• Carla Urbany

What is Thermally Treated Wood?

Updated: Oct 27

Definition: Thermal treatment is a chemical-free, heat & steam process that "cooks" the wood. The technique solidifies the polysaccharides, or sugars, inside the wood, which eliminates the food for fungi and insects, so the wood is highly resistant to rot. The process substantially reduces moisture in the wood, making it extremely stable. And finally, because the thermal process is chemical-free, this technique is not only sustainable, it's environmentally friendly—no leaching of chemicals.


Appearance: We stock thermal poplar and ash, however, any wood can be thermally modified. The wood itself maintains its original appearance, so if it starts as poplar, it still has the same mild grain pattern and texture as poplar. The thermal treatment process leaves the wood a consistent chocolate brown color throughout, so it's beautiful on its own. It looks great alongside other woods, and it can be used as a less expensive alternative to walnut. Ash also takes on the same dark coloring.


Workability: Thermal woods glue well, but because the wood is so dry, leave your glue up to sit twice as long as normal to ensure good adhesion. And for the same reason, you'll notice that when you're working with it, splinters of the wood are like dry twigs and break easily. In fact, the surface of thermally treated wood is actually quite dense and more resistant to dings, yet the wood is less flexible. It does turn well, just keep your tools sharp. And an interesting side note, when you cut thermal woods, it smells like burned wood.



Uses: We have customers who choose thermal treated poplar or thermal ash for

small projects, frames, tables and even cutting boards, but SURPRISE, the wood is actually an excellent choice for exterior use--not just as furniture. You'll see it as accent woods on commercial and residential buildings. As with all exterior woods, just be sure to use a UV topcoat to prevent the wood from aging naturally to a silvery-grey.

Thermally Treated Poplar and regular Poplar painted white were used to make this charming bedroom set. Even the light fixtures and mirror frames above the bed are thermally treated wood. Thanks to woodworker Chris Gielarowski for sharing his great work with us!

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