Heat-treated wood is an excellent choice for saunas due to its superior properties. Heat treatment significantly improves wood’s moisture resistance, dimensional stability, and thermal insulation capacity, making it an ideal material for the varying conditions in saunas. Heat-treated wood does not conduct heat, feels pleasant against the skin, and maintains its beautiful, darkened color tone for years. Aspen and alder are particularly excellent options for sauna bench wood when heat-treated.
What does heat treatment do to wood and why is it suitable for saunas?
Heat treatment changes the chemical structure of wood at high temperatures (170-230 °C) without chemicals, significantly improving the wood’s properties. During the process, the hemicellulose in the wood’s cell walls breaks down, which reduces the wood’s ability to bind moisture. As a result, heat-treated wood does not swell or shrink as readily as untreated wood.
Saunas have particularly demanding conditions for wood materials: high temperature, constant moisture, and rapid variations of these. Heat-treated wood withstands these changing conditions significantly better than ordinary wood. When wood does not absorb moisture as easily, it also does not move as the sauna’s humidity changes, which extends the material’s lifespan and keeps structures in better condition.
Additionally, heat treatment improves the wood’s thermal insulation capacity by approximately 20-30%. This means that heat-treated bench wood feels more pleasant against the skin even in a hot sauna. You don’t need to fear a burning sensation when sitting on a heat-treated bench.
Which wood species are best suited for saunas when heat-treated?
Aspen and alder are best suited for saunas when heat-treated due to their natural properties. These wood species are naturally knot-free and resin-free, and heat treatment further enhances their good properties. When heat-treated, aspen and alder are ideal bench materials, as they do not overheat and do not release splinters into the skin.
Aspen is a particularly popular material for sauna bench wood. It is a lightweight wood species with low density, which means it does not overheat in the sauna. When heat-treated, aspen’s pale yellowish tone transforms into a beautiful, warm brown, which brings a stylish appearance to the sauna. In addition to good technical properties, aspen is also beautiful and easy to work with.
Alder is another excellent option for sauna material. It is slightly darker than aspen and develops a deep, reddish-brown tone during heat treatment. Alder’s advantage is its natural resistance to moisture movement, which heat treatment further improves.
The selection also includes heat-treated wood products for various purposes, which is well suited for sauna panels and trim, for example. It offers a more affordable alternative compared to aspen and alder.
How does heat-treated wood withstand sauna moisture and temperature variations?
Heat-treated wood withstands sauna moisture and temperature variations significantly better than untreated wood because its equilibrium moisture content has decreased by up to 40-50%. This means that the wood reacts less to changes in air humidity and remains more stable in varying conditions. The continuous moisture and temperature changes in saunas do not cause as much stress to heat-treated wood.
Thanks to heat treatment, the wood’s dimensional stability improves by 30-80%, which practically means significantly less swelling and shrinkage. This is particularly important in saunas, where moisture and temperature vary constantly. When benches, panels, and trim maintain their dimensions, structures remain intact longer and, for example, gaps between boards do not widen with use.
Heat treatment also reduces the wood’s thermal conductivity, which means the wood does not feel burning hot even at high sauna temperatures. This significantly increases sauna comfort when you can sit on the benches without a towel without the burning hot sensation.
How long-lasting is heat-treated wood in saunas?
Heat-treated wood is significantly more long-lasting in saunas than untreated wood, often even 2-3 times more durable. Heat treatment significantly improves the wood’s biological durability because the wood’s sugar compounds break down during treatment, making it harder for mold and decay fungi to use the wood as nutrition.
Ordinary, untreated bench wood may need replacement after just a few years, especially in frequently used saunas. Heat-treated bench wood, on the other hand, can easily last 10-15 years or even longer when properly maintained. This makes heat-treated wood an economical choice in the long term, even though the initial investment is somewhat larger.
Longevity is also visible in the wood’s appearance. Heat-treated wood maintains its beautiful, dark tone for a long time and does not gray or yellow in the same way as untreated wood. This means your sauna looks stylish for years without the need for surface treatments or renewal.
With proper maintenance, you can extend the lifespan of heat-treated wood even further. Regular cleaning and adequate ventilation of the sauna after use are key to ensuring the material’s longevity.
Is heat-treated wood an ecological choice for saunas?
Heat-treated wood is a very ecological choice for saunas, as no chemicals are used in the process. Heat treatment is a completely natural method where the wood’s properties are improved using only heat and steam. This makes it an environmentally friendly alternative to chemically treated wood materials.
Finnish heat-treated wood is responsibly produced. When you choose domestic, Finnish-made heat-treated wood, you also support local production and reduce emissions from transportation. Finnish forest industry follows strict sustainable development principles that ensure forest regeneration.
The long lifespan of heat-treated wood also makes it an ecologically sensible choice. The longer a material lasts in use, the smaller its environmental impact. When bench structures last 2-3 times longer than those made from untreated wood, both material and labor are saved.
At the end of its lifespan, heat-treated wood can be recycled or used for energy, as it contains no harmful chemicals. This makes it an environmentally friendly choice throughout its entire lifecycle.
We at Pieksäwood have 20 years of experience in heat treatment, especially with aspen and alder. We manufacture all our products in Pieksämäki with a modern production line, which ensures high product quality. We offer a comprehensive selection of heat-treated sauna materials for various sauna implementations, which are both durable and beautiful. This way you can enjoy your sauna worry-free for years to come. For more information about our products and services, please contact us for expert guidance.