heat treatment service

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We heat treat wood

We heat treat various different tree species for many different companies. We specialise in the heat treatment of deciduous trees and precious wood.


Entirely poison-free heat-treated wood is a suitable choice for ecological and environmentally friendly construction.


We have our own, modern heat treatment kiln and equipment. We carry out both small and large-scale heat treatment needs in a professional, reliable and timely manner. As a small company, our strengths include our domestic approach and our flexibility according to customer needs.

Entirely poison-free, thermally modified wood wood is a suitable choice for ecological and environmentally friendly construction.
Heat-treated wood is suitable for saunas and bathrooms.
Heat treatment makes the wood harder and more durable.

Benefits of heat treatment

Heat-treated wood is suitable for many applications. In interior design, it can be used e.g. On the walls, ceilings, floors, saunas and for interior and exterior furnishing. Thermally modified wood wood is used outdoors for terraces, doors, windows and for the exterior cladding of buildings. In interior design, its benefits include its beautiful, hardwood-like appearance, resin-free properties and its ability to retain its dimensions. Suitable for indoor and outdoor use in all climates.

The heat treatment of wood is an entirely natural way to improve the properties of wood and its durability, because the process only uses hot air and water vapour and it does not require any chemicals. At the same time, the wood is given a beautiful brown tone and a pleasant woody scent.

Heat treatment is used to achieve e.g. the following benefits

  • The production of thermowood is ecological, and no poisons are used in its processing.
  • Heat-treated wood is clean, and it does not emit any chemicals or poisons into the indoor air.
  • The thermal conductivity of thermowood is reduced, which means it does not feel as hot against the skin. Therefore, it is well-suited for sauna premises.
  • Thermowood has excellent decay resistance, which increases its service life compared to untreated wood.
  • The moisture changes that occur in heat-treated wood is reduced by up to fifty percent compared to untreated wood, which means that the wood is stable, i.e. retains its dimensions better in premises where there are moisture and temperature fluctuations.
  • Heat-treated wood is resin-free.
  • As a result of heat treatment, wood is given a beautiful, stylish and evenly full-stained brown tone, and an almost hardwood-like appearance as well as pleasant scent (this indicates the external changes of the wood).
  • Thermally modified wood becomes harder, and therefore more durable.
  • Its ability to absorb water is reduced, which means its moisture resistance increases, so heat-treated wood is an excellent choice for wet rooms.
  • Heat-treated wood does not shrink, swell or twist, so heat treatment is a good foundation for surface-treated products. The surfaces will not crack or chip. The resin of the wood has been removed during the thermo modification process, so it will not be secreted through the surface layer after installation.

Entirely poison-free heat-treated wood is a suitable choice for ecological and environmentally friendly construction!

Lämpökäsittely on ekologinen, turvallinen ja myrkytön keino tehdä puusta kestävää.

How is heat treatment carried out?

Heat treatment is carried out with water vapour and a change of temperature. The duration of the thermo-treatment process is 1.5 – 3 days.

After the first stage of the process, the timber is fully dried at a temperature of +100 degrees. Then the temperature of the wood is gradually increased to 175 – 210 degrees for 2-3 hours, depending on the tree species, the thickness of the raw material and the desired colour tone. The structure of the wood changes during the process, when water and resin is removed from the wood and the wood becomes a stylish brown colour. Thereafter, the temperature of the timber is reduced to a normal temperature.

The popularity of heat treating wood has increased in recent years. The ecological process, which is based on water vapour and a high temperature, has been used to replace the chemical treatment of wood in order to improve the properties of wood. Heat treatment can be considered to provide wood protection without processing, and it does not emit any harmful substances into the soil. Thermo treatment improves the properties and appearance of wood: decay resistance, moisture resistance and thermal insulation improve, and the changes caused by moisture are reduced, and the wood gets an even, through-coloured brown tone.

The emissions of heat-treated wood into the surrounding air are extremely low. Thermally modified wood is classed in the best indoor air classification category, the M1 category.

Do you have any questions concerning heat treatment?


Thermopolar heat treatment service

We offer a comprehensive and flexible heat treatment service for further processing plants, sawmills and importers around Finland. Contact us!

Contact us!
Thermowood has excellent decay resistance, which increases its service life compared to untreated wood.