Preservative free timber – is it a realistic construction option?

Following on from my previous post, I’m going to talk some more about wood preservation.

In the UK today, standard practice in construction is to specify preservative treated timber for external use. But as I previously stated, there are many examples from the past – where houses and other buildings constructed from preservative-free timber are still performing well after hundreds of years. Look at Norwegian Stave churches as an example.

Designers in the past did not have access to preservative treatment, so they developed alternative means to ensure the longevity of their timber structures. They relied on appropriate design and detailing; and on using the correct species of naturally – treated timbers.

The design approach

The use today of preservatives is a necessary evil for many manufacturers but it comes with a cost to the environment and often only compensates for poor quality materials and design.

Wind and water will always attack our houses, so clever window and door designers looked to an example of another product routinely exposed to the weather – the car. Modern principles of car design maintain that – If you can’t stop water getting in, make sure it can get out. Cars on the roads these days rust less than they did 20 years ago, not just because of additional rust-proofing, but by applying the basic design principle that water should not become trapped inside panels.

High quality factory finished timber windows and doors from Broxwood are also designed to withstand the weather. Just like modern car design, any water that penetrates the frame structure is safely drained away through internal channels. So efficient is the design, that I’m confident our products could be supplied untreated with minimal impact on product life expectancy.

So why do we treat our products against rot?

Despite my confidence I wouldn’t blame potential customers for choosing alternative treated products so until there’s a real trend against preservatives Broxwood will continue to use them for additional peace of mind. However, the growing importance of environmental responsibility will drive our industry to examine alternative approaches to timber preservation. When that time comes I believe we will already be prepared with our advanced designed products of today.

Published on November 1st, 2011 by Olav Skretteberg


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