Durable outdoor wood, treated with linseed oil

This process uses hot linseed oil as an after treatment of traditional biocide treated timber used for siding and other outdoor uses.

With added pigment, the process results in a ready to use product which is exceptionally dimensionally stable and will not require any after treatment (painting) for 5 – 25 years, depending on the actual climatic conditions.

After high pressure impregnation, the moisture content is high. The treated wood is taken directly from the impregnation autoclave to the hot-oil autoclave, where it is dried down during 6-8 hours to a ready to use product with 14-16 % moisture. At the end of the process, the 1-2 mm penetration of linseed oil into the wood creates an envelope which effectively seals the surface of the wood. This reduces the fluctuation of the wood moisture content during the seasons significantly, thus giving the wood exceptional dimensional stability.

WTT has more than 20 years of experience with this value adding niche product. In the later years it has seen significant growth primarily on the Scandinavian markets, with reported annual growth rates of 30 %. WTT supplied a large full automatic plant with an annual capacity of 50.000 m3 in 2013 and in November 2016 we will supply a similar project to another customer.

For selected references, please visit the References page and continue reading about the hot-oil impregnation process here.

Check out our video of a full-automatic hot-oil plant.