IF YOU WANT TO USE TIMBER ON YOUR BUILDING, THE KNOWLEDGE IS OUT THERE
Autumn is a great time for tree-hugging and I came perilously close to doing that last month. Furniture maker Luke Hughes organised a CPD trip to Stourhead where, alongside the magnificent landscaped lake, there is an equally impressive forestry operation. It was fascinating to discover how the relationship between forester and client can lead to the discovery of new, high-value uses for elements that were previously considered valueless. And, equally, seeing a small-scale mobile sawmill that can cut all the cedar cladding for a building economically.
One architect on the trip lamented practitioners' lack of understanding of the production process of wood, compared to other materials. Timber is certainly complex, not least because there are so many species, all with different properties - properties which vary even within the output of a single tree. The Institute of Wood Science aims to increase understanding and its annual conference, also last month, covered topics ranging from the need to specify a wider range of hardwoods (purple heart, anybody? ) to the microwave treatment of radiata pine to improve its take-up of preservatives.
Research by Ivor Davies of Napier University into the durability of timber cladding has demonstrated that larch cladding is far more variable in its properties than previously assumed.
This is because juvenile heartwood, although difficult to differentiate visually, is far less durable than older heartwood. But the main lesson, after lots of study into wetting, sun direction etc. , was that the durability of cladding is determined by how it is designed and detailed. Common sense, yes, but well worth remembering. Our feature on timber cladding (pages 49-52) sets out some essentials, and plenty more guidance is available from organisations such as TRADA and wood.
for good. If you want to use timber in your buildings, lack of knowledge should not be an impediment. It is out there.