Thermotreated wood. What is Thermotreated wood?

Thermotreated wood. What is Thermotreated wood?

Heat-treated wood or wood thermotreated wood processed to over 170 ° C temperature. The heat treatment improves the wood rotting – and weather resistance, and thermal insulation and reduces the accumulation of water timber. At high temperature, the resin was released from wood.

Thermotreated wood products have been made for use of the indoor places such as walls, ceilings, floors, baths, furnishings and furniture. Outdoor Thermally treated wood is used for building facades, buildings in the courtyard and in the manufacture of joinery (doors, windows, furniture).

Preparation of thermotreated wood.

As soon as the timber is raised to a temperature of about 100 ° C, thereafter the temperature is increased more slowly. The raw materials must be pre-dried for at least 12%. The water vapor acts as a protective-gas form, thereby preventing cracking of the timber and to manipulate the chemical changes in the wood occurring. Wood moisture percentage drops to almost zero.
The actual duration of the heat treatment the temperature is increased according to the desired processing step, over 170 ° C,

Reducing the temperature and humidity of laws

The temperature is reduced by water spraying. The wood moisture is aligned with the use of the subject, the concentration usually exceeding 4 percent.

Heat treatment effect on the timber main features

moisture balance value is lowered
• decaying castle improved
• increased thermal insulation
• Wood is thoroughly colored
• The resin is removed
• Make improved survival
• flexural strength decreased slightly
• fracture toughness decreasedTihedus

The density is defined as the volume of the weight element, which is expressed in kg / m3. The heat treatment reduces the density of the wood slightly.


Wood is a direct link between the strength of the wood density. Heat treatment reduces the density of the wood and the strength properties also decrease, but the weight / volume ratio, however, remains in practice unchanged.

Bending Strength

Under a temperature of 200 ° C heat treatment made in a special timber flexural strength has no effect. Heat-treated lumber is not recommended, however, be used in load-bearing structures. The bending strength reduction is directly related to the wood knots, which are the branches of the strength due to the bending strength of the timber made of other wood väiksem.Lisaks affects the type of branches. Dead or partially dead branches of the timber volume more than knots.

Compressive Strength

The heat treatment does not reduce the compressive strength of wood. The effect may even be in some respects the opposite. The limit-load conditions of the heat-treated wood is not the same as the elasticity of the conventional timber. Have a significant impact compressive strength of wood density.

Shearing Strength

Conventional heat treatment temperature is relatively minimal, paragraph strength reduction.

Fracture toughness

Heat treatment reduces the risk of rupture strength of the timber, depending on the processing temperature of 30 to 40%.


Heat treatment is the lack of impact on the hardness of the wood. The hardness of the timber exhibits a greater effect on the density and the variation in the type of wood used.

Moisture Balance

Heat treatment reduces the moisture equilibrium value. Moisture balance of the treated wood at high temperature has a value 40-50% lower than that of the untreated wood.

Size persistence

The equilibrium moisture-heat treated is significantly improved due to the decrease in value of the persistence of the timber diameter. Heat-treated wood may be as tangential as well as radial expansion of the moisture is added to be 40 to 50% lower than the normal wood.

Water absorption

Heat treatment reduces the absorption of water in the timber. The respective course of the tests it has been found that the heat-treated wood is absorbed much less water than a conventional timber.

Thermal conductivity

The thermal conductivity is 20 to 25% lower than in a conventional timber under the same conditions. Thermal treatment improves the thermal insulation of wood.

Biological durability

Under laboratory conditions, the tests carried out under the heat treatment significantly improves the durability of the biological timber. Made based on the results of field trials are not recommended for use in constant contact with moist soil Thermally treated in places where it is necessary structural strength.


Under natural conditions, the moisture content of normal wood thermotreated wood compared to about half the size. Ultraviolet radiation resulting from the cracking of the surface is smaller than that of conventional thermotreated wood. UV radiation can still fade the original color of thermotreated wood. Is recommended to maintain the color of the timber, the surface of the UV-protection for the issuing means.

Thermotreated wood products overall classification.

Coniferous and deciduous trees overall classification comprises separate stages of heat treatment, based on the classification. Processing temperatures is determined from the final place of use requirements. Product names of species of Thermo-S and Thermo-D.

Thermotreated wood products overall classification.

Coniferous and deciduous trees overall classification comprises separate stages of heat treatment, based on the classification. Processing temperatures is determined from the final place of use requirements. Product names of species of Thermo-S and Thermo-D.


Thermally treated wood can be planed by conventional planing machines. An excellent surface quality of the workpiece can easily be achieved. Planers setting values ​​must, however, select a more or less the same as the setting values ​​in the hard timber.

A good end result can be a decent blades. The biggest threat to the division of the milling initial and final phase, when the wood is milled transverse direction. Milling careful planning can reduce the risk of splitting.

Surface treatment

Thermo-wood is a beautiful brown color. The initial hue and the preservation of the surface is recommended in order to avoid splitting the UV-protection for the surface treatment of giving. Surface treatments, such as oil-based function in the same way untreated wood. Water based surface treatment more slowly, so it is recommended to use a longer drying products.


PVAc adhesives based on the water absorption of the active into the wood. It is therefore recommended to apply PVAc adhesives for use in longer drying times and compressive than untreated wood. In addition, it is recommended to use adhesives, where the water content is minimal.

Polyurethane adhesives work well of thermally treated wood. Such adhesives, however, in need of curing of the moisture. Kõvastumisprotsessiks necessary to take either of wood or of moisture from the surrounding air. If both the timber and the air is dry, gluing may fail. Polyurethane adhesives, it is recommended the adhesive timber moisten.

Chemically curable adhesives work in the normal way.

Mechanical fixing

Heat treatment reduces the breaking strength of the wood bit. Self-drilling threaded components is recommended to use screws. Drilling a hole in advance reduces lõhenemisohtu. Fixing screws are recommended to use a stainless steel screw rare wood screws.

Nails hammer to hit nails should be at least 30 mm away from the end of the piece, or drill holes in advance. An excellent confirmation will be using pneumatic tools. Compressed air is used to adjust the force of impact, so that the nails penetrate enough, but not too deep into the wood surface.

In order to ensure the long-term structure, and to avoid the staining is recommended to use a humid environment, or stainless steel, acid-proof attachment of accessories. Electro-mounting of accessories may be used if the galvanized surface is kept intact, or the point of attachment is repainted.

Environmental protection

Thermotreated wood is eco-friendly and natural product. The production process is used only heat and water vapor. No chemical manufacturing process is used.