It is crucial to dry the wood so it can be used as a construction material. The truth is that for some of its possible applications the moisture content is not very important, for example in the case of fences, but for the construction of structures and houses it is of crucial importance. In some woods the moisture content can be higher than 200% and in order to become a reliable material it should have a moisture content of approximately 18%.
"Wood moisture" means the ratio between the weight of water in it and the weight of that wood when absolutely dry, i.e., without any water.
Reasons for the wood drying process:
1. Reduction of the risk of wood-decay fungi (when the moisture index is under 20% it becomes almost immune to this type of attacks) avoiding thus the lost of economic value of the wood;
2. Increase of wood hardness, i.e., by eliminating the water the raw material becomes stronger and more resistant.
3. Reduction of the dimensional movement of the wood, i.e., we all know that wood tends to shrink when it dries and to expand when it absorbs moisture. Through drying this trend significantly decreases as well as the trend that wood exhibits, as a "life" raw material, to naturally follow the path of its grain resulting in warping.
4. Treatability enhancement. When a wood piece has a moisture content under 20%, the impregnation/absorbing of chemicals, paints or oils becomes easier;
5. Increase of mechanical resistance. In comparison with a piece of moist wood, a previously dried wood piece presents a significant improvement of its mechanical properties such as: static bending, compression and hardness;
6. Increased workability. A dried wood is much easier to work, for example, when planing or sanding; it will not only reduce labour costs, as good results can be achieved faster, but also the obtained results will be of higher quality;
7. Increase of the bonding capacity making the laminated products production process easier as well as the application of other bonding materials;
8. Increase of the fixation capacity. Applying screws or bolts to dried pieces assures a better fixation since when the wood has moisture the hardware tends to loosen;
9. Enhancement of the wood natural insulation properties. A dried wood conducts less heat and also significantly increases its properties of electric and acoustic insulator;
10. Reduction in the transportation costs. If the wood looses water it will also lose weight allowing the transportation of more m3 of wood at once.