Because of the reality of wood movement and the potential problems tied to improperly dried wood, proper drying is an extremely important component in high-quality lumber. At J. Gibson McIlvain, we’re serious about achieving quality, and part of that is taking the time to ensure proper drying methods are used every single time.
Slow and Steady Drying
Really, there’s no secret to our method; it’s basically pretty simple. Drying schedules by species are widely published (just search on Google for lumber drying schedules by species), and they are easy to achieve with the right equipment.
When lumber is improperly dried, it’s typically not due to a lack of knowledge or ability, but rather a response to our hurried, instant gratification society. When demand eclipses supply and there is money to be made, many suppliers skip steps or rush the process in order to respond to customer requests.
At J. Gibson McIlvain, we are committed to proper drying, and we know that it takes time. We believe that having lumber as stable as possible when it leaves our yard and arrives on your jobsite is worth the wait.
Since we receive lumber from several continents, some lumber comes to us recently sawn and green, with a 25-50% moisture content. However, most imports come to us already dried to European standards of 12-15%; many domestic species are air dried and come to us with moisture levels ranging from 10-25%.
While there is a variance in time from the arrival of lumber to when it’s ready for sale, the same basic process can be applied to all lumber, regardless of how and when it comes our way.
Step 1: Air Drying
If you took a walk to the back of either our Maryland or our Connecticut lumber yards, you’ll find that it’s dedicated to air drying. While the exact timeframe varies, all our lumber spends some time back there, stacked and stickered and waiting. Stickers are spacers that separate boards, allowing even air flow around each board and promoting even release of moisture.
As you might guess, the wetter the wood is when it comes to us, the longer it needs to sit at the back of the yard. Typically, we paint or wax the ends of the boards to slow the release of moisture from the ends, preventing checks and cracks that can result from uneven or too rapid drying. More gentle on the wood, air drying is the safest way to allow the majority of excess moisture to be released from the wood. This step can take as little as a few weeks or many months, depending on how wet the lumber is when it arrives.
Because the air-drying process does not promote the setting of lignin that kiln drying does, air dried wood is softer and easier for working; however, it is not as stable as kiln-dried lumber. Even when kiln drying is desired, air drying is the best way to prepare the wood for the kiln.
Once the wood comes into an equilibrium with the local climate, it’s then ready for the kiln. Continue reading with Part 3.