Thermowood is created by processing different woods at high temperatures. For example, pine, ash, oak. The material is also called thermally modified wood in another way. In different countries, the material is produced in different ways. The best technology is considered to be from Finland. On it, wood is processed with limited air penetration, it is in water vapor at a temperature of + 150... + 240 degrees.
Heat treatment can be single-stage or multi-stage. In multi-stage processing, steam is supplied at a pressure of 1.6 bar. Rectification is also used, which means that nitrogen is supplied under pressure, as a result, thermal wood of the highest quality is formed.
Thermowood is divided into classes that have different types and properties. The class depends on the temperature of the supplied steam with which the wood is treated.
Classes
- If the wood is treated with steam up to +190 degrees, then it is classified as class 1. As a result, it slightly changes color, minimally improves properties.
- The tree is treated with steam up to +210 degrees - this is class 2. In wood, the color becomes darker, the strength increases. It is made resistant to decay.
- If steam is used up to +240 degrees, then this is class 3 thermal wood. It acquires a dark, rich color, maximum density and strength.
That is, when drying with steam, not only water is removed from the material, but also polysaccharides, due to which the wood can rot.
History of invention
They wanted to make wood stronger and more durable for a long time. It was boiled in oil, in a salt solution, placed in water for several days, and burned.
For the first time, thermally treating wood began in the 1930s in Germany by Strain and Hansen.
In the United States, the results of scientific developments were first published in 1960 by Kollman and Schneider.
But in Finland in the 1990s, a new technology for treating wood with water vapor at elevated temperatures was invented.
Material advantages:
- the coating stops absorbing moisture, as it becomes very dense;
- if the material is placed in water for a long time, then it will absorb no more than 8% of the total weight of water;
- it is resistant to adverse weather conditions;
- it does not crack, retains its size;
- very durable and resistant to mechanical stress;
- maintains environmental safety;
- increased resistance to fire;
- the material is made more decorative, since the texture is more clearly visible;
- the service life is increased;
- the coating is resistant to decay, mold and fungi, pests.
The downside is the expensive price.
Scope of use
The facades of the house are trimmed with material, terraces, gazebos are made of it, they are laid on the floor. It retains heat well in the room and does not heat up well at high temperatures.
The coating does not crack and does not rot. It does not dry out, it is not afraid of showers, sharp jumps in temperature.
There will be no cracks on the floor, it cannot be deformed. It doesn't need to be repaired every year.
True, the material that is used in saunas, baths, bathrooms needs finishing.
Thermoboard on the facade is a plank, lining, block house.
The material is laid in the paths in the garden. They are environmentally friendly, but they will last a very long time. They are not afraid of rain, they are resistant to wear and tear.
Although the material is made very resistant to water, changes in the atmosphere, pests, it can still change color from ultraviolet radiation, turn gray.
True, in this case, the structure of the material is destroyed only in the uppermost layer, and its strength does not change. But still, because of this, the material should be painted with natural oils. These are eco-friendly products that enhance the natural texture. They do not create a film on the surface, but penetrate deep inside.
How to paint?
Painted with oil using a brush that has natural or mixed bristles. The oil is rubbed along the fibers with a thin layer.
Colored oils are used, which protect the material from fading for a long time.
The coating is applied in 2 layers:
1. Stained with colored teak oil.
2. The second layer is applied to the composition, which is necessary for the product.
If the wood is vertically attached to the facade, then it is painted with a colored protective oil for outdoor use. If the material is used for floors, it is covered with colored terrace oil.
When painting facades, the finish is repainted once every 5 years.
The floor is advised to be repainted once every 2 years.
Thermally modified wood is a very beautiful and environmentally friendly material, durable and resistant to moisture.