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

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Introduction

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

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UK Cladding market materials

• No direct information on volumes of material used
  in UK market

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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
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• 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

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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

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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

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Cladding design then..

• Poor substrate selection
• Poor design
• Non specific fixings
• Poor finishing on site
• Adequately or poorly maintained
• Met service life??

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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

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Best practice design
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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
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Natural durability sufficient?
EN335 Use Class EN350 Natural durability EN460 BS8
417 Preservation (EN599 and EN351)
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Substrate quality BS942
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INNOVATION Substrate selection
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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

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Enhance durability and test

• Wood preservation
• Wood modification
• Wood coatings
• Combinations of the above

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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?

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INNOVATION Wood preservation

• Water-borne
• Multi functional
• Water repellent
• Colour
• Improved specification
• Improved quality of treated products

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BS8417 Preservation of timber - Recommendations
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WPA Manual
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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
• gt50 years of wood science
• Numerous technologies
• Stimulated by the need to consider alternatives
  to
• Conventional wood protection
• Non-sustainable hardwoods
• Exciting commercial reality

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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

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BRE Digest 504 (Nov 07)
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(No Transcript)
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(No Transcript)
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Uncoated cladding

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

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INNOVATION Coating system

• Water-borne
• Low VOC
• Extensibility
• Photostability
• Improved Environmental Profiles
• Full factory finish
• Powder coating

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Coating of a rough sawn
Coating of a smooth surface
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Microscopic view of a rough sawn surface
Microscopic view of a smooth surface
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Edge covering
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Film build
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Coating hardwood pore filling
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Timber cladding behind glass
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Full factory finished cladding
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INNOVATION Environmental Profiles

• The Code for Sustainable Homes
• The Green Guide to Specification
• Presenting the case for timber
• Improving product profiles

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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

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Specification tools
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INNOVATION Fire protection

• Multi functional
• Fire Safety Design
• Fire retardant pre-treatments BS 8414 Part 1 or 2
• Wood Protection Associations (WPA) Fire
  Retardant Manual

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INNOVATION Construction

• Off site construction
• Full factory finished
• Planned maintenance
• Site practice and skills

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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

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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

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BS6150
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Origin of maintenance specifications
housing stock owners painting
contractors
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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

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The integrated system?

• 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

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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

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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