ThermoWood Export & Supplier in Europe

For the production of thermowood, pine, spruce, and hardwoods such as ash, birch, and others are most commonly used. The wood can be either pre-dried or moist before the thermal modification process.

The main properties of thermally modified wood are:

• Resistance to decay – due to the significant reduction of hemicellulose, which serves as food for rot, the wood gains better resistance, and its expected lifespan is up to five times longer compared to untreated wood.

• Dimensional stability – with lower equilibrium moisture content, the wood’s radial and tangential swelling is reduced, allowing for the use of longer and wider boards.

• Color change – the wood develops a consistent color throughout. The final shade depends on the duration and temperature of the treatment, as well as the species of wood, ranging from light brown to chestnut or even mocha tones.

• Thermal insulation – thermally modified wood has about 20–25% lower thermal conductivity than untreated wood. This makes it highly suitable for saunas, steam rooms, and spaces where low heat conductivity is required, as well as for buildings with significant differences in indoor and outdoor temperatures and humidity levels.

• Resin removal – resins evaporate during the thermal process, making the material easier to work with and improving the quality of surface treatment.

Applications:
Thermowood can be used both indoors and outdoors. Thanks to its unique properties, it is an excellent material for terraces, cladding, and outdoor furniture. It is also suitable for flooring and for humid spaces such as bathrooms and saunas.

The production technology of thermowood is based on heating the wood up to 200°C with the use of steam.

First, the material is dried to almost 0% moisture content, after which it is re-moisturized with steam to around 5% moisture content. During the drying process, the wood fibers and cell structure undergo changes – the sugars present in the wood are broken down, leaving it without sufficient nutrients for decay or fungal growth. As a result, the wood absorbs less moisture and gains improved insulation properties.

In addition, resins and bacteria are removed during the process, leaving the final product as an almost sterile material.

Thermowood is most commonly used for facades, terraces, and saunas. Thanks to its unique properties, it is especially suitable for environments with high humidity levels.

Facade boards

• Mount on wooden or aluminum battens (minimum ventilation gap of 26 mm from the house wall) to prevent condensation.

• Leave at least 1 cm ventilation gap at the top and bottom of the facade.

• Wooden boards must not come into contact with the ground.

• Recommended batten spacing: maximum 50 cm.

• Fix with stainless steel screws or nails.

• Install thermowood boards with a minimum 3 mm gap.

Decking boards

• Mount on a ventilated substructure.

• A double substructure is recommended to ensure proper ventilation from all sides.

• Recommended batten spacing: maximum 50 cm.

• Fix with hidden fasteners from the side of the board or with stainless steel screws from the top.

• Leave 6–8 mm gaps between thermowood decking boards.

The advantages of thermowood remain even if it is left uncoated. Over time, exposure to UV radiation will cause the surface to develop a natural silver-grey patina, and small micro-cracks may appear in the wood. However, the material will not rot and will maintain its dimensional stability.