Kiln Drying Reclaimed Wood: A Key Step to Quality
Kiln Drying Wood Ensures Quality Reclaimed Wood Free From Insects or Defects
Our ThinClad reclaimed redwood paneling goes through kiln drying to ensure the quality and structural integrity for installation.
A dehumidification kiln. Image from the Wood Mill of Maine
Dehumidification drying system. (Dry Kiln Operator’s Manual. USDA, 1991)
Schematic of a dry kiln. (Dry Kiln Operator’s Manual. USDA, 1991)
What is Kiln Drying?
Kiln drying is the process of drying wood in a controlled environment, where temperature, air circulation and humidity are monitored and stabilized. The wood is slowly dried to a target point, protecting it from checking, warping or cupping. This is an alternative to air-dying the wood, which simply involves stacking the lumber outdoors over a period of time to dry.
Wood is a hydroscopic material, meaning that is absorbs and releases moisture from its environment until it reaches equilibrium (equilibrium moisture content, or EMC). Since the dimension of the wood fluctuates with different environments, it is important to bring the moisture content down to a workable level.
Why Kiln Drying is Important for Reclaimed Wood?
Kiln drying has multiple benefits, especially for reclaimed wood. With too much moisture, lumber can warp and twist or have adhesive failures with applying finishes. Kiln drying ensures the structural integrity of the wood, which increases its overall lifespan. In addition, drying the wood in this fashion also prevents the wood from shrinking later on, which makes the installation process much easier.
Beyond bringing the moisture down before moulding, milling or finishing, kiln drying the wood is important to increase strength of the wood and to eliminate any insects or fungus present in the wood. This is an especially essential step for processing reclaimed wood, which could have housed insects or fungus during its lifetime.
It is important to ask if your reclaimed wood is kiln dried, as it is not a regulation within the industry. We make sure to kiln dry all of our reclaimed wood to provide high-quality products that will last.
Types of Kiln Drying
There are many types of kilns, but the most common are dehumidification kilns and conventional kilns. A dehumidification kiln continuously recycles the heat throughout the chamber, rather than discharging the heat, as is with the conventional kiln. These kilns reach 95 to 100 degrees F and are heated with electric heat, unlike conventional kilns, which use gas. This is a more economical and environmental way to dry the wood compared to conventional drying.
A conventional kiln uses steam flowing into the kiln through pipes that radiate heat throughout the chamber. Moisture from the wood evaporates and is discharged out of the kiln as hot air. There are also solar kilns and vacuum kilns, though they are more rarely used for this process.
Acclimation After Kiln Drying
Even after kiln drying, reclaimed wood still has the ability to reabsorb moisture, unless it is completely sealed. It is crucial that the wood is carefully monitored in different environments. We recommend the wood get acclimated to the job site before installing, letting it adjust to the new environment. An accurate wood moisture meter can give a reliable read of the moisture content throughout the manufacturing and installation process.
Kiln drying reclaimed wood is an essential step in ensuring that the product is dimensionally stable and free from insects and fungus. This process is necessary for long-lasting reclaimed wood that will last (another) lifetime.
When searching for reclaimed wood supplier, make sure it is one that kiln dried their wood. At Anthology Woods, we make sure to kiln dry all of our reclaimed wood as part of our rigorous standards of quality. Browse our selection of reclaimed wood hardwood flooring and paneling to find a look that works for your project. As always, feel free to reach out with any questions. Our team is here to help!