury. The condition of the interior of the ruined shellof the tower was generally poor. In addition to thedecay of the timber stair and gallery, damp had pro-moted abundant plant growth on the walls andmicro-organic (slippery mould) growth on the newstone floor at the base of the tower (see Figure 10.2).Feral pigeons had colonised the many ledges andchambers of the tower’s interior and their guano con-tributed to the unhealthy environment.

Some elements of past repair work had exacer-bated rather than ameliorated the condition of thetower. Work to the wall heads had entailed formingscreeds that were either flat, allowing water to pene-trate through to the wall core, or had a slight fall tothe interior rather than to the exterior, which chan-nelled rainwater down the internal wall faces. By1998, when the tower closed, the internal wall sur-faces were virtually obscured by plant growth athigh level. The chalk quoins used internally haddecayed at a greater rate than the Bargate stone usedfor most of the internal facework and were recessedin profile, relative to adjacent rubble masonry. TheBargate stone ashlars of openings had also sufferedand losses had occurred, notably on the main westdoor, where large lenses of stone had detached andfractures were visible.

265

Chapter 10

Case studies

Opposite page Theatre of Marcellus. Medieval Romeadopted and adapted the arches of the Theatre of Marcellus as hous-ing (see Preface page xv). The illustration shows work of gentle clean-ing and surface filling of the blackened travertine in progress.

Ch10-H6429.qxd 10/14/06 3:47 PM Page 265

The external masonry face was relatively free oforganic growth, compared to the internal face. How-ever, localised growth of problem plants with invasiveroot systems had occurred externally in spite of a pro-gramme of masonry repair work carried out at thesame time that the new access stairs and gallery wereinstalled. Buddleia and other species had taken hold inseveral locations at high level, and their root systemshad penetrated the rubble masonry construction.Although some repointing had been carried out,plants had managed to gain footholds on masonrysurfaces, in open joints and crevices between stoneand mortar. Some past repair work had employedinappropriate, cement-based or cement-gauged

mortars, particularly on the few sections of survivingmedieval ashlar stonework on the east elevationpilaster buttresses.

Guildford Borough Council commissioned a con-dition survey of the tower, which was carried out in1999, with a view to applying for scheduled monu-ment consent for repair and conservation of thetower so that it could be reopened to the public. Dueto its position on the east side of a high and inaccess-ible motte, access was limited and the survey waslimited to ground-level examination, with whateveradditional access could be gained internally from thespiral stair in the north-west corner and the viewingcage at wall-head level. Consequently, access to

266 Conservation of Ruins

Figure 10.1 View of Guildford Castle’s tower keep from the south-west, with the slope of the motte visible in the foreground.

Ch10-H6429.qxd 10/14/06 3:47 PM Page 266

Case studies 267

internal elevations was better, although hindered byorganic growth, than access to external elevations,which was from ground level only. The option ofusing a cherry-picker (aerial access platform) wasexplored but the slopes of the motte were too steep;only one elevation (the east) would have beenaccessible by this method. Consequently, for thepurposes of initial survey, to produce recommenda-tions for work and to tender the work, survey wasbased on ground-level access only. Allowance was

made, however, in the tender documents and inbudget costs for additional, more detailed surveywork and for archaeological assessment from fullaccess scaffolding.

Condition survey

The decay of Hythe Beds stone

The condition of Hythe Beds stone within themasonry was found to vary considerably, depending

Figure 10.2 The internal south-east corner of the tower at wall-head level, illustrating the extent of plant colonisation and screedssloping into the tower.

Ch10-H6429.qxd 10/14/06 3:47 PM Page 267

to some extent on the original source of the stone.In general, the Hythe Beds used for the buttressesand quoins, which is largely replacement stone ofthe mid-twentieth century, was in much worse con-dition than the Bargate used for the rubble masonry.The Bargate rubble stones were generally moredurable, with a much higher fossil shell and pebblecontent. They exhibited very little surface decay. TheHythe Beds ashlar stones of the buttresses and quoinswere fine to medium grained without visible fossil orpebble content. These stones exhibited considerablesurface decay and it appeared that the binder/cement-ing medium (which in the case of Hythe Beds is cal-cium carbonate) of the stone has been attacked. Thesurfaces were friable to the touch, with large lenses ofstone (often in excess of 20mm in depth) detaching.Decay at the perimeter of Hythe Beds stones resultedin the opening of cracks at the stone–mortar interface,increasing the uptake of rainwater into the masonryjoints. The erosion of the Hythe Beds surfaces on thebuttresses is ongoing and stones replaced in 1989,including the stone inscribed with that date, haddecayed perceptibly by 1999, evidence of a very rapidrate of decay and poor durability.

Decay of Hythe Beds stone of the south-east cor-ner buttress was found to be extensive and there wasan essential need for some stone replacement. Thetile repairs carried out in 1914 had proved to bemore durable than the adjacent Hythe Beds stonesand stood proud of the ashlars (see Figure 4.57).Other Hythe Beds stones around the tile repairs hadbeen replaced in post-1914 repair programmes. Thestone of the central buttresses on the west and eastelevations was also badly affected.

Saturation of masonry and soiling

The saturation of masonry was more readily visiblefrom the interior of the tower, where a profusion ofplant life grew on the walls, especially at higherlevel. Externally, plants could be seen growing fromthe masonry face in a few places, notably on flatprojections such as window sills and at wall-headlevel. Permeability was a key factor in both decayand water retention, which had weakened the chalkand the Bargate ashlar as well as supporting a rangeof microflora. A pattern of dark discoloration on theexternal east wall of the castle had been visible formany years throughout all seasons of the year andwas believed to be due to the migration of moisture,and possibly iron oxides in the stone.

Some dark soiling was visible on the externalmasonry face, most notably on the east elevation.

This dark soiling, resulting from the deposition ofatmospheric pollutants, was also visible in patcheson the other elevations. A principal problem relat-ing to all the surviving ancient masonry was that itwas forced to act sacrificially to the more robustrestoration and refacing work. This was true parti-cularly of the calcareous sandstone ashlars survivingin the pilaster buttresses and dressings to openingsand of the internal chalk quoins. The situation wasmost critical where areas of this shelly Bargate hadbeen bedded up to weakened stone in rather imper-meable cement-gauged mortar. Rainwater, whichpermeated to the core of the thick wall, found theeasiest exit route through old, permeable stones andlime mortar.

Masonry joints

The mortar joints of the medieval rubble masonrywere generally slightly recessed from the faces of thestones. Joints in sections of repointed masonry weremore full and the character of masonry in these areas,especially at high level, was difficult to define. It wasuncertain at the outset how much of the existing rub-ble facework was original and how much had beenrefaced. Careful and close-range study of masonry in the course of repair work would later demonstratethat most of the existing rubble masonry, excludingthat at wall-head level, was medieval but this was notclear initially from ground-level survey.

Repointing carried out subsequent to rectifiedphotography in 1989 was, in many cases, quitepoorly finished and applied wet, with brush marksvisible on joint faces. A few holes made by masonrybees containing insect casings were noted on thewest elevation, but their overall impact on the point-ing was insignificant. The main problem stemmedfrom the use of cement-gauged mortar in the jointswhich, coupled with the dense, shelly Bargate, cre-ated a rather impermeable external skin.

Wall tops

The original form of wall head was uncertain at theoutset, although it was thought, on the basis of com-parison with great towers of similar date, that the mostlikely form was a crenellated parapet. The wall topshad been covered with what appeared to be a cement,lime and sand-based screed, which exhibited cracks,permitting water to enter the wall head underneath.The screeds had not been designed to shed rain-water to the exterior of the tower. The screeds wereeither laid more or less level or with a slight fall to the

268 Conservation of Ruins

Ch10-H6429.qxd 10/14/06 3:47 PM Page 268

interior of the tower. Elimination of this water catch-ment zone was identified as a priority.

Previous repairs

Ground-level survey indicated that the externalfaçade had been extensively rebuilt and repaired,but precisely how much of the masonry façade wasmedieval and how much later restoration workremained uncertain. The façade had been exten-sively repointed in the course of numerous phases ofpast repair work, which obscured the nature of themedieval facework (see Figure 10.3).

Historical research by Dr Mary Alexander ofGuildford Museum had identified the intervals ofrepair work listed in Table 10.1.1

Condition of the internal masonry

The exposure of the wall heads and internal eleva-tions to the weather since the seventeenth centuryhad led to saturation of the masonry, and the internalmasonry surfaces were covered in organic growthranging from algae to large plants. The plant growthwas particularly abundant at high level and beneathwindow sills, where concentrations of water downthe wall face.

The environment at ground level (below the‘principal floor’) was continuously damp, even in thesummer. The exposed and damp conditions had ledto extensive decay of the susceptible building stones.Hythe Beds had been used for most openings, prin-cipally for facing the main entrance passage, andchalk for the quoins forming the internal cornersand for the blind arcade of the chapel. Both HytheBeds and chalk were suffering ongoing decay. Themain entrance internally was in very poor condition,with extensive fractures through quoins. The frac-tured sections had detached substantially so that thestones sounded hollow when tapped and large spallshad detached in the past few years. The chalk surfaceswere powdery and small flakes and spalls haddetached over the entire surface of the stone, indica-tive of frost damage.

Rubble construction of this period was typicallyplastered and although no plastered medieval surfaceswere visible on the exterior of the keep, it was pre-sumed (and later confirmed in the course of conser-vation and archaeological study – see Figures 10.4and 10.5) that the external walls had been finishedwith lime-based plaster.2 The internal masonry sur-faces were certainly plastered. Remnants of plasterand paint survived internally, most notably in the

antechamber and main chamber of what is tradition-ally identified as the chapel, both on the vault and theblind arcade.3

Repair and conservation work

The scope of repair work defined by survey andwhich formed the basis for tendering included thefollowing elements:

● Consolidation of the wall tops. To eliminate waterpenetration to wall cores and shed water to theoutside faces, in the traditional ‘ancient monu-ments’ way. This involved resetting core work inhydraulic lime-based mortar to profiles whichclearly indicate the broken nature of the wall tops(before these were ‘rationalised’ in nineteenth andtwentieth century repair programmes) channellingall water away from the internal space (see Figure10.6).

● Replastering. Partial replastering was recom-mended for a number of reasons: to act as a pro-tective and ultimately sacrificial layer overdecaying stone; to reduce the substantial wateruptake into the walls, thus reducing moisturemovement-related decay and inhibiting thedevelopment of organic growth; to equalise thewater absorption between sound and decayedsurfaces; and to enhance the appearance andincrease the legibility of the masonry and itsrepairs. Replastering was to follow the contoursof facework, allowing masonry features, such ascourses of herringbone, to read as far as possible(Figure 10.7). External work was in hydrauliclime NHL2 whilst internal work, at principalfloor level only, was based on a high-calcium(putty) lime binder.

● Cleaning. Associated with replastering was clean-ing work. Plants and organic growth of variouskinds, as well as the black soiling deposits, had tobe removed in advance of plastering to ensureadhesion and sound bonding of the new plaster.

● Repointing. There was a need for localised repoint-ing and deep tamping to both ashlar and rubblework, to remove past repointing in inappropriatehard cement or cement-gauged mortars and otherdefective work. New plaster had to be applied toa sound substrate and any detached or hollowpointing was to be removed and renewed prior toreplastering.

● Limited replacement of ashlar stones. Since so littlemedieval ashlar work survived, replacement was tobe limited to ashlar stonework introduced in laterphases of repair, which had decayed at a rapid rate.

Case studies 269

Ch10-H6429.qxd 10/14/06 3:47 PM Page 269

Figure 10.3 Rectified photomosaic of the west elevation of the castle, annotated to show phases of construction and later alteration.

Ch10-H6429.qxd 10/14/06 3:47 PM Page 270

Limited rebuilding was carried out where masonrywas displaced by roots of woody plant species.

● Repair of medieval stonework. Pinning and groutingof ashlar masonry forming openings which exhibi-ted spalls and fractures.

● Construction of new internal perimeter gallery and ticket/custodian’s office at ground level inside the tower.

● Site trials. All aspects of the work were subject totrials to ensure satisfactory methods and materi-als. For example, replastering trials includedpreparation of mortar samples for approval of mortar composition, as well as application ofpanels of plaster to confirm colour, texture andfinish.

Case studies 271

Table 10.1 Intervals of repair work, Guildford Castle

1830s Restoration and refacing of the lower part of the east external wall and other repair work

1880s Major restoration, especially at wall-head level, under the direction of the borough surveyor, whenGuildford Borough acquired the site and laid out the gardens surrounding the castle, which are stillvisible today

1914 Extensive SPAB style tile repairs to the external south-east corner of the keep (corner buttresses ofthe south and east elevations)

1940s to 1950s Replacement of quoins on the pilaster buttresses on the north, south and west elevations. The entireplinth of the west wall and most of the plinth on the north and south walls was replaced

1989 Work included repointing, some stone replacement and formation of the screeds to the wall heads.Chalk was replaced with Portland stone

Figure 10.4 Blocked embrasure on the west elevation in the course of excavating fill to expose the plastered vertical face of the mer-lon.

Ch10-H6429.qxd 10/14/06 3:47 PM Page 271

272 Conservation of Ruins

Figure 10.5 Detail of Norman plaster (in Figure 10.5) applied to the merlon in the tower’s first phase of construction.

Figure 10.6 Existing flat screeds were removed and core work constructed to shed water off the wall heads and indicate their bro-ken form prior to ‘rationalisation’ in the nineteenth and twentieth centuries.

Ch10-H6429.qxd 10/14/06 3:47 PM Page 272

Case studies 273

An essential part of the site work was archaeologicalrecording, which was a condition of scheduled monu-ment consent.4 Before erection of scaffolding, allmasonry elevations were subject to rectified photog-raphy and photomosaics of the elevations produced(Figure 10.3). Measured survey was carried out topermit production of plans at each level. Scaffoldingwas designed to be completely independent of themonument and was secured by ground anchors ratherthan the usual masonry anchors. Once scaffold accesswas available the elevations were resurveyed at closerange. At the same time, cleaning and cutting out ofdefective pointing began. Removal of later pointingsoon revealed significant archaeological features,which would substantially alter the scope of work tothe tower. Vertical features had been noted duringrecording of the west elevation and close rangeinspection confirmed that these were the lines of acrenellated parapet (Figure 10.9). The line of theparapet survived best on the west and south eleva-tions, where it was clearly defined by a thin whitelayer of limewashed plaster applied over the horizon-tal and vertical faces of the embrasures. The line waslegible on the north and east, but was less intact. Thediscovery of the limewashed plaster was particularly

significant since so little evidence of the original treat-ment of external surfaces of Norman buildings hassurvived. The decision was taken to interpret the lineof the crenellated parapet in plaster on the externalelevations (Figure 10.14).

Archaeological investigation soon uncovered otherevidence for the form of the tower in its earliest phase.Masonry offsets on the internal west and east elevations had always been visible, but there wasuncertainty about their function, whether they origi-nally supported a floor or a roof. In the course of studyand work on the east elevation, four large channelswere identified, just above the height of the masonryoffset, which had functioned as drainage channels fora roof; they extended through the thickness of thewall and one contained the remnants of a lead chute(Figure 10.10). A further important discovery was theuncovering of a garderobe chute in the chamber atprincipal floor level, in the north-east corner. Prior tothis, the chamber in the south-east corner had beeninterpreted as the garderobe, which had reinforced thenotion of a tower consisting originally of two floorsraised above ground level. Once this notion was dis-pelled, by the discovery of the garderobe and the evi-dence of the crenellated parapet and the roof drainage

Figure 10.7 Plastering trials were carried out to establish the mortar mix and final appearance and finish.

Ch10-H6429.qxd 10/14/06 3:47 PM Page 273

outlets, the earliest form of the tower could be inter-preted: a single large chamber raised above groundlevel, over a basement, with a roof set behind (andprobably screened from ground level by) a crenellatedparapet. The survival of plaster on the upper surfacesof the parapet and the nature of the infill, with mortarand masonry matching that of the parapet itself, indi-cates the tower was raised at a relatively early(Norman) stage. It seems, in the absence of evidenceto the contrary and on the basis of recent discoveriesof the same arrangement at other early Norman towers, such as the White Tower of London andCastle Hedingham, that the tower walls were raisedwithout the addition of a second floor, with dummywindows, apparently for the visual effect externallyrather than to provide additional space internally.5

Together, the evidence for the early form of thetower was sufficient to form the basis for a proposalto construct a new roof at the same level as the ori-ginal, using the same roof drainage outlets. Proposals

were supported by archaeological evidence, notspeculative assumptions about the original construc-tion. The construction of a new roof would bringsubstantial benefits for the condition and sustainabil-ity of the tower in the long term. Principal amongthese was the protection the roof would provide forthe castle interior, by excluding rainwater and pre-venting organic growth from recurring. The intern-al environment would be considerably improved forvisitors as well. Pigeons could be excluded by metalmesh applied over openings. Acceptance of the pro-posal to re-roof the tower led to rethinking of theprovision for access at first floor level. In lieu of thegallery previously envisioned, a design was developedfor a complete floor (at first floor level) to stand independently of the tower masonry, on a concreteraft in the base of the tower. Introduction of a newroof and floor would define the original spaces andassist with interpretation of the tower, in particularof the principal chamber, which is thought to havefunctioned as an audience or presence chamber forthe new Norman rulers to receive and impress vassals.

274 Conservation of Ruins

Figure 10.9 Detail of line of crenellated parapet on southelevation, with Bargate rubble construction of merlon on the rightand infill of embrasure in flint on the left.

Figure 10.8 None of the Norman window mullions survivedand one was reinstated in the south window to support theremaining voussoirs and interpret the early window detail.

Ch10-H6429.qxd 10/14/06 3:47 PM Page 274

The new floor is a free-standing platform withsteel stanchions and main frame and oak boards. Theroof frame is of softwood and has a slatted board sof-fit and lead cover. There was no attempt to mimicthe original Norman roof and floor construction,since their exact forms were not determined. EnglishHeritage provided grant aid for the programme ofconservation. The successful conclusion of the workwas due to the dedication of all members of the pro-ject team:

● The Client – Guildford Borough CouncilLeisure Services ( Jim Miles, Head of Section andLance Boswell, Clerk of Works)

● Statutory Consent (English Heritage) JudithRoebuck (Inspector of Ancient Monuments) andRobert Williams (Architect)

● Conservation Advisors and Buildings Archae-ology – Ingram Consultancy (Prof. John Ashurst,Catherine Woolfitt and Graham Abrey)

● Metric Survey and Photographic Recording –Plowman Craven and Associates

● Main Contractor – Nimbus Conservation(Project Manager Manjit Phull, Site ManagerMartin O’Connor and a team of conservatorswhose skill and sensitivity to the significance ofthe fabric ensured that important archaeologicalfeatures were detected in the course of work)

● Structural Engineers – EJC Design Partnership( John Hamer)

● Historical Research – Dr Mary Alexander (Assist-ant Curator, Guildford Museum)

● Planning Supervisor/Project Manager – Madlin &Madison (William Woellwarth).

An interesting debate arose over the Norman win-dow in the south wall. The once plastered embrasuresand barrel vault of the window terminated on theouter face with a screen consisting of an apronupstand below a two-light opening and a rubble-filled

Case studies 275

Figure 10.10 Detail of channel for drainage of original roof through east elevation. View of external face which has beenunblocked.

Ch10-H6429.qxd 10/14/06 3:48 PM Page 275

tympanum. At some time in the nineteenth centurythe single column supporting a rectangular abacusand the springing of the two semicircular headedlights fell. It appears in early nineteenth centuryillustrations, although not in great detail. The typeof column is, however, plainly a circular columnwith a cushion cap.

The absence of this support was creating a prob-lem for the tympanum, which exhibited steppedcracks and would be the next feature to be lost if leftunaided. The usual rule of ‘minimal intervention’suggested the use of an anchor installed through anew abacus to support the twin arches and the tympanum by hanging them from the corework

276 Conservation of Ruins

Figure 10.11 Section through the tower showing design for new roof and floor.

Ch10-H6429.qxd 10/14/06 3:48 PM Page 276

Case studies 277

above. A proprietary anchor which could be placedand grouted in situ was proposed.

The proposal was contested on the grounds ofuncertainty about the integrity of the coreworkabove. If the core could not provide the necessaryanchorage the masonry at the face could be signifi-cantly weakened close to the south face to no bene-ficial effect. An alternative proposal was to reinstatea load-bearing column and abacus to return to theoriginal structural arrangement. This solution wasfinally adopted, although not with unanimous sup-port, because of the perceived ‘restoration’ involved.In spite of this, the structural problem has been sim-ply resolved and the opening made visually intelli-gible to visitors. No attempt to detail the column, itscapital or its abacus was made beyond cutting thebasic profiles and it could not be mistaken at anytime for original work. Architecturally, the workhas been generally acknowledged as a substantialgain (Figure 10.8).

These major additions to the scope of workentailed an extension of the project timescale andobviously additional costs, but the benefits havebeen substantial. The site reopened in 2004 withconsiderable public interest. Visitors can now viewpreviously inaccessible areas of the tower, includingthe various mural chambers, and can appreciate the original visual impact of the Norman presencechamber. The tower can now be maintained at highlevel, which was previously impossible without

Figure 10.12 View of new lead covered roof, looking north-west.

Figure 10.13 Internal view of plastered principal floor levelwith boarded soffit of new roof, prior to construction of new floorat level of base of new plaster.

Ch10-H6429.qxd 10/14/06 3:48 PM Page 277

erection of access scaffold. Anchor points for safetyharnesses and ladder have been installed, which can be accessed from roof level for removal of anyinvasive organic growth that might colonise the wallheads.

Notes and references

1. Alexander, M. (2004). Aspects of the Early History of Guildford and Its Castle. Thesis for Doctor ofPhilosophy, Dept of Archaeology and School ofHistory, University of Reading, April.

2. Fernie, E. (2002). The Architecture of Norman England,p. 279. Oxford University Press. He summarises cur-rent understanding of Norman treatment of buildingsurfaces:

Unpalatable as it may be to modern taste, with itsattachment to the ideal of truth to materials andappreciation of the texture and colour of stone, mostof the surfaces in Norman buildings were painted,not only the interiors or the portals on the exterior,but every aspect. The evidence for this is scatteredand sparse but undeniable … There is no reason to

think that this applied only to churches, as even thename of the White Tower, although it is a latemedieval one, suggests. Painted mortar joints couldin theory be seen as a wish to even up courses of dif-ferent sizes, but the way in which the lines arepainted is on the whole much less regular than thereal mortar joints. The painting must rather be dueto a view that a building was not considered finisheduntil the masonry had been hidden.

3. Howard, H. (1998). Guildford Castle: Scientific exami-nation of traces of paint remaining in the antechamber of themedieval chapel. Conservation of Wall PaintingDepartment, Courtauld Institute of Art, December(unpublished report).

4. See Woolfitt, C. (2005). Guildford Castle Tower Keep:Analysis and Assessment of the Great Tower. Preparedfor Guildford Borough Council (Ingram Consult-ancy Project 99011), July (unpublished report).

5. Parnell, G. (1998). The White Tower, the Tower ofLondon. Country Life, 192(28), 86 –89. For evidenceat Hedingham, see Dixon, P. and Marshall, P.(2003). The Great Tower at Hedingham Castle: areassessment. In Anglo Norman Castles (R. Liddiard,ed.), pp. 297–306. Boydell Press, Suffolk.

278 Conservation of Ruins

Figure 10.14 View of tower from south-west after completion of conservation work. (Compare with the same view in Figure10.1.)

Ch10-H6429.qxd 10/14/06 3:48 PM Page 278

Case studies 279

Case Study 2: Masada, Israel

John Ashurst, Asi Shalom and Catherine Woolfitt

Masada is located in Israel on the border between theJudean desert and the Dead Sea Valley. The name isthought to be an Aramaic form of hamesad, a fortress.1

No name could better describe the almost impreg-nable flat-topped dolomite mountain standing over400 metres above the Dead Sea (Figure 10.15). Thetop of the mountain measures 600m north to southand 300m east to west at its longest and widest points.Natural access is limited to a winding path on the east,the Snake Path, and from a gypsum outcrop, the‘white rock’, on the west, linked by a spur of rock tothe side of Masada, a geological phenomenon whichplayed a major role in the history of the fortress.

The almost sheer sides of the mountain are char-acterised by vertical fissuring, evidence of stressrelease as the rock was pushed upwards in geologic-al time. Although there is a tendency for surfacerock on the sides of the mountain to slide down-wards on the west and to topple over on the east,the stone itself is immensely durable. Unfortunately,

another rock was used for much of the masonry onthe mountain top; this is a poorly lithified limestoneof recent geological age with poor durability. Therocks of the mountain also provide materials formortar and plaster. Clay, gypsum and lime can all bewon locally, and were exploited in ways whichshowed a good understanding of weathering char-acteristics and technology. Big section timber hadto be imported from the north, but smaller sizesfrom olive and cypress trees were available closer tothe site. Everything else had to be brought overlandor on the surface of the Dead Sea.

Fortifications may have been raised on top of themountain by Hasmoneans (153–152 BC – BCE),but it is with the name of Herod that Masada is pri-marily and most famously linked as builder. In 40 BC(BCE) he had taken his family there in flight fromthe Parthians and left them in the care of his brotherand a garrison of 800 men. No doubt furtherimpressed after this experience with the naturalstrength of Masada and the prodigious water-holdingcapacity of its great cisterns cut out of the mountain,Herod, according to Josephus,2 furnished the fortressas a personal refuge from the uncertain moods of hisJewish people and from the antipathy of Cleopatra ofEgypt. This period, from between 37 and 31 BC(BCE) until the death of Herod, saw the most lavishdevelopment of the site with fortifications, improvedwater collection and enlargement of cisterns,immense store houses, gardens, pools and palaces;and in particular the construction of the spectacularthree-tiered Northern Palace located at the extremenorth tip of the plateau (Figure 10.16).

A Roman garrison was taken by surprise in 66 AD(CE) by Jewish zealots; the best known of these,Eleazar, was master of Masada until the fall ofJerusalem in 70AD, Flavius Silva and Legio XFretensis with his prisoners of war marched south totake the last major centre of rebellion by conquest in73 AD (CE). The well-known history of the siege, inthe spring of 74 AD (CE), has left a number of phys-ical marks on the site, the most notable of which is thesiege ramp on the west (Figure 10.17), raised on thespur of rock referred to above by the Jewish prisonersuntil it was high enough to bring up the siege towerand ram to break the casemate wall. At this point lotswere drawn by the zealot garrison to appoint execu-tioners for themselves to deny final victory to theRomans, and to avoid the inevitable killing andenslavement which would follow surrender. Whenthe wall was finally reached and the Roman assaultsucceeded in entering the fortress, only the bodies ofthe garrison were found amongst the plentiful

Figure 10.15 Aerial view of Masada from the north, withHerod’s Northern Palace showing in the foreground. Silvas siegeramp can be seen on the right.

Ch10-H6429.qxd 10/14/06 3:48 PM Page 279

280 Conservation of Ruins

supplies they had laid out, and a sole witness to theevent who had been hiding near the Northern Palace.2

Little is known about the subsequent occupation ofMasada, but it was home to a Byzantine communitywho built a church on the site, the ruins of which stillsurvive. The site was reidentified in the early nine-teenth century. Limited exploratory excavations werecarried out in the 1850s and the first professional sur-vey work in 1932. Scholarly studies of the 1950s werefollowed by the detailed excavation and recording of1963–64 and 1964–65 directed by Yadin.

Conservation of the Northern Palace

After 2000 years the Northern Palace, sometimesdescribed as the Hanging Palace, is both remarkablylegible and tantalisingly elusive. Fire, seismic activity,weathering and even archaeology have taken a serioustoll, but the desert climate has, on the whole, workedin favour of survival, so that, for instance, excavatorscould expose jewel-like coloured plaster on the lowerterrace of the Palace (see Chapter 5). Similarly, one ofthe remarkable experiences of Masada is to look out atthe largely intact Roman siege works of camps andcircumvallation on the mountain itself.

The aerial view of the palace (Figure 10.16)shows the great complex of buildings clustered at the northern end of the rock. Prominent at the upper level are the great store rooms, wheregrain, oil and wine could be kept in quantity. Not only the necessities but the luxuries of life were planned for by Herod. To the north of thestorage area is a great wall still largely intact andcovered with white plaster, which defines and pro-tects the palace precinct beyond, forming a kind ofpromontory fort, as this wall is defensible and, inspite of an impressive approach stair, has only a nar-row entrance with a guard room located at the east end.

The three levels of the Palace had three distinctfunctions. The upper level provided living accom-modation around the three sides of a courtyard. Thenorth side of the courtyard was extended in theform of a semicircular balcony, probably planted asa garden. The view from this point is spectacular,with views north, east and west, across the desertand the Dead Sea to the hills of present-day Jordan.This is personal and private accommodation in theRoman style, with black and white mosaic pave-ments and polished plaster.

Figure 10.16 Aerial detail view of the Northern Palace showing the three tiers, defensive wall at top and storehouses beyond.

Ch10-H6429.qxd 10/14/06 3:48 PM Page 280

The middle level was reached by a stair, shown byEhud Netzer in his reconstruction on the west side,the main climb being within a stair tower. The pre-cipitous sides of the mountain on the east and west areindicative of the enormous logistical problems associ-ated with any construction near to the edge of theplateau. An extraordinary, circular building (‘theTholos’) occupied the greater part of the terrace.Whether a library or simply a place to sit and enjoy theshade and whatever cool air could blow through theopen colonnade will remain a matter of speculation.

Certainly, it was a place to impress and entertain. Alarge part of this terrace is on made-up ground,requiring the construction of retaining walls.

A further stair on the east side led down to thelower terrace, the natural area of the rock shelfextended artificially and daringly, retained by greatrevetment walls. The lower terrace is the mostsplendid of all, containing a square structure with acentral dining room and peristyle through which,again, spectacular views could be enjoyed. The useof plaster at this level is ingenious and sophisticated.

Case studies 281

Figure 10.17 The middle terrace northern wall, showing at its base the coloured plasters of the triclinium on the lower terrace.The fragile condition of both rock and stones can be seen.

Ch10-H6429.qxd 10/14/06 3:48 PM Page 281

282 Conservation of Ruins

On the south wall a plaster surface is raised againstthe rock wall. Plaster fluting is used to enrich thecolumns and pilasters. The column capitals arecarved in stone and were painted and gilded, and thesupporting walls of the peristyle were decoratedwith richly coloured plaster imitating decorativestones such as porphyry and calcite. On the east side,adjacent to the south wall, a steep stair leads down toa small private bath house, perhaps the mostsecluded place on the mountain. Here are found acaldarium with remains of a hypocaust and mosaicfloor, a furnace room, a tepidarium and a frigidar-ium. Above the frigidarium is a small cistern linedwith ash plaster. Perhaps the most interesting sur-vival at this level is the frigidarium, a pool reached bya series of plastered steps and covered with a plas-tered vault. It is in this remote corner that theremains of three people were found at the time ofYadin’s excavation, a man with scale armour, awoman with braided hair intact and a child. Perhaps,inevitably, these three are associated by traditionwith the mass suicide of the zealots.

Conservation work

The organisation and training of a team of conser-vators directly employed by the Israel NationalParks Authority was established at an early stage andadvised and directed by Asi Shalom, an archaeolo-gist and conservator who had observed first handover many years and in many countries the destruc-tive potential of archaeology, and who would laterwrite a manual of conservation for archaeologists3

so that historic fabric and evidence would not besacrificed in pursuit of knowledge.

The training period involved visits from a num-ber of specialists from abroad, including an architectand archaeologist/conservator from the UK, withthe object of pooling experience and developing aprogramme and suitable techniques for the condi-tions found at Masada. Training walls were built,and lime and earth technology taught by exampleand practice. Before any of the fragile historic sur-faces were touched, the team had to establish afamiliarity with the materials and the environmen-tal conditions of Masada, directed by Shalom.

Categories of problems were identified and con-servative approaches developed to try to protect andextend the life of what had survived. Plans were alsodeveloped with the Parks Authority for futureschemes to enhance the visitor experience by allow-ing them to see more and by explaining in betterdetail the history and events which had taken place.

Stone conservation

The most obvious problem of the Northern Palacewas the dramatic deterioration of the weak lime-stone which had been used for ashlar work andwhich, without exception, had once been plastered.Large areas of this stone form the walls of the greatmiddle terrace platform supporting the Tholos andthe revetments of the middle and lower terrace(Figure 10.18). Protected by their lime plaster, thesestones remained secure, but loss of plaster meant thatthe stones were subjected to the combined effects of salt crystallisation damage and the scouring ofwind-blown sand. Great, cavernous holes developedwithin the gypsum-mortared boundaries of thestones, a spectacular kind of alveolar weatheringwhich could only end in the loss of entire walls. Thissituation posed the most serious threat in terms ofmajor potential losses of buildings. A second, safetyissue was also involved, and public access to thelower terrace would need to be limited or curtailedaltogether unless a solution could be found.

The usual procedure of cutting out and replacingbadly decayed stones with new stones was clearlyimpracticable in large walls which had become some-thing like a fragile egg crate. The rigid grid of the‘crate’ was formed by the joints and the stone adja-cent to the joints; the voids were the centres of thestone blocks. Mortar filling alone was also impracti-cable because of the large volume of material each fillwould require and the problems of curing such a volume without the development of shrinkage. Asolution was therefore devised based on the use ofstone tiles, bedded in lime mortar. The principleconsisted of cutting a level base at the bottom of eachcavity and raising a stack of tiles with mortared jointswithin the cavity until its roof was supported. Thisprocess provided, within each stone, a structural sup-port system which left the Herodian coursing in place(Figure 10.19).

To ensure the tight packing of the cavity and thatfull contact was made from top to bottom throughthe tile stack, the uppermost tile was mortared on itstop bed and wedged up into position so that theirregular top of the cavity was well filled with softmortar. The joint below this tile was dry-packedwith mortar using a tamping iron to maintain thiscritical contact. Slowly cured, the mortared tilestack restored the structural integrity of each stoneand provided protection against further erosion byweathering agencies.

Compatibility of the tile stacks with the weak-ened Herodian masonry was clearly of the utmost

Ch10-H6429.qxd 10/14/06 3:48 PM Page 282

importance, since fillings which were of superiorstrength and durability would place additionalstresses on the historic work and accelerate its decay.The material for the tiles was therefore selected fromsalvaged stones of the same age and condition whichhad fallen from the mountain and lay at various levelsbelow, many of them damaged and all of uncertainexact provenance. These stones were sawn into tilesof 40 –50 mm thicknesses. Mortar was based on a

mature lime putty with sand and limestone aggregateand a ceramic pozzolan. Water ratios were kept aslow as practicable and the repairs placed into well-wetted cavities before commencing the curingprocess of feeding them with mist sprays of waterbehind protective sun screens over periods of 10 –14days. Wet drapes of geotextile fabric were kept inplace overnight when the mountain began to giveback the heat of the day.

Case studies 283

Figure 10.18 The northern wall of the caldarium showing the fragile, egg crate-like form of the weathered stones (top centre)where they are not protected by plaster (bottom right).

Ch10-H6429.qxd 10/14/06 3:48 PM Page 283

The visual impact of considerable numbers of tilestacks within the walls was another potentially con-troversial issue. Sawn faces were tried but were toointrusively regular, so the tiles were split instead andeven worked with masonry chisels when in place toprovide more natural-looking faces. Washes of mudfrom the mountain were applied to soften the initialappearance of the tile stacks, a task which themountain subsequently took over itself as the fewheavy annual rainstorms flooded off the plateau top.Textures and colours were very quickly in completeharmony with the appearance of the weatheredHerodian walls (Figure 10.19).

The Tholos platform

Nowhere were the soft stone walls of greater con-cern than the great circular platform which oncesupported the Tholos on the middle terrace (Figure10.20). The outer wall of the terrace still retained itsstone copings but was severely reduced in load-bearing and retaining capacity by the weatheringagencies already described. Significant losses couldhave occurred at any time, with falls of masonrydamaging the lower terrace. Although some of the

surviving stones could be repaired using the tilestack system, there were large areas where the stoneswere too seriously deteriorated even for thisapproach, and other areas where the stone facingwas missing altogether. Without fairly substantialreplacement the risk, at least, of the outer edge ofthe platform falling was clear.

A decision was finally made to replace the missingstones with cast stones. There were three reasons forthis decision: new limestone was considered to betoo aggressive visually and in terms of comparativedurability; the use of new limestone was consideredto be too close to condoning a policy of restoration;and the use of new limestone ashlars would requiretoo exact a geometry to work in with the irregular-ities of the surviving Tholos plan. ‘Stones’ were castin wood moulds based on a moderately hydraulicnatural lime (NHL3.5), sand and porous aggregate toprovide a block of adequate compressive and flexuralstrengths with good water vapour permeability.Stone sizes were taken from the tail impressions ofthe missing stones, and the bedding mortar was limeputty-based with ceramic pozzolan. To provide theessential stability for a high wall in such a precariouslocation, stainless steel dog cramps and restraint

284 Conservation of Ruins

Figure 10.19 Repair of the cavernously decayed stones of the Northern Palace was carried out using “tiles” cut from salvage, weath-ered stone bedded in pozzolanic lime mortar. Each stone was repaired individually. Joints were packed with mortar and stone in the finalstages. The split faces of the tiles blend comfortably with the rough, weathered texture of the surviving masonry and are quickly colouredby the mud washing over the mountain during rainfall. Repaired stones are always easily identifiable at a 2 metre range.

Ch10-H6429.qxd 10/14/06 3:48 PM Page 284

Case studies 285

fixings of butterfly pattern were introduced (Figure10.22). All cast block surfaces were finally plasteredin a mud-coloured lime putty plaster to match theubiquitous undercoat plasters of Masada.

Building and decorative plaster

The importance of plaster on the buildings of Masadacan hardly be overemphasised both as a building andas a decorative finish. Although now weathered andstained by 2000 years of sand abrasion and mudwashing, so many areas of plaster survive that it is notdifficult to see how Herod’s palaces on the mountainappeared from a distance to be built of marble, shiningin the sun.2

As described above, the loss of plaster fromexposed areas of stone, some of them raised on thetop of precipitous cliffs, was, and is, a serious matter,leaving poorly durable stone at the mercy of weathe-ring. But the loss of the plaster itself is to be regret-ted and therefore avoided by the use of conservativemethods wherever possible; this especially appliedto decorative, modelled work or the coloured plas-ter described in Chapter 5. The consolidation ofplaster facings has been an important part of theconservation team’s activity at Masada from thebeginning, on areas of built up rubble and as liningsto walls, cisterns, columns and stairs.

The most common conservation problem is thereattachment of areas of plaster surviving as ‘islands’on natural rock or on worked stone faces. Theproblem can be exacerbated where these ‘islands’have been given cement-based mortar frames to try tohold them in place (see Chapter 4, ‘Mortar’). One ofthe difficulties with detaching sheets of plaster is thatdebris falls between the wall face and the plaster back,creating a wedging effect, so that simply pushing theplaster back onto a wet mortar slurry is not possiblewithout causing it to fracture. Sometimes the debriscan be extracted from the detached side with a vac-uum cleaner, or some openings have to be made inand below the collection zone from the face and thedebris washed out. In other cases it is only possible tore-adhere the plaster as it is found in its distorted pro-file by flushing and slowly grouting the void, a processaccompanied by some risk and requiring temporarysupports.

Almost every condition of plaster problem can befound on site at Masada, and there had to be devel-opment of a range of techniques and approaches bythe conservation team. In addition to weatheringattrition and physical damage, the ever-present reser-voirs of soluble salts blown in from the Dead Seaaccumulated everywhere and presented great prob-lems. Even the washing out of cavities behinddetachments and grouting with lime and ceramic

Figure 10.20 Early prototype of stone tile in lime mortar with a close texture to match stones in better condition. Thin mudwashes are already blending the repair into the background.

Ch10-H6429.qxd 10/14/06 3:48 PM Page 285

powder would activate salt reservoirs and reconnectthe back of the plaster with new supplies of salt fromthe rock, in the manner of a desalinating poultice.

The composition of plaster fills, supports and groutneeded, therefore, to be designed with all these con-ditions and hazards in mind. Thus, a finished materialwith poor capillarity and good water vapour permea-bility, provided by a good pore structure, and goodmodulus of elasticity was essential. Careful control ofshrinkage (see Chapter 4) by assiduous curingprocedures was paramount to success. Without this,shrinkage would encourage micro-cracking andevaporation zones within which salt crystallisation

would be encouraged. Success was very much basedon the refinement of the conservation materials andon the building up of the conservator’s skills, whichbecame considerable. Any failures were carefullyrecorded and analysed. Conservation disciplines andunderstanding were developed over many months on the site, and could have been achieved in noshorter way.

Herod’s private bath house: the frigidarium

Insights into the character and taste of Herod arenumerous on the site of Masada, but nowhere more

286 Conservation of Ruins

Figure 10.21 Work proceeding from a suspended scaffold placing cast blocks back on the line of missing stones.

Ch10-H6429.qxd 10/14/06 3:48 PM Page 286

Case studies 287

Figure 10.22 Assemblage of cast stones with stainless steel dowels and restraint fixings. The conservators are checking the finalposition of the face line.

than in the ruins of his Northern Palace and perhaps,within the palace, nowhere more than on the lowerterrace with its private bath house. The splendourof the palace in such a remote corner which seems tohang in space cannot fail to make an impression onthe visitor, especially at those times when few othersare present.

The small bath house reached by a staircase lead-ing down from the lower terrace in its south-eastcorner was designed and constructed with someingenuity. The building literally perches on theedge of a cliff and accommodates a disrobing room,caldarium, tepidarium, frigidarium and furnaceroom, all on a small, intimate scale. In spite of dam-age and significant losses, enough evidence of eachspace survived to be able to record and reconstruct,as a paper exercise, the whole of the complex, asEhud Netzer had demonstrated.4

There was, and remains, no public access downto the bath house for reasons of visitor safety, andbecause the surfaces of floors and walls were danger-ously fragile and vulnerable to damage. The vaultedspace which may have been a disrobing roomretained a low section of its eastern wall but thenorth-east corner had fallen away. The tepidarium

retained significant amounts of plaster, both under-coats with plasterers’ handprints in evidence andfine white finishes, and fragments of its whitemosaic floor. The caldarium had bases of thehypocaust pilae still in place, a small section of its floor and a niche with white mosaic, but its eastern wall, like the eastern wall of the adjacentfurnace room, had long ago fallen into the abyssbelow.

The frigidarium was the most complete of therooms, consisting of a deep, rock-cut pool reachedby seven plastered steps and approximately half of itsvaulted roof (Figure 10.26). The water-holdingplaster was still impressive, showing the same ingenu-ity that was used in the collection gutters, cisternand pool linings elsewhere on the mountain, and onwhich the impregnability of Masada depended(Figure 10.25). Such plasters, typically, have a baseof clay packing with small stones to close up fissuresand irregularities in the rock face, undercoats oflime plaster very rich in wood ash and charcoal, and a finish of fine, white lime plaster with a very close, almost polished surface. The water-holding capacity of these plasters is remarkable and was recently (2004) applied to the repaired and

Ch10-H6429.qxd 10/14/06 3:48 PM Page 287

288 Conservation of Ruins

part-reconstructed Herodian dam above Caesareawith great success (Figure 10.27). In the frigidar-ium, water marks at various levels were still much inevidence, testimony to the efficiency of the plasterover many decades. There survived at least tworepairs neatly applied over areas where the rock pro-file presumably came too close to the surface andlikely to be contemporary with the original con-struction. Above the broken vault was a small ash-plaster lined water system with floor channels and asquare outlet which must originally have been fittedwith a wooden plug; through this outlet water

collected in the cistern could be allowed to fall intothe pool below.

In the 1990s, fresh rock falls from the mountain,perhaps exacerbated by unauthorised visitors climb-ing above the bath house, were beginning to dam-age the plaster threshold and steps; even moreseriously, the broken edge of the frigidarium vaultwas becoming increasingly fragile and further losseswere imminent (Figure 10.28). Once again, themessage of the need for continuing monitoring,maintenance and protection following archaeologic-al examination was clear to read.

Figure 10.23 Detail of cast block fixing showing stainless steel dog cramps grouted in hydraulic lime and the dovetail fixingmethod back into the core of the rock. The fill between rock and cast rocks is a weak hydraulic lime and stone aggregate.

Ch10-H6429.qxd 10/14/06 3:48 PM Page 288

Case studies 289

Figure 10.24 During the progress of the facing work the surviving original stones can be seen in the foreground. Adjacent to themare two stones which have been repaired with split tile and lime mortar. Beyond the repairs can be seen three of the cast lime blockswith a roughened texture. The consolidated Tholos wall is now a mixture of original stone faces, repaired original stones and new caststones where the facing was missing. Every part of the original face was secured and saved.

Figure 10.25 Herodian plaster lining to the artificial gutters running around the mountain to collect water and deliver it into rock-cut cisterns.

Ch10-H6429.qxd 10/14/06 3:48 PM Page 289

290 Conservation of Ruins

The bath house is first made familiar to visitorsthrough the site guide and through the audio-visualinstructions in the new visitor centre. Although thebath is located at the extremity of their tour andrequires the expenditure of some energy to bereached, there is an understandable fascination onthe part of visitors to see the place where the threebodies were found, in the bottom of the frigid-arium, with their possible link to the suicide of thezealots. The quest is frustrated, currently, by a lack

of access, which encourages trespass, but this may beovercome if plans to recreate the full floor area ofthe lower terrace are implemented; from an extendedfloor it would be possible to look down into the bathhouse and see its layout without needing to go downinto its vulnerable plaster spaces (Figure 10.29).

In the short term it became urgent to protect theplaster profiles of the frigidarium from further rockfalls and to prevent the loss of more of the brokenedge of its roof vault and consequent loss of the

Figure 10.26 The authors seen in the plastered frigidarium. The steps and the walls still retain much of the original polished plas-ter in excellent condition, still capable of holding water.

Ch10-H6429.qxd 10/14/06 3:48 PM Page 290

Case studies 291

Figure 10.27 Detail of new water-holding plaster applied by Kimi Maman to the restored Herodian dam above Caesarea. Theplaster copies that of the Roman period.

Figure 10.28 Detail of the broken and freshly damaged edge of the frigidarium vault, showing its extreme fragility.

Ch10-H6429.qxd 10/14/06 3:48 PM Page 291

292 Conservation of Ruins

cistern above. Both possibilities were of immediateconcern in 1997.

The action plan agreed by the Israel Nature andParks Authority consultant, Asi Shalom, and the UKteam was to put back the missing section of the bro-ken vault over the bath to overcome all the threats inone structurally sound, visually harmonious way.The eastwards thrust of the new section of vaultrequired a counterfort which would be provided byputting back corework on the east wall of the frigi-darium to increase its height and weight, and by rais-ing, in the same way, the height of the buttressingcross wall between the furnace and the caldarium,shown as hatched areas in Figure 10.30.

Once installed and cured, and the new coreworkraised in salvaged material and hydraulic lime(NHL2) mortar, the process of installing the missingsection of vault could proceed.

The pool space was carefully cleaned to remove allloose debris and covered with geotextile fabric andsynthetic fibre sandbags to prevent any impact dam-age to the plastered steps and walls. A scaffold frameon base boards could then be raised to provide aworking platform below the springing line of thevault. From this base point vertical measurements

were taken from the springing base line to establishthe slightly distorted intrados line of the vault. Theprofiles obtained in this way were then translatedonto 18-mm plywood formers, joined horizontallyby 75 mm � 50 mm softwood framing, braced andscrewed together to make a strong rigid base onwhich to construct the new vault. The last stage(Figure 10.32) was to screw-fix three sheets of 6-mm ply over the formers to create a rigid shell onwhich the stones would be set. The third sheet ofplywood was introduced to allow for a plaster thick-ness on the surface of the vault.

The falsework was too heavy and unwieldy to slideinto position and was obstructed anyway by the layoutof the vault entrance, and thus was finally assembledand raised within the vault space, the last positioningbeing achieved with the use of wedges (Figure 10.33).

The new voussoirs from the vault were cut fromsalvaged stone and packed in NHL2 hydraulic limemortar. The finished vault is shown in Figure 10.34.

Summary

The techniques used in the consolidation activitieswere developed by a team sharing experiences and

Figure 10.29 View from the lower terrace of the small bathhouse complex during reinstatement of the vault.

Ch10-H6429.qxd 10/14/06 3:48 PM Page 292

Case studies 293

Figure 10.30 Sections through the frigidarium.

Figure 10.31 Completed form work seen against the raised eastern wall of the frigidarium.

Ch10-H6429.qxd 10/14/06 3:49 PM Page 293

294 Conservation of Ruins

Figure 10.32 Fixing the plywood sheathing to the vault former.

Figure 10.33 Completed formwork raised up into position under the old work.

Ch10-H6429.qxd 10/14/06 3:49 PM Page 294

Case studies 295

working on site in ‘real’ conditions. Undoubtedly,the familiarity of the Israeli members of the teamwith their environment and their local materialsgained over a number of years was fundamental tosuccess, and paralleled that experienced by ColinBurns and John Ashurst with John Ludlow’s conser-vation technicians in Ireland. The combination ofthis local experience and expertise combined withsympathetic team members from ‘outside’ creates apowerful resource in which there can be no roomfor the ‘prima donna’, because the achievements arerecognisably and demonstrably collective.

A useful aspect of the conservation work on aremote site is the furtherance of an ‘appropriatetechnology’. The advance of technology has, ofcourse, benefited conservation in many ways, espe-cially in recording systems and non-invasive inves-tigative techniques, but in many locations andsituations the technology of the twenty-first centuryis neither available nor affordable. In these situationsimprovisation, ingenuity, hand and eye skills, andminds trained to think logically, analytically andsometimes innovatively are what is needed. Andalways, essentially, a knowledge of the importance

of the site, a respect for its status and unflaggingenthusiasm.

Masada became a World Heritage site in 2002, aworthy recognition of its historic significance, butalso of the great efforts of those who had protectedand cared for it through many difficult years, not leastthe indefatigable Eitan Campbell, the site’s manager.Visitors today have a greatly improved experience on10 years ago, and will see and learn even more as con-servation plans are developed. The new status in noway diminishes the need to carefully watch andmaintain the historic fabric of Herod’s and otherbuildings on the mountain, and to seek to set stand-ards for other sites and other conservators.

Notes and references

1. Stern, E. (ed.) (1992). The New Encyclopaedia ofArchaeological Excavations in the Holy Land. Simon &Schuster.

2. Bella Judaicum Josephus Flavius.3. Shalom, A. (2006). Excavation and Conservation on

Archaeological Sites. Archaeology Conservation Center,Sede Boker Academy, Negev Region, Israel.

4. Netzer, E. Masada I-II-III.

Figure 10.34 Completed vault showing the caldarium and the edge of a precipice beyond.

Ch10-H6429.qxd 10/14/06 3:49 PM Page 295

Case Study 3: Gosport RailwayTerminal, UK

Margo Teasdale

Lay down your rails, ye nations near and farYoke your full trains to Steam’s triumphant car;Link town to town; unite in iron bandsThe long estranged and oft-embattled lands …Blessings on science and her handmaid steam!They make utopia only half a dream.

(Charles Mackay, Railways, 1946)

These cathedrals of the new humanity are the meetingpoints of nations, the centre where all converges, thenucleus of the huge stars whose iron rays stretch out tothe ends of the earth.

(Theophile Gautier, in Jean Dethier, All Stations, London, 19811)

Railway heritage

The railway architecture surviving from the nine-teenth century in England and abroad stands as testi-mony to an age which believed in slow, steadyprogress towards a better future for all. The railwaystations have been aptly compared to cathedrals, sym-bolic of the new technology of the industrial revolu-tion and the steam age. The designs created for them,by the leading architects and engineers of the day,combined innovative modern techniques and revivedtraditional styles to reassure the travelling public andappease the cynics who spoke against the railway’sdestruction of the countryside. From the grandeur ofthe large British city stations like St Pancras withtheir breathtaking iron and glass train-sheds to thesmall country wayside stations, the variety of stylesand designs that emerged have become highly valuedwhere they have survived with their colonnades,canopies, iron columns, turrets and platforms. TheBuilding News of 1875 declared that:

Railway termini and hotels are to the nineteenth cen-tury what monasteries and cathedrals were to the thir-teenth. They are truly the only representative buildingswe possess.

As railway mania spread, station designers across theworld took their lead from the innovations made inthe construction of the British railway network.British architects and engineers carried their know-ledge of railway construction to North America andthrough Asia, Africa and Australia. The international

phenomenon of railway building has many links stillworthy of exploration through the individuals andthe companies involved and the designs theyemployed in station architecture and engineering.

As railway networks all over the world have beengradually, and sometimes radically, reduced by thewithdrawal of successive government support for pas-senger and freight transport, so too has their builtinfrastructure. Since the 1960s, 4000 stations wentout of use in Britain. Many have been reused butmany have been demolished, leaving gaping holes inthe landscape and many bereft over their loss. Thewave of destruction which followed the demolitionof the great portico of Euston station in 1962 causedconservationists to comment that, since its establish-ment in 1947, British Rail had acquired for itself anall too deserved reputation as the ‘biggest corporatevandal’ and iconoclast Britain has seen since the Tudordissolution of the monasteries.2 In the United Statesthe premier New York station of the PennsylvaniaCentral Railway Company was demolished. In 1975Toronto’s Union Station was threatened with demoli-tion, causing a conservation movement to unify andlobby the Ontario Legislature for stronger protectionand its successful retention.

By the mid-1980s over 600 stations were listed asBuildings of Special Architectural or HistoricInterest under the Town and Country Planning Actin England. The Act protects railway stations fromdemolition and unsympathetic alterations. As thecriteria for listing favoured the oldest stations andengineering structures, the sites selected for listingrepresented the origins of the early railway networkbuilt by the many Victorian railway companies andtheir now world-renowned architects and engineers.To celebrate and recognise this rich railway heritage,the British Railways Board commissioned Biddleand Nock to assemble the landmark illustrated guideto the listed stations and their architectural history.One of the stations included in The Railway Heritageof Britain was the Gosport Railway Station, listed in1975, and built by the London and South WesternRailway.3 As one of the first generation of classicalstation designs, it was among Sir William Tite’s bestworks, surviving now as a roofless, railway ruin witha social history worthy of celebration in its own rightand testimony to the community that cherishes it.Gosport Railway terminal is, in many ways, the storyof Gosport; architecturally, the ruin is a reminder ofits one-time status and clientele.

Gosport peninsula is strategically located on thesouth central coast of England across the water fromthe historic dockyard at Portsmouth, on the Solent

296 Conservation of Ruins

Ch10-H6429.qxd 10/14/06 3:49 PM Page 296

Case studies 297

waterway. With Portsmouth it became the centre forelaborate defensive fortifications, built mainly fromthe seventeenth century. The construction of theRoyal Naval Hospital at Haslar was completed by1762. By the end of the eighteenth century Gosportwas a strongly walled naval town. In 1828 the wholeVictually Department for the Navy was transferred tothe north-east of the town while the gunpowder andarmaments depot developed to the north at Priddy’sHard. The town grew around the select resort andplace of residence of naval officers at Alverstoke.

Proposals for a railway to link London withSouthampton were confirmed by an Act of Parlia-ment by 1834. The decision to locate the railwayterminal at Gosport was partly as a result of difficul-ties in gaining local support and reluctance tobreach the fortifications at Portsmouth. Gosport’sramparts were close to the town centre and the sit-ing of Royal Clarence Yard made the locating of arailway terminal there convenient for the town andthe Admiralty. Once the links with Portsmouth weresecured with approval for a floating bridge link toPortsmouth in 1838, the London and SouthamptonRailway (LSR) secured the site for the terminalopposite the gates where the main turnpike roadentered the town through the fortifications. At thesame time, the LSR became the London and SouthWestern Railway (LSWR). The first branch railwayin Hampshire from Bishopstoke (later called Eastleigh)to Gosport was opened up in 1841. Gosport thenbecame a destination, along with Bournemouth, theIsle of Wight, Devon and north Cornwall, on the‘holiday line’. The line developed as a year-roundservice to the south coast, and became known for itsassociations with Queen Victoria at Windsor, EtonRiverside and Gosport, and with troop movementsduring both World Wars. The South Western was alsorenowned for technical innovations in locomotivedesign and the use of automatic signalling with sema-phore arms activated by low-pressure compressed air.3

Station plans

The architect, engineers and builders of the LSWRwere some of the best-known names of the period.Sir William Tite was a prolific Victorian architect,best known for the rebuilding of the Royal Exchangein London, which was well under way by the timeGosport was designed. Tite’s reputation as a stationdesigner was established, as one of his best railwaytermini had been constructed at Southampton by1840. Thomas Brassey, well known for associationswith Sir Morton Peto and Edward Betts, who built

the early Grand Trunk Railway in Canada, was con-tracted to oversee the construction of the line.Brassey subconstracted the building of the station tothe local builder David Nicolson. The station wasbuilt at a cost of £10 980, compared to the £1250spent on other stations at Fareham and Botley.4 Allthe skills and experience of the architect and thecontractors would be needed to meet the stringentrequirements of the Board of Ordnance who, byrights granted in the enabling Act of 1839, had con-trol over the siting, height and architectural form ofthe station to ensure that effective use of the fortifi-cations near the station was preserved. Unusually fora station, the intent of the Board of Ordnance was tohave it constructed as a defensible site that could beused by the Royal Engineers, if the need arose, toprotect the Gosport Lines.5

Tite’s drawings for the Gosport terminal submit-ted to the Board of Ordnance in 1840, for approval,were in the neoclassical style, showing a 14-bayTuscan and Doric colonnade, in Portland stone, ter-minating in large pavilions with rusticated archedopenings and parapets with miniature segmentalpediments. The designs had to be modified for theOrdnance by removing the upper floor to make asingle storey to provide an open line of fire, by erect-ing costly iron railings on brick bases on the eleva-tion facing the ramparts, and extra high parapets,broad gutters and a lead flat roof over the colonnadefor the use of troops on all four sides of the building.Fortunately, the elegance of Tite’s designs was notaltered to any degree that reduced the grand archi-tectural impact the building would make when itwas built. The station followed a linear plan com-mon to the first generation purpose-built railways,aligned along the departure and goods platformswith access controlled to departures through thebooking hall and waiting room. The original roof ofthe station was impressive, with heavy oak trussesspanning the track bed over both the goods and pas-senger platforms. The long, hipped roof frame wasfinished in slate and a rooflight the length of theridge provided an elegant roofline (Figure 10.35). A flat lead roof covered the colonnade.

Other influences on station plans and additionalproblems for the Board of Ordnance were createdwhen Prince Albert asked the Garrison Commanderto build a private station for the royal family withinthe secure site of Royal Clarence Yard. The royalfamily needed to travel in private for fleet reviewsand to board their yacht to Osborne House on theIsle of Wight. The construction of the Royal VictoriaStation was agreed and the railway line from Gosport

Ch10-H6429.qxd 10/14/06 3:49 PM Page 297

terminal was extended 600 feet through a new bricktunnel cut through the brick and clay defensive ram-parts. The long history of Queen Victoria’s arrivalsand departures from Gosport ended with her death atOsborne House in 1901, when she was brought toRoyal Clarence Yard to begin her last journey toLondon’s Waterloo Station.

The station plan was designed to accommodate thepassenger platform on the south side and the goodsplatform on the north side under one large roof span.Provision for separate departure and arrival platformswas never made. A separate goods shed was built tothe west of the goods platform that could house up to 10 wagons. Three tracks ran into the station from the west with a pair of turntables at each end formanoeuvring the trains for their return journey. Astationmaster’s house stood at the east end of the sta-tion and gardens were laid out to the south-west. Thestation yard developed to the north with shuntingroads built to move coal, a two-road engine shed,weighbridge, signal box, cattle dock and horse sta-bles.6 The station yard would have been a riot ofsounds, smells and activities as parcels, supplies of coal,fish, goods and Devon cattle for the navy arrived.

Adapting the station to meet technical, social andeconomic changes began very early after it was con-structed and continued through the decades it wasoperational. The story of the conditions and eventsthat underline the station’s history has been toldwith much enthusiasm by local and railway histor-ians, supported by a rich archive of old photographs,plans and maps. Soon after beginning operations,the openings for the trains had to be modified usingcast iron columns where they met the platforms, asthey were too close to the rail carriages.

World War II and the closure of operations

An important event occurred a century after itsopening on the night of 10 March 1941, which wasto have a dramatic impact on the station and markthe beginning of its demise. During one of the manyair raids on Portsmouth during World War II, anincendiary bomb lodged in the station roof and setthe timber framing on fire. Local accounts tell ofbrave acts to remove the loaded wagons in the yardand frightened horses from the stables, but there wasno ladder long enough to reach the roof.7 The fire

298 Conservation of Ruins

Figure 10.35 Sir William Tite’s Gosport Railway Terminal.

Ch10-H6429.qxd 10/14/06 3:49 PM Page 298

destroyed the offices and booking hall in the termin-al, and business had to be conducted from build-ings constructed at the west end of the passengerplatform. A metal Hillspan roof was erected, leavingthe passenger platform exposed to the weather(Figure 10.36).

After the war the strategic importance of the stationfor naval supplies and the movement of troops andhospital trains to Haslar declined. Passengers travellingto London preferred to leave from Portsmouth orused local trams and buses. Freight service continueduntil 1969 as the short-sighted Beeching Plan tookeffect in cutting all unessential rail traffic. The trackwas quickly removed, along with the steel-framedroof and all movable equipment. Within a shortperiod of time the station took on the appearance of a ruin. The vegetation that quickly took over thesite grew over the elegant colonnade and gave it aPiranesian character when it was photographed forthe National Railway Museum archive (Figure 10.37).

Recognition and conservation

By 1974 Hampshire County and Gosport BoroughCouncils, with admirable foresight, had acquiredthe old railway track bed and the station ruins in abold decision at a time when the qualities of indus-trial buildings and archaeological sites were not fullyappreciated (Figure 10.38). Industrial sites were stillassociated with the often harsh conditions of theworkers and only recently had industrial sites beenconsidered important to save for a more balancedunderstanding of the past. Aside from some textilemills in the north and remnants of Cornish tin min-ing, few eighteenth or nineteenth century industrialbuildings have survived the bombings of World WarII, and the clearances and redevelopments that fol-lowed in England, as ruined structures. The reuse ofindustrial buildings is now common practice andsocially desirable, as the work of SAVE Britain’sHeritage has so aptly illustrated.

Case studies 299

Figure 10.36 Hillspan roof installed after the original timber roof was destroyed by enemy action in 1941.

Ch10-H6429.qxd 10/14/06 3:49 PM Page 299

300 Conservation of Ruins

In 1975 Gosport terminal was listed as a buildingof Special Historic Architectural or Historic Interestand protected from demolition in English law. TheCounty Architect of Hampshire County Councilstated at the time that ‘wholesale renovation on thescale which would be required could hardly bedefended as conservation and the more satisfactorysolution might be to preserve the ruins as they stoodin an area of carefully designed landscaping’.8 Plansto remove charred timber, demolish dilapidatedsheds, consolidate and protect the brick wall tops,

retain stucco, stabilise chimneys, repair decayingboundary walls, clean and treat rusting iron, andremove vegetation were carried out over the nextfew decades. The Gosport Railway Society demon-strated their avid support by volunteering with siteclean-up, vegetation removal, and giving toursbefore health and safety requirements made visitsdifficult. In 1995 the iron railings to the stationentrance were repaired and sections reproduced,where they had crossed the track bed (Figures10.39–10.41). The elegant detail of the Victorian

Figure 10.37 Post Beeching Plan dereliction: the Terminal as a ruin.

Ch10-H6429.qxd 10/14/06 3:49 PM Page 300

Case studies 301

Figure 10.38 First sign of recognition of significance; acquisition of the Terminal ruins and track beds by Hampshire County andGosport Borough Councils.

Figure 10.39 Cement stucco used to replicate rusticatedmasonry is particularly vulnerable to the ruined condition of thebuilding and needs careful maintenance.

Figure 10.40 The tuscan order was used by Sir WilliamTite for the entrance colonnade, worked in portland stone, withscholarly detailing.

Ch10-H6429.qxd 10/14/06 3:49 PM Page 301

302 Conservation of Ruins

postal box, which is protected by listing and standsoutside the iron railings, was restored after 23 coatsof paint were removed (Figure 10.42). By this timethe goods yards had been sold and redeveloped forhousing.

Several proposals for reusing the station were madeand even included a scheme for indoor bowling, butnone were successful (Figures 10.43 and 10.44).Surprisingly late, an assessment of the historic value ofthe station was commissioned for the first time in2003, to use site history to interpret the extant fabricof the structures. The report concluded that, collec-tively, all the remaining structural elements of the sitewere of national significance and that more recordingand archaeological investigations of the station gardenswere needed (Figures 10.42–10.44). A companionecological survey was also commissioned and badgersets were discovered in the stationmaster’s garden areaof the site, which was to be given due consideration inany development proposals (see Chapter 6).

A ‘new life for Gosport Railway Station’9

Gosport Terminal has been recognised and saved as a ruin by national legislation, by the foresight and

intervention of the county at a crucial time inresponse to local planning, and by considerable com-munity interest and pressure. To date, the stationenvironment has been successfully safeguardedthrough planning initiatives respecting the need toincorporate the site and any development proposalsfor it within the grain of the St George’s BarracksConservation Area (Figure 10.45).

The future development of the Gosport Terminalsite is again in question, as it is now on the propertymarket with a development brief agreed by theowners and English Heritage which encourages acreative reuse scheme and some adjacent develop-ment, respectful of the historic significance of thesite (Figure 10.44). With plans to develop the pro-posed South Hampshire Rapid Transit tram systemturned down by the Labour government, it appearsthe former railway lines in the Gosport peninsulawill not be reused in any way to alleviate the trafficcongestion in the area. Given local interest in thestation, there is considerable scope for presentingand interpreting the history of the site. Significantly,the interpretation is generally considered by someto be best carried out through the retention of theterminal as a ruin, its aura of authenticity remaining

Figure 10.41 The quality and elegance of the Terminal buildings are a hallmark of the work of classical school architect SirWilliam Tite (1798-1873) and an important factor in the recognition of their significance.

Ch10-H6429.qxd 10/14/06 3:49 PM Page 302

Case studies 303

Figure 10.42 Restored railings and post box 1995.

Figure 10.43 The track bed space stimulated several proposals for re-roofing the Terminal for new uses.

Ch10-H6429.qxd 10/14/06 3:49 PM Page 303

304 Conservation of Ruins

Figure 10.44 Consideration of development briefs 2005. A proposal for adaptive re-use, including re-creation of elements of SirWilliam Tite’s design. Proposals to retain the Terminal as a ruin have considerable local support.

Figure 10.45 The new 170 metre high Spinnaker Tower commemorating the area’s great naval traditions, seen from the ruin ofthe Gosport Terminal, commemorating the importance of the railway era.

Ch10-H6429.qxd 10/14/06 3:49 PM Page 304

Case studies 305

undiluted by adaptive reuse and its story ready to betold. Clearly, however, there is also considerablescope for reusing and restoring the exterior of thebooking hall, at least in part, for community use bya suitable investor with an interest in and commit-ment to historic preservation.

The future looks promising as the station is in anarea experiencing much regeneration. The historicnaval docklands at Portsmouth used to stage the200th anniversary of the British victory at the Battleof Trafalgar, in 2005, and Royal Clarence Yard arebeing restored and redeveloped with private andpublic sector investments. The new 170-metre-high Spinnaker Tower overlooks the historic navalports of Portsmouth and Gosport, and commemor-ates the great naval traditions of the area in its design (Figure 10.48). Similarly, as long as the com-munity continues to value its elegant railway ruin,Gosport Terminal will be a reminder of and amemorial to the romance of its industrial, royal andmilitary past.

Notes and references

1. Excerpts from Richards, J. and MacKenzie, J. M.(1986). The Railway Station: A Social History, pp. 3and 17. Oxford University Press, Oxford.

2. Binney, M. and Pearce, D. (1986). Quoted in TheRailway Station: A Social History, p. 36.

3. Biddle, G. and Nock, O. S. (1983). The RailwayHeritage of Britain: 150 Years of Railway Architectureand Engineering, p. 203. Michael Joseph.

4. Oppitz, L. (2003). Lost Railways of Hampshire, p. 86.Countryside Books, Newbury, Berkshire.

5. Eley, P. The Battle of Gosport Railway Station1840 –1841; www.discoverycentres.co.uk.

6. Keat, P. (1996). You are not putting a hole in mywall. Gosport Railway Society, p. 19.

7. Keat, P. (1996). You are not putting a hole in mywall. Gosport Railway Society, p. 24.

8. Hampshire County Council (1974). Report onListed Buildings Owned by Hampshire CountyCouncil.

9. Taylor, A. (2005). Promise of New Life for GosportRailway Station; www.hants.gov.uk, 9 November.

Ch10-H6429.qxd 10/14/06 3:49 PM Page 305

Quarry at Thassos. The voracious Roman hunger for marble to adorn their cities of travertine, tufa, tuff and brick resulted in a greatexpansion of quarrying throughout the empire. Tasio marble, Marmor thasium, from the island of Thassos in the northern Aegeanmay be found in the Pantheon, the Forum of Nerva and the pyramid of Cestius. The almost blue–white marble is seen here sparklingin the sun, the old quarry workings plainly visible, the quarry floor now partly submerged beneath the sea. Here was the birthplace ofnumerous ancient buildings, some surviving, some now ruins, others returned to the land or the water. The quarry itself is now a ruinof spectacular beauty, a site to be preserved, a memorial to industry, to commerce, and to men and women who wanted to live in build-ings fit for Gods.

Epilogue-H6429.qxd 10/17/06 2:31 PM Page 306

The planning process in essence is about bringing the rightpeople and organisations together with the correct infor-mation. Identifying the individuals and organisations toparticipate in the process is, therefore, critical to success inmaking good decisions about a site.

( Jeanne Marie Teutonico and GaetanoPalumbo, Management Planning for ArchaeologicalSites, GCI, Los Angeles, 2000 – Proceedingsof an international workshop, Corinth, Greece,May 2000)

This book has identified a wide range of threats tohistoric ruins and their sites, and has discussed andillustrated ways in which these risks can be confrontedand reduced by properly informed survey, recording,protection, conservation and presentation.

There is, however, an additional threat to the qual-ity of survival which is implied by Gaetano Palumboin the extract above, from the Corinth Workshop.The planning and management processes must be theresponsibility of the ‘right people’. Who, then, are the‘wrong people’?

On the historic site the ‘wrong’ man or woman cansoon be identified by their lack of genuine interest andrespect for the skills and experience of their col-leagues. At more senior management levels within aheritage protection organisation, and even more atnational, political levels, the identification becomesmore difficult. Of course, the manager or politicianneeds a more diverse range of skills and abilities andhas more complex responsibilities than the site con-servator. But if they have nothing of the interest andcommitment of a good conservator to the heritage

site they will almost certainly be dangerous for it.More seriously, they may be dangerous for many sites and perhaps to the future of their country’s heritage.

National policies are telling. For instance, morethan one country has created a government depart-ment whose responsibilities include interests as diverseas culture and sport. There is something disturbinglymiscellaneous about grouping heritage, the arts andsport together as a leisure industry, and when budgetrestrictions begin, as they always do, heritage is thefirst to suffer.

Perhaps there is little that can be said here aboutthe politicians, except to ask that they expect and getthe best from their senior civil servants, and that theyin turn listen to their directors. But the directors andtheir managers with heritage responsibilities must beknowledgeable and enthusiastic about their charges,and in some way be able to demonstrate their fitnessand competence for the post. Managers who find itexpedient to pay lip service to the heritage but can-not demonstrate a personal interest and a will to pro-tect their sites and their specialist staff are as easy toidentify as poor site conservators, although they aremore difficult to move.

When charters have been drawn up, policies for-mulated and budgets agreed, ruins and their sites arein the hands of individuals who may be using pub-lic funds. The right people are those who know thevalue of their sites and the privilege of their posi-tion, and are prepared to take their custodial dutiesseriously. Without them, the heritage of ruins,amongst other historic buildings and sites, will pay.

307

Epilogue

John Ashurst

Epilogue-H6429.qxd 10/17/06 2:31 PM Page 307

This page intentionally left blank

Appendix 1

Materials and techniques

John Ashurst and Colin Burns

(These figures first appeared in Mortars, Plasters and Renders in Conservation, Ashurst, John, EcclesiasticalArchitects and Surveyor Association, 2003)

1.1 • Traditional lime production; the processing of limestone, marble, coral or shell to produce non-hydraulic lime, usually as lime putty.

• Traditional lime production; the processing of limestone with clay ‘impurities’ to produce hydrauliclime, usually as a powder (but see text of Chapter 4).

1.2 Lime mortar and plaster in ruin sites; problems related to carbonation and solubility.

1.3 Tools for joint and core treatment; cutting out, pointing, clearing out and deep tamping.Techniques for cutting out, filling and finishing joints (see descriptions in Chapter 4).

309

App 1-H6429.qxd 10/17/06 4:49 PM Page 309

310 Conservation of Ruins

1.1 Traditional lime production

Lime cycle: Non hydraulic lime

App 1-H6429.qxd 10/17/06 4:49 PM Page 310

Appendix 1 311

Lime cycle: Hydraulic lime

App 1-H6429.qxd 10/17/06 4:49 PM Page 311

312 Conservation of Ruins

1.2 Lime mortar and plaster in ruin sites

Most frequent observations by the early custodiansof those ruin buildings thought to be worthy ofpreservation focused on the damage caused by inva-sive woody plants such as ivy (see Chapters 4 and 6)and the problems of mortar, especially of coreexposed on wall heads and broken wall ends. Early20th century specifications almost invariably sawPortland cement as a key component in capping bro-ken walls to enable them to resist rain and frost andin grouts to fill voids in wall core. The specifiers wereconcerned at the evidence they saw of old mortarsoftening and spalling and washing out of wall cores,and needed to find an answer. Unfortunately,although several good hydraulic limes were availableto them, and although they recognised the need toavoid the use of cement in pointing ancient masonry,they chose cement mortar, or cement gauged limemortar, as the answer (see Chapter 4).

Part of the problem was the saturated condition ofmany of the walls being consolidated for the first time,and the time it took for lime mortar, even their bluelias hydraulic lime mortar, to develop strength in suchconditions. The problem remains familiar today andrelates primarily to the issue of carbonation. Thelower the hydraulicity of the lime used, the more crit-ical the carbonation process becomes and the morevulnerable will the ruin be to weathering agencies.Carbonation describes the conversion of calciumhydroxide (slaked lime) to calcium carbonate. Bothun-carbonated lime and carbonated lime in the formof calcite are soluble in water, calcite more sparinglyso. The solubility of these materials in water increaseswith low temperatures, so that ruins in cold, wet envi-ronments are particularly susceptible; it does not nec-essarily follow that mortars in ruinous structures inhot, dry climates are immune from the problem, espe-cially when clay and gypsum mortars are concerned.

Examples of binder solubility problems inruins (see Chapter 4)

● Some of the binder is dissolved from core mortarexposed on broken wall heads and ends, reducingthe ability of the mortar to resist cycles of wet-ting-drying, freeze-thaw, and salt crystallisation.

● Water penetrating the core forms channels andvoids within the wall allowing water entry andretention and creating instability, especially if thecore is of poor quality.

● Water penetrating the interface between the tailends of facings and core weakens the mortar andreduces the ability of a composite wall to performas an integral whole. Facings may detach and fall.

● As part of the above processes some of the dis-solved binder migrates into the pores of the stonesand onto wall surfaces where it is re-deposited in the form of hard, calcite skins. In the case of sandstone facings, this process can play a part inencouraging decay, manifesting itself in the formof dramatically rounded arisses with flaking, pow-dery stone surfaces.

● Washing out of joints at wall bases due to down-ward migration of water in the core and/or tosplash zones, causes the wall to lean and distort(see Chapter 2).

● Newly excavated masonry in sound conditioncan begin to deteriorate rapidly as mortar fromwhich the binder has been leached begins to dryout and is subject to migration and crystallisationof soluble salts and to washing.

● Unprotected plaster detaches and crumbles aswater gains access to the wall interface, softeningthe body of the plaster, washing out some of thebinder and causing it to fall.

Obstacles to carbonation of lime mortarsand plasters (of particular significance toremedial works on ruins)

For carbonation to take place, air and water need tobe present. In the absence of air contact, for instance,calcium hydroxide in the form of lime putty willremain soft indefinitely, as is well known. But air con-tact may be denied, or at least significantly reduced, inother ways, as follows:

● Successful, rapid carbonation of the surface ofmortar joints at wall faces may severely inhibitprogressive carbonation of mortar deep in thewall core behind, especially if the masonry con-sists of dense, rather impermeable stones and themortar aggregate is of similar material.

● Walls which have been saturated for long periods oftime, or even wall heads which have been exposedto a long, wet summer may so severely delay thecarbonation of new mortar used in the consolida-tion of wall heads or joints that it is easily destroyedby frost and/or heavy rain as winter advances.

● Voided, composite walls which have been exten-sively irrigated and grouted may severely delaythe carbonation of new jointing material or plas-ter applied to the wall surfaces, so that they failduring the first winter’s exposure.

App 1-H6429.qxd 10/17/06 4:49 PM Page 312

● Insufficient water will also seriously inhibit thecarbonation of new mortar and plaster. This sit-uation most commonly arises through rapid lossof water to dry masonry (inadequate pre-wetting),or as the result of exposure to strong, dryingwinds or sun, or simply because a rather dry mixwith a low water:lime ratio has been used.

Response to carbonation and solubilityproblems

The use of natural hydraulic limes is advocated for anumber of reasons (see Chapter 4) including the

reduction of reliance on carbonation alone to pro-vide the necessary resistance to wet weather and wetground conditions. But there is “free” or “avail-able” lime even in hydraulic lime-based mortars andplasters which needs to carbonate significantly, or itremains susceptible to water. The use of porousaggregates, of pozzolans and of careful water man-agement in preparation and curing stages are imper-ative to ensure the good long term performance ofmortar and plaster in vulnerable ruin contexts (seedescriptions of mortar mixes in Chapter 4).

Appendix 1 313

App 1-H6429.qxd 10/17/06 4:49 PM Page 313

1.3 Tools for joint and core treatment

314 Conservation of Ruins

Tools for joints

App 1-H6429.qxd 10/17/06 4:49 PM Page 314

Appendix 1 315

Tools for joints

App 1-H6429.qxd 10/17/06 4:49 PM Page 315

316 Conservation of Ruins

Joint techniques: cutting out

App 1-H6429.qxd 10/17/06 4:49 PM Page 316

Appendix 1 317

Joint techniques: filling

App 1-H6429.qxd 10/17/06 4:49 PM Page 317

318 Conservation of Ruins

Joint techniques: finishing

App 1-H6429.qxd 10/17/06 4:50 PM Page 318

319

Appendix 2

Structural interventions

John Ashurst and Colin Burns

Jon Avent

2.1 The use of temporary supports to hold a leaning wall in position before consolidation,Mourneabbey, Ireland. Consolidation of these walls is illustrated in Chapter 4.

2.2a A proposal to raise corework on the line of a missing wall to provide a permanent reinforced 2.2b hydraulic lime-based concrete buttress.

2.3 Overhanging masonry, typical of some broken walls and often at high level, sometimes requires theintroduction of cantilever restraint bars. Where possible, corework is corbelled out beneath the over-hang to provide optional or additional support, but its character must be carefully matched to ‘nat-ural’ exposures of core.

2.4 Re-alignment of leaning wall at Cymer Abbey.

App 2-H6429.qxd 10/17/06 4:50 PM Page 319

2.1 Temporary supports

App 2-H6429.qxd 10/17/06 4:50 PM Page 320

App 2-H6429.qxd 10/17/06 4:50 PM Page 321

2.2a Permanent supports

App 2-H6429.qxd 10/17/06 4:50 PM Page 322

2.2b

App 2-H6429.qxd 10/17/06 4:50 PM Page 323

324 Conservation of Ruins

2.3 Cantilever support

App 2-H6429.qxd 10/17/06 4:50 PM Page 324

2.4 Re-alignment of leaning wall (Cymer Abbey, Wales)

Jon Avent, BSc Ceng MI Struct E of MannWilliams, Civil Structural Engineers was asked byCADW, the Heritage Organisation of Wales, toinvestigate the history and ongoing movement to anarcade wall in the ruin of Cymer Abbey, Dolgellau.

His report and conclusions, reproduced here bykind permission of CADW, led to the implementa-tion of the recommendation to jack the leaning wallback into a near vertical alignment. This work wassuccessfully completed in 2005. Stitching of the wallwas carried out with Cintec anchors. The assistanceof John Brooks of Cintec in identifying this projectis gratefully acknowledged.

Appendix 2 325

App 2-H6429.qxd 10/17/06 4:50 PM Page 325

326 Conservation of Ruins

Cymer Abbey, Dolgellau (structural report), reproduced with permission

App 2-H6429.qxd 10/17/06 4:50 PM Page 326

Appendix 2 327

App 2-H6429.qxd 10/17/06 4:50 PM Page 327

328 Conservation of Ruins

App 2-H6429.qxd 10/17/06 4:50 PM Page 328

Appendix 2 329

App 2-H6429.qxd 10/17/06 4:50 PM Page 329

330 Conservation of Ruins

App 2-H6429.qxd 10/17/06 4:50 PM Page 330

The selection of personnel with good potential as ‘conser-vation technicians’ to work on historic sites with ruinedbuildings where no specific craft skills training is necessar-ily required is difficult in the extreme, and requires goodinsight and extensive site experience on the part of theinterviewer. The successful conservation team developedand trained by Cork County Council in Ireland was askedwhat guidelines they would give on selecting new trainees.

Tadg Buckley, Foreman of the Cork team, provided thefollowing answers to John Ashurst:

Q: What indications might be discerned, from the appli-cation, of the suitability of the candidate?

A: Pre-interview, dissect beefed-up CVs, study the smallprint, look for continuity in the person through theirwork record and/or their involvement in sport, etc.,hobbies. In particular, the mature candidate will haveshown initiative.

Q: What indicators of suitability might you pick up atinterview?

A: At interview, look to the person who can be passionateabout their particular hobby or previous work experi-ence. If asked correctly they will be only too willing toelaborate. Worthy of note: any person who gives oftheir time voluntarily to organisations, etc. Look forenthusiasm, openness, awareness of the natural environ-ment, attitude – respect or lack of it for same. Look forperception of honesty and possible sense of values.

Beware of other agendas, like ‘I cannot wait tobuild stone walls’, test their reaction with ‘you maybe unlikely to benefit from promotion due to smallstaffing numbers’. Note their attitude towards author-ity, their acceptance of it.

Would you yourself be comfortable working inclose proximity with this person or would you feelhim best suited to your nasty neighbour. Beware ofthe overbearing person, he will always be that way.

Q: What probationary period would you consider suitablefor a new candidate you believe to show promise?

A: The probationary period could be 12 months or lessif proper cultivation of the new employee is correctlyapplied. Philosophy and conservation ethos and best

practice are clearly identified – enthusiasm, or lack ofit, will soon be apparent to all. Beware of detractors ofthis philosophy challenging accepted conservationbest-practice guidelines rather than questioning with aview to learning.

Q: How suitable is the ‘loner’ for this kind of activity?A: By its very nature the job dictates the ‘loner’ aspects.

Each of us has our comfort zone within the team’senvirons and can develop on our own with firmtutoring and observation. The obvious loner will failat interview.

Q: What signs will you look for in the probationaryperiod that the candidate is going to succeed or, alter-natively, is having difficulties?

A: If symptoms of dissent appear and interest is waningon the team, then management have messed up. Ifyour own team has a clear agenda, uncomplicatedplanning, proper coordination of all site business, andthe knowledge that they and their work is of hugeimportance, then there is no place for the idle mind.

Observe the little things they manifest and/or keep atight rein on the philosophical direction at all times, yetallow natural talent and enthusiasm to express itself, toharness that enthusiasm and steer it in the right direc-tion. Show openness to new thinking and new ideas.Embrace consensus yet hold the reins. Impart a sense ofvalues and importance. Understand that we are purelycustodians of what we are charged with, we are trav-ellers in time. Lack of knowledge can never be a fault –encourage the unsure and build confidence. Clarifyalways the understood philosophy, read the reaction toit, build on the weaknesses, look for and promote agood work ethic; this may have to be constantly fol-lowed through with some individuals otherwise stan-dards will fall and conservation will suffer.

Postscript

The above comments, interpretations and assessments weregarnered from non-academic, non-professional sources –just the experiences and observations from the school of life.

331

Appendix 3

Implementation of work – personnel selection

Tadg Buckley

App 3-H6429.qxd 10/17/06 4:51 PM Page 331

Figure A4.1 The Alamo: 1836 and 2006.

App 4-H6429.qxd 10/17/06 2:31 PM Page 332

I was introduced to the Alamo as an interesting studyfor this book by the conservator/restorer RachelSabino-Gunaratna, practising in the UK but herselfa Texan, born in Spain. Through her kind directionand that of her uncle, the architect Charles John ofSan Antonio, I made contact with Elaine Parker ofthe Daughters of the Republic of Texas (DRT) andDr Bruce Winders, historian and curator at the Alamo.

The focus of interest lay in the internationalrecognition of the Alamo through books and films(especially the latter), and the image of a desert mission-cum-fortress garrisoned by a small group ofTexans in 1836 against the army of General AntonioLopez de Santa Anna. The fall of the fort after a 13-day siege and the death of such well-known figures as James Bowie, David Crockett and WilliamB. Travis are implanted in every movie-goer’s mind,as must be the Texan army’s battle-cry of ‘Rememberthe Alamo!’ at the battle of San Jacinto some sevenweeks later.

But how does this imagery survive a visit to theAlamo site today, located now in downtown SanAntonio amongst the noise and bustle of a moderncity? More than 2.5 million visitors each year come to see the ‘old mission’. How does ‘authenticity’ comeinto the experience, and can anything ‘real’ survive?These and other questions relating to the visitorexperience were very courteously answered by Dr Winders as follows.

Q: What is the importance and significance of theAlamo site to the state, the nation and inter-nationally? What survives from the principalperiod of significance? Who is responsible for thecare, preservation and presentation of the site,and since when? Who are the ‘stakeholders’?Who makes the policy?

A: The Alamo is recognized as a symbol of the continual fight for freedom. Although there are other interpretations of the Alamo’smeaning, the courageous stand against over-whelming odds places the 1836 battle in a con-text that visitors worldwide understand and appreciate.

The Alamo began its existence as Mission SanAntonio de Valero. Construction on the missioncompound commenced in 1724 and continueduntil Spanish officials secularised the site in 1793.Only two buildings remain from the original mis-sion compound, the church and the old conventoor Long Barrack.

The State of Texas owns the Alamo. However,in 1905, the Legislature granted the Daughters ofthe Republic of Texas guardianship of the sitewith two stipulations: (1) that the site be main-tained as a ‘sacred memorial to the men whoimmolated themselves upon that hallowedground’ and (2) that they accept financial respon-sibility for the site without any monetary assis-tance from the state.

The stakeholders are the State of Texas, theDaughters of the Republic of Texas, and thepublic.

Policy for the Alamo is set by the Daughters ofthe Republic of Texas, through a DRT adminis-trative group called the Alamo Committee, whoreport to the DRT’s board of management. TheDRT, however, employs a professional staff thatconducts programming and the day-to-dayoperations of the site.

Q: What is it that attracts visitors to the Alamo?What do they come to see, experience, learn?Do many of them know?

333

Appendix 4

Visitors Perceptions (The Alamo, San Antonio, Texas)

Bruce Winders

App 4-H6429.qxd 10/17/06 2:31 PM Page 333

334 Conservation of Ruins

A: Alamo visitors can be divided into two basicgroups: the curious and the reverent. The Alamo’sprominent location in downtown San Antoniomakes it easy for visitors to reach. These arepeople usually who have heard of the Alamo andtake the opportunity to see what is here. Thereverent are people to whom the Alamo is animportant event in their lives (historical, popularculture or both) and come here much as pilgrimsdo to other shrines.

Visitors expect to have a meaningful experi-ence when they come to the Alamo. For some,it is to learn why it is important to ‘Rememberthe Alamo!’ For others, it is just enough to beon the actual site of the epic battle.

Many visitors have either no idea what hap-pened at the Alamo or ideas that were shaped bymovies and other forms of popular culture. Ourphilosophy is that commemoration cannot takeplace without education. To that end, weattempt to present a meaningful and current his-torical interpretation of the Texas Revolutionand the Battle of the Alamo.

Q: What value is placed by visitors on authenticity ofthe site and its setting? Does it matter what isoriginal, what is restored, what is reconstructed,what is speculative? Are differences betweenthese categories made clear? How much does itmatter?

A: Visitors hope to find the Alamo much as it was in1836, an image reinforced by movies. Many areconfused and disappointed to find it in an urbansetting. An important part of our interpretation isto explain why that expectation cannot be met.Once visitors learn about the historic evolutionof the site, though, they express a deeper appreci-ation for having an expanded vision of theAlamo.

Q: How important to visitor numbers are the visi-tor facilities? Not just car parking, restaurantsand washrooms, but interpretative displays, off-site reconstructions and models, bookshops andeducational facilities?

A: These are very important to the visitors becauseso much about the site has changed since 1836. It is an important way for visitors to make themental adjustment between what they want orexpect to find and what is actually here.

Q: How important is the siting and design of newvisitor facility buildings and services perceived

to be? Who controls planning and developmentof the historic site?

A: A new visitor centre would be helpful but it isnot especially practical. One reason is that theAlamo does not charge admission and thereforedoes not have one central location throughwhich the public enters. Thus, a visitor centrewould not serve the traditional purpose of orient-ing visitors before they actually visit the site. Amajor obstacle is the fact the church building(which to many people is the Alamo) faces a plazathat is owned by the City of San Antonio.Although the plaza is the logical place for a visitorcentre, one will never be built there.

Planning and development for the Alamo isdone by the Daughters of the Republic of Texasin consultation with the Texas HistoricalAssociation.

Q: At what stage is the economic benefit of largevisitor numbers seen to be outweighed by phys-ical damage to the site, or even by loss of ‘qual-ity of experience’. What mitigating measures canbe or have been taken to protect the site fromthe adverse effects of too many visitors?

A: Nearly three million visitors come to the Alamoeach year. On one hand, such a large visitorshipis needed as more than 90 per cent of the site’soperating budget is raised through gift shopsales. However, on high traffic days, it is easy toconclude that the large crowds negatively affectthe experience of visiting the Alamo.Unobtrusive barriers (stanchions and chains) areused to discourage direct contact with sensitivesurfaces such as historic walls.

I also asked Rachel Sabino-Gunaratna who hasknown the Alamo site over many years and who isalso familiar with much of the context of this bookto provide her comments on the visitor experience.

The urban backdrop, together with the numerousamendments and modifications to the immediatesetting of the Alamo, is indeed a far cry from the siteof the 1830s (Figure A4.2). Only a committed visi-tor, with a great deal of reliance on available mapsand models, would be able to discern original fabricfrom subsequent interventions. This is not, ofcourse, the fault of the present custodians of the sitebut a simple matter of history. A number of majordevelopments have taken place, which make thepresentation and interpretation of the site so prob-lematical. Firstly, as stated by Dr Winders, almost theentire mission compound lies under what is now

App 4-H6429.qxd 10/17/06 2:31 PM Page 334

Appendix 4 335

Alamo Plaza and Alamo Street, with only part of theeastern side surviving in the form of the LongBarrack. Secondly, the area to the east of the missionhas been laid out as a semiformal ornamental parkand is surrounded by masonry walls similar enoughto style and material to the original elements of thesite as to be confusing. As a memorial to the fallen,this green and peaceful setting works well; as aninterpretation of the site as it was in the first half ofthe nineteenth century it is disorienting in theextreme. Further, the Sales Museum, built in 1936immediately east of the line of the Convento court-yard, closely echoes the architecture and construc-tion of the Shrine (Figure A4.3). The contextualdifficulty presented by the iconography and style ofthe Sales Museum is compounded by the fact that avisitor entrance is located directly in front of it.Lastly, the Shrine itself is recognisable only in planform; the iconic roofline of its restored west front isthe result of post-siege military reconstruction.

Concepts of historic site presentation and interpre-tation change with time, but past examples, whetherthey are now considered successful or not, becomepart of the history of the site. At the present time,when all periods of intervention are seen as valid sub-jects for preservation, it is unfashionable to considerexceptions and alternatives to this philosophy, unlesssome modification to what exists truly serves to pres-ent the original fabric in a clearer and better light.

Without knowing all the complexities and interestsinvolved, that any visitor to the Alamo suggest whatmight be done in the future to enhance and improvethe site seems a bit presumptuous. Nevertheless, in thecontext of this book, and perhaps only here at the edi-tor’s request, it is possible to set out the observations ofone visitor, who has known the site since childhood,which could conceivably be enacted, given the neces-sary funding (predictably only one of the obstacles torealising such proposals).

From the Alamo archives, one image is particularlystriking. Less than ten years after Santa Anna’s troopstook back the Alamo from Travis’ garrison of volun-teers, 1st Lieutenant Edmund Blake of the USATopographical Engineers made a detailed drawing ofthe west front of the church (Figure A4.4 – Ruins ofthe Alamo in 1845 from a sketch upon a map of thecountry in the vicinity of San Antonio de Bexar).

The derelict, post-siege appearance of the churchmay be thought by some to have an impact far moremoving than that of the restored shrine seen by visi-tors today. In some ways, it provides an interestingparallel with the ruins of the church at Oradour surGlâne described in the introduction. In both cases, itis the ‘untouched’ ruined condition, the result of aviolent event, which makes the site so emotive andgives it, still, such immediacy. Would partial unroof-ing and unpicking of the upper restoration level ofthe west front ever be possible, letting the original

Figure A4.2 Reconstruction of the ‘Fall of the Alamo’ 1885 by T. Gentliz. In this depiction the Mexican army is already inthe main compound (left). The timber palisade with its artillery (centre) has been abandoned. The Long Barrack, its courtyardbeyond and the church building are still defended. The landscape provides an interesting contrast with the modern site context(Reproduced by kind permission of the Daughters of the Republic of Texas).

App 4-H6429.qxd 10/17/06 2:31 PM Page 335

336 Conservation of Ruins

Figure A4.3 ‘Ruins of the Alamo in 1845 from a sketch upon a map of the country in the vicinity of San Antonio de Bexarmade by J. Edmund Blake, 1st Lieut. Topographical Engineers USA’ (DRT) (Reproduced by kind permission of the Daughters ofthe Republic of Texas).

Figure A4.4 The ‘Alamo Church and Plaza’. Post 1860 rebuild of the west façade of the Church building and of its roof(DRT) (Reproduced by kind permission of the Daughters of the Republic of Texas).

App 4-H6429.qxd 10/17/06 2:32 PM Page 336

Appendix 4 337

Figure A4.5 A view across the modern Plaza of the west front of the Church building showing the Alamo in its new context.Photo Rachel Sabino-Gunaratna.

Figure A4.6 View across the modern plaza. Compare with similar view in 4.4. Photo Rachel Sabino-Gunaratna.

App 4-H6429.qxd 10/17/06 2:32 PM Page 337

338 Conservation of Ruins

fabric depicted by Blake to be experienced again?The link with the Alamo’s defenders would then bemore real than it is at present.

Similarly, although recall of the main compoundis now impossible, it is not inconceivable that theconvento courtyard could be reconstructed on theknown lines and to the original height using adobeblocks. This would also entail removing the twenti-eth century landscaping in this area and replacing itwith native plants, thereby providing a much closeridea of how conditions would have been within thecompound.

There are markers around Alamo Plaza showing,in part, the extent of the main compound – thoughthese could certainly be made more emphatic. Butanother interesting and useful aid to the visitor wouldbe the recreation of a section of the palisade from thesoutheast corner of the church, on its known line.

Fortunately for those who are interested, anenhanced understanding of the original characterand setting of the Alamo can be gained by following

the Mission Trail: comprised of four missions, con-temporary with the Alamo, which today are activeparishes within the Archdiocese of San Antonio andwhose lands have been designated by the NationalPark Service.

In particular, the mission of San Jose demonstratesthe potential nineteenth century military value ofthe church enclosed by a defensible perimeter wall;San Juan Capistrano provides the best indication ofan uncluttered desert environment. All four, includ-ing the missions of Concepción and San Franciscode la Espada, alongside a visit to the Alamo, con-tribute something to the experience of how SanAntonio de Valero would have been.

The Alamo is, of course, more than a memorial.Even in its depleted state, surrounded by modernlandscape and buildings, it is still ‘the real thing’.Any means of device by which the interested orpotentially interested visitor can understand andexperience that reality is likely to be justified.

Figure A4.7 The peaceful, green, park setting to the south of the Church building (The Shrine). Compare with the view in 4.4.Photo Rachel Sabino-Gunaratna.

App 4-H6429.qxd 10/17/06 2:32 PM Page 338

In some countries archaeological and historical siteslie in open country outside the jurisdiction of nationaland local parks and nature reserves. The unattendedsites often do not receive any benign attention in theform of recording, monitoring, emergency treatmentor conservation measures.

The exposure of such sites, whether abandonedarchaeological excavations or neglected monuments,leads inevitably to ongoing deterioration from yearto year. These sites, often of undoubted historic valueand sometimes in a surprising state of preservation,suffer only because of their modern geographicallocation. National or local authorities responsible formaintaining historic sites are overburdened by theirown conservation and maintenance responsibilities,and frequently suffer from lack of funding.

Public interest and concern for neglected monu-ments and their condition can be harnessed andutilised to help to change their fate, but the processesinvolved in utilising this resource take a great deal ofeffort and time. The great number of abandonedruins in some parts of the world make it impossiblefor them to be included in existing secure borders orto create new security around them; it often seems asthough these abandoned and forgotten sites aredoomed to complete destruction.

Can anything be done?

Regular monitoring and preventive measures are vitalto the survival of these sites, as this book has shown.Once the state of preservation and immediate threats

to the sites are recognised and documented, itbecomes much easier to find funds for emergencyintervention and temporary protection.

What is needed?

A proposed model for intervention involves the following:

● Identification and categorisation of mappedruins/monuments on existing land surveys andsurveys of antiquities.

● Obtaining existing GIS maps of the geographicallocation of the sites.

● Utilising the human resource potential; contactthose whose interest, occupations or researchescause them to frequent abandoned sites (such people could be land and building surveyors,nature rangers, students of archaeology, geology,ecology, etc., and instructors from field schoolsand other educational establishments).

● Assigning management responsibility for operat-ing the model to an authority such as a naturereserve or heritage body at local or national level.

● Assimilating marked sites from land and antiquity surveys onto the regional GIS maps andassigning them an identification number whichcorresponds to the survey’s number.

● Creating a field record sheet with a very shortdescription of the ruins and sites of the region,detailing their period, function and content.

339

Appendix 5

Monitoring and maintaining abandoned ruins and sites

Asi Shalom

App 5-H6429.qxd 10/17/06 4:51 PM Page 339

● Providing a short two-hour training presentationon the nature and characteristics of decay ofexposed sites, the physical threats which are pre-sented, methods and times of monitoring, import-ance of preventive measures, all summarised in aone-page chart.

● A one-page site evaluation form which is userfriendly and simple to complete, detailing theimmediate threat to the site.

Utilising the model

For the model to work it is first necessary to identifyand then inform interested members of the public,students, professionals, etc. of the potential signifi-cance of their contribution to the saving of thesesites. To do this requires someone with the specialistknowledge and the communication skills to raisecuriosity and stimulate enthusiasm, and the desire tobe voluntarily involved. This may be implemented asfollows:

● Provide a short illustrated training presentationto the interested groups with specific details of

how their familiarity with their sites can be usedto advantage by training them to see aspects ofcondition and threats to survival, and to play arole in saving the sites for the future.

● Lead an exercise with the potential groups in filling out the simple site evaluation forms.

● Providing each participant with a folder contain-ing the GIS maps of their regions showing theabandoned sites, the page with the site descrip-tions, the chart summarising the methods of moni-toring and its importance, documenting andrecognising the threats, and a few printed copiesand a computer disc of the evaluation form.

● A short, joint visit to their region and some ofthe abandoned sites with a responsible trainer,ideally before critical seasons, to set out and clar-ify the simplicity of documenting and of theevaluation process.

● Establish a collection point and contact with theresponsible authority who will record and processthe submitted forms, alerting, organising and find-ing funds and trained conservation teams to inter-vene, save and prevent the destruction of theabandoned ruins.

340 Conservation of Ruins

App 5-H6429.qxd 10/17/06 4:51 PM Page 340

abrasion, 221access, 256

for disabled visitors, 260platforms, 68

Acropolis, 152, 153aggregate, 134air lime, 134Akrotiri, Santorini, 179, 180algae, 226allies of degradation, 27Alois Riegl, 5Alveolar, 53anastylosis, xxi, 251archaeological investigation, 159archaeologist, 55arches, 32architect, 56architectural historian, 56Artemis, temple, xxiiAthena Nike, 153Athenian Agora, 152Athens, 152, 155Australia, 11, 23Austrian Archaeological

Institute, 180authenticity, 7AutoCAD, 71

badgers, 202Baines, Frank, 83Balanos, xxiBallinaskellings Castle, Ireland, 220Bargate rubble stones, 268barnacles, 226basic surveys, 58Baths of Constantine, 20, 36Battle Abbey, 125, 126Beauvais, 27Beeching Plan, 299Beit She’an, 155benign neglect, 209, 255Bernard Fielden, xxv

Beth Shean, 1, 124, 253, 254Biagio, Rebecca, xxiiiBignor, West Sussex, 177, 184Billingsgate Roman Bath House,

London, 191biocide, 196biodiversity, 198biological survey, 197blind arches, 34, 35Board of Ordnance, 297Boito, Camillo, 5Brading Roman villa, Isle of

Wight, 184Bramfield Hall, 31Brassey, 297breeding seasons, 198British ail, 296Brittany, 21broken arch, 114bryophytes, 205building surveyor, 55buildings archaeology, 159buried environment, 164Burra Charter, 148Butrint, Albania, 105, 198, 239Byland, xix, 86, 112Byward Tower, 139, 140, 141Byzantine mosaic, 163Byzantine synagogue, Ein Gedi,

Israel, 180

Caernarvon, 86caldarium, 287Camillo Boito, 5Carrigahold Castle, County Clare,

Ireland, 226, 231–232Case studies:

Carrigaholt Castle, Co. Clare231–232

Gosport Railway Terminal, UK,296 –305

Guildford Castle, UK, 265–278

Masada, Israel, 279–295Medieval waterfront building,

Drogheda, Ireland, 229–231

Castle Acre Castle, 100Castlecove Castle, Ireland, 232Çatalhöyök, Turkey, 173Cathedral of St Michael, 150ceramic, 134Cesis Castle in Latvia, 21Chaco Canyon, New Mexico, 175charcoal, 134Charles Peers, 83Charlotte Trumpler, xxixCharnel House, Spitalfields,

London, 191Chateau de Lacoste, 42Chedworth Roman Villa, 172, 177,

184Chysauster, 47Clarendon Palace, 110clay, 279clay particles, 17Cleeve Abbey, 181, 185client brief, 78climate change, 215climatic effects, 21coastal assessment, 216coastal erosion, 215cockatoos, 27Colinvaux, 195Colosseum, 153comprehensive surveys, 59condition survey, 147conservation

management plan, 207movement, 4technicians, 235work, 280

conservators on site, 144conserve as found, 250, 252corbels, 32

341

Index

Index-H6429.qxd 10/17/06 2:39 PM Page 341

core facework, 103Cornwall, 21corrosion, 221corrugated sheets, 168County Cork, 92Coventry, xxcrack gauge, 29Crichton Castle, Scotland, 259cupolas, 35Cuzco, 136cyclical conditions, 12

Dead Sea, 279decorative stone pavements, 180diaphragm pump, 120Disability Discrimination Act

(DDA), 208disabled access, 261documentary research, 57dog cramps, 141domestic animals, 262Dorchester, Dorset, 181, 186drawn survey work, 159Drogheda, 229–231Dunstanburgh Castle,

Northumberland, 256, 261, 262

earth walls, 136echinoids, 226ecology, 195Ehud Netzer, 279Ein Gedi, Israel, 180, 182embedded steel, 40English Heritage, 168, 235, 245English Nature, 202environmental control, 181environmental impact, 179Ephesus, Turkey, xx, xxi, 180Epidaurus, 155Epsom, xxixErechtheion temples, 153Euston station, 296exemplars, 244exposed steel, 40

facilities and infrastructure, 257fauna, 190fauna, 201feasibility studies, 59feral pigeons, 190Fielden, Bernard, xxvfire, 28Fishbourne Roman Palace, West

Sussex, 183Flag Fen, 171floors, 142flora, 190, 198foam packaging, 168

Fort Brockhurst, 138Fortress of Louisbourg, 149Fountains Abbey, Yorkshire, xix,

250fractures, 108Frank Baines, 83frigidarium, 286, 287, 290frost, 22furnace room, 287Furness Abbey, 86, 125, 127

gastropods, 226Gela, 179geo-mesh, 168geomorphological assessment, 217geotextile, 143, 161, 167Getty Conservation Institute, 172Giovannoni, Gustavo, 5goats, 206Goethe, xviiGoodrich, 86Gosport Railway Terminal, Gosport,

296 –305Grand Trunk Railway, Canada,

297gravity grouting, 118ground movement, 15groundwater, 178guano, 202Guildford Castle, 30, 47, 75, 125,

128, 157, 265–278Gustavo Giovannoni, 5gypsum, 131, 279

Haddenham, 31Hadrian’s Wall, 132Hagar Qim Temple, Malta, 190Hampshire County Council, 300Hardwick, Philip, 83Harvey, William, 87Harwick, Philip, 83Hatshepsut, xliv, 10Helmsley Castle, Yorkshire,

256, 257Heraclea Minoa theatre, 179Herculaneum, xvii, xx, xxii, 2Heritage Lottery Fund, 156Herod the Great, xxviHerodian plaster, 289Herodian port, Caesarea, 212hexashelter, 190historian, 56historic restoration, 4Holytex™, 174honeycomb weathering, 226horizon marker, 161Horvat Minim (Khirbet al-Minya),

Israel, 173

House of Tiles, Lerna, Greece, 179human failings, 27Hythe Beds Stones, 267, 268, 270

ICCROM, 172ICOMOS, 6, 7insulated quilts, 168internal masonry, 270International Committee for the

Conservation of Mosaics(ICCM), 172

interpretation, 159, 255inter-tidal survey, 217Isaiah, 195Israel, 154, 155Israel Nature and National Parks

Protection Authority(INNPPA), 159

ivy canopies, 198

jays, 27Jedburgh, 86Jerash, xx, xxii, 9Jerusalem, xxviJervaulx Abbey, 250, 251John Ludlow, 238John Ruskin, 4Jokilehto, 179Juvan Castle, 158

Kaiser Wilhelm Gedachtniskirche,150

Kenilworth Castle, 98Kilve Chantry, 9Kirby Hall, xliiiKunstwollen, 5

ladders, 68Latvia, 24, 39Lauderdale House, 155legislative requirements, 261leopards, 201lichens, 199, 225light, 190lighting strikes, 21lighting, 260lime, 279lime putty, 134limpets, 226livestock, 262London and South Western Railway

(LSWR), 297Lottery Fund, 156Lowenthal, xxviLudlow, John, 238

Macauley, Rose, xxixmaintenance work, 56, 156, 261

342 Index

Index-H6429.qxd 10/17/06 2:39 PM Page 342

Mamshit, 154managed decline, 209, 254Manosque, France, 20marine environment, 214marine organisms, 223Masada, Isreal, 139, 154, 239,

279–295Masonry, 40

joints, 268structure, 17

mass concrete, 37materials analyst, 56McSwynes Castle, Donegal, 220Merton Abbey, xxixmetakaolin, 134MEWPS, 68microclimate, 179Minoan Palace, 151Mnajdra Temple, Malta, 190mobile elevated work platforms, 68modern conservation theory, 3, 4Modern Movement, xxmoles, 202Morris, William, 4Mortar, 102, 129–135mosaic pavements, 161mosses, 199Mostar, xxMourne Abbey, 111Muchelney, Somerset, 252Museum of London Archaeology

Service, (MoLAS), 168, 172mussels, 223Muxloe, 86Myross Church, 92

Nara conference, 7Nara Document on Authenticity,

148National Parks Service in the USA,

159National Railway Museum, 299natural hydraulic limes, 135needle-punched geotextiles, 168Neolithic trackway, 168Netley, 86New York station, 296Newstead Abbey, 49, 50, 72Nietzsche, 3Nonsuch Palace, xxixnon-woven, 168Norman plaster, 272Northern Palace at Masada, 154,

279, 285, 287Nunney Castle, 112

Odeion of Herodes Atticus, 155Office of Works, 83

Okehampton Castle, UK, 137Old Arsenal, 24Old Gorhambury, 140Old Sarum, 99Opus sectile, 180Oradour Sur Glane, xxviii, xxix,

150Orange, 23, 24organic growth, 191organisational roles, 237, 238Orpheus mosaic, 172

padded quilts, 168Palace of Knossos, 151Pantheon, 36Parks Canada, 159Parthenon, xx, xxi, xliv, 153Pattress plates, 113pavements, 171Peers, Charles, 83perlite, 168Peterborough, 171Pevensey, xliii, 8, 132Pevensey Castle, 197pH conditions, 198Philip Harwick, 83philological restoration, 4photographic survey work, 159photovoltaic panels, 259pintles, 141Pitt-Rivers, General, 83Planning, 160planning frames, 93, 103Planning Policy Guidance, (PPG),

148plantgrowth, 56plaster, 141plastic sheets, 168plywood, 168polychaete worms, 226polyethylene glycol, 164Pompeii, xvii, xx, xxi, 2, 8, 147Pont Julien, 33Portland cement, 53Portsmouth, 296power supply, 258Powys, A.R. 235pozzolana, 130, 131, 134, 135presentation, 249previous repairs, 269Prince Albert, 297procurement options, 207project management, 160property management surveys, 59protective enclosures, 177Purbeck Marble, 38

Queen Victoria, Windsor, 297

rabbits, 201Railway Heritage of Britain, 296rain degradation, 12rainwater management, 189rats, 27Rebecca Biagio, xxiiireburial, 161, 162, 176reconstruction, 150, 251recording, 159, 160

and monitoring, 216rectified photographs, 71Red Cross, 28reinforced concrete, 37relative humidity, 190relieving lintels, 34remedial action, 15, 19replastering, 271replication, 255Reshat Gega, 238restoration, 250restraining cramps, 112retaining walls, 31reversibility, 159Riegl, Alois, 5Rievaulx, xix, 85, 86Riga Charter, 148Riga Old Town, 43ring beam, 115Ring of Kerry, 232risk assessment, 261risk mapping, 228Roche Abbey, Yorkshire, 250Roman amphitheatre in London,

166Roman baths, 191Roman city walls, London, 191Roman mosaic at Lopen in

Somerset, 172Roman town house, Dorchester,

Dorset, 181, 186Roman Villa del Casale, Piazza

Armerina, 179Roman villas, Bignor, West Sussex,

177Rose Macauley, xxixRose Theatre, 171Rosslare Fort, 231Royal Exchange, 297ruinettes, 236Rushen Abbey, 107Ruskin, John, 4rust growth, 37

salts, 190Sanctuary of Asklepios, 155sand, 168Santa Sophia, 27Santorini, 130

Index 343

Index-H6429.qxd 10/17/06 2:39 PM Page 343

scaffolding, 66schedule of defects, 61scheduled ancient monument, 148scientific restoriation, 4sea level, 215security, 258, 260, 261seismic effects, 19servicing sites, 258shear cracks, 29, 30shelter coat, 141shelters, 177Sheriff Hutton Castle, 111, 113signage, 260silts, 18Sir William Tite, 297site archaeology, 65site-based investigation, 57site-based investigation, 61slag, 134slumping, 19SNCOs, 202Society for the Protection of

Ancient Buildings, 4, 125soft capping, 204soft tops, 103Solomon’s Temple, xxvsoluble salts, 164SPAB, 4, 124specialist contractors, 238Split, xxSt Luke’s Church, London, 73St Pancras, London, 296St Paul’s Cathedral, London, 85Stanley-Price, 179starlings, 27Station plans, 297Statutory Nature Conservation

Organisations, 202steam gun, 141steel, 40stitching systems, 116Stoa of Attalos, 152Stoa of the Athenians, 1stone conservation, 282stone repairs, 126stone replacement, 121stonemason, 56Stourhead, Wiltshire, 250Stowe, Buckinghamshire, 250structural archaeology, 89structural engineer, 56structural surveys, 61

structure failure, 11stylistic restoration, 3Suffolk, 31survey drawings, 71survey work, 191sustainability, 160, 190sustainable tourism, 247Sweet Track, 168synthetic packaging, 168

tarpaulins, 168Tarragona, xxTeatro di Marcello, xxTel Dan, Israel, 137, 180, 182Temple Mount, xxvTemple of Saturn, 144temporary protection, 167temporary protective measures, 164temporary supports, 89tenders, 243, 244tension cracks, 29tensional bands, 42tepidarium, 287Terralys™, 167Terram™, 167terrapins, 203thermal fluctuations, 189Tholos wall, 284Thomas Brassey, 297Thornton Abbey, 99tie bars, 141tile pavement, 181tile, 171Tintern Abbey, 84Tite, Sir William, 297Tivoli, 131torsion bars, 111tourism, 247Town and Country Planning Act, 296traditional approach, 3Trei’r Ceiri, 135, 136Trumpler, Charlotte, xxix

undermining, 219underwater survey, 218UNESCO, 5, 147, 153University of Bradford, 168unmortared walls, 134

vandalism, 28vaults, 35Venice Charter, 7, 148

ventilation, 190vermiculite, 168Viollet-le-Duc, xxi, 4virgin sites, 64visitor access, 207visitors, 246, 263visual integrity, 7vitrified bricks, 39voids, 117vortex scour, 25vulnerability, 161

wall ends, 103wall head treatment, 98wall paintings, 165wall systems, 30wall tops, 93, 268, 271war, 28water lime, 134Water-holding plaster, 290waterlogged sites, 168waterlogged timbers, 164Waterlow Park, Highgate, London,

51, 52, 54, 55, 74, 155wave action, 221wave quarrying, 222Waverley Abbey, 110West Dean College, Sussex, 238Westminster, 85Wexford Harbour, 231Whitby, 86White Mansfield, 53Wichert wall, 31Wildlife Act, 202William Harvey, 87William Morris, 4William Woodward, 85, 86Winckelmann, xviiwind, 24, 189Wolvesey Castle, 125, 129wood ash, 135Woodchester Roman villa, 172Woodward, William, 85, 86World Heritage List of UNESCO,

6, 9World Heritage Sites, 147

Zeugma, Turkey, 174

344 Index

Index-H6429.qxd 10/17/06 2:39 PM Page 344