WHAT IS THERMALLY MODIFIED WOOD?
The Thermally Modified Wood production technology is based on wood heating up to 160-220 °C (180 - 200 °C in the NordTraders dryer) with a steam supply.
The material is first dried to almost 0% humidity and then is humidified again to about 5% humidity. In the course of the drying process, wood fiber cells are changing - the sugar contained in the wood splits and the wood has no more nutrients for decay or creation of a breeding grounds for fungus; the wood no longer absorbs moisture well and has better insulation properties. The resin and bacteria are also eliminated and the final product is almost a sterile material.
Pine, fir and deciduous trees, such as ash, birch, etc. are most commonly used in the production of Thermally Modified Wood. Wood can be pre-dried or damp before heat treatment.
The properties of Thermally Modified Wood are the following:
- decay resistance - thanks to the heavily reduced hemicellulose, which is a feed for decay, the tree gains better resistance to it and its life expectancy is five times longer that of untreated wood;
- stability - with less equilibrium humidity the radial and tangential wood swelling also decreases, allowing to use the materials of longer and wider sizes;
- discoloration - the wood obtains the color thoroughly, and the discoloration depends on the duration of the treatment, temperature, and type of wood, but the color may vary from light brown to chestnut or even mocha;
- heat conductivity - Thermally Modified Wood has about 20-25% less heat conductivity than untreated wood and it is therefore well suited for saunas and rooms where the thermal conductivity should be low or for the buildings, where is a greater difference between indoor and outdoor temperatures and humidity level;
- resins - they evaporate as a result of the thermal process, and this material is friendlier to the user and has a significant role in surface treatment.
Thermally Modified Wood can be used both outside and inside. The properties of this material make it well suited for terraces, cladding of houses, outdoor furniture. It can be used for floors and on the premises with high humidity, such as bathrooms.