Using BIM in Small Architectural Practices:Barriers and Benefits for Retrofit Projects.James MunroDirector, Granit Chartered ArchitectsNov 26th 2015

Q: Do we BIM?A: We've been BIM’ing it for yearsQ: Lonely or Collaboratively?A: Lonely, but we’re working on making friends

Introduction to Granit Architects Technology & Working Partnerships 3 Case Studies Benefits and Barriers to BIM for Retrofit

Granit Chartered Architects:

• Chartered practice based in Clapham, South London

• 20 staff• Passion for sustainable and low

energy buildings• Members of AECB and Green

RegisterPhoto of summer party

• 90 current jobs

• 85% private client – residential

• 15% Commercial clients –

residential

• 10% new build

• 90% refurbishment / extensions

• Average construction value £400k

• Range of £250K - £5m

Practice Ambitions:• Be experts in designing low energy, high

performance buildings• Use BIM to further improve collaboration within the

construction value chain• Use BIM modeling to trouble shoot pre-construction

and construct better buildings

Lonely BIM (level 1)• 3D model all survey info / existing

buildings• 3D information & schedules RIBA stages

1-6• 2D info added at Stage 4• Import & Export PDF / DXF / Sketchup

Collaborative BIM (level 2)• Import & Export IFC• BIMX model – clients / QS / contractors

Technology & Working Partnerships

Key points:• Retrofit to pre-1919 property• Construction 2011-2013• Existing GIA- 115 sqm• Complete GIA – 180 sqm

Primary Energy use:• Pre works – 300-400kWh/m2/yr

(estimated)• CO2 – 97Kg CO2/m2yr

Financial:• Contract Value £300K• Retrofit and renewable measures

£75K• Predicted pay back 10-15 years

Case Study 1 – Lambourn Road, Clapham

Project Objectives:

• To demonstrate best practice for retrofit in solid wall housing

• Enable us to give best advice to our clients on energy saving measures

• Test bed for renewable technology

• Achieve standards in energy efficiency approaching the retrofit for the future program target

• Develop collaborative techniques to deliver an efficient design service

• Monitor results and evaluate

Existing property:

• Solid brick walls (external and party walls)

• Conservation area – front façade to be retained

• Suspended timber floors• Single glazed sash windows• Non-insulated pitched roof• 20 year old gas boiler and

HWT• Background vents / Rapid

extractors to bathrooms• Open fireplace

Existing House – 3D Model

Existing House – 3D Model

• RIBA Stage 2 Planning Consent and Conservation area consent

• 3D views for consultation• Client sign off• Assessment of orientation

and solar gain

RIBA Stages 3-4

• Solid brick walls EWI for flank, rear and all new walls

• All thermal envelopes upgraded

• New warm roof construction

• Reduced risk of thermal bridging

RIBA Stages 3-4

• Solid brick walls IWI for existing walls (historic detailing retained and repaired)

• New pitched warm roof construction

• Floor junctions and lintels – possible thermal bridging details identified

RIBA Stages 3-4

• 4 different wall types identified

External junctions analysed in 2D and 3DU values:• Roofs: 0.16• New external walls: 0.15• Refurbed walls: 0.18• Floors: 0.14• Windows: 1.2

RIBA Stages 3-4: 3D to 2D Construction Drawings

RIBA Stages 3 – 4

• MVHR design – 2D CAD overlays integrated into 3D model

• Coordination of ducting with service voids structure

RIBA Stages 5

• Construction Stage• Re-survey follow strip

out• Hand over of

information for project file

• Adjustment to design and construction details

• Quality control paramount

• Communication of air tightness and thermal bridging strategy to contractor/sub-contractor

RIBA Stages 6-7

• 18 month monitoring of energy usage

• Thermal imagery• Marketing / Open House

2013/14

Top image: air permeability test• Result: 3.54 m3 / (h.m2) @50

PA• Enerphit <1• New build 1-3 (10 under regs)

Bottom image: thermal bridging analysis

Summary of Energy / CO2 Reduction

Information sourced from www.lowenergybuildings.org.uk

Pre works Energy - 300-400kWh/m2/yr (estimated)CO2 – 97Kg CO2/m2yr

Post works Energy – 183/m2/yr - 61% reductionCO2 – 38Kg CO2/m2yr - 40% reduction

Post completion – Summary

• BIM modeling assisted with identifying key junctions & co-ordination of M and E

• 3D model can disguise building structure/materials

• Quality of contractor and sub-contractors key factor in meeting energy efficiency

• Communication to team, including end user vital

• Commissioning or balancing of MVHR to get best performance

Key points:• Enlargement and refurbishment of

house• Existing GIA – 293 sqm• Complete GIA – 600 sqm• Construction 2014 – present

Structures: HRWM and E: RLA Building services

Primary Energy use:• Pre works - 250kWh/m2/yr

(estimated)• Post retrofit - TBC

Contract Value £3 Million

Case Study 2 – Prince of Wales Drive, Battersea

RIBA Stage 0-1 Existing house - 3D model

RIBA Stage 2 - Planning

Integration of structures - Sketch up file export / DWG import (Not IFC)

RIBA Stages 3-4

RIBA Stages 3-4M and EMVHR – DWG Export/ImportClash Mark up by hand

RIBA – Stage 4Full design coordination

RIBA – Stage 4Full design coordination

RIBA – Stage 3 – 4Full BIM model assisting interior design process

RIBA – Stage 3 – 4Kitchen Design - 3ds file Export / 2D PDFS and DWGs Import

RIBA – Stage 3 – 4BIMx File sharing with client

RIBA – Stage 3-4Full BIM scheduling for Client, QS, and contractor

Summary

• BIM modeling assisted with coordination of M and E / Structures and suppliers

• All consultants exchange in 2D CAD

• Technical design influenced subsequent planning amendments

• Size of project / Fees for Stages 3-4 justify investment in full BIM model

• BIMx model for client/contractor and 3D clay renders easily delivered

• Enlargement and refurbishment of post war house.

• Fully upgraded to exceed Part L of regulations

• Existing GIA - 183 sqm• Complete GIA – 406 sqm

Construction 2013-2015

• Structures – Mitchinson Macken

• MVHR – Built Environment Technology

• Contract Value £1.1 Million

Case Study 3 – Abercorn Place, St Johns Wood

Survey company 2D CAD to 3D model

Structural Engineer – 2D CAD to 3D model

MVHR supplier 2D CAD to 3D model

Specialist stair company – Export Sketch up file / Import 2D DWGs

Building detailing – identifying potential cold bridging details in fabric.

3D and 2D drawing communicated to contractor.

Summary

• Post war house- rational orthogonal shape assisted CAD model

• BIM modeling assisted with coordination of M and E / Structures and specialist stair design

• All consultants exchange in 2D CAD

• Stair design developed and exchanged in 3D model (Sketchup file)

Benefits of BIM for retrofit projects Clash detection between structure / architectural / M

and E Existing, demolition and new elements can be

viewed simultaneously Thermal bridging junctions identified Easier for client to visualise concepts (extra service) 3d construction details to communicate to contractor Hand over of 3D file to project file Archicad Eco Designerstar Virtual Energy use = Real energy use

Barriers of BIM for retrofit projects: Getting consultants on board for all project types More time up front in 3d modeling Financial investment for client Working with existing buildings (real buildings are not

square) Can disguise reality of construction details Not a substitute for site inspection / Quality control

Comments from consultants:“We are embracing BIM, all our models are modeled in Revit in 3D. Even small projects” HRW Engineers

“ We do not intend to embrace BIM, yet, due to no demand from clients, and issues of cost and training” RLA Building Services

“ What’s an IFC file? Tried Revit once, found it very time consuming and long winded. Use Autocad!” Technician at Mitchison Macken

Thank you

Email: james@granit.co.ukTelephone: +44(0)20 7924 4555

Website: www.granit.co.ukTwitter: @LondonArchitect