1. Jim Hooker BSc FIoR
Technical Director
How to avoid leaky roofs
SIG Design & Technology technical seminar

2. How do you make a roof?
Client
Main contractor
Specialist
Designer
Manufacturer

3. Client
• Define performance requirement
– Secondary functions
– Access
– Appearance
– Maintenance strategy
• Budget for sustainability
• Be prepared to review

4. Designer
• Respond to performance requirement
• Don’t just replicate the last job
• Defend the specification
• Don’t subcontract key design features:
– Drainage and U-value
– Dimensional constraints
– Loadings
– Detailing
• Be ready to REVIEW

5. Main contractor
• Respect NBS Specification J42
– 210 Secure, free-draining, weatherproof
– 610 Grading to correct falls…Moisture
content and stability of substrate: Must
not impair integrity of roof.
– 920 Electronic roof integrity test …Testing
authority: . . . . . .
• Plan and manage protection
• Plan sequencing
• Check installer credentials

6. Manufacturer
• Not just a product
• Provide a holistic service
– Current certification
– Calculation service
– Indemnity for design advice
– Off-site installer training linked to VQ
– Installer database
– On-site inspection and enforcement
• Manage expectations on appearance

7. Specialist
• Keep up to date
• Be proactive – assist in design
• Develop the workforce
– Train
– Card
– Supervise
• Protect the work

9. Everybody should…
Exploit the centre of excellence

10. What is a centre of excellence?
Guidance
• Design Guide
• Product evaluation
• Drainage
• Acoustics
• Sealants
• Safety
• Guarantees
• Testing for integrity
ALL FREE DOWNLOADS
FREE TELEPHONE ADVICE

11. Component standards
• PIR insulation
• EPS insulation
• XPS insulation
• MW insulation
• Fasteners
• Rooflights
• Roof access hatches
• Top-fixed safety anchors
• Membrane-line gutters
• Roof edge and lightning protection
ALL FREE DOWNLOADS
What is a centre of excellence?
BIM Objects

12. A careers centre
• Resources and curriculum
• Apprenticeship
• Upskilling
• Product installation training
What is a centre of excellence?

13. SPRA is that resource
A modern trade association
• Supply chain
• Accountable
• In touch
• Market-focussed
• Web-based media + human helpline
• Developing sustainable systems
• Committed to developing the workforce

14. Who is SPRA?
13
Membrane
manufacturers
(>70% of output)
26
Associates
40
Contractors
Individual trained installers

15. Design checklist
• Falls: minimum 1:80 finished “at any point.” 
• Keep it simple: avoid gutters and sumps. 
• Wind loading: accurate, calculated, applied. 
• Dead loading: pedestrian, services. 
• Thermal: backstop, average, bridging. 
• Warranty: ensure continuity. 
• Integrity testing: design for it. 
• Detailing: height, weathering, clearance to build. 
Use for design development, review and survey

16. Products - critical factors
• Independent certification: SPRA requires BBA. 
• Compatibility: with adjacent components. 
• Appearance: it must match expectations. 
• Repairable: straightforward, reliable procedure. 
• Support: SPRA requires full design support. 
• Track record: examples of similar UK installations. 
• Details: for all system types. 
• Training: quality and duration of course. 
• Field inspection: frequency; record. 

17. Installation - critical factors
No British Standards - SPRA sets industry standards
• Protect: deck, and roof system. 
• Storage: be aware of requirements. 
• Wind: use of adhesives/layout of fasteners. 
• Welding: tests, samples, inspection. 
• Access: specialist must have possession. 
• Testing: use a qualified independent provider. 

18. Green roofing and SUDS
Bio-diverse Extensive - sedum
Bio-diverse in
education
Extensive (sedum) in
education
Extensive (sedum) in
leisure

19. Rain-screen

20. Replication

21. enquiries@spra.co.uk
0845 1547188
Anycomments?