43.48 Per Length(Inc.VAT)

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Product card thermally modified wood. Wood is a natural product and each type of wood has certain properties. These can wrongly be seen as lower quality. At THERMINO® we think it is important to inform you about this in advance. That is why we tell you in this product card what you can expect from modified wood, so that you can determine whether this is the right choice. There are various types of wood that are not very durable if they are used outdoors without treatment, including: ayous, fraké and pine wood. By thermally modifying these types of wood, the lifespan – also outside – is considerably extended. Thermal modification is a sustainable process in which the wood is processed by heat and steam, without the use of chemicals. Thermal modification makes the woods just as durable as hardwood with an average lifespan of 20 years. Thermally modified wood is lightweight and is therefore widely used as facade cladding. It is of course also possible to make a fence out of it or to use the wood as a wall in your roof.

The process of thermal modification

The thermal treatment of wood consists of three steps. In the first step, the wood is dried back in a calm condition to a moisture content of approximately 10%.

The second step is the so-called thermal treatment. The wood is placed in a vacuum environment and the temperature is raised to 200°C. Due to the heat, glucose and other substances are baked out of the wood and the cell structure of the wood changes completely.

As soon as the above process stops, the wood automatically cools down and gets a moisture content of 3 to 4%. This so that the wood does not become brittle and can be processed properly. The wood is then planed into the various profiles.

Product Features

SENSITIVE TO DAMAGE | Thermally modified wood is drier than fresh wood and is therefore more susceptible to damage. We advise you to transport the wood carefully. The ends of the planks in particular can be damaged more quickly by impacts, for example.

LIGHT WEIGHT | By extracting moisture from the wood, thermally modified wood becomes lighter in weight. This makes the wood very suitable for facade cladding, for example. It is less stressful and can be processed more easily at height, because it is less heavy than untreated wood.

ENVIRONMENTALLY FRIENDLY | Thermal modification is only done by means of heat and steam, so without the use of chemicals. That makes the wood an environmentally friendly choice. In addition, the lifespan of the wood is extended and in that time a new tree can grow again. By choosing thermally modified wood, you also help prevent deforestation.

ASSEMBLY INSTRUCTIONS | If you are going to install thermally modified wood, it is important to follow the installation instructions. Pay particular attention to good ventilation and mount the wood at least 5 to 10 cm above the ground. If moisture penetrates the wood, it can deform. Use stainless steel mounting material for mounting. Apply your nails, then use a nylon hammer. If you opt for facade screws, always pre-drill the wood.

KNOTS | Spruce wood naturally contains knots, these are places where a branch has been on the tree. Knots are often round or oval and can fall out of the wood when dry. These knots are also visible in thermally modified firing. You can replace these knots and glue them. Knots are unavoidable and have no influence on the quality of the wood.

TEARS | A big difference compared to other garden wood is that thermally modified wood has little wood effect. Nevertheless, it remains a natural product and there is a small chance of cracks occurring. These do not affect the quality of the wood.

GRAYING | The thermal treatment gives the wood a beautiful dark colour. Over time, this color will turn gray under the influence of weather conditions. This is a natural property that also occurs in other types of wood. Do you want to keep the original color? Then we recommend that you treat the wood with a stain before application. Or opt for colored thermally modified wood. The wood is then sprayed in the desired color.

DIFFERENCES IN COLOR AND STRUCTURE | Since wood comes from trees, no two planks are the same. The color and structure of the wood can therefore differ. Under the influence of weather conditions, the color difference will converge more. Even with colored wood, the color can sometimes differ slightly. We recommend that you order colored wood in one go as much as possible, so that the wood comes from one batch. This reduces the chance of color difference.

BLACK STAINS | Sometimes parts of thermally modified wood may have black spots. These are fungi that grow from spores in the air and ‘attach’ themselves to the wood, as it were. The wood provides a breeding ground because sugars are released on the surface of the wood during the production process. The fungi disappear by themselves or can be removed by means of water and possibly green soap. These spots do not affect the quality of the wood.

Thermino Installation Manual


Our delivery times are Mon – Fri: 8am – 5pm excluding weekends and bank holidays.

We deliver material from our fleet of transport, we also use external haulage companies.


4′ 8′ 12′ 16′ 20′
DUBLIN NORTH 50 50 50 50 50
DUBLIN SOUTH 50 65 65 65 65
50 100 150 150 250
MUNSTER 50 100 150 200 250
CONNAUGHT 50 100 150 200 250
ULSTER 50 100 150 200 250

This is how THERMINO ® makes wood more sustainable

Thermal modification is a specialist process that requires knowledge and a careful working method. At THERMINO® we make our products suitable for a beautiful wooden facade or durable fence in an environmentally friendly way. Thanks to steam and heat, the composition of the wood changes and we make the wood more durable, strong and weather-resistant. We do not use any chemicals in our process.

During the thermal process, there are checks at several times so that we can guarantee that EXTRION® thermowood is of the highest quality.

Step 1 : expel moisture

The wood is prepared for thermal modification. We place the wood in the oven and with heat we ensure that the moisture disappears from the wood. We add steam to prevent the wood from cracking or burning.

Step 2 : thermal modification

In this phase, the composition of the wood changes: chemical and physical changes take place due to thermal decomposition of hemicelluloses. Resin and other extractants leave the wood and the color changes.

Step 3 :Maintain moisture level

The thermally modified wood is almost ready. In the final stage, the moisture content is reduced to about 4%. This makes the wood dimensionally stable and less brittle. The result: beautiful wood with a considerably longer lifespan.