Summary
¦ Defra says a warmer, wetter climate for the UK is inevitable.
¦ It will increase risk to timber from insects and damp.
¦ It is only a matter of time before termites become a threat in southern England.
¦ Improved guidance on timber protection standards to meet climate change impacts is a priority.
¦ Interest in wood protection technology is growing.
Carbon benefits and sustainability are the environmental factors driving the renaissance in the use of wood. What is only just being recognised are the implications of another environmental factor – climate change – on the performance of wood currently being used in buildings with a life expectancy of 50-80 years.
A warmer, wetter climate for the UK is now regarded as inevitable, according to Defra UK Climate Projections 2009. Another inevitability is that this brings an increased risk of fungal decay and insect attack to untreated wood.
The Climate Change Act 2008 requires that public and statutory organisations take action to adapt to these changes. BSI has identified 13 potential climate change impacts on standards that need to be addressed if a building is to have a long life. As a consequence, earlier this year, British Standards committees were instructed to review climate change impacts and incorporate new guidance where appropriate.
BSI Committee B515 deals with the wood preservation standard BS 8417. Although a revised draft of BS 8417 is in its public consultation phase, WPA and B515 chairman Dr Chris Coggins said that consideration of a warmer and wetter climate is not included in the current draft recommendations but that this could change in the new year.
“Improved guidance on timber protection standards to meet climate change impacts are being treated as a priority,” said Dr Coggins, who is leading a BS 8417 climate change task group to produce recommendations.
“Building designers can’t afford to wait for climate change to reveal its full effects over time; they need to act now by specifying timber that’s fit to take on climate change challenges and particularly the risk posed by termites and house longhorn beetle.”
Termites have spread from southern Europe through France and Germany and are now found in Calais. Occasional isolated outbreaks have occurred in the UK, most recently in North Devon. The government has funded extensive attempts to eradicate this outbreak but without total success as yet. It is probably only a matter of time before termites become a threat in southern England. The house longhorn beetle is active in north-west Surrey and all softwood roofing timbers in that area must be treated, but outbreaks in other areas are not unknown and as temperatures increase its sphere of influence could expand.
The BS 8417 task group is expected to report to BSI early in 2011 but the WPA has been flagging up climate change impacts for several years. WPA first published a Climate Change Guidance Note in 1996, highlighting the increased risk to non-durable timber from insects, particularly termites and house longhorn beetle, and from damp penetration caused by driving rain, condensation and flash flooding. We also highlighted that wood was perfectly capable of being protected by an appropriate preservative treatment tailored to the application. About the same time, BRE published a report on climate change impact on UK Building Regulations which also highlighted the potential spread of termites, house longhorn beetle and other insects. It appears that Building Regulations did not respond to this advice.
Nevertheless, the WPA is lobbying the Communities & Local Government Department on wood and fire protection issues. When the coalition government announced a review of UK Building Regulations in July, the WPA took the opportunity to call for a clearer definition of the requirements for preservative and fire protection treatments. One of the main points we highlighted related to the likely increased threat to construction timber posed by climate change and how this could be overcome. And while most designers accept the need to treat softwood components exposed to the elements, for many internal structural applications and roofing timbers treatment has tended to be viewed as optional and the risk of insect attack disregarded altogether. The WPA believes the move by BSI to factor climate change impacts into BS 8417 guidance is likely to change this.
The renewed interest in wood protection technology is reflected in the significant increase in requests for specification guidance the WPA is receiving, particularly from architects. Over the past year the numbers registering on the WPA architects’ wood treatment helpline has more than trebled to close to 400, which indicates to us a changing attitude to the benefits of pre-treated and modified woods.
The WPA strategy is focused on raising awareness about the quality treatment of wood and being the champion for its specification as a modern, relevant construction material. Climate change will inevitably open opportunities for preservative treatments and modified woods and the WPA intends to help develop those opportunities by providing the essential generic technical guidance that supplements BS 8417 and other standards.
