Graphical Construction Glossary >> Woodwork. >> >> Air Dried Lumber

Air Dried Lumber

In woodworking. The oldest method of drying out or seasoning timber. Allowing air to circulate naturally around the lumber.

Kiln Dried Lumber

In woodworking. A method of seasoning timber using heated kilns to dry the timber to the required moisture content.

Seasoning Lumber

In woodworking. A method treating timber to dry out excess moisture and bring it to the required moisture content.

Green Lumber

Lumber that has not been seasoned

Trees when they are felled contain a quite large proportion of moisture. In this state it is said to be green. Green lumber has it's uses and there has been a revival in building large timber framed buildings out of green timber, much as it was used for centuries.

Green timber is softer and easier to work than lumber that has been seasoned. It is prone to shrinking, splitting and twisting. As a result the joints in green lumber frames are designed to be tightened up during or after the material naturally dries out.

Lumber is seasoned to dry out in a controlled way so that when it is used it will remain basically in the same shape.

Natural air drying is is facilitated by stacking the planks straight and not twisted on timber skids and then separating each layer with lathes of wood as seen at the side.

Air drying is very slow, say a minimum of two years depending on the size of the material and it can take up to 5 or 7 years. So it is very wasteful of time and space.

Kiln dried lumber has been placed in a heated kiln for a period of time. Modern kilns often have continuously moving carriages taking the lumber slowly through the kiln. Temperature and moisture content are monitored to achieve optimum results for the intended use of the seasoned lumber.

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