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Tantimber employs an advanced Thermal Modification Process; to ensure Tantimber products meet international standards for quality and endurance in various climate and weather conditions. Here’s an overview of their Thermowood process:

Thermal Modification

Tantimber’s wood products undergo high-quality thermal modification at international standards. This process involves raising the internal temperature of the wood to above 200 degrees Celsius (392 degrees Fahrenheit). The key goal is to minimize dehumidification and deformation behavior in the wood.

Quality Standards

Tantimber maintains strict quality standards throughout the thermal modification process and at all stages of production. By releasing relative humidity from the timber, Thermowood products gain moisture resistance, resistance to decay, and excellent dimensional stability, even when exposed to outdoor weather conditions.


Importantly, Thermowood is a natural process that doesn’t involve the use of chemicals. This means it doesn’t leave any toxic residue on the final product, aligning with Tantimber’s environmentally responsible practices.

Biological Durability

Tantimber’s products are classified in Biological Durability Class 1 and Class 2 according to European Technical Norms EN 350-2 and EN 355. This classification underscores their ability to withstand biological challenges and maintain their integrity over time.

Enduring and Environmentally Responsible

Tantimber’s Thermowood process results in products that are both enduring and environmentally responsible, meeting international quality standards and contributing to sustainable and long-lasting wood solutions.

By implementing advanced process steps and maintaining strict quality standards throughout thermal modification, Tantimber ensures that its products offer exceptional dimensional stability and durability in outdoor weather conditions. Tantimber’s commitment to using natural processes without harmful chemicals contributes to the eco-friendliness of our wood products.

Watch Thermowood Process Video

The Process

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The thermal modification process employed by Tantimber is a precise and controlled procedure conducted in specialized heating chambers, monitored by experienced specialists using computer systems. Here’s an overview of their process:

Specialized Heating Chambers

Tantimber’s thermal modification process takes place within carefully designed heating chambers equipped with specialized sensors. These sensors play a crucial role in maintaining precise control over the process.

Wood Species

Tantimber’s thermal modification process is based on many years of experience and is adapted to different wood species and their intended purposes. While the details may vary, the fundamental principle remains consistent.

Computer Control

Advanced computer systems are employed to monitor and control the heating chambers, ensuring that the process parameters are maintained at optimal levels.

Experienced Specialists

Tantimber’s team of experienced specialists oversees the entire process. Their expertise ensures that the thermal modification process is conducted with precision and accuracy.

Moisture Reduction

The process starts with the reduction of the wood’s moisture content to 0% over a specific period, which typically lasts between 38 to 76 hours.

Cooling and Steaming

Following thermal modification, the wood is cooled with steam as part of the final stages of the process to reach it’s final moisture content of 4-7%.

Peak Temperatures

After achieving the desired moisture level at 0%, the temperature within the chamber is raised to the necessary level to initiate the thermal modification. This controlled temperature increase is a critical phase of the process.


Throughout the entire thermal modification process, only temperature and steam are used. This chemical-free approach aligns with Tantimber’s commitment to environmentally responsible practices.

Controlled Reactions and Audited Production

Tantimber’s specialists employ heat to stimulate physical and chemical reactions within the wood, carefully adjusting process parameters to achieve desired product characteristics. Additionally, their commitment to quality and consistency is demonstrated through regular audits by third-party entities, specifically through the Thermowood Association. This combination of controlled reactions and audited production ensures high-quality, consistent wood products.

Biological Durability

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Tantimber’s Thermally Modified Timber (TMT) products exhibit remarkable biological durability and offer numerous advantages over conventional wood products, WPC (Wood-Plastic Composite), and impregnated materials:

Biological Durability

The high-temperature treatment applied during the Thermowood process results in Tantimber products having enhanced properties, particularly in terms of biological durability. The process effectively reduces the moisture content within the wood to 4-7%. This low moisture level makes Tantimber products highly resistant to attacks by wood-decay organisms such as fungi, insects, and other pests. This enhanced biological durability is a critical feature for products exposed to outdoor and harsh conditions.

Durability Class

Tantimber Thermowood Products are classified into Durability Class-1 and Durability Class-2, depending on the wood species, in accordance with European Norms CEN/TS 15679 and EN 350-2. This classification underscores their resilience and ability to withstand the challenges posed by various environmental factors.


Tantimber products have an extended lifespan, with durability increased to a minimum of 25 years. This longevity makes them an ideal choice for demanding applications in harsh conditions and diverse weather conditions. Their resistance to deterioration ensures that Tantimber products maintain their quality over time, reducing the need for frequent replacements.


One of the key advantages of wood is its ease of maintenance. Unlike many industrial products, wood can be renewed and maintained, contributing to its economic and environmental sustainability. Tantimber Thermowood products are designed for easy maintenance, allowing for the preservation of their quality and aesthetic appeal over the years. This feature adds value to customers by reducing the long-term costs associated with product replacement.

Incorporating Tantimber Thermowood products not only enhances the visual appeal of spaces with warmth, dignity, naturalness, and tranquility but also provides a practical, durable, and environmentally conscious solution for various applications. Tantimber’s commitment to quality and sustainability underscores their role as a trusted provider of high-performance wood products.

By employing this attentive Thermowood process, Tantimber is able to produce wood products with enhanced durability, stability, and resistance to biological decay while maintaining their commitment to sustainability and environmental responsibility.

Why To Use Thermowood

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The transformation of wood through thermal modification results in a range of advantageous changes to its physical and chemical properties:

Moisture Reduction and Chemical Transformation

Heating wood during thermal modification leads to the release of moisture and a transformation in its chemical composition.

Reduced Absorbency

Thermal modification markedly lowers wood absorbency, reducing swelling in moist conditions, ideal for outdoor use with varying weather conditions.

Enhanced Dimensional Stability

Thermally modified wood has enhanced dimensional stability, minimizing expansion and contraction due to environmental changes, which helps maintain structural integrity.

Improved Biological Resistance

Modification deters pests and microorganisms, enhancing wood’s resistance to decay. This natural resilience reduces the need for toxic chemical treatments.

Superior Heat and Sound Insulation

Thermally modified wood offers superior heat and sound insulation properties compared to untreated wood, potentially enhancing energy efficiency and acoustic comfort in buildings.

Easy to work

With a lower weight and density, thermally modified wood is easier to work with mechanically, simplifying construction and installation processes.

Enhanced Aesthetics

Thermally modified wood boasts a beautiful, throughout penetrated colour. It retains its attractive appearance over time.

Chemical-Free, Safe & Recyclable

Thermowood’s chemical-free process ensures safety, and its products are recyclable with no hazardous substances at the end of life.

Enhanced Wood Properties

The thermal modification process leads to a range of advantageous changes in wood, making it more durable, stable, and environmentally friendly, while also providing superior insulation properties.

ThermoWood® Handbook

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Updated ThermoWood® handbook has been published. You can download and print the handbook in Downloads section of the web service. The handbook was published in English, German, French and Finnish.

View Thermowood Handbook