The Swedish hardwood sawmills are today experiencing problems of finding profitable markets for products containing for instance knots and red- or brown heartwood. By using hardwood outdoor possibilities would open up for finding use of this kind of wood. In many cases outdoor applications set other requirements than the applications where hardwood normally are used, i.e. furniture, carpentry, floors and kitchens. Those applications mainly focus on the aesthetical requirements while the technical requirements are of secondary importance.
One major critical issue when considering outdoor use of hardwood is the durability. The durability is affected by the biological, mechanical and thermal degrading were, the biological degrading are the most severe, regarding service life of the material. The biological degrading of wood is affected by the ability of absorbing moisture and then especially the capillary characteristic of the wood becomes important.
In this project the characteristics of different Swedish hardwood species are studied regarding outdoor durability with a special focus on the capillary characteristics. Suggestions are made of how to treat and manufacture the most important hardwood species in Sweden (considering volume) alder, aspen, beech, birch and oak for use in outdoor applications.
Keywords: Hardwood for outdoor applications,Capillary characteristics, Durability
Authors
Jimmy Johansson
Växjö University, Sweden
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