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The German Association for Building with Earth [Dachverband Lehm e.V.] (Eds.)

Rules governing building with earth

Definitions, building materials and components

3rd revised edition

Draft, November 2007

A project by the German Association for Building with Earth, Weimar (Eds.),

supported by funding from the Federal Foundation for the Environment (DBU).

Authors

Franz VolhardUlrich Röhlen

With the collaboration of

Dr.-Ing. Christof Ziegert

Working group

Prof. Dr.-Ing. Klaus DierksStephan JörchelUlrich RöhlenDr.-Ing. Horst SchroederFranz VolhardDr.-Ing. Christof Ziegert

The information, data, results and so on contained in this book were compiled with the co-operation of the experts in the field in accordance with the state of the art and scrutinised with the utmost care by the authors, the editorial committee and the publishing company. Nevertheless, errors cannot be completely ruled out. For that reason, no responsibility can be accepted for any inaccuracies in content.

The rules governing building with earth were incorporated into the Berlin Institute for Structural Engineering’s specimen list of technical regulations on 26 February 2008, thereby becoming recommended for implementation within building inspection in Germany’s constituent Länder.

The obligations arising from Directive 98/34/EC of the European Parliament and of the Council of 22 June 1998 laying down a procedure for the provision of information in the field of technical standards and regulations and of rules on Information Society services (OJ L 204 p. 37), most recently amended by Directive 98/48/EC of the European Parliament and of the Council of 20 July 1998 (OJ L 217, p. 18), have been met.

Editorial information

The German Association for Building with Earth, Weimar (Eds.)


Authors: Franz Volhard, Ulrich Röhlen

With the collaboration of: Christof Ziegert

Produced: November 2007

CIP short title entry …

This document is protected by copyright. Any turning to account of the work without the consent of the publishers is not permitted and is punishable by law. This applies in particular to reproductions, translations, microfilming and processing in electronic systems.

First published May 19992nd revised edition May 20023rd revised edition February 2008

Publishers: Vieweg & Sohn

We wish to thank the following for their collaboration:

Contributions through subject-matter expertise and discussion (editorial committee)

Eckhard Beuchel, Lehmbau Beuchel, CrimmitschauJörg Depta, LehmBauWerk GbR, BerlinManfred Drach, Ingenieurbüro Drach, BerlinGerhard Forg, Maxit Deutschland GmbH, BreisachIrmela Fromme, BAUFACHFRAU Berlin e.V. Philipp Liebig, Ziegelwerk Grün, ReinheimHeiner Lippe, architect, HanoverVeit Mach, MACH 2 architects, Reichshof-DenklingenRoland Meingast, Natur&Lehmbaustoffe GmbH, Tattendorf (Austria)Jörg Meyer, conluto - Bauen mit Lehm, Blomberg-GroßenmarpeProfessor of Civil Engineering Gernot Minke, Building Research Institute of

the University of KasselRichard Rath, graduate civil engineer, BerlinGeorgios Schade, Lehmbautechnik Georgios Schade, Seelze/LetterThilo Schneider, LehmBaustoffe Thilo Schneider, KleinfahnerHannah Schreckenbach, architect, MagdeburgRoderich Seefried, LebensRaum, Wald-Rothenlachen.

Contents

CONTENTSFOREWORD X

FOREWORD TO 2ND EDITION XII

FOREWORD TO 3ND REVISED EDITION XII

1. GENERAL 11.1 Area of application 1

1.2 Definition 1

1.3 General requirements 11.3.1 Planning of construction 11.3.2 Execution of construction 11.3.3 Manufacturers 2

2. BUILDING EARTH 32.1 Definitions 3

2.2 Types of earth and earth deposits 3

2.3 Extraction of building earth 42.3.1 Dug earth 42.3.2 Dry earth and powdered clay 42.3.3 Recycled earth 42.4 Inspection of building earth 52.4.1 General 52.4.2 Requirements 52.4.3 Basic tests 52.4.4 Laboratory tests 8

Sampling 8Determining the binding strength (binding strength test) 8Determination of plasticity 9Determination of the mineral framework (grain size distribution pursuant to DIN 18123) 10

Annex 1 to Chapter 2. Building earth 10Binding strength test, method of testing 10

I


3. EARTHEN BUILDING MATERIALS 143.1 General 143.1.1 Definitions 143.1.2 Labelling of earthen building materials (declaration) 143.1.3 Composition and preparation of earthen building materials

143.1.4 Classification of building materials 153.1.5 Abbreviations 153.1.6 Use of earthen building materials 163.1.7 Re-use, recycling and disposal of earthen building materials

173.2 Rammed earth (STL) 173.2.1 Definition 173.2.2 Use 173.2.3 Composition 17

Building earth 17Additives 17

3.2.4 Preparation 183.2.5 Testing 18

Particle density 18Compressive strength 18Measure of shrinkage 19

3.2.6 Labelling 193.3 Cob (WL) 193.3.1 Definition 193.3.2 Use 203.3.3 Composition 20



Particle density 20Compressive strength 20

3.3.6 Labelling 213.4 Fibrous clay, clay straw (FL, SL) 213.4.1 Definition 213.4.2 Use 213.4.3 Composition 21

II

Contents



Particle density 22Shrinkage, suitability 22

3.4.6 Labelling 233.5 Light clay (LL) 233.5.1 Definition 233.5.2 Use 233.5.3 Composition 24

Building earth 24Lightweight additives 24Mixing ratios 24


Particle density 25Consistency of the slurry 25Sturdiness 26

3.5.6 Labelling 263.6 Earth fillings (LT) 263.6.1 Definition 263.6.2 Use 263.6.3 Composition 273.6.4 Preparation 273.6.5 Testing 27

Particle density 273.6.6 Labelling 273.7 Earth blocks (LS) 273.7.1 Definitions 273.7.2 Use 283.7.3 Composition and production 293.7.4 Suitability 303.7.5 Testing 30

Format 30Particle density 30Compressive strength 31

3.7.6 Labelling 31

III


3.8 Clay panels (LP) 323.8.1 Definition 323.8.2 Use 323.8.3 Composition and manufacture 323.8.4 Testing 33

Particle density 333.8.5 Labelling 333.9 Earth mortars 333.9.1 Definition 333.9.2 Use 333.9.3 Composition 343.9.4 Preparation 34

General 34Building site mortars 34Factory materials mortars 35Factory-supplied mortars 35Recycled mortars 35

3.9.5 Requirements 353.9.6 Testing 36

Sampling 36Particle density (hardened mortar) 36Compressive strength 36Measure of shrinkage 36Shrinkage (building site sample) 36

3.9.7 Labelling 36

4. COMPONENTS BUILT WITH EARTH 384.1 Load-bearing walls 384.1.1 General 38

Definition 38Works management, special requirements 38Building period 38Protection against weather during the execution of the building work39

4.1.2 Construction 39Moistureproofing 39Requirements 39Reinforcement 40Anchoring of the walls 40

IV

Contents

Supports and openings 404.1.3 Execution of earth block walls 44

Building material 44Fabrication 44

4.1.4 Execution of rammed earth walls 45Building material 45Fabrication 45Drying 45Measures to make plaster adhere 45

4.1.4 Execution of cob walls 45Building material 45Fabrication 45Drying 46

4.1.6 Repair of load-bearing earth walls 464.2 Vaulting 46

Definition 46Building materials 46Planning and works management 46Building period 46Protection against weather during the execution of the building work47proof of stability 47Construction 47Moistureproofing 47Execution 47

4.3 Non-loadbearing walls and infill 474.3.1 Infill of framed walls 48

Definition 48Building materials 48Building period 48Protection against weather during execution of the building work 48Drying 48Wattle and daub 48Strutting with daub 49Rolled struts (including cob) 49Light clay 49Masonry infill 49

4.3.2 Non-loadbearing rammed earth walls 50Construction 50

4.3.3 Non-loadbearing masonry 50

V


Building materials 50Construction 50Execution 51

4.3.4 Light clay walls in damp installation 51Definition 51Building material 51Building period 51Construction 51Execution 52Drying 52Attachments 53Testing 53

4.3.5 Clay panel walls 53Definition 53Construction 53Execution 54

4.3.6 Stacked earth walls 54Definition 54Building materials 54Execution 54Cladding 54

4.3.7 Extruded walls 54Definition 54Building materials 55Construction 55Execution 55Drying 55Further processing 55Testing 55

4.3.8 Plastered insulating boards 56Definition 56Building materials 56Construction 56Execution 56Further processing 56

4.4 Joist ceilings 57Definition 57

4.4.1 Strut ceilings 57Definition 57

VI

Contents

Building materials 57Construction 57Execution 57Drying 58

4.4.2 Inserted ceilings 58Definition 58Building materials 58Construction 59Execution 59Drying 59

4.4.3 Flooring 59Definition 59Building materials 59Construction 59

4.4.4 Ceilings with clay panels 60Definition 60Building materials 60Construction 60Execution 60Further processing 60

4.4.5 Infill of roof slopes 604.5 Plastering/rendering 614.5.1 General 61

Uses 61Definitions 61Guidelines for planning 61Requirements 62Execution 62

4.5.2 Earthen plastering/rendering 63Suitability 63Requirements 64Plaster mortars/rendering 64Plastering/rendering systems 64Application and surface treatment 65Drying 66Further treatment 66Repair and renovation 67

4.5.3 Other plastering/rendering on earthen bases. 67Plaster mortars/rendering 67

VII


Plastering/rendering systems 67Execution 67

4.5.4 Special features of exterior rendering for visible latticework68

Loading 68Plastering/rendering systems for framework render/plaster 69

4.6 Rammed earth floors 69

4.7 Facings in dry construction 70Definition 70Building material 70Construction 70

4.8 Other components 714.8.1 Basement masonry walls and skirting 71

Definitions 71Preclusion 71

5. SPECIFICATIONS FOR BUILDING MATERIALS AND COMPONENTS 72

5.1 Particle density 72

5.2 Strength 725.2.1 Compressive strength 725.3 Heat 745.3.1 Thermal insulation 745.3.2 Heat retention 755.4 Moisture 765.4.1 Susceptibility to water and moisture 765.4.2 Diffusion of vapour 765.4.3 Moisture conductivity 765.4.4 Practical moisture content 775.4.5 Sorption 775.4.6 Drying 775.5 Fire behaviour 785.5.1 Fire behaviour of earthen building materials 785.5.2 Fire behaviour of components built with earth 795.6 Noise-insulating characteristics 815.6.1 Dampening of airborne noise by walls 81

VIII

Contents

5.6.2 Noise-insulating characteristics of wood joist ceilings 815.7 Windproofness 82

5.8 Durability 82

6. TERMS OF CONTRACT FOR EARTHEN BUILDING SERVICES 83

7. STANDARDS 857.1 Standards cited 85

7.2 Former standards on building with earth 86

8. KEYWORD INDEX 88

PROJECT PARTICIPANTS 103Rules governing building with earth 103Authors 103With the collaboration of 103Working group 103Project management 103Contributors to previous editions 104

Working group 104Subject-matter expertise and advice 104Contributions to discussions 104

IX


FOREWORD

Building with earth has a long history in Europe and in Germany. In framed building and in massive load-bearing, earth was formerly one of the principal building materials but it has been superseded by modern industrial building materials. Most recently, in the post-war period of the 20th century, building with earth was seen to offer the chance to counter the shortage of fired, load-bearing building materials, particularly in rural areas.

Since the beginning of the 1980s, earth has begun to be used again as a building material in Germany. A new interest has arisen and the possibilities of new uses and products are being sought. Earthen building materials are also of high value environmentally. The raw material can be obtained locally in an environmentally sound way. Processing into a building material does not require much energy to be used. Appropriately constructed, earthen building materials can be re-used. Their disposal is unproblematic. Properly employed, earthen building materials are tried and tested and assuredly safe from a human health point of view. Building with earth allows for the integration of a large proportion of personal contribution. However, the characteristics of earthen building materials also include susceptibility to water and, compared to comparable building products, lesser sturdiness. For a large range of building tasks, however, the properties of earthen building materials are entirely satisfactory. They can be suitably optimised for their use without much expenditure of energy. Some simple structural measures also make it possible to produce load-bearing components out of earthen building materials.

The establishment of a consolidated collection of rules and the comprehensive documentation of known techniques was first undertaken in the Order on building with earth of 1944. The said Order on structures built with earth was adopted for building inspection purposes in 1951 as DIN 18951. Further prestandards and draft standards continued to be produced up until 1956 but were not adopted. In 1971 all the standards were withdrawn on the grounds of being out-dated. However, according to a 1982 opinion issued by the Hessian Minister of the Interior, they were to be regarded, along with more recent decrees by the Minister with a similar content – in the absence of successor legislation – as “state-of-the-art” for building inspection purposes for the approval of structures built with earth,

X

Foreword

with the result that no documentary proofs need be furnished in individual cases for the fitness for purpose of those methods of building with earth covered by the old standards.

However, these old standards are only able to correspond to an unsatisfactory degree to the manifold and sometimes new applications for earthen building materials and the multitude of new earthen building materials. The standards primarily regulated load-bearing earthen constructions, whereas earthen building materials are nowadays primarily used for non-loadbearing purposes. In addition, the various editions of the standards were no longer co-ordinated and have to be viewed, nowadays, as obsolete in large parts, although they remain highly useful because of the knowledge they contain.

The non-profitmaking German Association for Building with Earth, which had been founded by experts, architects, businessmen, handicraft companies and representatives of institutions in 1992, set itself the urgent task of drawing up a new regulatory framework. The aim was to incorporate the old standards, insofar as they were viable, with historical experience being combined with more recently acquired knowledge from practice in building over recent years. Supported by the Federal Foundation for the Environment (DBU), a first draft was produced in 1997 by a project group within the Association, fine-tuned over numerous technical discussions with invited participants and publicly presented at LEHM 97 [an international conference on building with earth] in Viersen, Germany. The results of the discussion and additional written comments and suggestions were incorporated. The present Rules governing building with earth thus represent not only the state of the art but also the consensus of the experts in the field of building with earth. In so doing, they go beyond serving to protect consumers and help to prevent failures and disappointments. Another, and in fact the primary, aim of the project was to facilitate a new and up-to-date regulation of building inspections.

All earthen building materials and components that are deemed to be currently in need of regulation have been included, whereas applications that are currently subsidiary, such as earth shingling, have not been included, reference instead being made to specialist literature or the old standards.

XI


FOREWORD TO 2ND EDITION

The German Association for Building with Earth’s Rules on building with earth have had great resonance since they were first published.

They were incorporated into the Berlin Institute for Structural Engineering’s specimen list of technical building regulations in 1998, thereby becoming recommended for implementation within building inspection in Germany’s constituent Länder. Eleven German Länder have since followed this recommendation. In the other Länder, building with earth is an “unregulated method of construction” for which authorisation must be obtained for individual cases, reference being made to the specimen list and its implementation in the other Länder. The former DIN standards on building with earth ceased to be of significance once the Rules governing building with earth came out. The application of the Rules governing building with earth has thus far been limited to single and two-storey single-family properties containing up to two dwellings. For other applications it has continued to be the case that documentary proofs of usability under building law are required. The relevant standards apply, in the version currently in force, in respect of the documentary proofs of fire protection, sound-proofing and thermal insulation. As far as thermal insulation is concerned, the thermal conduction figures for earthen building materials in DIN 4108-4 have latterly been updated in line with the Rules governing building with earth.

This second edition has been adopted, aside from a few minor corrections, unaltered.

April 2002 The German Association for Building with Earth [Dachverband Lehm e.V.]

FOREWORD TO 3ND REVISED EDITION

In the course of 2006 and 2007 the Rules governing building with earth were brought into line with recent experience and requirements. The process of finding a consensus largely followed the procedure described

XII

Foreword

above for the first edition. The overhaul was carried out by the German Association for Building with Earth and supported by the Federal Foundation for the Environment (DBU).

As in the past, the state of the art in the production and use of earthen building materials unstabilised by additional binders is described. There are hardly any examples of use or experience with stabilised earthen building materials in Germany, for which reason it seems unnecessary to regulate this area. In other countries, on the other hand, building materials of such a nature are state-of-the-art and are thus covered by building regulations.

Coating materials (earth dyes, earth renders) are not covered, as a result of the apparently limited need for regulation.

Modal verbs have been used as envisaged by the Association of German Engineers (VDI), as follows:

- Must/have to: provisions involving ‘must’ or ‘have to’ are fundamentally binding.

- ‘Should’: provisions involving ‘should’ allow parties applying the provision two options, namely either to comply or to explain why failure to comply is justified in this particular case.

- ‘Can’: parties applying the provision can choose whether or not to comply with the stipulation.

November 2007 The German Association for Building with Earth [Dachverband Lehm e.V.]

XIII

1. General

1. GENERAL

1.1 Area of application

These Rules apply to prefabricated or locally produced earthen building materials where the sole binding agent is earth. Stabilised earthen building materials whose water solubility or sturdiness is altered by means of other binding agents or the addition of chemically active substances are not subject to these rules.

1.2 Definition

Building with earth means building using earthen building materials in load-bearing and non-loadbearing applications.

1.3 General requirements

1.3.1 Planning of construction

In structures and components built with earth, weatherproofing and structural moistureproofing must be ensured in a durable fashion. The ability to dry and time to dry for earthen building materials installed in a moist or wet condition must be ensured.

1.3.2 Execution of construction

The preparation of building materials and the execution of building work, particularly in the case of self-execution, must be directed by a skilled worker experienced in building with earth. A person may be regarded as meeting these specifications if he/she possesses the theoretical knowledge of building with earth and has acquired a degree of experience in the building of structures with earth such that he/she has mastered the technical and working rules of building with earth. Special requirements are laid down for the execution of load-bearing walls and vaults under 4.1.1.

1


Earthen components must be protected from the effects of the weather during building.

Earthen building materials must be able to dry as quickly as possible.

1.3.3 Manufacturers

Earthen building materials may be produced on-site or prefabricated by manufacturers. Self-manufacture usually requires direction.

2

2. Building earth

2. BUILDING EARTH

2.1 Definitions

Earth is the product of the weathering of prehistoric rock found on a particular site or transported there by natural processes. The earth that occurs can very greatly regionally and locally. From a technical construction point of view, earth is a natural mix of clay minerals with a binding strength and silty, sandy to stony constituents that make up the mineral framework.

Building earth is earth suitable for the manufacture of earthen building materials.

The binding strength of a building earth depends on the nature and proportion of clay minerals. Building earth is categorised according to its binding strength as, for example, “thin” or “fat” and, from a given binding strength, as “clay”.

The plasticity (shapability) of building earth also depends on the nature and proportion of clay minerals.

2.2 Types of earth and earth deposits

Mountain earth or slope wash, resting on the rock from which it has formed as a result of weathering, or on the slopes beneath. The mineral framework primarily consists of angular rocky detritus of varying grain sizes.

Boulder clay is a glacially deposited type of earth. The mineral framework consists of rounded grains.

Marl is a boulder clay containing calcium carbonate.

Alluvium has been de-sludged from previous deposit sites by running water and then deposited again in calm water. Alluvium is a sometimes interfused with weak lenses of sand, gravel or rubble. It is also possible for humus to be mixed in.

3


Loessial soil is derived from loess by means of the leaching of the lime content therefrom. Loess is a wind-blown fine sand containing lime and clay. Loessial soil has a very fine-grained mineral framework and often a low clay content.

2.3 Extraction of building earth

Building earth must be free of contaminants and harmful foreign matter.

Building earth should be stored such that it is protected from rain.

2.3.1 Dug earth

Dug earth is ground-moist earth extracted from soil that has had growth. It must be extracted from a sufficient depth and be free of roots and all humus fractions.

For mechanical preparation, building earth should be free of building rubble and other impurities.

For manual preparation, dug earth should be dug to be as crumbly as possible. To make it easier to work, the dug earth may first be weathered, aged or dried.

2.3.2 Dry earth and powdered clay

Dry earth is dried, and where appropriate pulverised, dug earth.

Powdered clay is dried, pulverised clay. Powdered clay can also be used to increase the binding strength of thin building earth.

2.3.3 Recycled earth

Recycled earth is made from demolition components of recycled, dry comminuted earthen building materials.

Earth that is heavily salted, has traces of dry rot or is humified may not be re-used. It must be ensured that the earth is not polluted during removal and storage.

4

2. Building earth

2.4 Inspection of building earth

2.4.1 General

The aim of inspecting building earth is to identify and denominate the essential technical building characteristics in order to be able to assess their suitability for the production of earthen building materials. However, the characteristics of (prepared) earthen building materials cannot be directly deduced from the characteristics of the building earth and are not the object of building earth inspections.

The essential characteristics of building earth to be investigated are:

- binding strength, plasticity,

- mineral framework, distribution of grain sizes

- other constituents (contaminants, humus).

2.4.2 Requirements

Inspections shall be carried out on building earth with which earthen building materials are to be manufactured.

Building earth used to produce earthen building materials at the factory shall be inspected for suitability by the manufacturer (inbound inspection). The results of the earth inspection shall be documented, specifying the inspection methods pursuant to 2.4.3 and 2.4.4. Sampling and the inspection intervals selected must be suitable for detecting possible differences in similar consignments, as well as within a single consignment.

Building earth delivered to the building site for manufacture of earthen building materials shall be inspected for suitability by the processor. The process followed can be analogous to the above.

Building earth supplied as a product can be labelled with documentation of the inspection results.

2.4.3 Basic tests

Basic tests serve to provide an oriented evaluation of the characteristics of the earth. Execution requires experience. The test results shall be

5


confirmed by repetitions. If there are doubts about the suitability of the earth, laboratory tests pursuant to 2.4.4 shall be could out.

Dug earth samples shall be taken from sufficient depth to avoid humus and shall be labelled. For tests with ground-moist samples the earth must be dry enough to enable it to be just rolled into a ball.

Ball-forming test To asses the binding strength, the ground-moist earth is shaped by hand into a number of balls of around 5 cm in diameter. Fat earth sticks to the hands when being shaped, while excessively thin earth is no longer capable of being shaped and easily falls apart after drying.

Ball-drop test Balls shaped when ground-moist can be dropped, once dried, onto a solid surface from a height of 80 cm. A ball made of fat earth does not burst into pieces; one made of thin earth breaks into a few pieces, while one made of very thin earth into many pieces that crumble apart sandily at the point of impact.

Cutting test (cf. DIN 4022-1) When cutting a ground-moist sample with a knife a shiny surface indicates fat earth or clay, while a dull surface indicates silt with low binding strength.

Dry strength test (cf. DIN 4022-1) The resistance of a dried sample to crumbling and pulverisation sheds light on the nature and magnitude of the fines content. Building earth only breaks up after considerable pressure from a finger into a number of pieces; a sample of fat earth cannot be broken up by finger pressure.

Friction test (cf. DIN 4022-1) Clay earth feels soapy and sticks to the fingers. It cannot be removed when dry without being washed off.

Determination of the mineral framework A differentiation is made in the building earth, on the basis of the leading dimensions of the sand, between:

- coarse sand (above 0.2 mm and up to 2.0 mm),

- fine sand (0.2 mm down to the point at which it is still just about perceptible to the touch), and

- silty (no longer perceptible to the touch).

0.2 mm is approximately equal to the size of the point of a pin. Earth of mixed grain sizes is listed in order of fractions. For instance: silty to fine sandy earth.

6

2. Building earth

The earth can be assessed in the ground-moist state by visual appearance in the palm of the hand, but it is better to assess fluidified earth in a porcelain dish. To precisely denominate the sample, laboratory tests pursuant to 2.4.4 are required.

Smell test (cf. DIN 4022-1) The smell of humus in the damp sample indicates the presence of organic constituents. Heating the damp sample can make this particularly recognisable. Earth of this nature cannot be used as building earth.

Determination of colour The colour of the earth indicates its chemical composition. The colour of the ground-moist earth is characterised. Earth colours range from grey to yellow-brown, earth brown, red-brown to red. Darker colours can indicate the presence of humus fractions. The colour of the earth is otherwise insignificant in terms of usability.

Determination of the lime content (cf. DIN 4022-1) Dripping diluted hydrochloric acid (3 parts water to 1 part hydrochloric acid) onto the sample results in a strong, enduring effervescence, a weak one or none at all. A natural content of lime reduces the binding strength of the building earth. This can be detected by means of the binding strength test pursuant to 2.4.4.

7


2.4.4 Laboratory tests

Technical tests specific to the field of building with earth are available as test methods. Geotechnical tests can be adapted to the purposes of investigating building with earth and can mostly be applied in a simplified form. There are correspondences between the technical classification systems of geotechnical engineering and building with earth, but the names of the building earths and types of soil have not, thus far, been harmonised.

Laboratory tests are required where it is not possible to make a definitive judgement on the basis of the basic tests or if the experience so to do is lacking.

Sampling

The composition of earth often varies in its deposition sites. For that reason, as many samples must be taken as are required to assess the entire deposition site from which building earth is extracted.

The samples shall be labelled according to the site of extraction. Multiple samples of 2 litres each from the same deposition site shall be numbered and their distance and direction from the first sample and the depth shall also be specified. No samples may be taken at a depth of less than 50 cm. Samples must be free of organic matter.

Determining the binding strength (binding strength test)

The binding strength test pursuant to DIN V 18952 sheet 2 provides immediate results on the technical suitability, from a building with earth point of view, of the building earth for the various applications. The thinning effect of any lime content present is also detected.

Brief description The resistance that plastic earth puts forward in the tensile test is called binding strength. In order to determine the binding strength, the earth is carefully prepared and brought to a defined test consistency. A test body is then formed, which test body is then ruptured in the test device. The binding strength is given in g/cm2 or N/mm2.

Earth with a binding strength below 50 g/cm2 cannot be further differentiated through the binding strength test. In general, such earth is

8

2. Building earth

not suitable for use as building earth. The potential suitability of such earth for specific purposes shall be tested in other, suitable ways.

For the exact method of testing see Annex 1 at the end of this chapter.

Table 2-1Classification of building earth by binding strength

Designation Binding strength (c/cm2)Very thin 50 – 80Thin >80 – 110Almost fat >110 – 200Fat >200 – 280Very fat >280 – 360Clay >360

Note: 100g/cm2 = 1.0 N/cm2

Determination of plasticity

The standards DIN 4022, DIN 18122 and DIN 18196 that have been introduced for earth-moving and soil engineering can be applied for investigating and denominating building earth.

The plastic characteristics of soils are differentiated on the basis of their water content at the liquid limit wL:

- slight plasticity < 35%

- medium plasticity 35-50%

- pronounced plasticity > 50%.

The plasticity index, as the difference of the water content at the liquid limit wLand the plastic limit wP, makes it possible to differentiate by physical soil behaviour between clay and silt:

Plasticity number IP = wL-wP

9


- Clay: IP ≥ 7%andIP ≥ 0.73 (wL-20)%

- Silt: IP < 4%andIP < 0.73 (wL-20)%

The plasticity is dependent on the binding strength.

Determination of the mineral framework (grain size distribution pursuant to DIN 18123)

The mineral framework of building earth can be determined in more detail pursuant to DIN 18123 (Soil, Determination of grain-size distribution) by sieving for the wet separation of fines and illustrated via a grain size distribution line. For the purposes of building with earth, the following gradation of sieving is generally sufficient:

0.06 – 0.25 – 1.0 – 2.0 mm

Building earth is denominated according to the mass of the predominant grain sizes in the following sequence:

- gravel > 2mm

- coarse sand0.2 to 2 mm1)

- Fine sand 0.06 to 0.2 mm

- Silt < 0.06 mm

1) Note: for the purposes of building with earth, medium sand (0.2 to 0.6 mm) and coarse sand (0.6 to 2.0 mm) as defined by DIN 4022-1 need not be differentiated and are grouped together as ‘coarse sand’.

Determining the grain-size distribution by sedimentation pursuant to DIN 18123 makes it possible to differentiate between the mass fractions of clay and silt in the fine grain range (< 0.06 mm) but is not suitable for determining plastic behaviour or binding strength.

10

2. Building earth

Annex 1 to Chapter 2. Building earth

Binding strength test, method of testing

Preparation of earth sample

Each test requires around ¾ of a litre of earth that is as dry as possible and no more than ground-moist. All grain sizes in the mineral framework above 2 mm shall be removed from the sample by sorting or sieving the dried, pulverised earth. The earth is beaten flat on a metal plate in a near-groundmoist state using a hammer with a head surface of 2.5 cm x 2.5 cm one hit at a time adding a small amount of water, until there is a cohesive pancake is formed. The pancake is then removed from the plate using a knife and cut into strips. The strips are then to be placed next to one another edgewise and hammered. This process is repeated until there is no longer any perceptible irregular structure on the underside of the pancake. If the earth required drying at the beginning of the preparation, it must be left to rest under a damp cloth for 6 hours after the hammering, or 12 hours in the case of fat earth. Whilst being left to rest, the moisture spreads evenly throughout the entire mass of earth.

Producing the test consistency

200 g of the prepared earth are pounded multiple times such that they are compacted on the plate. Directly thereafter, a ball is formed by hand. Being shaped for a prolonged period dehumidifies the surface of the ball, as a result of which it no longer has the same consistency throughout. The ball is then dropped onto a flat, inelastic plate. The height of the drop is 2 m from the centre of the ball. The earth has the test consistency if the diameter of the flattening is 50 mm. If the flattening is not circular, the difference between the largest and the smallest diameter may not exceed 2 mm.

Production of the test body

Earth at the test consistency in 3 layers is beaten by hand using a mallet as depicted in Figure 2 into a shape for the test body as per Figure 1 b until no further compaction is possible. The test body is smoothed out on both sides using a straight-edged knife. The test body loses its shape if it is

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dropped from a height of 10 cm onto a hard surface. At least 3 test bodies shall be made.

Tensile test

The test body is fastened into the test device shown in Figure 3 straight after preparation and the load of dry sand of 1 mm in grain size is introduced from the container shown in Figure 4 (or some other suitable test equipment), until the test body ruptures. The increase in load should be even and amount to no more than 750 g/minute.

The binding strength of a building earth is the average result of three tensile tests, which tests may only deviate from one another by 10%. It is expressed in g/cm2 or N/mm2. The calculated cross-section of the test body is 5 cm2. The weight of the lower half of the test body is not taken into account.

Figure 2-1 Test body for binding strength test (pursuant to DIN V 18952, sheet 2)

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2. Building earth

Key to figure:

Bild Figure

Gestalt des Probekörpers zur Bindekraftprüfung Form of the text body for binding strength test

Form für den Probekörper nach Bild 1a Template of the test body as per Figure 1a

Unterlegplatte für die Formen nach Bild 1b Packing block for the templates as per

Figure 1b

Zugfestigkeitsprüfer Tensile strength tester

Stampfer für Probekörper Mallet for test body

Einlaufgerät Feeding device

Inhalt 2,5 Liter Content 2.5 litres

Schieber Sliding valve

Rinne Channel

Galgen Support

Schnitt Section

Ansicht Front view

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3. EARTHEN BUILDING MATERIALS

3.1 General

3.1.1 Definitions

Earthen building materials are unshaped or shaped building materials of unfired earth with or without additives. Additives may be added in order to reduce shrinkage, cracking and susceptibility to water, to increase thermal insulation or tensile strength and resistance to pressure and abrasion or to make the materials more workable. Additives may be organic (plant-based) or mineral-based.

“Earthen building materials” within the meaning of these Rules refers solely to earth-bonded materials. Such materials achieve their sturdiness only by drying and if acted on by water at any point will become soft and shapeable again.

The reduction in volume on drying out is known as shrinkage. The measure of shrinkage represents the linear shrinkage of an earth prism after drying out.

3.1.2 Labelling of earthen building materials (declaration)

Factory-produced earthen building materials shall be labelled. The labelling should include all the characteristic values required for each building material and a full specification of the substances used to produce it.

The labelling should be clearly legible on the packaging or on a sheet accompanying the delivery.

3.1.3 Composition and preparation of earthen building materials

Earthen building materials are produced from building earth and optionally additives. Preparation covers the mixing process, with or without the addition of water, and all other work necessary to produce what are at this stage unshaped earthen building materials.

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3. Earthen building materials

The purpose of preparation is to produce a homogeneous mass of starting materials that is ready-to-use and to unlock and evenly distribute the clay minerals that provide binding strength.

Whenever earthen building materials are prepared it must be absolutely ensured that contamination with any kind of humus is prevented.

Starting materials, mixing ratios and mixing processes shall be selected such that the requirements that are made of the various building materials can be met in the best possible way. References in Chapter 3 to the suitability of building earth and to mix ratios thus serve in this regard only as rules of thumb for a rough approach. The evaluation of the finished building materials is decided by their characteristics.

3.1.4 Classification of building materials

Earthen building materials are classified by density, additives, processing or use. These Rules cover the following earthen building materials:

- Rammed earth (3.2)

- Cob (3.3)

- Fibrous clay, clay straw (3.4)

- Light clay (3.5)

- Earth fillings (3.6)

- Earth blocks (3.7)

- Clay panels (3.8)

- Earth mortars (3.9)

3.1.5 Abbreviations

The following (German-language) abbreviations are used for earthen building materials:

Rammed earth STL

Cob WL

Fibrous clay, clay straw FL, SL

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Light clay LL

- Wood light clay HLL

- Straw light clay SLL

- Fibrous light clay FLL

- Mineral light clay MLL

Earth filling LT

Earth blocks LS

Clay panels LP

Earth mortars LM

- Earth masonry mortars LMM

- Earth plaster mortars/rendering LPM

- Sprayed earth mortars LSM

3.1.6 Use of earthen building materials

Earthen building materials can be differentiated, amongst other things, by the degree of prefabrication, their static function, the place in which they are prepared or their degree of moisture at installation.

Unshaped building materials include earth mortars and light clay preparations, shaped building materials include earth blocks and clay panels.

Load-bearing earthen building materials with sufficient compressive strength include earth blocks and rammed earth. Materials that are useful only for framing, in other words not having a load-bearing function, include clay straw and light clay.

Building materials that are installed damp are shaped into a building material or applied on-site. Form dry installation, dried bricks are built into walls using mortar. In dry construction, panels are laid dry.

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3.1.7 Re-use, recycling and disposal of earthen building materials

Appropriately constructed, earthen building materials can be re-used. Recycling is possible by means of mechanical comminution and re-preparation with water. The potential for contamination with salts that are counter to building use must be watched out for. Earthen building materials can be landfilled in an environmentally friendly manner.

3.2 Rammed earth (STL)

3.2.1 Definition

Rammed earth is an earthen building material prepared ground-moist. The dried, compacted building material has a particle density of 1700 to 2400 kg/m3. Adding lightweight additives makes it possible to achieve lower densities.

3.2.2 Use

For rammed earth walls, the building material is compacted in a working formwork; for the production of earth blocks it is pressed in moulds or manually rammed; for rammed earth floors it is compacted flat.

3.2.3 Composition

Building earth

Thin to fat building earths may be used to produce rammed earth. The binding strength may be increased by the addition of powdered clay. Very fat building earths and clays are only capable of being processed into homogeneous rammed earth mixtures with difficulty.

Naturally mixed-grained to stony earth (such as mountain earth or slope wash) is particularly well-suited.

Additives

Preparation involving additives is necessary if the building earth has too high a measure of shrinkage and thus cannot be used as a building material without addition or in order to increase compressive strength and,

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where appropriate, weather-resistance. Mineral-based additives are coarse sand, gravel or grit. Crushed mineral matter is particularly suitable. A wide-ranging distribution of grain sizes shall be observed. Organic additives include straw up to around 10 cm in length or fine fibres (flax, hemp). Mixtures of these are possible.

In thin earth, the volume ratios of building earth to additives is 1:1 to 1:2, in fat earth it may be up to 1:2.5. If fibres are mixed in, the quantity used depends on the binding strength of the building earth and the type of fibres. Experience shows that the addition of fibres amounts to up to 10 kg per m3 of building earth.

3.2.4 Preparation

Preparation takes place by hand or using suitable mixing technology. Preparation is complete when the building earth is homogeneously mixed and uniformly moist. The ready-to-use rammed earth has a ground-moist consistency. The rammed earth must be well-compacted without yielding too much under the mallet. The appropriate preparation consistency shall be checked and monitored by the executing parties prior to and during installation.

In order to reduce cracking due to shrinkage, the measure of shrinkage of the compacted building material pursuant to 3.2.5 should not exceed 2% and in visible components it should not exceed around 0.5%.

3.2.5 Testing

Particle density

Test cubes of side 20 cm shall be produced at the same compression ratio as on the building site. The rounded average of at least three tests shall be the decisive value. Individual values may not deviate from the average value by more than 10%.

Compressive strength

Compressive strength is determined on at least three test cubes. The smallest individual value is definitive. The test cubes shall be produced at the same compression ratio as on the building site and shall be of side 20 cm. It is not permitted to accelerate drying. It shall be tested whether

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equalised dampness is achieved under normal indoor conditions, usually after 6 weeks. Before building commences, the first batch shall be tested, then building-site mixes approximately every 10 m3 and factory mixes approximately every 50 m3.

Measure of shrinkage

The measure of shrinkage is measured on a test body of 600 mm in length, 100 mm in width and approximately 50 mm in height, on which two gauge marks are carved at a distance of 500 mm apart. Stones that impede production of the test body are sifted out. After removal from the formwork, the test body is laid on a membrane and dried naturally. The final measure of shrinkage is measured. Before building commences, the first batch shall be tested, then building-site mixes approximately every 10 m3 and factory mixes approximately every 50 m3.

3.2.6 Labelling

The building material classification shall be specified as “rammed earth” or the abbreviation “STL”.

The particle density of the dry building material shall be specified in kg/m3, rounded to the nearest 100 kg/m3. Deviations of ± 10% are permissible.

The compressive strength shall be specified in N/mm2, rounded off to one decimal place. The value specified must not be gone below. Rammed earth usable for non-loadbearing purposes, and only such earth, may, as an alternative, bear a note to that effect.

The measure of shrinkage shall be specified as a percentage, rounded to one decimal place. The value specified must not be exceeded.

3.3 Cob (WL)

3.3.1 Definition

Cob is a mixture of straw and earth prepared soft. The dried building material has a particle density of 1400 to 1700 kg/m3.

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3.3.2 Use

Cob is used to repair historic cobwork walls and to build new load-bearing or non-loadbearing walls.

3.3.3 Composition

Building earth

All types of building earth can be used for cob. Only very fat earth and clay are unsuitable, together with stony earth.

Additives

Straw of 30 to 40 cm in length is used as additive. Too high a proportion of short straw is to be avoided. In thin earth, around 20 kg of straw is assumed per m3 of loose earth, in fat earth it may be up to 25 kg.

3.3.4 Preparation

Earth and straw are added alternately, water is poured on top and worked through. Preparation is complete when the building earth is uniformly mixed with the additive. Before installation, the freshly prepared building material should be left to rest (mature).

3.3.5 Testing

Particle density

The particle density is determined from test cubes of side 20 cm that are to be produced as on the building site. The rounded average value from at least three tests shall be definitive. Individual values may not deviate by more than 10% from the average value.


Compressive strength is determined on at least three test cubes. The smallest individual value is definitive. The test cubes shall be produced and compressed as on the building site and shall be of side 20 cm. It is not permitted to accelerate drying. It shall be tested whether equalised dampness is achieved under normal indoor conditions. Before building

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commences, the first batch shall be tested, then building-site mixes approximately every 10 m3 and factory mixes approximately every 50 m3.

3.3.6 Labelling

The building material classification shall be specified as “cob” or the abbreviation “WL”.


The compressive strength shall be specified in N/mm2, rounded off to one decimal place. The value specified must not be gone below. Cob usable for non-loadbearing purposes, and only such cob, may, as an alternative, bear a note to that effect.

3.4 Fibrous clay, clay straw (FL, SL)

3.4.1 Definition

Fibrous clay is generally a soft to pulpy prepared mixture of plant fibres and earth. Where fibrous clay is prepared using straw the resultant building material is called clay straw. The dried building material has a particle density of 1200 to 1700 kg/m3.

3.4.2 Use

Clay straw (fibrous clay) is used as an infill material for framed walls and joist ceilings and is also used for plastering-type applications. If pressed in moulds, earth blocks or clay panels can be produced.

3.4.3 Composition

Building earth

Earth classified by binding strength as very thin to thin can be used as building earth.

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Where fibrous clay is prepared by hand, it is recommended to use a sand-free, silty building earth in order to look after the hands in question.

Additives

Soft types of straw such as rye, oats, barley and coarse hay or other plant fibres in lengths suited to the purpose at hand. Straw, for example, is used in lengths of 5 to 25 cm. Fibrous clay can also be thinned with sand. The density of additives (mass fraction of the additive/m3 of the component) should be as high as possible to ensure low shrinkage and to build the framework. This density is around 40 to 60 kg/m3 in the case of straw. In the case of finer or shorter fibres, the fractions are higher.

3.4.4 Preparation

The building earth is prepared in a soft to pulpy consistency and mixed with the straw/fibres.

Suitable mixing ratios are determined by experimentation, in dependence on the starting materials used and the purpose. Preparation is complete when the building earth is uniformly mixed with the additive. The fibres must be enclosed by earth at all points.

Where clay straw (fibrous clay) from old timber framing is re-prepared it may be additionally thinned with sand or fibres. Fibres also act as reinforcement.

3.4.5 Testing

Particle density

Test cubes of side 20 cm shall be produced as on the building site. The rounded average value from at least three tests shall be definitive. Individual values may not deviate by more than 10% from the average value.

Shrinkage, suitability

The suitability of the building material can be evaluated by means of a component sample. Clay straw prepared with sufficient straw exhibits close to zero shrinkage or cracking. The lack of cracking does not have to be a requirement in every case, however.

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3.4.6 Labelling

The building material classification shall be specified as “clay straw” or “fibrous clay” or the abbreviation “FL” or “SL” as appropriate.


3.5 Light clay (LL)

3.5.1 Definition

Light clay is an earthen building material with a particle density of 300 to 1200 kg/m3. The earth is prepared in a runny to pulpy state and mixed with organic or mineral lightweight additives.

Light (300 to 800 kg/m3) and heavy mixtures (900 to 1200 kg/m3) are differentiated according to particle density.

Light clay can have additional labelling according to the type of lightweight additive used, e.g.:

Straw light clay (SLL)

Fibrous light clay (FLL)

Wood light clay (HLL)

Mineral light clay (MLL).

3.5.2 Use

Light clay is used for exterior and interior walls, facing formwork or ceiling infills.

The building material is compacted into formwork in the moist state or shaped into bricks, large elements or panels.

Light clay is used to enclose spaces and may not bear any load save its own weight.

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3.5.3 Composition

Building earth

For light mixtures an earth classified according to its binding strength as at least almost fat should be used. Very fat earth or else clay or powdered clay that can be turned into slurry may also be used. Thin to very thin earth should only be used for very heavy mixtures.

It is recommended to use a building earth with a silty mineral framework.

The building earth must be free of humus or other organic impurities.

Lightweight additives

Organic additives include all kinds of straw, wood chippings and all other plant-based fibrous materials that are sufficiently resistant to the moisture of installation. Fibrous additives should be no longer than the shortest dimension of the building material or component being produced.

Mineral-based additives include all porous natural or artificial rock such as pumice, expanded clay, perlite, expanded shale, expanded glass and so on.

Mixtures of the various additives are permitted.

Mixing ratios

Suitable mixing ratios are determined by experimentation, in dependence on the starting materials used. The density of additives (mass fraction of the additive/m3 of the component) should be as high as possible in order to build the framework, largely irrespective of whether it is lightweight or heavy mixtures that are in question. The particle density realised is decided by the mass fraction of the earth, which fills the spaces between the additives to a greater or lesser extent. The additive densities for baled straw, for example are around 60-90 kg/m3. In the case of wood chippings they around 300kg/m3, while for mineral-based lightweight additives they are around 300-600 kg/m3.

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3.5.4 Preparation

The building earth or clay is slurried with water and mixed with the lightweight additives in a runny to pulpy consistency. The slurry is prepared either manually or in suitable stirring machines or mixers.

Fat earth can be prepared to be runny but thinner earth should be prepared to be of a pulpy consistency.

The additives have slurry poured on them, are immersed in the slurry or are machine-mixed with it. Before installation, the freshly prepared building material should be left to rest (souring).

Lightweight mixtures have an open structure in which the lightweight additives are only bound by the earth. Heavy mixtures, on the other hand, have a closed structure.

Composition and preparation shall be chosen in such a way that, in the prepared building material, as well as in the shaped component, organic additives, above all, are evenly enclosed by earth. The shaped dry building material should exhibit a sturdiness sufficient for its intended use.

Provided that these requirements are met, even methods of preparation that deviate from the above description may be used.

3.5.5 Testing

Particle density

Test cubes of side 20 cm shall be produced as on the building site. The rounded average value from at least three tests shall be definitive. Individual values may not deviate by more than 10% from the average value.

Consistency of the slurry

The prepared building material, or where appropriate a component sample, is checked to ensure the reliable enclosing of the additives with earth slurry. A consistent consistency of the slurry can be checked by means of the slump, determined as the diameter of 100 ml of slurry poured on a sheet of metal or glass.

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Sturdiness

The sturdiness of the building material can be evaluated by means of a component sample. No compression test is required.

3.5.6 Labelling

The building material classification shall be specified as “light clay”(with the additive also being specified) or the abbreviation “LL” (or “HLL”, “SLL”, “FLL” or “MLL” as appropriate).


3.6 Earth fillings (LT)

3.6.1 Definition

Earth fillings are earth-bonded, free-flowing preparations of building earth and additives to fill horizontal components. The dried building materials have particle densities of 300 to 2200 kg/m3. Earth fillings with a particle density below 1200 kg/m3 can also be called light earth fillings.

Earth fillings may also be designated in accordance with their additive, as in the following examples:

sand/earth filling

wood/earth filling

wood/light earth filling

building earth filling (no additives).

3.6.2 Use

Earth fillings are used to provide mass filling for ceilings and to fill cavities. Earth fillings can be produced in various particle densities to provide the desired characteristics.

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3.6.3 Composition

Earth fillings consist of building earth or mixtures of building earth and additives. All types of building earth are suitable. The additives may be mineral-based or organic. Suitable mixing ratios are determined by experimentation, in dependence on the starting materials used.

3.6.4 Preparation

The building earth is mixed with the additives either by hand or mechanically. Installation should take place in a ground-moist state.

3.6.5 Testing

Particle density

The test bodies shall be produced for earth fillings and compressed as on the building site and shall be of side 20 cm. The rounded average of at least three tests shall be the decisive value. Individual values may not deviate from the average value by more than 10%.

3.6.6 Labelling

The building material classification shall be specified as “earth filling” or “fibrous clay”, as appropriate, or the abbreviation “LT”.


3.7 Earth blocks (LS)

3.7.1 Definitions

All dried, cuboid earthen building materials are generally referred to as earth blocks.

Earth blocks with a particle density below 1200 kg/m3 can also be called light earth blocks.

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3.7.2 Use

Earth blocks are divided into use classes in Table 3-1 depending on their intended purpose and loading.

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Table 3-1Earth block use classes

Use class UsesI Plastered exterior walling that is exposed to the

elementsII Faced, weather-proofed external walling,

indoor wallingIII Dry use (flooring, stacked walls)

Earth blocks of Use Class I must have a homogeneous structure, adequate resistance to water and frost and may only exhibit a small amount of swelling behaviour. Where the compressive strength is adequate, they can be used for load-bearing masonry. Class I blocks should be used as unperforated full blocks, not counting handle holes. Honeycomb bricks are not permitted.

Earth blocks of Use Class II must exhibit adequate sturdiness and may not swell excessively when taking on moisture in wall-building and plastering in the course of the use envisaged. Where the compressive strength is adequate, they can be used for load-bearing masonry. Class II blocks should exhibit a proportion of no more than 15% of cavities derived from their manufacture.

Earth blocks of Use Class III must be sufficiently sturdy for the use envisaged. There is no restriction on the proportion of cavities in Class III blocks.

Earth blocks must be dried for wall-building and must be as free as possible of shrinkage cracks.

If earth blocks are used for load-bearing purposes, they must meet at least Strength Class 2. In other words the smallest individual value of the compressive strength under 3.7.7 must be at least 2 N/mm2 and the average must be at least 2.5 N/mm2. The requirements laid down in Table 4.1 of Section 4.1 shall be satisfied.

3.7.3 Composition and production

Earth blocks are produced from earthen building materials or from prepared building earth. In the manual moulding method, soft earthen building material is beaten (“thrown”) into mould frameworks and then

29


levelled off. In the compression method, the earthen building material is pressed into moulds in the ground-moist state. In the extrusion moulding method the blocks are cut from a continuous slab moulded by a die relief. Optimised additives and reduced moulding pressure make it possible to produce a sufficiently homogeneous structure.

Earth blocks may also be prepared on-site using similar, suitable methods such as ramming into moulds.

Green bricks is the name given to certain “green” blocks from brick production that are intended for firing but are used unfired. They are usually produced using the extrusion moulding method with, for the most part, high compaction, from earth and clay preparations.

3.7.4 Suitability

The categorisation of earth blocks into Use Classes I and II is to be done by the manufacturers on their own responsibility.

Shaped, moulded and rammed earth blocks generally exhibit the characteristics necessary for Class I. In the case of extrusion-moulded earth blocks, particular attention must be paid to their characteristics (sturdiness, homogeneity, water-resistance, swelling behaviour).

Green bricks are susceptible to breaking, dissolve quickly in water and have a dense, shell-like structure derived from their manufacture. When they take on water they swell considerably. Green bricks may not be used in Class I, while their suitability for Class II is to be tested by the user.

3.7.5 Testing

Format

The dimensions are determined in a method analogous to DIN V 105-1.

Particle density

The blocks themselves may be used as test bodies. The rounded average of at least three tests shall be the decisive value. Individual values may not deviate from the average value by more than 10%.

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The compressive strength of earth blocks shall be [tested] pursuant to DIN V 105-1. Standard and thin-format blocks shall be halved and the two halves laid atop one another with a cement mortar layer no more than 5 mm thick. In order to even out any unevenness, the top and bottom of the test body so produced shall be smoothed out with no more than 5 mm of cement mortar. Full bricks of larger formats (above 113 mm in height) shall be tested over the entire block, as shall perforated bricks. Six test bodies shall be the required number of samples.

The pressure shall be applied perpendicular to the direction of laying, as is the case in brickwork. The compressive strength is determined from the breaking load determined in the compression test in relation to the surface area of the test body (including any cavities). The compressive strength shall be stipulated in the test report in N/mm2, rounded off to one decimal place.

Earth blocks used for load-bearing purposes shall be categorised by strength class. In so doing, the smallest individual value of the test series may not be less than the strength class value. The average must be 25% above the strength class value. Earth blocks used for load-bearing purposes must be of at least Strength Class 2 – in other words the smallest individual value must be above 2 N/mm2 and the average must be above 2.5 N/mm2. Repetition tests shall be performed every 50 m3 on factory-produced earth blocks and every 10 m3 on hand-shaped earth blocks. Three test bodies shall be tested.

3.7.6 Labelling

The building material classification shall be specified as “earth block” or “light earth block”, as appropriate, or the abbreviation “LS”. In addition, the use class and the method of manufacture shall be specified.

The format can be specified as a format abbreviation in line with DIN V 105-1 Table 5 and/or as length x width x height rounded to whole numbers in mm or to one decimal place in cm. What is referred to are the minimum and maximum permissible measurements and the permissible measurement ranges pursuant to DIN V 105-1 Table 2. In formats other than those of the standards, the minimum and maximum permissible

31


measurements and the permissible measurement ranges shall apply on a proportional basis.

The particle density shall be specified in kg/m3, rounded to the nearest 100 kg/m3. Deviations of ± 10% are permissible.

In the case of earth blocks used for load-bearing purposes, the block strength class shall be specified. Earth blocks usable for non-loadbearing purposes, and only such blocks, may, as an alternative, bear a note to that effect.

3.8 Clay panels (LP)

3.8.1 Definition

Clay panels are building materials in panel form. Clay panels with a particle density below 1200 kg/m3 can also be called light clay panels.

3.8.2 Use

Clay panels are built into walls or linked together dry. These panels are used in non-loadbearing walls, as infill panels in joist ceilings or sloping roofs and as flooring.

Thin clay panels are used as facings and in dry construction. In addition, they are also used as plaster base panels.

3.8.3 Composition and manufacture

Clay panels are manufactured as unshaped earthen building materials. Other production methods include extrusion moulding, individual moulding, brushing and jacketed production. Clay panels can also be produced on-site using suitable methods.

In order to increase flexural strength and durability on transport, reinforcements such as wooden slats, bamboo or reeds may be incorporated.

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3.8.4 Testing

Particle density

Clay panels are cut to a suitable size to form test bodies. The rounded average of at least three tests shall be the decisive value. Individual values may not deviate from the average value by more than 10%.

3.8.5 Labelling

The building material classification shall be specified as “clay panel” or “light clay panel”, as appropriate, or the abbreviation “LP”.

The particle density shall be specified in kg/m3, rounded to the nearest 100 kg/m3. Deviations of ± 10% are permissible.

3.9 Earth mortars

3.9.1 Definition

Earth mortars are building earths thinned with fine-grained or fine-fibred additives. Mortars with a dry particle density below 1200 kg/m3 can also be called light earth mortars.

3.9.2 Use

Earth masonry mortars (LMM) and light earth mortars are used as mortars for earth blocks or artificial stone, fired stone or natural stone.

Sprayed earth mortars (LSM) and sprayed light earth mortars are used as infill for wooden constructions, to produce facing formwork and interior walls and as infill for ceilings. This category does not cover sprayed plaster mortars/rendering.

Earth plaster mortars/rendering (LPM) and light earth plaster mortars/rendering are used for resurfacing walls and ceilings indoors or in outdoor areas protected from weathering.

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3.9.3 Composition

Earth mortars are produced from building earth with suitable additives. The starting materials must be selected such that the characteristics of the finished mortar comply with the requirements of these Rules.

The characteristics of earth mortars essentially depend on the binding strength of the building earth. It is recommended to use a building earth that is not too lean, is free of stones and has a grain size below 5 mm.

The additives used for earth mortars are sand, chopped straw or other plant-based fibrous materials. For light earth mortars suitable mineral or plant-based light additives are used. For plaster mortars/rendering historical or regional additives such as whey or dung may also be used, where experience and the necessary testing are in place.

3.9.4 Preparation

General

Earth mortars should be thinned to the extent that shrinkage cracking is no longer exhibited after drying. Thinning beyond this reduces the compressive strength of the mortar and the adhesive strength and abrasion resistance of plastering. In plaster undercoats a small extent of shrinkage cracks can be tolerated.

Earth mortars must be thinned and prepared, depending on their purpose, to be machine or trowel-ready.

Building site mortars

Building site mortars are made up from individual starting materials and mixed on the building site. Due to the very differing starting materials in building with earth, binding mixing ratios cannot be prescribed. Formulations are determined by experience and local building tradition.

Mixes produced on site must be free of large grains above 5 mm. Dug earth should be left to mature and should be well mixed. Special attention must be paid to the homogeneity of the mix.

The freshly prepared building material can be worked immediately or after it has been allowed to rest (mature).

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Factory materials mortars

Factory materials processed mortars are made up from the starting materials supplied by the manufacturer (such as crushed earths) and mixed to the formulation on the building site (adding sand, for example).

Factory-supplied mortars

Factory-supplied mortars are supplied dry or ground-moist and mixed with water on the building site according to the manufacturer’s instructions.

Recycled mortars

Earth mortars can be re-prepared from recycled masonry mortar, old plastering or clay straw and water, provided the material used is free of impurities (such as salt). If cracks form in the re-preparation process, the mix can be thinned using additional sand or straw.

3.9.5 Requirements

Depending on the intended use and loading, masonry mortars, plaster mortars/rendering and sprayed mortars have to meet differing requirements and exhibit specific characteristics.

These are essentially as follows:

- compressive strength,- dry particle density, and- measure of shrinkage.

The mortar supplied must comply with the requirements and the values stipulated. In the case of factory-supplied mortars and factory materials mortars the initial inspection and the factory production control shall proceed in line with DIN EN 998.

In the case of building site mortars, suitability can be tested using a component sample and other samples. If the intended use so requires, the requirements for factory-supplied mortars shall apply as appropriate (e.g. the required compressive strength for load-bearing walls).

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3.9.6 Testing

Sampling

Sampling should be based on DIN EN 1015-2.

Particle density (hardened mortar)

Test cubes of side 10 cm shall be produced as on the building site. Alternatively, prisms may be used for compression testing (see below). The rounded average of at least three tests shall be the decisive value. Individual values may not deviate from the average value by more than 10%.


The compressive strength is tested using three air-dried prisms in accordance with DIN EN 1015-11. The smallest individual value is definitive. The samples are produced using mortar in the preparation-ready consistency.

Measure of shrinkage

The linear measure of shrinkage is determined on three prisms with the dimensions 160 mm x 40 mm x 40 mm. After removal from the formwork, the test bodies are laid out on a membrane and air-dried. The final measure of shrinkage is measured. The samples are produced using mortar with a consistency of 140 mm slump, in accordance with DIN EN 1015-3.

Shrinkage (building site sample)

The propensity of the mortar to crack can be estimated using a sample surface.

3.9.7 Labelling

The building material classification shall be specified as “earth masonry mortar ”, “sprayed earth mortar ” or “earth plaster mortar/rendering” depending on the intended use, preceded by the word “light” where appropriate. As an alternative, the abbreviations “LMM”, “LSM” or “LPM” can be used.

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The particle density of the dried mortar shall be specified in kg/m3, rounded to the nearest 100 kg/m3. Deviations of ± 10% are permissible.

The compressive strength of the earth masonry mortar shall be specified in N/mm2, rounded to one decimal place. The value specified must not be gone below. Earth masonry mortar usable for non-loadbearing purposes, and only such earth masonry mortar, may, as an alternative, bear a note to that effect.

The measure of shrinkage shall be specified as a percentage, rounded to one decimal place. The value specified must not be exceeded.

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4. COMPONENTS BUILT WITH EARTH

4.1 Load-bearing walls

The design of buildings constructed of load-bearing components built with earth shall for the time being continue to follow the global safety factor approach, which is reflected in the reduction of the compressive strength to permissible stresses. Conversion to design using partial safety factors in accordance with DIN 1055-100 is in preparation.

Proof of the stability of load-bearing walls may be furnished using the following method if the prerequisites contained in this chapter and in particular in Tables T 4-1 and T 4-2 are satisfied.

4.1.1 General

The plan for buildings with load-bearing walls made of earthen building materials needs to take account of the material properties and the method of manufacture.

Definition

Walls and pillars are classed as load-bearing if they bear vertical and/or horizontal loads and/or serve to provide reinforcement of load-bearing walls to prevent them buckling.

Works management, special requirements

Buildings with load-bearing earth walls should only be used with instruction and supervision from skilled workers that are sufficiently experienced in the manufacture of load-bearing components built with earth (see 1.3.2).

Building period

When damp, earth can be susceptible to frost heave. Rammed earth walls and cob walls are endangered by frost for longer than walls made of hydraulically bound building materials. Earth block walls may only be used if the absence of frost can be guaranteed.

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4. Components built with earth

Protection against weather during the execution of the building work

During execution and drying, the top and sides of all components built of earth must be shielded from heavy rain by means of protective covers.

The cover must be put on

a) if it starts to rain, andb) at the end of the working day.

4.1.2 Construction

In principle, combining with other solid building materials should be avoided on account of the differing settlement behaviour . Combined masonry in particular is not permitted within a single layer.

Moistureproofing

Load-bearing components built with earth must be reliably protected against contact with soil moisture or spray water - including in damp rooms. Particular care is required on flood plains. A damp-proof course shall be provided to protect against rising damp. However, earth walls may not be erected directly on top of damp-proof courses. They shall be separated from the damp-proof course by a layer at least 5 cm thick made of waterproof materials. External skirting projections are not permitted immediately at the foot of earth walls.

Earth walls may not be erected directly on top of solid floor panels on which water may accumulate. They must stand on a waterproof layer that is at least 5 cm thick. The water must be able to drain away at all times.

Requirements

Proof shall be furnished in accordance with Tables T 4-1 and T 4-2 with regard to load-bearing walls and the building materials used. Proof shall be furnished on a case-by-case basis for greater storey heights and greater distances between transverse walls.

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Reinforcement

The stability of loaded walls must be adequately ensured by means of reinforcing transverse walls or ceilings or by other means, so that any horizontal forces e.g. wind forces, are also safely conducted to the subsoil.

Ceilings shall be designed as rigid sheets, which shall be connected to the walls accordingly. Alternatively, ring beams, the static properties of which have been proven, shall be present . In all other cases, the absorption of the wind forces shall be proven by calculation.

Proof of spatial rigidity may be dispensed with if reinforcing walls in accordance with T 4-2 are present in the longitudinal and transverse directions of the structure.

If the reinforcing transverse walls are interrupted by openings, the distance from the reinforcing wall to the first opening must be ≥1/4 of the height of the storey, but at least 75 cm. The reinforcing walls must extend to the skirting or basement masonry walls without any great weakening or misalignment.

Reinforcing transverse walls must be erected at the same time as the walls that are to be reinforced on account of differing settlement. In the case of rammed earth walls reinforced on one side, tension rods shall be placed at the level of the ceiling and at 1/3 and 2/3 of the wall height, penetrating at least 1.5 m into the transverse walls. If simultaneous erection is particularly difficult from a construction point of view, masonry walls shall be interlocked and rammed earth walls shall be connected together or with masonry walls using a 5 cm deep channel in the wall that is to be reinforced.

Anchoring of the walls

Exterior walls must be connected to the ceiling by wall ties in a manner resistant to tensile forces. Gable walls must be protected against wind pressure and wind suction by means of wall ties at the roofing bond.

Supports and openings

The building materials to be used for the supports for ceilings, main beams and door and window lintels shall be selected according to the stresses that occur. The distribution of pressure under point loads can be estimated to be 60°. The loads shall be directed as centrally as possible.

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Otherwise, the influence of eccentricity shall be taken into account in connection with the stress analysis.

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T 4-1Requirements pertaining to load-bearing walls1) constructed of earthen building materials 1 Masonry made of

earth blocks in MG II

Masonry made of earth blocks2)

with earth mortar3)

Rammed earth Cob

2 Proofs3 With 1-2 full

storeys4)Stone strength class

Stone strength class

Compressive strength and measure of shrinkage


4 Stone strength class or compressive strength [N/mm2]

2 3 4 2 3 4 2 3 4 1

5 Permissible compressive stresses [N/mm2]5)

0.3 0.4 0.5 0.3 0.46) 0.56) 0.3 0.4 0.5 0.2

6 Measure of shrinkage [%]

- - ≤ 2

7 Minimum wall thickness for external walls [cm]7)

36.5 36.5 32.5 40

8 Minimum wall thickness for internal walls [cm]8)

24 24 24 40

9 Minimum cross section of pillar-style walls [cm2]

1300 1300 1600 3200

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Footnotes to Table T 4-11) permissible storey height ≤ 3.25 m2) also other artificial stone or natural stone of any kind3) including mortar of MG I4) storey height ≤ 3.25 m, in the case of a full storey max. wall height including jamb wall 4

m above the upper edge of the skirting5) in the case of pillar-style walls, the permissible stress should be decreased to 1.5 times

the minimum cross-section using the factor 0.8.6) permissible in connection with proof of the compressive strength of mortar on a level with

the relevant stone strength7) a minimum wall thickness of 24 cm is permissible in the case of single-storey structures

that are not used for the permanent accommodation of people and have a storey height of

≤ 2.5 m. Compliance with the permissible compressive stress and the guarantee of spatial

stability shall be proven.8) Conditions: Storey height ≤ 2.75 m, live load including addition for parting wall

≤ 2.75 kN/m², only permissible as intermediate support for continuous ceilings with spans

of ≤ 4.5 m or in the case of the arrangement of a centring strip on a ring beam 6.0 m.

Deviation from these conditions requires the same thickness as the external walls.

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T 4-2Reinforcing transverse wallsWall thicknesses and maximum distances

Thickness of the reinforcing,

loaded wall

Storey height Minimum thickness of the

reinforcing transverse

walls

Maximum centre spacing

(cm) (m) (cm) (m)24 to 36.5 ≤ 3.25 11.5 4.5

>36.5 to 49 ≤ 3.25 17.5 6.0>49 to 61.5 ≤ 3.50 24 7.0

Supports for lintels shall be at least 24 cm deep. Where calculations require larger support lengths, the deflection of the lintel shall be limited to l/500. Alternatively, the wall areas that are subject to higher loads can be executed with a higher masonry strength.

Door and window reveals should not consist of different building materials at the level of the openings due to differing settlements .

Grooves and recesses in load-bearing earth walls are permissible without further proof, provided their arrangement and dimensions comply with the limit values in DIN 1053-1 Table 10. If these limit values are exceeded, this is required to be noted in the proof of stability.

4.1.3 Execution of earth block walls

Building material

Earth block walls are built of earth blocks with earth mortars or other mortars. The blocks must be stored in a dry place.

Fabrication

The butt joints and coursing joints shall be filled with mortar to a thickness of approximately 1 cm. Rammed and pressed blocks should be laid in such a way that the wall load acts in the direction of ramming or pressing. Earth blocks shall be bonded in a manner fit for purpose. The compressive strength of the mortar shall be tailored to the strength of the earth blocks.

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Joints on external surfaces can be raked out to a depth of 1 cm to improve the adhesion of the lime render.

4.1.4 Execution of rammed earth walls

Building material

Rammed earth is used as the building material for rammed earth walls. The building material should be protected when stored.

Fabrication

The rammed earth is placed in a rigid formwork to a depth of approximately 10 to 15 cm, according to the material and compaction equipment, and compacted. Horizontal reinforcing fillers can reduce the tendency for cracks to form.

Drying

The drying times shall be taken into account when planning the building period.

Measures to make plaster adhere

External lime rendering adheres to larger mineral components on the wall surface. Surfaces with stony additives are cleaned using a steel broom. In the case of walls made of fine-grained rammed earth, the adhesion of plaster can be achieved by means of rammed stone or mortar strips, indentations or plaster base.

4.1.4 Execution of cob walls

Building material

Cob walls are built of cob.

Fabrication

The walls are built up in sweeping layers without formwork with a fork in courses around 80 cm high. The individual courses are cut off flush with the building line once they have dried out sufficiently. Cob walls must not be plastered for at least a year on account of settlement and deformation.

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Drying

The drying times shall be taken into account when planning the building period. Damp earthen building materials must be able to dry as quickly as possible. Moisture penetration for too long can cause organic additives to rot, weaken adjacent wood components and cause the corrosion of steel components.

4.1.6 Repair of load-bearing earth walls

Repairs must be carried out in keeping with the building material. Damaged parts or parts that have been penetrated by salts are cut out down to the preserved material and replaced by earth block masonry in earth mortar. Smaller defects can be pre-wetted and filled with a suitable earthen building material. Larger sections of wall can be executed using stocks of similar building materials. Care shall be taken to provide adequate bonding by means of grooves, interlocking or anchoring.

4.2 Vaulting

Definition

Clay vaults are structures curved on one side, domes are structures curved on two sides. Barrel vaults are low clay vaults with short spans used as load-bearing fillings between beams or girders.

Building materials

Vaults are built of earth blocks in earth or lime mortar. The compressive strength of the building materials used shall be proven.

Planning and works management

The planning and works management of vaulted constructions may only be transferred to sufficiently experienced experts.

Building period

Vaults may only be built if the absence of frost can be guaranteed.

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Protection against weather during the execution of the building work

During execution and drying, the top and sides of all components built of earth must be shielded from heavy rain by means of protective covers.

The cover must be put on

a) if it starts to rain, and

b) at the end of the working day.

Any moisture penetration could jeopardise stability. The construction of canopies is recommended.

proof of stability

Stability shall, in any case, be determined. Proof shall be furnished with regard to vaulted ceilings in accordance with DIN 1053-1.

Construction

Vaults should as far as possible be loaded with normal forces only on account of the low flexural tensile strength of the masonry. Pressure line shapes are therefore recommended. For small spans, normal circles, which are easier to make, can be sufficient.

Moistureproofing

Vaulted components exposed to weathering are given a protective roof construction or a roof waterproofing sheet. Base points shall be reliably protected.

Execution

The blocks shall be laid with flush joints. For the execution, sufficiently stable working formwork is used or the walls can be built free-hand using appropriate masonry guides.

4.3 Non-loadbearing walls and infill

Non-loadbearing walls and infill are mainly subject to dead load only, as well as to wind forces in the building shell. They do not have a reinforcing effect. Non-loadbearing walls must satisfy the requirements of DIN 4103.

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Grooves and recesses should not exceed the dimension limits in accordance with DIN 1053-1.

4.3.1 Infill of framed walls

Definition

Infill is understood to be filling with earthen building materials. The infilling methods are consistent with the framework construction, divided into small sections.

Building materials

Clay straw, light clay and earth blocks of the appropriate use class and earth mortars are used as building materials.

Building period

When damp, earth can freeze. Earthen building materials such as clay straw and light clay or even earth mortar that are installed damp are at risk from frost for longer than walls made of hydraulically bound materials.

Protection against weather during execution of the building work

Earth framework shall be protected against heavy rain.

Drying

The drying times shall be taken into account when planning the building period. Components built with earth must be able to dry as quickly as possible. Moisture penetration for too long can cause organic additives to rot, weaken adjacent wood components and cause the corrosion of steel components. Surfaces that remain damp for a long time can mould.

Wattle and daub

The wattle or wickerwork) is made of canes that are weaved into strutting. The struts, sawn or split and pointed at the end, are inserted into grooves, slots or holes in the framework beams. The position of the strutting is measured from the flush face and is approximately 5 cm. Stable, straight and durable canes (e.g. willow or hazel) are suitable for the wattle. The

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canes should not be displaced during application and they should be spaced according to the method of application chosen.

It must be possible for the daub, consisting of clay straw with a pulpy consistency, to be pressed through the canes. Inner and outer layers should be applied one after the other. The first application should have dried. Timber framing that is to be plastered should be even and set back from the flush edge of the beams by the same thickness as the plaster.

To ensure the adhesion of the lime render the surface should be suitably roughened, unless a special render base is provided. Clay straw mixtures with as high a proportion of straw as possible are recommended, this straw being combed out of the surface using comb strokes or similar techniques. In the case of sandy clay straw with a smaller proportion of straw, holes must be made in the surface to improve render adhesion.

When repairing timber framing, the new clay straw should correspond to the existing material as closely as possible. Reused clay straw can, where appropriate, be thinned (see 3.4.4).

Strutting with daub

The struts are placed close together and clay straw or light clay straw is worked, rolled or spread into the spaces in between.

Rolled struts (including cob)

The wall should first be staked out in a dry condition. The timber frames are made from individual rolled struts that are prefabricated on a table. The clay straw or light clay straw is wrapped round the struts and the fresh rolls are pushed one on top of the other into the beam grooves.

Light clay

Infill made of light clay with moist placement is executed by analogy with Chapter 4.3.4.

Masonry infill

Earth blocks: The timber frames are lined with earth blocks or light earth blocks and earth masonry mortar. An adequate bond between the framework and the wall lining on at least two opposing sides shall be ensured by means of triangular battens, beam grooves or stainless steel

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nails placed at intervals of approximately 25 cm. Trapezoid or rectangular battens are only recommended if the blocks are grooved accordingly.

To ensure the adhesion of lime render, the joints should be raked out to a maximum depth of 1 cm if no special render base is provided.

Other masonry using earth mortars: In the case of wall linings of brick, rubble or other artificial blocks with earth mortar, the procedure shall be carried out as above, but the raking out of the joints is dispensed with.

4.3.2 Non-loadbearing rammed earth walls

Construction

Non-loadbearing rammed earth walls are executed in the same way as load-bearing rammed earth walls (se 4.1.4). The minimum wall thickness is 20 cm; a slenderness of 20 should not be exceeded.

4.3.3 Non-loadbearing masonry

Building materials

For non-loadbearing earth masonry, earth blocks of the appropriate use class are used, laid using earth or lime mortar.

Green bricks are not suitable for use as the base for render or for the direct application of lime render.

Construction

Earth masonry must be reliably protected against contact with soil moisture or spray water.

Below masonry consisting of green bricks and below storey high walls a waterproof layer shall be provided that extends at least 5 cm above the top of the finished floor.

The masonry must be sufficiently stable and adequately reinforced or be suitably bound to the supporting framework.

Masoned inner shells should be supported on each storey. From a slenderness of h/d ≥ 15 they shall be secured against buckling by suitable

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means, e.g. by vertical wooden posts or wall ties. Inner shells that are to be extensively backfilled with light clay must be at least 11.5 cm thick.

Execution

The butt joints and coursing joints shall be filled with mortar to a thickness of approximately 1 cm. Earth blocks shall be bonded in a manner fit for purpose.

The bulk density of the earth masonry mortar should roughly correspond to the bulk density of the block.

Connected walls should be erected at the same time. In the case of continuous inner shells, only one storey may be built per day.

4.3.4 Light clay walls in damp installation

Definition

The wall infill of a load-bearing framework is constructed in formwork on site using ground-moist to plastic light clay.

Building material

Light clay with organic or mineral additives is used as the building material. The bulk density of the light clay should be at least 600 kg/m3. Lighter mixtures must be sufficiently solid or be installed behind suitable permanent formwork.

Building period

Where there are drying problems, mechanical drying of the structures is recommended. Dry installation is largely independent of the frost period.

Construction

The load-bearing framework and, where relevant, a filler framework, shall be constructed, without consideration of the infill, in such a way that wind loads are removed and, for example, cladding can be attached. As a protection against collapse, the intervals should be smaller than 1 m, or sufficiently stable horizontal reinforcing bars should be installed. Connection between infill and load-bearing structure must be ensured. The

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wall thickness of the filler framework can be used to secure working formwork or permanent formwork.

In damp installation with organic additives and in the case of unprotected timber structures the wall thickness shall in principle be restricted to 30 cm. Unhindered drying on both sides is a prerequisite. Open and air-permeable plaster bases that can be used as permanent formwork, such as woven reeds or similar materials, do not hinder drying.

Layers or inner shells that can dry out from one side only must not be more than 15 cm thick. If the side that is impermeable to air consists of vapour-permeable building materials with good capillary conductivity (e.g. bricks or earthen building materials), such layers can exceptionally be up to 20 cm thick. Lightweight building panels with no capillary conductivity, made for example of reeds or wood wool, are classed as impervious formwork.

The suitability of differing executions and wall thicknesses shall be established by testing.

Light clay walls must be statically discharged on each storey. Their height should not exceed 4.0 m. The structure and infill must be reliably protected against contact with soil moisture or spray water. In order to make the walls impervious to wind, structural parts that penetrate through the external wall should be avoided.

Execution

Light clay is compacted in formwork or permanent formwork . Working formwork should be removed as soon as possible so as not to delay drying out.

The infill should be placed in as even a density as possible without cavities. Surfaces that are to be plastered should be sufficiently firm and true to dimensions.

Drying

The drying times shall be taken into account when planning the building period. Damp earthen building materials must be able to dry as quickly as possible. Moisture penetration for too long can cause organic additives to rot, weaken adjacent wood components and cause the corrosion of steel components. Surfaces that remain damp for a long time can mould. It shall be ensured by means of good ventilation that drying outside air can spread

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along all light clay components. If this is not sufficient, mechanical drying of the structures is necessary. The walls should be protected against heavy rain.

Before applying plaster, the light clay must have dried out. A wind-proofing clay grout can be applied immediately after removal of the formwork.

Attachments

Suitable auxiliary structures can be provided in the wall for the attachment of heavy objects.

Testing

The dry state necessary for further work is determined by visual inspection.

A more exact result should be obtained by drying and weighing a sample extracted from the centre of the wall by core drilling or through another opening. This test need only be carried out where justified in individual cases. Light clay components are considered to be sufficiently dry if they have a moisture content of approximately uv = 10%.

It has also proved valuable to determine the moisture content of adjacent timber components.

4.3.5 Clay panel walls

Definition

Non-loadbearing walls or infill are constructed of clay or light clay panels.

Construction

Shear walls and infill must be sufficiently stable and adequately reinforced or be suitably bound to the supporting framework, particularly if they provide protection against collapse, reinforcement of a facade or if they dissipate wind loads.

The requirements pertaining to structural moisture protection in Chapter 4.3.3 Non-loadbearing masonry shall be satisfied mutatis mutandis.

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Execution

Clay panels are built into walls using mortar or are placed dry using fastenings.

4.3.6 Stacked earth walls

Definition

Stacked earth walls are non-loadbearing facing formwork or infill that is emplaced dry without using mortar.

Building materials

Suitable earthen building materials are earth blocks, light earth blocks, clay panels or green bricks.

Execution

Blocks should be placed in a horizontal position bonded together and shall be secured every 50 cm upwards with a horizontally mounted connecting strip or a board. The connecting strips shall be adequately secured. If the strips are used to attach subsequent coverings made of dry building panels, the vertical distance between the strips can be smaller if necessary. Above window and door lintels, rising stacked walls shall be supported by squared timber or lath structures of adequate size.

If the walls are plastered wet, the butt joints between the blocks can be left open approximately 5 mm. A plaster base or reinforcing fabric shall be provided.

Cladding

The walls can be clad with dry building panels or plastered. In the case of plaster, the butt joints should be left open 5 mm and a plaster base or reinforcing fabric should be used.

4.3.7 Extruded walls

Definition

Wall infills or facing formwork are made using the extrusion method. In contrast to extruded plaster coats, the coat thickness starts at 3 cm.

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Building materials

Earth or light clay extruded mortar, or even pumpable clay straw or fibrous clay is used as the building materials.

Construction

Applications using the earth extrusion method require a lattice lath into which the (fibrous) coat penetrates or a flat base with carrying capacity to which the coat adheres. This can be formed of masonry or lightweight building panels, for example. In order to keep the coat flush, a level post or lath construction over which the plaster is applied is recommended.

Execution

The wall shell is plastered using a plastering machine. In the case of flat bases, up to a maximum of 5 cm can be applied in one session. Further coats can be applied after the appropriate drying periods.

Drying

The drying times shall be taken into account when planning the building period. Components built with earth must be able to dry as quickly as possible. Moisture penetration for too long can cause organic additives to rot, weaken adjacent wood components and cause the corrosion of steel components. If natural ventilation is not adequate for sufficiently fast drying, mechanical drying of the structures is necessary. Components built with earth that take too long to dry can mould.

Further processing

Once they are fully dry, the surfaces can be soaked, smoothed and painted, or they can be plastered or covered.

Testing

Boring can be used to test that the surfaces are dry.

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4.3.8 Plastered insulating boards

Definition

For internal insulation, thermal insulation sheets are plastered over their entire surface on existing walls or ceilings.

Building materials

Sufficiently adhesive earth mortar is used for the mortar bed. Calcium silicate panels, wood wool lightweight building panels, soft fibre wood panels or reed panels, for example, are suitable for use as thermal insulation sheets.

Construction

The adhesive layer must cover the entire surface to a thickness of at least 0.5 cm. Adhesive layers of more than 3.0 cm are not permissible for reasons relating to drying.

Moistureproofing shall be taken into account when dimensioning the internal insulation. This applies in particular in the case of framed walls exposed to weather.

Execution

The adhesive layer shall be flat. The mortar is applied to the surfaces that are to be insulated or to the back of the sheets. Immediately afterwards, the thermal insulating sheets are pressed firmly into the tough-plastic earth mortar. Extensive full-surface contact between sheet and earth mortar must be ensured. For this purpose, additional attachment using screws or dowels may be used.

Further processing

The thermal insulation sheets are usually plastered or covered. In this regard, opportunity for the bedding mortar to dry out shall be taken into consideration.

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4.4 Joist ceilings

Definition

Earthen building materials are installed as infill between the panels of joint ceilings or used as flooring. The structure, layer thickness and building materials used are selected according to the intended thermal, noise or fire insulation requirements.

4.4.1 Strut ceilings

Definition

In the case of strut ceilings struts or laths bear the earth infill.

Building materials

Clay straw (or fibrous clay) and light clay straw with a soft consistency are primarily used as earthen building materials. For preparation, soft long-stalked straw is preferred (rye, oat, barley).

The struts made of coniferous timber or hardwood can be sawn or split. Round or half-round timber can also be used if the cross-sections are large enough.

Construction

The struts (or laths) are held in lateral beam grooves, rest on lateral support laths or else a lath is attached along the top of the beam. Normal cross-sections of lathing with a spacing of around 8 pieces/m are sufficient to transfer the load.

Execution

Before commencing work with earth, the struts are cut to the required length with a small excess and are fitted between the ceiling beams without displacing the beams. In the case of rolled and light clay ceilings, the struts are taken out and reinstalled in the same place with the earth.

Rolled ceilings are made from individual, prefabricated rolled struts. Clay straw or light clay straw is rolled around the struts on a table and the struts

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are then pushed into the ceiling one after another while still damp and later levelled off above and below with clay straw. Whole and half rolled ceilings are differentiated according to their installation height.

Packed light clay ceilings are made of light clay packed into working formwork together with the struts. Once the formwork has been removed, the underside is a level plaster base.

In the case of lattice ceilings a lattice made out of laths or half-round timber is attached between, above or below the beams, with very soft, long-stalked clay straw or fibrous clay pushed through from above. Any tongues hanging down are smoothed out from below.

In the case of a lattice ceiling with plaster base, plaster base is placed on the lattice grid and this is topped up with clay straw or light clay.

In the case of lattice plaster ceilings, a lattice attached with a smaller gap and made of thin lattice laths has clay straw, fibrous clay or earth mortar pressed through from one side and smoothed off.

After drying, strut and lattice ceilings are ready for plastering, if required.

Drying

The drying times shall be taken into account when planning the building period. Damp earthen building materials must be able to dry as quickly as possible. Moisture penetration for too long can cause organic additives to rot, weaken adjacent wood components and cause the corrosion of steel components. Strut ceilings must not be walked on while they are drying.

4.4.2 Inserted ceilings

Definition

A formwork "inserted" between the beams and filled with a substance is described as an insert.

Building materials

Earth, light clay or building earth fillings are used as earthen building materials, the latter also in a dry state. In addition, any type of earth blocks and green bricks or unreinforced clay panels can also be laid.

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Construction

The formwork rests on lateral support laths. It can be made of boards, slabs, lightweight building panels or earthen dry building panels. Depending on the earthen building material used and the design of the joints, protection against dripping shall be provided.

Execution

Damp earthen building materials are lightly compacted and smoothed on the top. Open joints of blocks and panels laid dry can be swept with earth or sand or, to increase noise insulation, filled air-tight with mortar.

Drying

The drying times shall be taken into account when planning the building period. Damp earthen building materials must be able to dry as quickly as possible. Moisture penetration for too long can cause organic additives to rot, weaken adjacent wood components and cause the corrosion of steel components. If natural ventilation is not adequate for sufficiently fast drying, mechanical drying of the structures is necessary. Components that take too long to dry can mould.

4.4.3 Flooring

Definition

Earthen building materials rest flat, usually on continuous planking on the frame of joists.

Building materials

With a view to swift progress of the building work and quick accessibility, preformed dry building materials such as earth blocks, green bricks and unreinforced clay panels are appropriate for flooring. In principle, however, it is also possible to use earthen building materials installed damp. Their weakness or decreased stability under the load of the floor covering shall be taken into account.

Construction

The planking shall be designed for static loading.

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Depending on the earthen building material used and the design of the joints, protection against dripping shall be provided.

4.4.4 Ceilings with clay panels

Definition

Joist ceilings that are infilled with clay panels.

Building materials

Clay panels are used as building materials. Reinforced and unreinforced clay panels are only used as self-supporting panels.

Construction

Reinforcing bars for clay panels should rest on the top of beams or on support laths. For this purpose, the panels are folded along the side.

Execution

The panels can be laid dry. Where the dimensional accuracy is low, pasting the panels together using earth mortar, something that can also be used for defects, is recommended.

Further processing

The underside of panels can be plastered.

4.4.5 Infill of roof slopes

Taking into account the particular geometric features and the course of the construction, the infill of roof slopes can, where appropriate, be provided with temporary weather protection such as ceiling constructions.

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4.5 Plastering/rendering

4.5.1 General

Uses

These Rules cover uses of plastering/rendering where either the plaster mortar/rendering or the base consist of earthen building materials, namely:

- earthen plastering/rendering on earthen or other bases,

- other plastering/rendering on earthen bases.

Unless regulated otherwise in these Rules, the relevant standards, in particular DIN EN 998-1 and DIN V 18550 shall apply.

Thin coatings of < 3 mm, earthen coating materials and stabilised earthen plastering/rendering are not plastering/rendering within the meaning of these Rules.

Definitions

Plastering/rendering is a coating produced from plaster mortars/rendering and applied to walls, ceilings and roof slopes that only attains its final characteristics once hardened on the building structure.

The plaster/render base is the component that is to be plastered/rendered. The plaster/render undercoat means the lower layers of a plastering/rendering, as the plaster/render finishing coat is the top layer. A plaster/render layer is applied from the same mortar (fresh on fresh) in one or more operation(s). The method of plastering/rendering refers to the nature of the application, in particular the surface work, for instance roughened, smoothed, etc. (for definitions, cf. DIN EN 998-1 and DIN V 18550).

Guidelines for planning

Plastering/rendering serves as a covering and surface design and performs physical building tasks. The requirements to be applied to the plastering/rendering and plastering/rendering systems shall be laid down in the course of planning, in particular the sturdiness required and the method

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of plastering/rendering, account being taken of the properties of the plaster/render base.

Requirements

In general, plastering/rendering must be applied evenly to the base, the individual layers showing good adhesion towards each other. Within the individual layers, the mortar should possess an even structure. The sturdiness of the plastering/rendering should be adapted to the plaster/render base and plastering/rendering use in question. The abrasion resistance and surface characteristics shall be selected in dependence on plastering/rendering use.

The surface of the plastering/rendering should be free of cracks. Hairline cracks are nothing to be concerned about provided that they do not have a negative impact on the technical and optical value of the plastering/rendering.

Interior plastering consisting of plaster mortars with mineral binders should, as it bears paint and wallpaper, meet the usual requirements of Category CSII (compressive strength 1.5 to 5.0 N/mm2) pursuant to DIN EN 998-1. Earthen plastering/rendering should, correspondingly, have a compressive strength of ≥1.5 N/mm2.

Exterior rendering must be weatherproof, which is to say that the rendering system must be able to withstand the action of moisture and varying temperatures, especially on those sides facing the predominant winds (weather-exposed sides).

Execution

At the time of execution the component should be sufficiently dry. The shrinking and setting of earthen bases must be finished.

The plaster/render base shall be carefully checked, and where necessary prepared, in order to achieve good adhesion of the plastering/rendering to the base.

The plastering/rendering base should be true to size such that the plastering/rendering can be applied with an even thickness. The plaster/render base must be even, capable of bearing, dust-free and free of contaminants. Stock bases may not contain salts that are counter to

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building use. The component must be frost-free up to a sufficient hardening of the plastering/rendering (not below +5 °C).

All steps that help to create a sound and durable adhesion of the plastering/rendering represent the preparation of the plaster/render base. Too rapid or too uneven a dehydration of the plaster/render base shall be prevented, depending on the plastering/rendering system. Loose constituents shall be removed or stabilised. Dust on the top surface shall be brushed off or bound in by dampening. If a level course is required, its strength must be in line with the plastering/rendering structure. The strength, handle and adhesion of the plaster/render base can be improved by spray rendering consisting of earth mortars or other mortars, suitable hardeners, bonding layers and primers. Areas with penetrating substances shall be properly sealed off.

Plaster/render carriers facilitate the adhesion of the plastering/rendering largely independent of the base. They are used on smooth bases (such as wood) or uncertain bases (such as wood, mixed bases).

4.5.2 Earthen plastering/rendering

Suitability

Earthen plastering/rendering is predominantly suitable as interior plastering. As, like other earthen building materials, it is susceptible to water, earthen plastering/rendering is only suitable for components outdoors where these are protected from the effects of the weather. With sufficient experience, however, it is possible to achieve good results even with components which are acted upon by rain – using suitable mortar additives such as whey, dung or fine fibres and special surface treatments.

Earthen plastering/rendering is suitable for the plastering/rendering of earthen building materials and other plaster/render bases that are common in building. In order to assess the suitability of the plastering/rendering system and the nature of the preparation of the plaster/render base, a component sample shall be taken.

Earthen plasters/renders can have very widely varying strength characteristics depending on the composition and processing of the plaster mortars/rendering used and the treatment of the surface. In general they are suited to surfaces that are under little mechanical loading. Where the loading is greater (such as is the case in stairways and corridors), the

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suitability of the plastering/rendering system shall be examined on a case-by-case basis. Flaws in light-coloured paints on dark earthen plastering/rendering always have a negative impact on the visual aesthetic. Component samples or other samples are recommended.

Earthen plastering/rendering is suitable for rooms with a normal humidity, which includes domestic kitchens and bathrooms where the humidity is not durably raised. Where it is anticipated that the wallpaper will be changed frequently, it is recommended that other types of plaster be used. That said, earthen plastering/rendering is only suited to tiling to a limited extent.

Requirements

Earthen interior plasters should satisfy the requirements under 4.5.1. Plasters that are applied soft should also be adapted to the intended purpose of plastering and to the plaster base. There must be sufficient strength for further treatment (coating).

The measure of shrinkage pursuant to 3.9.6 should be no more than 2%. Where fibrous matter is mixed in, on thin application of careful post-treatment and for small surfaces, a measure of shrinkage of more than 2% can be without problems. A small extent of shrinkage cracks can be tolerated in plaster undercoats provided that sufficient mechanical adhesion to the base is ensured and that such cracks do not show through where thin plaster finishing coats are applied. Plaster finishing coats shall be applied so as to be as crack-free as possible.

Special requirements for the surface design, such as a uniformity of colour and structure or evenness shall be laid down on a case-by-case basis. Sufficiently large surface samples or specimens under the defined light conditions are suitable for this purpose.

Plaster mortars/rendering

Earth mortars pursuant to 3.9 are used for earthen interior plastering. Plasters can also be produced with applications of clay straw or fibrous clay pursuant to 3.4.

Plastering/rendering systems

The selection of the plastering/rendering system is based on the plastering/rendering base and the requirements for the

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plastering/rendering, the method of plastering/rendering in accordance with the surface sought.

Single-course earthen plastering/rendering can be employed on all flushly, true-to-size and evenly absorptive bases. The standard thickness of plastering/rendering is 10 to 15 mm, or 3 to 5 mm on flush surfaces (thin-course plastering/rendering). Where the plastering/rendering or coatings are applied too thinly, however, (masonry) joints in the base can show through.

Multi-course earthen plastering/rendering is used on all other bases. They are also necessary where the plastered/rendered surface sought cannot be produced without a preparatory plaster/render undercoat. A multi-course configuration is also recommended in order to achieve certain thicknesses of plastering/rendering or where a reinforcing fabric is to be built in. Any plaster/render undercoat should be sufficiently dry before application of the plaster/render finishing coat to rule out later shrinkage cracks. Multi-course plasters/renders are 5 to 20 mm thick.

Earthen plasters/renders are generally applied in multiple courses to wall-mounted heating systems.

The specifications of the heating or plastering/rendering manufacturer shall be observed in respect of the plastering/rendering superstructure, plastering/rendering thicknesses, reinforcements and behaviour under heating.

The suitability of other plastering/rendering systems can be demonstrated by proven experience or through component testing.

Application and surface treatment

The plastering/rendering is applied either by hand or mechanically. It can be projected or smeared on. In the case of plastering/rendering produced on-site, a work specimen should be built. In the case of ready-made products the manufacturer’s instructions must be observed. Plastering/rendering-reinforcement fabrics shall be plastered in in accordance with the technical regulations. It is recommended, in the light of the softness of earthen plastering/rendering, to round off edges or provide corner-protecting profiles. Earthen plastering/rendering can be roughened, felted or smoothed.

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Drying

Drying times shall be taken into account when planning the building period. Earthen plastering/rendering must be able to dry as quickly as possible. If natural ventilation is not adequate for sufficiently quick drying, mechanical drying of the structures is necessary. Earthen plastering/rendering that takes too long to dry can mould. This can be avoided if proper drying is supervised at short intervals by means, for example, of a drying log.

Further treatment

Earthen plastering/rendering can be left as is in terms of colour or can be further treated by painting or coating. The plaster/render must be sufficiently dry for further treatment. This dryness can be determined by means of visual inspection. Earthen plastering forming the base for frescoes is an exception to this. Surfaces that are to be sanded should be brushed off before further treatment.

Earthen plastering/rendering left as is in terms of colour can be consolidated where required. In such cases work specimens are recommended.

Paints are to be applied to earthen bases in line with experience, technical regulations and the manufacturer’s instructions. Thin, porous paints such as loam or lime paints are recommended. Solid, thick and layer-building paints tend to demask. Where lime slurries are used the earthen plastering/rendering base must be carefully soaked. Where appropriate, the earthen plastering/rendering surfaces must first be primed or consolidated by rubbing a slurry of fine sand and lime into them.

Thin lime plasters of the mortar group PI pursuant to DIN V 18550 shall be applied to sufficiently coarse and carefully pre-soaked bases in a thickness of 3 to 5 mm.

For wallpaper, sufficiently smooth earthen plasters may be pre-treated with a suitable primer. Waste sheets may be applied in order subsequently to strip the wallpaper. Wallpaper that is to be stripped shall be carefully wetted.

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Repair and renovation

In the event of flaws and damage, the earthen plastering shall be soaked, before re-plastering or filling takes place using earth mortar or a suitable surfacer.

For the purposes of touching up, earthen plaster surfaces can be soaked and reprocessed.

4.5.3 Other plastering/rendering on earthen bases.

Plaster mortars/rendering

The plaster mortar/rendering should be as soft, elastic and diffusible as possible in line with the earthen base. In the case of interior plastering, standard lime, lime/gypsum or gypsum mortars may suitably be used.

In the case of exterior rendering, lime mortars of the mortar groups P I or P II may be used. On protected sides, mortar group P I (cf. DIN V 18550, DIN EN 998-1) is sufficient.

Plastering/rendering systems

Interior plasters are applied in standard thicknesses while for exterior renders the thickness of render should be at least 20 mm on surfaces subject to rain, with multiple courses being required. The general plastering/rendering rule which states that mortar strengths should be increased towards the base is often inapplicable in building with earth as the protective plaster/render finishing coats are, for the most part, harder than the earth bases. Bases must therefore be prepared accordingly or provided with plaster/render carriers. Hard topcoats on soft bases can also sound hollow on tap testing, even when there is sufficient adhesion with the plaster/render.

Execution

The plaster mortars/rendering are processed in accordance with the relevant regulations, standards and manufacturers’ instructions. A soaking of the strongly absorbent earthen bases prevents mortars from drying out too quickly and encourages them to set. Preparation by means of machine spraying improves the mechanical adhesion onto the earthen bases. The appropriate fabric for the plaster mortars/rendering in question are used as

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a means of reinforcement for the plastering/rendering. Plaster/render surfaces can be separated from neighbouring components by means of a fine cut by a knife or trowel.

Lime exterior renders should only be applied in suitable weather conditions. After application they may need follow-up treatment. In order to protect against frost they shall be suitably painted in good time.

4.5.4 Special features of exterior rendering for visible latticework

Loading

Exterior rendering for visible latticework is exposed to special loading conditions on weather-exposed sides. Water that penetrates marginal joints can cause the topcoat of render to peel from the soft base. Additional joint sealing in turn prevents moisture that has penetrated in patches from drying out. Lateral pressure from the beams onto the framework can lead to shear stresses and spalling between the render and the base. The loading on the render increases the morea) stress there is on the framework from driving rain and the more the

expanding and shrinking of the beams leads to large grooves;b) thermal deformation is brought about by strong sunshine and dark

colouring occurs on the beams;c) the individual beams of the framework tend only to warp (newly

incorporated wood, as well as old wood);d) the entire building structure is subject to deformation;e) there are additional stresses such as vibration caused by road traffic.

A careful assessment of the loading in accordance with the relevant climatic and site-based conditions is a requirement for choosing the appropriate plastering/rendering system. It is possible for this assessment to result in a decision that visible latticework must be done without. Otherwise permanent maintenance of the high-loading surfaces must be included in the calculations.

The timing of the rendering shall be chosen to be so late that the deformations of construction, shrinkage and settlement of the earthen bases and the warping of the wooden components caused by the moisture of installation has largely concluded. In the case of the framework render for visible latticework a heating period should be awaited, at the least.

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Plastering/rendering systems for framework render/plasterLime plastering/rendering on an earthen base: The plastering/rendering mechanically adheres to a roughened or perforated earthen base. The adhesion between the lime plastering/rendering and the earth can be improved by means of a lime mortar slurry that is vigorously worked into the pre-soaked lime base using the felted board. The plastering/rendering is applied in two coats with a total thickness of around 15 mm. The additional incorporation of a plaster/render reinforcement can increase durability.

Lime plastering/rendering on plaster/render carriers: If visible latticework is put in place despite heavy loading the mortar grain shall be set in accordance with a suitable plaster/render carrier. In order to better bind the plaster/render and the plaster/render base, a lime mortar slurry may be worked in (see above). The plaster/render carrier and the fixing agent must be weatherproof. Fixing takes place in the framework rather than onto the beams. The additional incorporation of a plaster/render reinforcement can increase durability.

Lime facing plaster/render on an earthen base: Where loads are small or where a plastering/rendering system on site has proved its durability, an earthen base and a lime plaster/render of around 5 mm can be used. For the plastering/rendering base and facing plaster/render, fibre-reinforced mortars are recommended. The earthen base is suited to roughening. For preparation purposes, a lime mortar slurry can be worked in (see above).

4.6 Rammed earth floors

In order to produce rammed earth floors, rammed earth is added in layers compacted by means of vibration, ramming or beating.

The structure and surface properties of rammed earth floors shall be in accordance with the substructure and the planned use. The individual layers can be installed once the formation of shrinkage cracks in the layer beneath has been completed. It is not necessary to await compete drying out.

In order to reduce the formation of cracks, rammed earth with a low measure of shrinkage can be used, flat reinforcing fabrics can be incorporated and use can be made of insulating edge props. Cracks in the use surface can be closed by means of re-pressing. For a more high-order use, the surface should be largely sealed off from rammed earth floors and

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be substantially free of cracks. Resistance to abrasion can be increased, inter alia, by the use of oils and waxes. Such substances shall only be applied once the entire installation has largely dried out. The addition of a wax coating makes it possible to produce a wipeable surface.

4.7 Facings in dry construction

Definition

Facings in dry construction consist of clay panels that are nailed or screwed to substructures. They are also applied as dry render to planar bases.

Building material

Clay panels or light clay panels may be used.

Construction

The construction of facings for internal walls, ceilings and roofs and of noise-dampening facing formwork shall be executed as is usual in dry construction and in accordance with manufacturers’ instructions.

The centre distance between substructures is generally 30 – 50 cm. The panels shall be affixed as per the manufacturers’ instructions. For the application of facings, the base must be sufficiently even, sturdy, dry and free of dust. Fine-grained, adhesive earthen mortars or adhesives are suitable for applying clay panels. Absorbent bases shall be pre-soaked. The manufacturers’ instructions shall be observed.

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4.8 Other components

4.8.1 Basement masonry walls and skirting

Definitions

Basement masonry walls means masonry below ground level or that has no contact with the ground, excluding internal walls within basements.

The skirting is the area of a masonry wall exposed to splashwater.

Preclusion

Earthen building materials may not be used for foundations, basement masonry walls and skirting masonry walls. Any parts of a basement storey that have no contact with the soil may not be manufactured of load-bearing earthen building materials.

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5. SPECIFICATIONS FOR BUILDING MATERIALS AND COMPONENTS

5.1 Particle densityTable 5-1Dry particle density of earthen building materialsBuilding material Particle density

(kg/m³)from to

Rammed earth 1700 2400Cob 1400 1700Fibrous clay/clay straw 1200 1700Light clay 300 1200Earth fillings 300 2200Earth blocks 600 2200Clay panels 300 1800Earth mortars 600 1800

5.2 Strength

5.2.1 Compressive strength

The compressive strength of the building material is determined on the basis of the material-specific compressive strength tests (cf. 3 Earthen building materials). The following table contains average values determined by experiment.

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5. Specifications for building materials and components

Table 5-2Compressive strength of earthen building materialsEmpirical dataBuilding material Particle density

(kg/m³)Compressive strength(N/mm2)

Rammed earth with mineral additive

2000 - 2200 3 - 5

Rammed earth with fibrous additive

1700 - 2000 2 - 3

Cob 1400 - 1700 1Earth blocks 1600 - 2200 2 - 4

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5.3 Heat

5.3.1 Thermal insulation

The following table sets out the calculated values for thermal conductivity. Values that are more favourable must be demonstrated pursuant to DIN 52611 or DIN 52612.

Table 5-3 Calculated values for the thermal conductivity of earthen building materials 1)

Particle density(kg/m³)

Thermal conductivityλ R.(W/mK)

2200 1.40 2)

2000 1.101800 0.911600 0.731400 0.591200 0.471000 0.35900 0.30800 0.25700 0.21600 0.17500 0.14400 0.12 2)

300 0.10 2)

1) Cf. DIN V 4108-4: 2002-022) The values are derived from the least favourable data from the literature and previous standards.

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5.3.2 Heat retention

The specific heat capacity c of earthen building materials depends on the particle density, the nature and the proportion of additives. The following table sets out calculated values.

T 5-4Specific heat capacity c of earthen building materials (kJ/kgK)


Additives,mineral-based

Additives,organic

Sand, gravel, Straw Fine fibres

Wood chippings

≥1600 1.0 1.0 1.0 1.01400 1.0 1.0 1.1 1.11200 1.0 1.0 1.1 1.21000 1.0 1.1 1.1 1.3800 1.0 1.1 1.2 1.4600 1.0 1.1 1.3 1.5400 - 1.2 1.4 -

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5.4 Moisture

5.4.1 Susceptibility to water and moisture

Unprotected components building with earth are susceptible to water. The action of water, even over a brief period (heavy rain, burst pipes, floods), can jeopardise stability.

Unprotected components built with earth are susceptible to moisture. The sustained action of moisture (rising damp, roof damage) can lead to a reduction in strength, the growth of mildew, the rotting of organic constituents, the humification of the building material and the destruction of the wooden structure. Delayed drying of building materials can also have this effect.

Earthen building materials are not susceptible to the hygroscopic action of moisture (sorption).

On the other hand, the water solubility of earth means that it can always easily be re-used in a new form and after sustained use.

5.4.2 Diffusion of vapourTable 5-5Standard values for the water vapour diffusion resistance factor µ of earthen building materials


µ (-)

from to300 2200 5/10

5.4.3 Moisture conductivity

Earthen building materials are fine-pored substances that are conductive of moisture by capillary action and are capable of quickly transferring moisture absorbed to the surface and then giving it off when such drying is not hindered.

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5.4.4 Practical moisture content

Practical moisture content means the moisture content that is only exceeded on rare occasions in the course of normal practical building conditions.

5.4.5 Sorption

The hygroscopic moisture take-up by untreated earth surfaces is relatively high (approximately equal to untreated softwood).

5.4.6 Drying

Moisture conductivity and diffusion capacity assist the drying of earthen building materials.

The drying times of earthen building materials and components installed in moist condition are co-determined by the following factors:

- the time of year, weathering

- the degree of moisture of installation

- the thickness of layers and walls

- the nature of permanent formwork

- the positioning of the component (indoors/outdoors)

- airing of the building

- weatherproofing.

The drying times of blocks and panels are also dependent on their size, their moisture at production and the drying conditions.

Components are regarded as sufficiently dry for further processing when settling and shrinking have largely been concluded and the humification of the organic components can be ruled out.

They are regarded as dry when they have attained the equalised dampness of the earthen building material in question.

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5.5 Fire behaviour

5.5.1 Fire behaviour of earthen building materials

Earth with mineral additives is categorised in Building Materials Class A1 (non-combustible) under DIN 4102-4. Earthen building materials specifically are not classified.

Table 5-8 Fire behaviour of earthen building materials Collated from DIN and research results

Additive Required particle density for the

earthen building material (kg/m3)

Classification

Mineral 1) No requirement Non-combustiblePlant-based fibrous matter

“properly mixed in in accordance with the norms

of building with earth”

≥1700 Non-combustible

Straw 3) >1200 Non-combustibleStraw 3) >600 Not easily

flammableWood chippings 3) >1400 Non-combustibleWood chippings 3) >800 Not easily

flammableSawmill shavings 3) >1600 Non-combustible

Sawdust 3) >2000 Non-combustibleHemp, flax shives 3) >600 Not easily

flammable

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1) Cf. DIN 4102-4: 1994-032) Cf. DIN 18951 sheet 1: 1951-013) According to research into evaluating the fire behaviour of earthen building materials in the course of thesis work at the MFPA [the Materials Research and Testing Body for the Construction Industry] in Leipzig, Germany, pursuant to DIN 4102-1.

5.5.2 Fire behaviour of components built with earth

The following tables contain components using earthen building materials, classified pursuant to DIN 4102-4 (1994) or previous standards.

Table 5-9Fire-resistance class of walls made of earthen building materials

Component ClassificationMassive wallsMassive earthen (Building Materials Class A) walls of masonry or rammed earth of a thickness of 24 cm 1)

F 90 A

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Framed walls with filled frameworkStipulations: wooden cross section of at least 100 x 100 mm in the case of single-sided or at least 120 x 120 mm in the case of two-sided exposure to fire,infill with puddle (clay straw infilling), facing on at least one side (with 15 mm of render/plaster, for example) 2)

F 30 B

1) According to DIN V 18954: 1956 2) Cf. DIN 4102-4 4.11: 1994-03, Section 4.11. Specifics on the stipulations can be found here.

Table 5-10Fire-resistance class of wood joist ceilings with earthen building materials

Component Classificationa) Wood joist ceiling with completely open wood joists exposed to fire on three sidesCeiling covering, for example of any given thickness of earthen building materials, depending on distance and cross section of joists, formwork, structure of floor 1)

F 30 B to F 60 B

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b) Wood joist ceiling with covered joistsSound floor with puddle ≥ 60 mmor crossbeams (strutting) with puddle, depending on distance of joists, upper formwork, lower facing 2)

a) Ceiling coverings(only in respect of fire exposure on the surface)Covering of ≥ 50 mm of earth 3)

F 30

Notes:1) Cf. DIN 4102-4 1994-03 (5.3.2) and Table 62. Specifics on the stipulations can be found here.2) Cf. DIN 4102-4: 1994-03 (5.3.3) and Tables 56 and 63. Specifics on the stipulations can be found here.3) Cf. DIN 4102-4: 1970-02 (4.2)

5.6 Noise-insulating characteristics

The noise-insulating characteristics of components are determined in accordance with Supplemental Sheet 1 to DIN 4109 Sound insulation in buildings (11/1989).

5.6.1 Dampening of airborne noise by walls

For the earthen building materials covered by the standard, given their greater softness, at least the noise-insulating characteristics equivalent to those of porous concrete and lightweight aggregate concrete of the corresponding particle density class can be assumed.

Skeleton-built walls with infill consisting of heavy building materials are not covered by the standard.

5.6.2 Noise-insulating characteristics of wood joist ceilings

For the earthen building materials covered by the standard, at least the noise-insulating characteristics corresponding to those of other bulk building materials such as concrete slabs (cf. DIN 4109, Supplemental Sheet 1, Table 34) can be assumed.

DIN 4109 (1962), Sheets 3 and 5 cover further ceiling structures.

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5.7 Windproofness

Earthen building materials are regarded as windproof where the surface has a density of 900 kg/m3 or above. Otherwise plastering on at least one side is regarded as sufficient windproofing.

5.8 Durability

Wood and plant-based fibres enclosed by dry earth are durably protected. With proper moisture-proofing and normal building maintenance structures built with earth can achieve extraordinarily long lifespans, as old structures that are hundreds of years old demonstrate.

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6. Terms of contract for earthen building services

6. TERMS OF CONTRACT FOR EARTHEN BUILDING SERVICES

With reference to the delimitation of incidental services and special services and to billing and billing units, the execution of various components built with earth can be assigned to the following fields of construction or rules under Part C of the German construction contract procedures (German abbreviation: VOB):

Table 6-1Assignment of fields of work with earth4.1.3 Earth block walls Masonry work DIN 183304.1.4 Rammed earth

wallsConcrete and reinforced concrete works

DIN 18331

4.1.5 Cob walls Masonry work DIN 183304.2 Vaulting Masonry work DIN 183304.3.1 Brick nogging for

framed wallsMasonry work DIN 18330

4.3.2 Non-loadbearing rammed earth walls

Concrete and reinforced concrete works

DIN 18331

4.3.3 Non-loadbearing masonry

Masonry work DIN 18330

4.3.4 Light clay walls in damp installation

Concrete and reinforced concrete works

DIN 18331

4.3.5 Clay panel walls Masonry work DIN 183304.3.6 Stacked earth

wallsMasonry work DIN 18330

4.3.7 Extruded walls Concrete and reinforced concrete works

DIN 18331

4.3.8 Plastered insulating boards

Plaster and stucco works

DIN 18350

4.4 Joist ceilings Masonry work DIN 183304.5 Plastering/

renderingPlaster and stucco works

DIN 18350

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4.6 Rammed earth floors

Floor screed works DIN 18353

4.7 Facings in dry construction

Dry construction works

DIN 18340

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7. Standards

7. STANDARDS

7.1 Standards cited

DIN V 105-1 Clay masonry units; Solid bricks and vertically perforated bricks

DIN EN 998-1 Specification for mortar for masonry - Part 1: Rendering and plastering mortar;

DIN EN 998-2 Specification for mortar for masonry - Part 2: Masonry mortar;

DIN EN 1015-2 Methods of test for mortar for masonry - Part 2: Bulk sampling of mortars and preparation of test mortars

DIN EN 1015-3 Methods of test for mortar for masonry - Part 3: Determination of consistence of fresh mortar (by flow table)

DIN EN 1015-11 Methods of test for mortar for masonry - Part 11: Determination of flexural and compressive strength of hardened mortar

DIN EN 1015-12 Methods of test for mortar for masonry - Part 12: Determination of adhesive strength of hardened rendering and plastering mortars on substrates

DIN 1053-1 Masonry; Part 1: Design and construction

DIN 1055-100 Actions on structures: Basis of design, safety concept and design rules

DIN 4022-1 (1969) Subsoil and groundwater; Classification and description of soil and rock; borehole logging of soil and rock not involving continuous core sample recovery

DIN 4102 Fire behaviour of building materials and components

DIN 4102 Fire behaviour of building materials and components, sheet 4 (2/1970)

DIN 4103 Lightweight partitions

DIN 4108 Thermal insulation and energy economy in buildings

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DIN 4109 Sound insulation in buildings

DIN 4109 Sound insulation in buildings (1962)

DIN 4172 Modular co-ordination in building construction

DIN 18122-1 Soil, investigation and testing - Consistency limits; Determination of liquid limit and plastic limit

DIN 18122-2 Soil, investigation and testing - Consistency limits; Determination of the shrinkage limit

DIN 18123 Soil, investigation and testing - Consistency limits; Determination of grain-size distribution

DIN 18196 Earthworks and foundations; Soil classification for civil engineering purposes

DIN V 18550 Plastering/rendering and plastering/rendering systems - Execution

DIN 52611 Determination of thermal resistance of building elements

DIN 52612 determination of thermal conductivity by means of the guarded hot plate apparatus

German construction contract procedures (German abbreviation: VOB), Part CGeneral technical terms of contract (German abbreviation: ATV) for building works

DIN 18330 Masonry work

DIN 18331 Concrete and reinforced concrete works

DIN 18340 Dry construction works

DIN 18350 Plaster and stucco works

DIN 18353 Floor screed works

7.2 Former standards on building with earth

DIN 1169 Earth mortars for masonry and plastering/rendering (1947)

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7. Standards

DIN 18951 Sheet 1 Structures built with earth, Regulations governing their execution (1/51)Sheet 2 ditto, Explanatory notes (1/51)

Prestandard DIN 18952 Sheet 1 Building earth, terms and definitions, types (5/56)Sheet 2 Inspection of building earth (10/56)

Prestandard DIN 18953 Building earth, components built with earthSheet 1 Use of building earth (5/56)Sheet 2 Masoned earth walls (5/56)

Sheet 3 Rammed earth walls (5/56)

Sheet 4 Cob earth walls (5/56)

Sheet 5 Light clay walls in framing structures (5/56)

Sheet 6 Earthen floors (5/56)

Prestandard DIN 18954 Execution of structures built with earth, guidelines (5/56)

Prestandard DIN 18955 Building earth, components built with earth, protection from moisture (8/56)

Prestandard DIN 18956 Plastering/rendering on components built with earth (8/56)

Prestandard DIN 18957 Earthen shingle roofs (8/56)

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Lehmbau Regeln

8. KEYWORD INDEX

88

8. Keyword index

.Anfang Index.

abbreviations, 15abrasion resistance, 34, 62action of moisture, 76addition of water, 14additives, 14additives, declaration, 14adhesion of lime render, 49, 50adhesion of plaster to clay straw, 49adhesion of plaster to rammed earth, 45adhesion of plaster/render, 63adhesion of plastering/rendering, 67adhesion of render to masonry, 45adhesive strength, earth mortars, 34ageing, 4airing, 77alluvium, 3anchoring, load-bearing walls, 40assignment of fields of work, work with

earth, 83attachments in light clay, 53ball-drop test, 6ball-forming test, 6barrel vaults, 46basement masonry walls, 71basic tests,inspection of building earth, 5billing, 83binding strength, 3, 5, 8, 9, 10binding strength test, 8, 10block strength class, 29, 31, 32boulder clay, 3brick production, 30brickwork using earth mortars, 33building earth, 3building earth, binding strength test, 8,

10building earth, classification by binding

strength, 9

building earth, extraction, 4building earth, inspection, 5building earth, organic constituents, 7building earth, sampling, 8building earth, suitability, 5, 6, 15building maintenance, 82building mat class, fire protection, 78building material specifications, 72building period, infill, 48building period, light clay walls, 51building period, load-bearing walls, 38building period, vaults, 46building site mortars, 34, 35building with earth, 1canes, 48capillary conductivity, 52case-by-case authorisation, XIIceiling reinforcement, 40ceilings, 26ceilings with clay panels, 60centring strip, 43classification of building materials, 15clay, 3, 9, 10clay grout, 53clay minerals, 3, 15clay panel ceilings, 60clay panels, 16, 32, 53clay panels, facings, 70clay straw, 15, 21, 49, 57clay straw daub, 49clay straw framework, repair, 49clay straw plastering/rendering, 64clay vaults, 46coarse hay, 22coarse sand, 6, 10coatings, 61cob, 15, 19, 42, 45, 49

89


cob walls, 45colour, building earth, 7comb strokes, 49combined masonry, 39component specifications, 72COMPONENTS BUILT WITH EARTH,

38composition, earth plaster

mortars/rendering, 34composition, earthen building materials,

14compression method, 30compressive strength, 42, 46, 72compressive strength of earth blocks, 31compressive strength of earth mortars,

34compressive strength of mortar, 42compressive strength testing of rammed

earth, 18compressive stresses, permissible, 42conductivity by capillary action, 76connecting strips, stacked walls, 54consistency of mortar testing, 36contaminant, 5contamination, 15contents, declaration, 14cracking, 14cutting test, 6dampening of airborne noise, 81damp-proof course, 39daub, 49declaration, 14density of additives, 22, 24deposition site, 8designation of the building earth, 9determination of plasticity, 9diffusion, 76, 77diffusion of vapour, 76DIN 1053-1, 47

DIN 1169, 86DIN 18122, 9DIN 18123, 10DIN 18196, 9DIN 18951, X, 78, 87DIN 18951 to -57, 87DIN 4022, 9DIN 4022-1, 6, 7DIN 4102-4, 78, 80, 81DIN 4103, 47DIN 4108-4, XIIDIN 52611, 74DIN 52612, 74DIN EN 998-1, 61DIN standards on building with earth, XIIDIN V 105-1, 31DIN V 18550, 61DIN V 18952 sheet 2, 8DIN V 18952, sheet 2, 12DIN V 18954, 80DIN V 4108-4, 74direction for self-manufacture, 2disposal of earthen building materials,

17distribution of grain sizes, 5domes, 46door and window reveals, 44dry construction, 70dry earth, 4dry particle density, 72dry strength test, building earth, 6drying, 1, 76drying log, 66drying of building materials, 76drying of structures, 51drying of the structures, 55, 66drying time, 77dug earth, 4dung, 34, 63

90

8. Keyword index

durability, 82earth, 3earth block masonry, 42earth block masonry, non-loadbearing,

50earth block use classes, 29earth block walls, 44earth blocks, 16, 27, 42, 49earth blocks, strength class, 42earth blocks, use classes, 29earth bonding, 14earth deposits, 3earth filling, 16, 26earth masonry mortars, 16, 33earth mortar, 42, 56earth mortars, 16, 33, 50, 64earth mortars, abrasion resistance, 34earth mortars, adhesive strength, 34earth mortars, compressive strength, 34earth plaster mortars/rendering, 16, 33,

34earth shingling, XIearth spray mortars, 33earthen building materials, 14earthen building materials,

abbreviations, 15earthen coating materials, 61earthen plastering/rendering, 61, 63earthen plastering/rendering, adhesion

to the base, 64earthen plastering/rendering,

application, 65earthen plastering/rendering,

compressive strength, 62earthen plastering/rendering, drying, 66earthen plastering/rendering, flaws, 64earthen plastering/rendering, further

treatment, 66

earthen plastering/rendering, plastering/rendering systems, 64

earthen plastering/rendering, repair, 67earthen plastering/rendering,

requirements, 64earthen plastering/rendering, sanded

surfaces, 66earthen plastering/rendering, shrinkage

cracking, 64earthen plastering/rendering, stabilised,

61earthen plastering/rendering, suitability,

63earthen plastering/rendering, surface

treatment, 65earth-moving and soil engineering, 9equalised dampness, 77execution of construction, 1expanded clay, 24experience, 1, 5, 38exterior rendering, 63, 67exterior rendering for visible latticework,

68exterior rendering, framework render, 68exterior rendering, requirements, 62exterior walls, 40extruded walls, 54extrusion moulding method, 30extrusion technique, 54fabric, 67facings with clay panels, 70factory materials mortars, 35factory-supplied mortars, 35fat earth, 3, 9fibrous clay, 15, 21fibrous clay plastering/rendering, 64fibrous light clay, 16, 23filler framework, light clay walls, 51fine sand, 6, 10

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fire behaviour of components built with earth, 79, 80

fire behaviour of earthen building materials, 78

fire-resistance class, 79, 80flooring, 59floors made of rammed earth, 69format of earth blocks, 30, 31formwork, inserted ceilings, 59formwork, light clay walls, 52formwork, rammed earth walls, 45framed walls, 48, 80framework plastering/rendering,

plastering/rendering systems, 69framework render, 68friction test, 6gable walls, 40geotechnical tests, 8grain size distribution, 10grain size distribution line, 10gravel, 10green bricks, 30, 50ground-moist, 71gypsum plaster, 67hairline cracks in plastering/rendering,

62hardening of the plaster/render base, 63heat retention, 75heavily salted, 4heavy rain, 48, 76humification, 76humus, 4, 7, 15imperviousness to wind, light clay walls,

52inbound inspection, building earth, 5infill, 47, 48initial inspection, 35inner shells made of light clay, 52inner shells, masoned, 50

inserted ceilings, 58inspection methods, building earth, 5inspection of building earth, 5installation moisture, 77insulating boards, plastered, 56interior plastering, 63, 67interior plastering, requirements, 62interlocking, 40internal insulation consisting of plastered

insulating boards, 56joint sealing, framework

plastering/rendering, 68joist ceilings, 57knife cut, 68labelling of clay panels, 33labelling of clay straw, 23labelling of cob, 21labelling of earth blocks, 31labelling of earth fillings, 27labelling of earth mortars, 36labelling of light clay, 26labelling of rammed earth, 19labelling, earthen building materials, 14laboratory tests, 6laboratory tests, building earth, 7, 8lattice ceiling, 58lattice plaster ceiling, 58lattice, earth extruded walls, 55Lehmstapelwände, 54lifespan, 82light clay, 16, 23light clay ceilings, 58light clay panels, 32light clay straw, 49, 57light clay walls, 51light earth blocks, 27light earth masonry mortars, 33light earth mortars, 33light earth plaster mortars/rendering, 33

92

8. Keyword index

lightweight additives, 24lime content, 7, 8lime exterior render, 68lime mortar slurry, 66lime paints, 66lime plaster, 66, 67lime plastering/rendering, 69lime plastering/rendering on

plaster/render carriers, 69lime render adhesion, 45lime/gypsum plaster, 67liquid limit, 9live load, 43load-bearing framework, light clay walls,

51load-bearing walls, 39Load-bearing walls, 38load-bearing walls, repair, 46load-bearing walls, requirements, 42loam paints, 66loessial soil, 4machine spraying, 67manual moulding method, 29manufacturers, 2marl, 3masonry infill, 49masonry mortars, 33masonry strength, 44masonry using earth mortars, 50masonry with earth mortar, 43masonry, non-loadbearing, 50massive walls, 79material specifications, 72measure of shrinkage, 19, 42measure of shrinkage for earth mortars,

36mechanical drying of structures, 53method of manufacture for earth blocks,

31

method of plastering/rendering, 61mildew, 76mineral framework, 3, 5, 6, 10mineral light clay, 16, 23mineral-based additives, 14, 75mineral-based light additives, 24minimum wall thickness, load-bearing

walls, 42mixing of clay straw, 22mixing of cob, 20mixing of earth fillings, 27mixing of earth mortars, 34mixing of light clay, 24mixing of rammed earth, 18mixing ratios, 15moisture, 76moisture conductivity, 76moisture protection, non-loadbearing

masonry, 50moisture take-up, hygroscopic, 77moistureproofing, 1Moistureproofing, load-bearing walls, 39mortar additives, earthen

plastering/rendering, 63mortar group, lime mortar, 42mortar group, lime mortars, 66, 67mortar group, load-bearing walls, 42mortar strips, 45mould, earthen plastering/rendering, 66mould, light clay, 52mountain earth, 3multi-course plastering/rendering, 65noise-insulating characteristics, 81non-combustible, 78non-loadbearing masonry, 50non-loadbearing rammed earth walls, 50non-loadbearing walls, 47not easily flammable, 78openings, 40

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Order on building with earth, Xorganic additives, 14, 75other components, 71paints on earthen plastering/rendering,

66partial safety factors, 38particle density, 72permanent formwork, 52, 58, 77permissible compressive stresses, 42pillar, 38planning of construction, 1plant-based additives, 14plaster base, 52plaster mortars/rendering, 33plaster mortars/rendering on earthen

bases, 67plaster/render base, 61, 65plaster/render carriers, 63, 67plaster/render layer, 61plastering/rendering, 61plastering/rendering adhesion, 62plastering/rendering cracks, 62plastering/rendering on earthen bases,

61plastering/rendering system, 61plastering/rendering systems for

framework plastering/rendering, 69plastering/rendering, guidelines for

planning, 61plastering/rendering, loading, 68plastering/rendering, requirements, 62plastic characteristics, 9plasticity, 3, 5plasticity index, 9powdered clay, 4practical moisture content, 77preparation of earthen building

materials, 14prestandards for building with earth, X

primers, 63production control, 35production processes for earth blocks,

29proof in respect of load-bearing walls, 42proportion of clay, 3protection against collapse, 51protection against weather, 39, 47, 48puddle, 80, 81pumice, 24rain protection, 39rammed earth, 15, 17, 42rammed earth floor, 17rammed earth floors, 69rammed earth walls, 45, 50recycled mortars, 35recycling earth, 4reed tissue, 52reinforcement, 40reinforcement for plastering/rendering,

68reinforcement of clay panels, 60reinforcing fabric, 65reinforcing fillers in rammed earth walls,

45reinforcing transverse walls, 44repair, clay straw framework, 49repair, load-bearing earth walls, 46re-prepared, 22resistance to abrasion, 14resistance to pressure, 14re-use, 17re-useability, 76reveals, 44ring beams, 40Ringbalken, 43rolled ceilings, 57rolled struts, 49roof slope, 60

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8. Keyword index

rotting, 76rules of thumb, 15safety factor, 38salt, 35salt contamination, 17, 46sampling, plaster mortars/rendering, 35,

64sedimentation, 10self-execution, 1services, delimitation in accordance with

VOB, 83settlement, 39, 44, 45, 68shrinkage, 14shrinkage cracking, 34sieving, 10silt, 6, 10silty, 6single-course earthen

plastering/rendering, 65skilled worker, 1skilled workers, 38, 46skirting, 71skirting projections, 39slenderness, 50slope wash, 3slump, mortar, 36slump, slurry, 25slurry, 25slurry consistency, light clay, 25smell test, building earth, 7soaking of the base, 67soapy, 6soil moisture, 50, 52sorption, 76, 77specific heat capacity c, 75splashwater, 71spray mortars, 33spray rendering, 63spray water, 39, 50

sprayed earth mortars, 16sprayed light earth mortars, 33stabilised earthen building materials, 1stabilised earthen plastering/rendering,

61stability, 40, 76stacked earth walls, 54stacking technique, 54standards, 85stone strength class, 42stony earth, 17storey heights, 39, 43straw, 22, 24straw light clay, 16, 23strength class of earth blocks, 29, 31, 32strut ceilings, 57struts, 48, 49, 57Strutting with daub, 49sturdiness plastering/rendering, 61sturdiness, plastering/rendering, 62supports, 40surface work, plastering/rendering, 61susceptibility to moisture, 76susceptibility to water, 14, 76swelling behaviour, 30swelling behaviour, earth blocks, 29, 30tensile strength, 14tensile test, 8, 11tension rods, 40TERMS OF CONTRACT FOR earthen

building SERVICES, 83test consistency, 8, 11test methods, building earth, 8testing of clay panels, 33testing of clay straw, 22testing of cob, 20testing of earth blocks, 30testing of earth fillings, 27testing of earth mortars, 36

95


testing of light clay, 25testing rammed earth, 18thermal conduction figures, XIIthermal conductivity, 74thermal insulation, 14, 74thermal insulation sheets, plastered, 56thin coatings, 61thin earth, 3, 9thin-course plastering/rendering, 65tiling on earthen plastering/rendering, 64timber joist ceilings, 57time to dry, 1transverse walls, 44triangular battens, 49trowel cut, 68trowel-ready, 34types of earth, 3use classes for earth blocks, 30use of earthen building materials, 16Vaulting, 46VOB Part C, 83wall thickness, 77wall thickness, light clay, 52wall thickness, load-bearing walls, 42,

44

wall ties, 40wall-mounted heating systems with

earthen plastering/rendering, 65wallpaper on earthen plaster, 64wallpaper on earthen

plastering/rendering, 66walls, non-loadbearing, 47water solubility, 76waterproof layer, 39, 50wattle and daub, 48weathering, 4weatherproofing, 1, 77whey, 34wickerwork, 48windproofness, 82wood chippings, 24, 75wood joist ceilings, 80wood joist ceilings, noise-insulating

characteristics, 81wood light clay, 16, 23, 24work with earth, 83working formword, 58working formwork, 52works management, 38, 46woven reeds, 52

.End Index.

96

Project participants

PROJECT PARTICIPANTS


A project by the German Association for Building with Earth, Weimar (Eds.),

supported by funding from the Federal Foundation for the Environment (DBU), Osnabrück.

Authors

Dipl.-Ing. Franz Volhard, Architect BDA (German Association of Architects), DarmstadtDipl.-Ing. Ulrich Röhlen, CLAYTEC e.K., Viersen

With the collaboration of

Dr.-Ing. Christof Ziegert, ZRS Architekten Ingenieure, Berlin

Working group

Prof. Dr.-Ing. Klaus Dierks, Institute for Design, Construction, the Building Industry and Building Law, Berlin Technical UniversityDipl.-Ing. Stephan Jörchel, Ingenieurbüro S. Jörchel, WeimarDipl.-Ing. Ulrich Röhlen, CLAYTEC e.K., ViersenDr.-Ing. Horst Schroeder, Bauhaus University WeimarDipl.-Ing. Franz Volhard, Architect BDA (German Association of Architects), DarmstadtDr.-Ing. Christof Ziegert, ZRS Architekten Ingenieure, Berlin

Project management

Dr.-Ing. Horst Schroeder, Bauhaus University Weimar

97


Contributors to previous editions

Working group

Peter Breidenbach, Manfred Drach, Dr.-Ing. Thomas Kleespies, Heiner Lippe, Günter zur Nieden, Anke Richter, Ulrich Röhlen, Dr.-Ing. Horst Schroeder, Prof Heinz G. Sieber, Franz Volhard

Subject-matter expertise and advice

Eckhard Beuchel, Sven Börjesson, Martin Breidenbach, Dr.-Ing. Heinrich Bruckner, Hugo Houben, Irmela Fromme, Veit Mach, Dr.-Ing. Hans-Ulrich Rönn, Burkard Rüger, Jens-Uwe Schulz, Helmut Zeitter, Christof Ziegert

Contributions to discussions

Franz Bauer, W. Ehrich, Waldemar Eider, Bernhard Gaul, Alwine Gillessen, Carl Giskes, Karin Halbritter, Stephan Jörchel, Khudadad Khademi, Andreas Krewet, Tomas Lemcke, Prof. Dr.-Ing. Gernot Minke, Johannes Paulus Lehmann, Michael Nothelfer, Guido Röber, Reinhold Rönz, Sascha Rummel, Georgios Schade, Frank Schneider, Jens-Uwe Schulz, Prof. Dr.-Ing. Jörg Schulze, Ingolf Stein, Ziegelei Ott

98

Documents

E6-1-99 bereinigt für Ausdruck []f.Stich · Web viewClay vaults are structures curved on one side, domes are structures curved on two sides. Barrel vaults are low clay vaults with