Effect of coatings on the durability of birch and spruce plywood:Part 1: Weathering performance

Several different coated birch and spruce plywood types were investigated in Finland using outdoor weathering. The weather performance of the tested coated birch plywood was good compared with uncoated birch and spruce plywood. The paint base film coated and painted birch plywood performed well in outdoor testing at VTT's test site. Phenol film coated plywood was sensitive to UV light, but only a little cracking and mould growth was found after several years outdoor weathering. Edge sealing with acrylate paint protected well the plywood specimens during the exposure. Moisture content of coated birch plywood was less variable and it did not exceed the critical level needed for the early development of decay. The overall results clearly show that birch plywood is better substrate for film coatings