Among finishing materials, heat-treated wood, which is distinguished by its unique performance characteristics, aesthetic appearance and wide range of applications. Thermowood is an excellent analogue of natural wood.
Properties and scope of application
Wood is an environmentally friendly natural material, which has an excellent texture and is absolutely safe for human health. However, without additional processing, wood is not able to withstand adverse external factors such as high humidity, the action of biological microorganisms and insects.
The modern method of processing wood raw materials, thermal modification, has made it possible to obtain a new high-quality finishing material that has found wide demand in the market. Thermowood is lumber that has undergone additional heat treatment at temperatures from 180 to 240 degrees without the use of synthetic additives and compounds.
Thermowood is a unique finishing material that combines an environmentally friendly composition and amazing physical and mechanical properties:
- Dimensional stability when exposed to adverse factors environment– temperatures and moisture (unlike untreated wood, this indicator improves by 10-15 times, reducing the risk of swelling in a humid environment is reduced to 90%).
- Hygroscopicity. Wood moisture content is reduced to 4-8 percent, which is significantly lower compared to industrial drying of lumber in special chambers. The ability to absorb moisture in thermowood is reduced by 5-6 times. With a long stay in a humid environment and directly in water, the maximum humidity of the raw material does not exceed 9-10 percent, natural drying occurs almost instantly.
- Long service life, resistance to biological damage. Processing wood at high temperatures leads to the decomposition of polysaccharides, which, provided the humidity of the raw materials is low, minimizes the risk of damage by microorganisms, mold and fungus.
- High thermal conductivity. Thermowood is an ideal material for finishing baths and saunas, since it thermal insulation characteristics 30 percent higher than that of natural wood.
- High wood density ensures water repulsion without additional treatment; lumber does not absorb moisture from the air. Wood after heat treatment is resistant to mechanical stress.
- Ecological cleanliness, absolute safety for the human body and the environment.
- High fire safety. The hardness and density of thermally treated wood determine the slow combustion of the raw material.
- Aesthetic appearance thermowood. After heat treatment decorative properties lumber is noticeably improved - a spectacular wood structure and a noble dark shade appear. Heat treatment gives even inexpensive wood the appearance of valuable wood.
Thermowood is widely used for interior and exterior finishing houses, baths and saunas. Due to high strength, dimensional stability and resistance to adverse external factors, a facade made of thermally treated wood will not lose its original appearance even after a long time.
However, the high cost of lumber makes it economically unfeasible for use as interior decoration (wall and floor decoration). Thermally treated wood is most in demand in the following areas: facades, terraces, open street areas, verandas, gazebos, fences, railings, decorative items (flooring, outdoor furniture).
The only drawback of lumber is its high fragility. Sawing of thermal wood should be carried out with a special tool with small teeth at high speeds with a low feed of the workpiece. Failure to comply with the cutting conditions and requirements leads to the workpiece bursting.
Do-it-yourself thermowood production technology
Modern technology for the production of thermowood involves prolonged exposure to high temperatures on hardwood and coniferous species. The main species used are pine, oak and ash, and in more rare cases spruce.
Under the influence of high temperatures, the structure and density of wood changes, as a result of which it becomes hollow. Polysaccharides, resin, and cellulose almost completely burn out of wood, and the fibers of the lumber are modified (“caramelized”).
The production of thermowood in industrial conditions and with your own hands is carried out in three stages. At the first stage, forced drying of the workpieces is carried out to reduce the moisture level as much as possible. The duration of wood drying depends on the type of raw material used and the size of the workpiece.
The production of thermowood is carried out using several methods:
- Single stage. Standard processing of lumber under the influence of heated steam up to 180-200 degrees.
- Multi-stage. Wood processing with superheated steam under pressure is carried out in several stages. This technology The production of thermowood is used mainly for raw materials that have not been previously dried. At the first stage, the workpieces are treated with hot steam in a pressure chamber, and at the second stage they are additionally dried.
- Hot oil treatment. Lumber blanks are placed in a container with oil and then slowly heated. During processing, wood absorbs a small amount of oils, which increases its resistance to moisture.
- Processing in an inert gas environment. Treatment of workpieces in nitrogen at high blood pressure and low oxygen levels. This method allows you to obtain thermowood of the highest quality.
The technology for the production of thermally treated wood involves exposing the workpiece to superheated steam at a temperature of 150 to 240 degrees, which allows the finished thermal wood to be classified into three groups:
- First grade. Processing of raw materials at a temperature of no more than 150 degrees, the finished lumber has a slightly tinted tint and the lowest technical and operational characteristics;
- Second class. The wood is treated with steam at temperatures up to 210 degrees, the lumber acquires high strength and hardness, resistance to rotting and decomposition. The shade of wood is more saturated;
- Third class. The highest class of thermally treated wood, after firing at temperatures up to 240 degrees, the lumber receives the highest strength, hardness and resistance to adverse external factors.
Heat treatment of workpieces is carried out in special closed cells within 24 hours. Heated steam acts as a protective medium; it prevents the combustion of lumber and actively participates in chemical reactions.
On last stage making thermowood with your own hands (hardening) the lumber is subjected to long-term cooling with constant monitoring of the percentage of moisture in the wood (at the level of 6-7 percent). The wood does not require final processing.
Thermowood, having adequately proven itself as a modern finishes baths and a number of facilities of our private and corporate clients, is ideal for internal and external cladding houses, saunas and baths, installation of floors, including modular parquet, open terraces, patio, garden paths and basin areas, manufacturing of stairs, interior items, as well as garden furniture, elements landscape design and fencing.
To make thermal wood more durable, we recommend that you always coat the boards with compounds that protect against exposure to sunlight.
Thermowood fades in the sun, and protective finishing coatings can not only additionally protect it from exposure external environment, make it brighter, emphasize the structure advantageously, but also protect from ultraviolet exposure.
The treatment increases wear resistance, reduces the possibility of cracks and revitalizes the surface.
Please note that before installing street structures, boards should be coated with the selected composition on all sides, following the manufacturer’s recommendations at a temperature not lower than +16-18 degrees. Before starting work, it is recommended to clean the surface from dust and dirt.
- Tikkurila Valtti wood oil;
- Special oils for Osmo wood.
- For thermal wood in baths and saunas, Tikkurila Supi Laudesuoya oil is suitable to protect the shelf.
During construction or finishing works Wood was and still is the favorite material. But to wooden materials served for a long time, did not rot, did not swell or dry out, they have to be pre-treated with various chemicals.
But not everyone wants to deal with chemistry, which is why heat-treated wood has now become widely used.
Many people wonder what heat-treated wood is? These are wooden products that have undergone heat treatment at high temperatures without the addition of chemicals.
Thanks to this treatment, the tree receives a lot positive qualities:
Wood thermal treatment technology
This technology was invented by Finnish specialists.
It consists of several processing stages:
- - first, the wood is dried by placing it in a drying chamber for a long time at a temperature of 100-300 degrees. At this stage of processing, all moisture is removed from the wood;
- - heat treatment - for such treatment, hot steam is released into the chamber where the wood is located, the temperature there is above 250 degrees.
IMPORTANT! Heat treatment takes about 3 hours. Finally, the heat-treated wood is cooled, reducing the temperature in the chamber, the humidity of the product is 4-6%.
There are different heat treatments:
- — single-stage;
- - multi-stage - with this treatment, steam is supplied under a certain pressure.
IMPORTANT! For the production of thermowood highest quality It is not air steam that is supplied under pressure, but nitrogen (rectification is performed). Wood may differ in appearance, shade and properties if treated with different steam temperatures, therefore its price will be different.
Therefore, it is divided into classes:
- - first class - steam treatment up to 190 o C, the shade changes slightly, the properties are improved to a minimum;
- - second class - steam treatment up to 210 o C, the shade turns out darker, the strength of the wood increases, and also the resistance to the rotting process becomes higher;
- - third class - steam treatment up to 240 o C, wood has saturated dark shades, here all properties are increased to the maximum (strength, stability, density).
IMPORTANT! Before buying thermal wood, check what class it is and decide what shade you need it for construction.
How to make heat-treated wood at home yourself?
Buying thermally treated wood is not difficult, for example, buy in St. Petersburg or buy in Moscow; it is now sold everywhere. But usually only in specialized stores. Only the cost for it is much higher than for ordinary tree. Therefore, many craftsmen often ask this question - how can you make such wood with your own hands at home?
If you really want to do this, it is possible. Only the process of making thermowood is very labor-intensive, but the result is worth it.
To make a thermal chamber we will need the following elements:
A container of water is placed in the thermowood chamber to allow water to evaporate due to the high temperature. This will prevent the wood from catching fire. To maintain a high temperature, the chamber must be well heated.
IMPORTANT! The chamber must be sealed tightly, because if oxygen gets in there, there is a risk of wood fire.
This option is suitable if you need to process wooden products large sizes. For processing small pieces of wood, there is another way to do it yourself. Take wood, boil it for 1.5 hours, then wrap it in rags or paper and dry these wooden products near a stove, radiator or heater.
Use of heat-treated wood
Due to its positive qualities, thermowood is universal material. It can be used for construction garden gazebo, . Looks great as an external finishing material for the facade of a house, and can also serve as a floor covering.
Facade thermowood– presented in the form , . The beautiful appearance of such products lasts a long time and does not require much care.
In wet areas( , ) we can also often see the use of thermal boards. It does not heat up much and is not afraid of humidity.
Although heat-treated wood has many advantages, it also has a disadvantage - under the influence of sunlight, the surface fades over time and the shade becomes gray. But only the most is damaged upper layer, it remains durable inside. In order to prevent fading, you can additionally treat the thermowood oil products. After which such wood will serve you for a long time, and delight the eye with its beautiful appearance.
Another drawback is, of course, the cost of such wood, but we have described to you the opportunity to make it yourself, which will be much more profitable.
Wood has been used for building houses for a very long time, but, unfortunately, it does not have the same strength as concrete or hardware. Over time, untreated wood begins to rot and nothing can be done about it.
However, if still on initial stage, before building a house, the wood will be heat treated with your own hands, then this is the most in a positive way will affect the durability of the wooden structure.
How it is performed on equipment specially designed for this was described earlier. It is very difficult to heat treat wood with your own hands.
There are several ways to do this:
- Extend the “life” of wood using various antiseptics, methods of tarring and burning wood;
- Artificially age wood.
Wood without special treatment quickly rots, this is a fact. However, by treating it with antiseptics, you can significantly increase the life of the wood.
Today there are a very large number of ways to protect wood from rotting, including tarring the wood, firing it, and treating it with antiseptic drugs against fungus.
If we talk about burning and tarring wood, then these methods most likely relate to folk methods protection wooden products. The wood is fired blowtorch or gas burner. However, first, before this, the wood is slightly moistened with water, after which it is fired until Brown surfaces.
After the wood has been fired, it is necessary to clean off the carbon deposits on the wood using a metal brush. Firing wood will give ordinary wood an “aging” effect. At the same time, the material will be reliably protected from fungi and mold for a very long time.
Of course, it is impossible to achieve in this way the characteristics that factory-made thermal wood has, but you can get as close to them as possible without having absolutely no specialized equipment Can.
Wood can also be protected by chemicals specifically designed for these purposes. Methods for preserving and preserving wood have proven themselves to be the best for quite some time.
When preserving wood, the outside of the material is treated with appropriate protective agents for this purpose. It is also important that it is possible to antisepticize wood already on a ready-made wooden building, which was erected and operated.
To do this, the outside is treated with an antiseptic. load-bearing beams houses, logs and ceilings, as well as door and window blocks.
Video heat treatment of wood
Tremodwood is a wood material that is exposed to temperature (from 180 to 230 degrees Celsius) without the use of chemical reagents. Such wood is not subject to rotting, drying out and cracking. Laboratory indicators show a 30% advantage over conventional timber.
Because the market price finished products are quite high, many specialists and home craftsmen are thinking about how to make thermowood with their own hands. Everything in technology is quite simple, the main thing is to follow the nuances, otherwise you can simply ruin everything.
Required tools and materials
To make thermowood you will need:
- wood (coniferous species are cheaper and more accessible; it is best to take linden or birch);
- oven (the more, the better);
- container with water (to prevent the material from igniting when high temperature).
It all depends on the purpose of making thermowood. If you need to make small fittings, then regular ones will do. kitchen oven. If you want to dry long boards, you will need either a professional kiln or a homemade kiln, such as one made from a railroad tank.
Step-by-step manufacturing instructions
There are two manufacturing options. The first is suitable for those who do not have a suitable kiln and do not need to burn large volumes of wood. The second is for those who still have a stove that is more or less suitable for such purposes.
Cooking in water
- Place the preparations in a large pan, bucket or barrel.
- Pour in required amount water.
- Place on fire (it is important to maintain maximum temperature).
- If the water evaporates, add boiling water.
- Boil for 2 hours.
- Take out the blanks.
- Wrap in newspapers (several layers).
- Place near a heat source.
In a few days you will receive wonderful material that will fully meet the requirements you need.
Firing in a kiln
First you need to make sure that the wood is dry. It is important that it is not treated with chemicals, paints or varnish.
- Preheat oven to 200 degrees.
- Place the workpieces on a wire rack, which is best placed in the lower part of the oven (you can first lay down paper).
- Place a container of water at the top.
- Dry the wood in the oven for 2 hours.
- After 2 hours, add water to the container.
- Reduce temperature to 100 degrees.
- Wait another half hour.
Such wood will last you a very long time. It tolerates any temperature well and does not require the use of reagents.
Thermowood is a modification of wood that has undergone pre-drying and heat treatment at high temperatures (depending on the density of the wood from 140 to 270 °C in order to change its properties.
It has long been known that wood becomes more resistant when exposed to high temperatures. However, only over the past years has this phenomenon been studied by scientists, and as a result, such a building material as thermowood has appeared. To be more precise, the method was invented by the Finns, who were interested in the heat treatment of wood without chemical additives.
Currently, such wood is also available in other countries. Moreover, thermowood from local wood varieties can replace much more sustainable tropical wood varieties, such as bangkirai or teak. However, when applying this building material It is impossible to do without chemistry completely. Wood turns gray despite heat treatment, so if you want to get noble color, it has to be protected with chemical blockers from ultraviolet radiation.
IN drying chambers The wood is heated within a few hours to a temperature above 200 ° C. In this case, the cellulose (xylose) partially burns and the qualities of the wood change. It has a lower equilibrium moisture content and becomes darker due to the process of “caramelization”. The internal qualities of wood also change. Therefore, on cuts and in places of drilling, it has the same color and the same strength. The resin is completely removed from coniferous wood. In combination with water, heat treatment leads to the hydrolysis of various components wood The currently known methods for producing thermowood can be divided into four groups:
1. One-step steam treatment. In this case, units like drying chambers are used, into which steam is supplied after loading the material. At the same time, the oxygen content in the air of these installations is reduced to 3.5%, which at temperatures of 150-200ºC slows down the oxidation (combustion) of wood. When processing pre-dried wood, the total duration of the process is about three days. It is also possible to process raw material, but in this case the duration of the process will be longer, taking into account the drying time itself.
2. Multi-stage processing. Wet wood is treated for 4-5 hours with saturated steam or water (cooking process) at a temperature of 150-200ºC. The process itself takes place in a sealed container under pressure up to 1.6 MPa. After this, the wood is dried in a chamber for 3-4 days to the final moisture content (about 10%). During the hardening phase, the wood is heated again to a temperature of 170-190ºC for 14-16 hours.
3. Processing in hot oil. Dry wood is immersed in vegetable oil and slowly heated to a temperature of 180-220ºC. The duration of this treatment is 2-4 hours. In this case, oil is additionally absorbed by the wood, which depends on the size of the material (surface) and can be adjusted. The duration of the process is approximately a day.
4. Processing in an inert gas environment. This process is known as Retification, or, as they call it in Russia, retification (not to be confused with rectification). In this case, instead of water steam or oil, the wood is treated in a nitrogen environment with an oxygen content of up to 2% at elevated pressure.
1. The first and most important quality that thermowood has is dimensional stability. This characteristic is responsible for ensuring that no external factors can influence your thermowood to lose its marketable appearance. Natural wood, as is known, is deformed by moisture, but thermowood is not. This is due to the fact that thermowood has practically zero equilibrium moisture content, and the ability to absorb water vapor in TMD also tends to zero.
2. Another important property that thermowood has is increased strength and durability. Thanks to heat treatment, the “life” of boards increases by more than 20 times! This amazing metamorphosis is due to the fact that when a tree is exposed to high temperatures, polysaccharide substances disintegrate in the tree! As a result, the wood acquires the highest protective qualities, which completely eliminate the possibility of “fungus”, mold or insects.
3. Thermowood has increased fire resistance, unlike natural wood. We all know well that natural wood flares up instantly. Naturally, this is one of his most negative qualities. Thermowood, thanks to the modification process, has become much less fire hazardous. This quality of TMD is, of course, an important guarantee of your peace of mind.
4. Thermowood has enormous aesthetic potential, which is key factor for originality and beauty of design. After modification, thermowood in its structure becomes similar to noble species of tropical trees. But Decoration Materials It is almost impossible to purchase tropical trees in Russia, they are in short supply and cost a lot of money, but thermal wood, despite its elite quality and quality, is affordable to the majority of consumers. Important detail also another thing is that, due to its aesthetic characteristics, thermowood, having durability tropical species wood, surpasses them. In a word, thermowood is a level higher than elite varieties of tropical wood, while standing lower.
Applications of thermowood
The possibilities of using thermowood depend on the specific properties that it acquires after modification. Each manufacturer independently determines for itself those market segments that can be filled with its product. As a rule, thermowood is used in the following areas of production:
- Construction and cladding of houses, siding of houses and buildings, external finishing facades;
- Interior finishing and decoration of premises;
- Finishing of saunas, baths, swimming pools, bathrooms, piers, bridges and other objects that have direct contact with water;
- Manufacturing of furniture, components and musical instruments;
- Manufacturing of doors, windows, and other structural elements where stability of the product geometry is important;
- Production of floors (parquet, parquet board, frieze, batten), including multi-colored and warm floors;
- Manufacturing of terraces, verandas, gazebos, garden structures, fences, children's play complexes;
- Yacht and shipbuilding (decks, interior decoration, furniture);
- Any design solutions, restoration (platbands, baseboards, window sills, boards and tiles for bathrooms and kitchens, solid solid sinks, bathtubs, landscape design elements).
1. Color change when exposed to ultraviolet radiation. Long term exposure solar radiation ordinary wood and thermowood are gradually becoming grey colour. When staying under straight lines for a long time sun rays Small cracks and discoloration may occur. To avoid this, varnishing, painting and the use of pigmented surface agents for UV protection are recommended.
2. The smell of thermowood. In the process of any of the options for thermal modification of wood, highly volatile components, resins, and so on are distilled from it. And at the same time, a number of other easily volatile chemical compounds are formed. The most “unpleasant” of them are furfural and wood vinegar. The higher the modification temperature (modification level), the more of these components are formed and found in the wood. These chemical compounds evaporate from it quite easily. But this requires exposure in ventilated areas or additional processing after modification.
3. The disadvantages of thermowood include increased fragility, which makes the use of thermowood undesirable as a material for the construction load-bearing structures. Therefore, when sawing material, to prevent chipping, high-speed machines with disks with sharpened carbide teeth are required. The same requirements apply to equipment for milling and grinding. It is also not recommended to bury thermowood into the ground, because Heat treatment technologies have not yet been developed to effectively use materials in contact with the ground.
Patents and licenses for the production of thermowood
1. Finnish technology Thermowood. The developers and manufacturers of the equipment are the Finnish companies Lunawood Oy, Stellac Oy, Tekmaheat Oy, Valutec Oy, Italian company Baschild, French company BCI-MBS (Le Bois Perdure technology). Their peculiarity is that the thermal modification of wood is carried out in a protective atmosphere of water vapor at temperatures of 185-212°C. The main capacities for the production of thermowood are represented by precisely such equipment.
2. Dutch technology Plato. The developer and manufacturer of the equipment is PLATO-Wood (Providing Lasting Advanced Timber - We offer Durable Progressive Wood for Replacement). Its peculiarity is the implementation of thermal modification by cyclic hydrothermolysis (thermal hydrolysis) of wood at temperatures of 160-190°C.
3. French technology Retification, which is sometimes called steam stabilization technology. The developer of the technology is the Mining Institute in Saint-Etienne, the manufacturer of the equipment is REI from the same city. The thermal modification itself is carried out at a temperature of 220-250°C in an environment of unsaturated water vapor. REI is actively promoting wood rectification chambers on the market with payload volumes from 1.5 to 8 m3.
4. German technology based on drying wood in liquid organic substances. This technology uses various vegetable oils(flaxseed, sunflower, rapeseed, etc.), and the heat treatment itself is carried out at four temperature conditions.
5. In other European countries, in Canada, Ukraine and the Russian Federation, several heat treatment technologies similar to the above technologies have been implemented. The process of producing thermal wood can be divided into the following stages: increasing the temperature in the chamber to 130-150 ° C and drying at high temperatures with a decrease in humidity to almost zero. Then the temperature in the chamber and, accordingly, the wood itself increases in an environment of saturated water vapor to a temperature of 200-240°C. In this case, a slight overpressure compared to atmospheric. At this stage, the wood is given certain properties and color, i.e. it turns out new material- thermowood. Next, the temperature decreases and the wood moisture content is brought to a level of 4-6%.
