Heat-treated Wood - Options For Long-lasting, Sustainable Exteriors

By Author: Stevan Gerrand
Total Articles: 53
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People have known for centuries that when they burned wood with a torch, the wood suddenly became more resistant to weather when used outdoors. However, it wasn’t until the current century that this process was perfected into the heat treatment wood method we know about now.

Heat treatment enables even softwoods to be hardened into durable building options that will stand up to the test of weather and time. Today’s heat treatment methods have greatly expanded the number of woods that are available to us to use in building projects. Instead of being limited to the hardest woods, we can now use lower valued types of wood like poplar, birch, alder, or beech. These woods can be used safely indoors or outdoors.

Here’s how the thermal treatment process works:
1. Lumber is heated up to temperatures greater than 200 degrees Celsius

2. As the wood is heated, the chemical structure begins to change, affecting the physical and biological properties of the lumber.

3. After the heat treatment is complete (usually in about 24 hours), the lumber has a number of beneficial new properties, like greatly ...
... reduced water absorption, better dimensional stability (due to the fact that it’s absorbing less than 50 percent of the water it could before treatment), and greater ability to resist rotting and microbial attackers like fungi.

4. The heat treatment process requires only heat. Since no chemicals are used (like they are in the pressure treatment process), heat treatment is much more environmentally friendly than the alternative.

Early versions of heat treatment made wood very brittle and dry, although today the process has been optimized to solve these problems. Now lumber that has been treated with heat is exceptionally strong. The durability and longevity of heat treated lumber can be extended and even increased by properly finishing and coating your projects after they are complete.

Tips for Using Heat-Treated Wood in Outdoor Applications

Through the years numerous scientific tests have been conducted on heat treated wood as people have looked for ways to improve the results even further. Some of these tests have focused on the use of heat treated wood in outdoor applications. While the benefits of using heat treated wood are extensive, studies show that the only way for this type of lumber to last a long time is to coat it properly so that it becomes resistant to weather. On average, it takes only a week to 21 days for cracks to appear in uncoated wood that has been treated with heat.

Of course there are numerous products on the market that claim to weatherize wood so that it can be used for outdoor applications, not all of these products perform up to par. Many oils and stains that are solvent-based just do not stand up to the challenge posed by exposing wood to the elements.

However, the best results for coating heat treated wood seem to come from a special water-based primer that is resistant to the sun’s ultraviolet rays. That primer however, even had to be followed by a special top coat that gets applied in two coats. For best results, use a top coat that has been modified so that it works well on heat treated lumber. Also to expand the life of wood used outdoors, use enhanced low VOC-penetrating products.

As long as you care for your outdoor wood projects properly, you shouldn’t have to worry about having to replace the wood often.

Boone Valley offers crane mats for all of your construction needs. Their products services customers nationwide, and are the only supplier you need for all types of heat treated lumber for export.