Thermal Modificaction


Between our expert wood scientists and exceedingly high sourcing standards, that’s all we need to create products that set the bar for rot resistance and longevity.

Thermal modification gives our products many advantages

Highest durability class

Most dimensionally stable in changing weather conditions

Does not become as hot in the sun

Chemical-free modification

Lower moisture content makes the material lighter

No need to handle our products as hazardous waste

Thermal modification penetrates far below the wood’s surface

Unlike chemical impregnation, heat-treating wood enhances it throughout, not just the outer surface. The result is boards that are stable and durable in every sense. Quality is paramount for us. At Thermory, we believe product quality is paramount, so we work hard on mastering our technology and innovate to stay ahead.

Thermal modification requires a master’s dedication and skilful hand

The process takes place in a heating chamber with special sensors, controlled by experienced specialists using computer.

Thermory’s quality is ensured by a special thermal modification process developed based on 20 years of experience, which varies by species and purpose of use. The principle is the same: the moisture level of the wood is reduced to 0% over a period of 35-46 hours and then the temperature is raised to the necessary level, followed by the cooling and misting of the wood. At all times during the process, only temperature and steam are used. Heat triggers physical and chemical reactions in the wood and we control the process by adjusting the moisture.


The peak temperature depends on the type of wood and where the product is to be used

  • intense thermal modification: the temperature is at least 215 degrees, which makes our wood products ideal for use in outdoor settings
  • medium thermal modification: the peak temperature is 190 degrees, which is suitable for wood for indoor use

Thermal modification makes wood more durable and stable

During thermal modification, wood’s density decreases and its structure changes.

  • Wood’s physical and chemical properties change in the course of thermal modification. Changes take place in both the physical and the chemical composition of the wood. When it is heated, wood gives off moisture and the chemical components undergo transformation.
  • Thermal modification lowers wood’s absorbency, so exposure to moisture no longer makes the wood expand as much. It also improves dimensional stability, expanding and contracting less in outdoor conditions.
  • The lower internal stresses in thermally modified wood also reduce material consumption in construction.
  • Wood’s biological resistance increases as the nutrients in wood are modified during thermal modification, becoming less available to pests and microorganisms. This increases the durability of wood in outdoor conditions in particular, and wood does not need to be impregnated with toxic substances.
  • Thermally modified wood’s heat and sound insulating characteristics are as much as 30% superior to those of natural wood.
  • Thermally modified wood has a lower weight and density and the wood becomes mechanically easier to work with.
  • Thermally modifying wood gives it a beautiful, deep colour that makes thermally modified ash a great alternative to tropical hardwood.

Our products are tested

We know our thermally modified wood products are top of the line. If the correct installation techniques are used, they will last for decades. Our products are consistently proven through third-party test results.


Your next project with Thermory

Once you use Thermory, you’ll never look at wood the same way again. For decking, cladding, porch flooring or anything else you use wood for, Thermory sets the bar for beauty and longevity.

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Creating lasting value

Our boards are a stunning combination of natural beauty and enhanced function. The results of our innovative process are products that are highly rot resistant without sacrificing strength or pliability. Products with extraordinary longevity and rich, beautiful color. We have one goal: creating lasting value.

Thermally modified wood is suitable for interiors and exteriors, homes and, thanks to its durability, public areas. Facades, decks and balconies, saunas, swimming pool areas, flooring, walls and roofs.

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An Estonian company. The world market leader.