3.5 : 木材の乾燥

Consider an unseasoned lumber used for flooring—the lumber contracts when the moisture evaporates, creating gaps at the joints of the floor.

Wood swells when it absorbs moisture and contracts upon drying.

The quantity of moisture in the wood that matches the surrounding air is known as the equilibrium moisture content.

Seasoning stops the wood from shrinking after construction, avoiding structural harm and aesthetic damage in the built structure.

Air drying is a seasoning method where the lumber is loosely stacked, adequately elevated from the ground, kept apart for proper ventilation, and aligned to prevent bending. Each pile is shielded from rain and snow under a waterproof roof.

Seasoning is also done by kiln drying, wherein lumber is seasoned by arranging it in the kiln like in air drying.

Standard framing lumber is dried to 19 percent moisture for stability. For shrinkage control, structural lumber is dried to 15 percent.

Distortions are observed in seasoned lumber that vary based on the original position of the wood piece within the tree.