Innovation in exterior cladding and its planned maintenance

1. Innovation in exterior cladding and its planned maintenance 22 November 2007 Ed Suttie, BRE Geoff Taylor, Sikkens

2. Introduction • Exterior timber cladding • Durability • Innovations to improve durability • System durability • Planned maintenance • Conclude

3. UK Cladding market : materials • No direct information on volumes of material used in UK market

4. Sustainability and Life Cycle Water Energy Resources Waste Emissions Forestry Harvest Process Manufacture Construction Second life... In service Maintenance Demolition End of life Energy recovery

5. Raw materials Design and specification Manufacture and quality control Build/install phase Use phase • The performance of timber cladding and thus whether service life is met is influenced at all stages • Need to objectively assess the importance of each component of a system and its contribution to delivery of service life

6. Durability • Capability of a building or its parts to perform its required function over a specified period of time under the influence of the agents anticipated in service • Material of biological origin - need for protection • Biological durability • Prevent moisture ingress

7. Delivering durability • Timber species • Substrate selection • Cladding design • Pre-treatment • End grain protection • Primer or base stain • Top coat • Finishing of the product • Storage, transport • Installation • Planned Maintenance

8. Cladding design then….. • Poor substrate selection • Poor design • Non specific fixings • Poor finishing on site • Adequately or poorly maintained Met service life??

9. Cladding design now…. • Substrate selection • Best practice design • Fully factory finished • Just in time delivery • Fitted by qualified installers • Planned maintenance and care package Extended service life

10. Best practice design

11. ISO15686 Service Life Prediction Factor method ISO 15686 ESL = RSL x A x B x C x D x E x F x G A quality of components (durability) B design level C work execution level D indoor environment E outdoor environment F usage conditions G maintenance level

12. Natural durability sufficient? EN335 Use Class EN350 Natural durability EN460 BS8417 Preservation (EN599 and EN351)

13. Substrate quality BS942

14. INNOVATION: Substrate selection

15. Durability enhancement • Upgrade to DC1 • Costly, market acceptance? • Accept that for the chosen design and for timber species of low durability, to maintain the desired appearance, to deliver an acceptable service life then the durability will require enhancing Enhancing durability Permanence of characteristic Planned maintenance

16. Enhance durability and test • Wood preservation • Wood modification • Wood coatings • Combinations of the above

17. Challenges Wood preservation • Restrictions on traditional products (CCA alternatives) • Registration under Biocidal Products Directive • Penetration and retention Exterior wood coatings • Low maintenance • Full factory finishing • Low VOC coatings and processes Wood modification • Lack of fit with standards • Track record?

18. INNOVATION: Wood preservation • Water-borne • Multi functional • Water repellent • Colour • Improved specification • Improved quality of treated products

19. BS8417 Preservation of timber - Recommendations

20. WPA Manual

21. INNOVATION: Wood modification • The action on wood by chemical, biological or physical means creating a new material - “modified wood” - with a desired property enhancement for the service life of the wood product • >50 years of wood science • Numerous technologies • Stimulated by the need to consider alternatives to • Conventional wood protection • Non-sustainable hardwoods • Exciting commercial reality

22. Wood Modification • Modified wood technologies can… • Resist decay organisms (biological durability) • Minimise shrinking and swelling of the wood in changing moisture conditions (dimensional stability) • Confer hardness and wear resistance • Prolong the life of exterior wood coatings • Compete effectively with less sustainable materials • Improve end of life options • Thermal modification ThermoWood® • Acetylation AccoyaTM • Densification Indurite*

23. BRE Digest 504 (Nov 07)

26. Uncoated cladding • Typically uncoated cladding with non-uniform colour changes can lead to dissatisfaction • Brush applied maintenance coatings

27. INNOVATION: Coating system • Water-borne • Low VOC • Extensibility • Photostability • Improved Environmental Profiles • Full factory finish • Powder coating

28. Coating of a rough sawn Coating of a smooth surface

29. Microscopic view of a rough sawn surface Microscopic view of a smooth surface

30. Edge covering

31. Film build

32. Coating hardwood – pore filling

33. Timber cladding behind glass

34. Full factory finished cladding

35. INNOVATION: Environmental Profiles • The Code for Sustainable Homes • The Green Guide to Specification • Presenting the case for timber • Improving product profiles

36. Code for Sustainable Homes 2007 • Single national standard for England • EcoHomes in Wales, Scotland, Northern Ireland and for refurbishment • Industry guide for design and construction for more sustainable new homes • A step change in sustainable building practice for new homes

37. Specification tools

38. INNOVATION: Fire protection • Multi functional • Fire Safety Design • Fire retardant pre-treatments BS 8414 Part 1 or 2 • Wood Protection Association’s (WPA) Fire Retardant Manual

39. INNOVATION: Construction • Off site construction • Full factory finished • Planned maintenance • Site practice and skills

40. Offsite construction • Modern methods of construction • Pre-manufacture • Less storage area on site • Quality of workmanship • Improved safety levels • Fast assembly • Reduced costs • Lower labour costs • Less waste • Less plant hire • Dimensional accuracy • Less disruption • Enhanced durability

41. INNOVATION: Planned Maintenance • £1 billion pa maintenance of buildings • Redecoration and maintenance painting of exterior wood is significant • Demands ‘value for money’ • Reduce unnecessary maintenance activities • Reduce costs of incorrect surveys • Improve process selection • Higher standards of performance and quality • Improve site practices • Minimise waste • Move away from short-term first costs

42. BS6150

43. Origin of maintenance specifications housing stock owners painting contractors

44. Partnership and responsibility • Coatings manufacturer and contractor led with housing stock owners • Improved product performance • Raising skill levels • Improved maintenance practices • Maximise service life • Extend maintenance intervals

45. The performance of timber cladding and thus whether service life is met is influenced at all stages First costs sensitive, quality, consistent Best practice, control, confidence in supply chain Skills Skills, partnership, value Whole life costs sensitive, partnership, planned maintenance Raw materials Design and specification Manufacture & Quality Control Build/install phase Use phase The integrated system?

46. Conclusions • Design, durability and planned maintenance can deliver • Raising standards • Robust technologies fostered • New partnerships to ensure service life • Cladding product accreditation scheme • Holistic approach – durable integrated system

47. Conclusions • Great opportunity for exterior timber cladding • fully factory finished • new substrates • offsite construction • Move from a material orientated approach to an integrated product approach • Use the wood science! • Timber cladding delivered in partnership between the technology holder, the manufacturer, the specifier, the coating system company, the maintenance contractor and the building user/owner