Drying Green Wood
Getting a load of freshly cut lumber can bring out several emotions. First, the excitement from getting your hands on the rawest of raw materials. Then the anticipation of fine, quality boards for your projects. Finally, panic sets in as you try to figure out what to do about drying the green wood before it checks, bows and twists its way into the firewood pile.
Fortunately, air drying your lumber outdoors is the easiest, least expensive way to dry lumber with minimal waste. By following a few basic techniques, your green lumber will eventually find its way to your workshop.
Simply put, you need to build a stack that allows air to circulate around each board, keep the stack off the ground to avoid moisture from ruining the wood and keep the sun and rain off the lumber.
While the ideal place for air drying lumber is in a shelter such as an open shed, you can stack it anywhere it is protected from direct sun.
Starting from the ground up, lay a solid base with cement blocks and 4″ beams on top, spaced about 16″ apart so they will be perpendicular to your boards and accommodate the full length of your boards without overhang.
On top of the beams, which must be level with each other, lay your first course of stickers. Stickers are used to separate the boards from each other and allow for air circulation. They should be made from dry wood and must all be the same thickness, around 1″-thick at a minimum. Avoid sappy woods or woods that may leach color when in contact with moisture, such as cedar and oak.
Next, lay your first layer of boards. It is easiest to stack your lumber if the boards are all the same length and thickness. Otherwise, stacking will take careful planning, because the entire stack should be rectangular, with spacing between the boards as consistent as possible to promote even air circulation.
On each layer, the boards must all be the same thickness, and they must line up at the ends without overhanging. Leave 1″ or so between the boards, with shorter boards on the interior of the pile and full-length boards at the sides. The shorter boards should be staggered so the ends on the interior of the stack don’t line up. This reduces large open spaces and promotes slow, even drying.
Each successive layer of stickers must line up vertically with the previous layer of stickers, otherwise you will end up with bowed or cupped boards.
Continue this process until your pile is complete.Then add a final course of stickers and add a cover of old boards, plywood, etc. to protect the pile from sun and rain. This cover should extend over the edges of the stack if your stack isn’t already sheltered. Weigh the stack down with bricks or other heavy items to reduce the possibility of warping. To slow down the rate of moisture loss and minimize end checking, coat the exposed ends of each board with latex paint or paint specially designed for this.
Once your stack is finished, simply wait for it to dry. While the general rule of thumb is one year of drying for every inch of thickness, the species you are drying, weather conditions and the time of year you begin drying can influence this significantly. No published times can adequately compensate for the huge variations in drying rates, so unless you are in a rush, plan your lumber drying carefully to allow adequate time. Ideal moisture content for interior wood in dry, arid areas will be considerably lower than in humid areas. Consult with professional cabinet shops in your area for relevant ranges.