Wood Conditioning & Storage
Wood is one of the most popular and beautiful natural materials in the world. Wood is a living material and requires a well balanced storage environment. Wood is a hygroscopic material. Always containing water, it constantly exchanges water vapour with the air, absorbing it when the relative humidity is high, and releasing it when relative humidity is low. Since wood swells as it absorbs water, and contracts as it releases water, both it’s moisture content and dimensions are influenced by the relative humidity of the surrounding air.
Damp wood is heavy and difficult to work whilst dry wood will warp and split.
What is “moisture content” of wood?
The desired moisture content of both softwoods and hardwoods is dependent to some extent on the type of wood, and on the intended use.
Wood moisture content is equal to the weight of water contained in the wood divided by the oven-dry weight of the wood, expressed as a percent. A wood moisture content of 8 to 10% is achieved at 40% to 55% relative humidity. Heated wood stores have an unpredictable effect on the wood’s moisture content as temperature influences the relative humidity.
A desiccant dehumidifier maintains the store’s relative humidity within the desired range irrespective of the store temperature. The climate will remain constant and the wood will be maintained at the correct moisture content.
Suppliers wishing is to guarantee the quality of their wood product should consider using desiccant dehumidifiers in their stores. If wood is stored in a humidity controlled single skin PVC building, there is the added advantage of low air infiltration rates (low moisture gains), so operating costs are kept to an absolute minimum.