In Lumber Drying 101, we examined the benefits of proper drying as well as pros and cons of kiln drying. Here at J. Gibson McIlvain Lumber, we use a time-tested drying process that leads to optimal lumber stability. Since quality is our main priority, we’re willing to take the extra time and effort to achieve the best results.
Step 1: Air Drying
In the back corners of our lumber yards in Maryland and elsewhere, you’ll find stacked and stickered lumber drying in the open air. Stickers, small spacers between boards that allow for air flow around them, allow for moisture to be evenly released.
In order to prevent checking and cracking, we paint or wax the ends of the boards to slow moisture release from the ends. This drying method is safest for the wood because it does not promote setting of the lignin like kiln drying will; on the flip side, solely air-dried lumber will not be as stable as kiln-dried lumber will be; however, lumber that is air dried but not kiln dried will be easier to work with.
When air drying is the first step, rather than the only step, it allows the wood to come into an equilibrium with the local climate, making it better prepared for safe kiln drying. The amount of time needed for air drying depends on how wet the wood is, starting out; the timeframe can range from a few weeks to several months.
Step 2: Kiln Drying
Once the wood has come to an equilibrium with the local climate through air drying, it can safely be moved to one of our drying kilns. We have 10 boiler-powered kilns that are efficiently heated by sawdust generated by our own millworks operation.
The time and temperature needed for kiln drying depends largely on the species at hand. Denser species require more time, sometimes more than a month. Less dense species can achieve optimal drying in mere weeks. Some unique species, such as Spanish Cedar, require careful handling. Such a highly resinous wood is especially prone to weeping every time it is cut. The resulting sticky resin stains make finishing almost impossible.
Here at J. Gibson McIlvain Lumber, we have the benefit of rare kilns — some of the only ones in North America — that can get hot enough to set the sap and resin in order to prevent that problematic weeping. The higher temperature also increases the chance of case hardening, though, making it necessary to slow the pace for heat up and cool down. Of course, exercising such caution increases the time such species spend in the kiln, but it is time well spent.
Failing to take the precautions and time necessary to properly dry lumber can lead to damage that doesn’t surface until a project has already been begun. The only way to avoid the costly results of improperly dried lumber is to take the time needed to dry it properly, and you can trust J. Gibson McIlvain to do just that.