Thermo-treated wood (also known as Thermally modified wood or Thermowood) is a material produced after the treatment of wood at high temperature (180º – 220º C) in a special thermo camera. Thermo-treated wood material is completely natural because no chemicals are used in the process, only temperature and pressure, but shows very good resistance to fungi and rot. Therefore, thermowood is an excellent and environmentally friendly alternative to impregnated wood products.


  • After the treatment Thermowood gets very valuable properties:

    • Stability – significantly decreases expansion or shrinkage of the material due to the influence of the external environment.

    Thanks to the dimensional stability of thermowood in comparison to untreated wood it makes it as an excellent choice for decking and cladding.

    • Resistance to decay causing fungi.

    Thermo treatment of wood changes the structure of chemicellulose, a component of wood, and significantly lowers the moisture level; as a result thermowood no longer contains appropriate nutrients and conditions for the fungi to develop.

    • Thermowood material does not contain resin, and as the resin is not secreted anymore it is very important for long-lasting effect of oiling or painting.
    • In general, the wood after treatment serves at least 5 times longer than untreated wood.

    When it comes to durability, the expected lifetime of thermally modified pine/spruce is at least 30 years without the need for a chemical preservative against various wood-decay organisms as thermowood is categorized under natural resistance class 2 (durable).

    • Thermal conductivity is reduced which means that thermowood does not heat up or cool down in different conditions as untreated wood and is a good material for thermal insulation.
    • Thermally modified wood gets a visually attractive, nice brown color.

    Over time, under the influence of UV radiation from sunlight, the color of thermowood changes to grey, the same way as for untreated wood products. To keep the desired color and to enhance the surface protection it is highly recommended to apply some surface treatment. For our customers we offer oiling/painting of decking/cladding with professional oils/paints that are designed and tested for treatment of thermowood.

    • Thermowood can be used indoors or outdoors, in all climatic conditions.