Studying Weathering Performance of Coatings on Thermally Modified Wood
M Nejad, M Dadbin, P Cooper
Thermal modification and degree of improved properties depends on wood species and treatment parameters. Southern pine and spruce are the two common wood species for decking, fences and siding in North America. This study was the first to evaluate coating performance when applied on oil-heat-treated southern pine and spruce wood samples. Water uptake, colour and gloss changes of samples were analysed before and then every month for the first three months and then every six-months during 18 months of natural weathering in Toronto, Canada. The results showed the coated heat-treated woods had lower water uptake, lower colour change and overall better appearance ranking than coated-untreated wood samples. Spruce samples that were used in the study had lower checking and splitting and in general superior performance compared to southern pine treated samples. Notably, the average moisture content of treated spruce wood samples were significantly lower than southern pine, which explains lower checking and better coatings’ appearance.