Architect James Munro was asked to speak at the Knowledge Transfer Network's Front Meeting of Skills event all about BIM. BIM is short for building information modelling and it is a key tool in how Granit designs buildings. Not only does BIM enable us to design effectively and communicate design choices to our clients via 3D visuals, it is also key in how we collaborate with the other professionals such as structural, or M&E engineers. This presentation was specifically about how to use BIM for green retrofit projects and James talked a lot about Granit's project at 1 Lambourn Road - which we designed and built as an example of what's possible with green retrofit. There are also two other schemes where we have used BIM extensively throughout the design process, one in Battersea and the other St John's Wood.

1. Using BIM in Small Architectural Practices:
Barriers and Benefits for Retrofit Projects.
James Munro
Director, Granit Chartered Architects
Nov 26th 2015

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

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

4. Granit Chartered Architects:
• Chartered practice based in Clapham,
South London
• 20 staff
• Passion for sustainable and low energy
buildings
• Members of AECB and Green Register
Photo of summer party

5. • 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. Existing House – 3D Model

12. Existing House – 3D Model

13. • RIBA Stage 2 Planning
Consent and Conservation
area consent
• 3D views for consultation
• Client sign off
• Assessment of orientation and
solar gain

14. 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

15. 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

16. RIBA Stages 3-4
• 4 different wall types identified
External junctions analysed in 2D
and 3D
U values:
• Roofs: 0.16
• New external walls: 0.15
• Refurbed walls: 0.18
• Floors: 0.14
• Windows: 1.2

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

18. RIBA Stages 3 – 4
• MVHR design – 2D
CAD overlays
integrated into 3D
model
• Coordination of
ducting with service
voids structure

20. 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

21. 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

22. kWh/m².yr
Primary Energy consumption kWh/m².yr
Your Energy
183 kWh/m².yr
UK average
Pre-retrofit Primary Energy Post-retrofit Primary Energy (measured)
0
200
400
600
800
1000

23. kg CO /m².yr
Your CO emissions kg CO /m².yr
38 kg CO /m².yr
Your CO
Pre-retrofit CO emissions Post-retrofit CO emissions
0
25
50
75
100
125
150
175

24. 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% reduction
CO2 – 38Kg CO2/m2yr - 40% reduction

25. 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

26. Key points:
• Enlargement and refurbishment of house
• Existing GIA – 293 sqm
• Complete GIA – 600 sqm
• Construction 2014 – present
Structures: HRW
M 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

27. RIBA Stage 0-1 Existing
house - 3D model

28. RIBA Stage 2 - Planning

29. Integration of
structures - Sketch up
file export / DWG
import (Not IFC)
RIBA Stages 3-4

30. RIBA Stages 3-4
M and E
MVHR – DWG
Export/Import
Clash Mark up by hand

31. RIBA – Stage 4
Full design
coordination

32. RIBA – Stage 4
Full design
coordination

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

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

36. RIBA – Stage 3 – 4
BIMx File sharing with
client

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

38. 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

39. • 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

40. Survey company 2D CAD to 3D model

41. Structural Engineer – 2D CAD to 3D model

42. MVHR supplier 2D CAD to 3D model

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

44. Building detailing – identifying potential cold bridging details in fabric.
3D and 2D drawing communicated to contractor.

45. 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)

46. 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

47. 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

48. 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

49. Thank you
Email: james@granit.co.uk
Telephone: +44(0)20 7924 4555
Website: www.granit.co.uk
Twitter: @LondonArchitect