Double beam: construction of a house using Finnish technology. House of double timber: reviews

It is known even to the beginning builder that chopped houses have two main drawbacks: thin walls and shrinkage of crowns. The latter occurs in connection with the shrinkage of timber. Therefore, techniques are used to prevent deformation of walls and contribute to their effective insulation. According to existing standards, the walls of the house must be no thinner than 20 cm.

Solving this problem allows the technology of double beams, which was first used by builders in Finland. The country has a small number of fairly thick trees that could be used to build houses, while protecting them from the severe frosts characteristic of the region.

What is the essence of the new technology?

Finnish engineers have managed to develop a technology that allows building warm wooden houses with relatively low financial costs. It was called "double bar". In fact, this technology has little to do with the bar in the usual sense. Its essence lies in the fact that to achieve the proper thickness of the walls use two sheet piling boards, between which is a layer of insulation.

Houses on double-beam technology are characterized by improved thermal insulation characteristics, compared to houses from solid timber of similar cross-section. Compared with the insulated glued beam, this technology does not use adhesive compounds. Heater is often used as an ecowool or mineral wool.

Double beam: production

The production of material for the construction of houses using double-bar technology differs from the manufacture of a conventional profiled beam. It is carried out on special equipment - a fully or partially automated chopping line.

It is carried out in several stages:

• Manufacturing of a workpiece;
• Drilling holes for fastening the edging board;
• Chaskonarezanie;
• Grooming;
• Cutting the workpiece;
• Removal of residues;
• marking;
• Insulation by the material;
• packaging.

Benefits

The main advantage of a double-beam house is high energy efficiency. The thickness of its walls does not depend on the diameter of the log or beam. The layer of insulation is selected in accordance with the requirements specified in the generally accepted thermal engineering standards. The second advantage of the technology is the minimal shrinkage of walls, oscillating in the range of 1-2%.

To start full-fledged operation of the house, built on the Finnish technology, you can after the assembly of the walls and roof. Ordinary houses made of timber can not be used immediately, because you have to wait until the tree has dried and the crowns "will" fall into place. In this case, there is no need to wait.

Installation of the house from a double bar is relatively simple, not labor-consuming and does not require the use of complex construction equipment, which has a favorable effect on the time of erection of the house and financial costs. In parallel with the assembly of walls, heat insulation work is carried out, filling the space between the boards. Walls in houses from a double beam should not be further insulated and trimmed.

disadvantages

"Double beam", despite many advantages, has a number of shortcomings. The most significant include shrinkage insulation, but it occurs only when using mineral wool. There is also a possibility of cracks appearing.
They can be formed in connection with the uneven shrinkage of the skin of the external and internal boards used for houses built using double-beam technology. Reviews builders assure that in practice, such problems do not arise at all. At a minimum, there were no comments.

Experience of application in the domestic market

In the domestic market, technology has been used since recently, so no one will guarantee that the wooden houses will fully perform their functions in our climatic conditions. You just need to trust the Finnish experience of housing construction, since they have been building houses from double timber for more than 20 years and successfully operate buildings in their more severe climatic conditions.

It is not possible to build a house on this technology independently, because for its high-quality construction we need boards treated with special machines. It is also necessary to cut the thorns, grooves and mating dents intended for corner joints. Without a team of specialists and the acquisition of a housekeeper, it will not work out in any way. Therefore, to save on financial costs is problematic.

Structural strength

The technology of the double beam is not comparable to the usual frame construction, where the insulation is between two thin walls. In this case, everything is held on uneven bars. There is also a subset of this technology - a "double mini-bar". Its construction is similar, but the walls in it are more subtle.

Increased strength of the structure is also provided by joists if they are embedded in walls during construction. In technology, you can use only dry lumber, which largely affects the strength of the house as a whole. This is due to the fact that drying the bar leads to a loss of 13% moisture, due to which molecular bonds are broken. In the future, the beam will give exactly the same amount of moisture that it will absorb. Therefore, there will be no deformation.

Steam insulation

For the erection of houses, whose walls consist of several floors, an important issue is the vapor barrier. Without its consideration, it is not recommended to build. The double beam is an exception, despite the fact that the walls of houses built on this technology will inevitably absorb moisture after a certain time. Therefore there is an opinion that a heater between the beams is the place of rot formation. At the same time, construction companies specializing in the construction of houses on this technology, argue that no pre-eminent problems previously did not deliver a double beam. The reviews of the owners coincide that it is sufficient to use the film only in the floors.

But there are exceptions. Some owners are concerned about the lack of vapor barrier as such, therefore during construction use a windproof membrane, which is applied after the insulation. Experienced builders are skeptical about this, because it will not allow the walls to breathe freely, but they can last much longer.

Ecowool as a wall warmer

When building a wooden house, not impregnated with harmful synthetic resin, the best option is to use a harmless insulation. The optimal material is ecowool, the main component of which is cellulose. It does not rot, does not shrink and is not prone to fire.

Calculations for the material are as follows:

• Acoustic insulation - 46 dB;
• Dew point - condensate will not occur under standard conditions;
• Insulation - 0,13 m ² per m ^{2 of the} wall;
• Coefficient of thermal conductivity - 0.2 W / m ² .

The ecowool is blown dry in the interbranch space. The height should be no more than three meters. The procedure is carried out in stages. But here there are certain difficulties: the eco-wool in the "double bar" is blown out the same way as inside the frame walls. If the last wells are closed and reach the required density is not difficult, then the material is more covered and, as a consequence, can settle. Experienced builders have found a way out of this situation and use a special blow molding plant. Recently, mineral wool has found great application.

Mineral wool as a heater

The material is reliable, environmentally friendly and relatively inexpensive. If mineral wool is used as a heater, it is necessary to arrange a vapor barrier of the room (for ecowools this is not done). In addition, over time it cracks and, as a consequence, empty empty cavities within the walls are formed. Therefore, the material will have to be covered with an antiseptic inside and outside.

Sawdust

For the warming of walls, it is recommended to use stale sawdust. If you have at hand only fresh, then they can be soaked for 24 hours in lime and only after that knead. The procedure is as follows: ² mesh of sawdust and two sacks of cement are covered in the mixer. All slightly moisturize, mix, fall asleep in the space between the walls and rammer. A significant drawback of the material are mice, mold or otsyrivanie.

Bulk pulp

The material effectively performs the task of warming the walls. Often in the construction of insulation and do not use, because they believe that the air itself is an excellent insulation. But it is important to understand that it serves as a thermal insulation only in the case when it is stationary. This is the task of other materials: they create a large number of cavities with "fixed" air.

Sometimes polyurethane foam is used, but it is relatively expensive, so it was not widely used in construction. In this case, the material releases toxic substances and after a certain time is destroyed.

Box walls are insulated with linen fiber. Suitable is also chopped straw or other material that does not cake with time. It is also important to remember its compatibility with wood.

Stages of erecting a house using double-bar technology

Reviews convince that the independent construction of the house will go only at a loss to its quality, so it is impossible to do without specialists. The construction of the house includes the following stages:

• Sketch development (project). It includes the selected construction plan, the rendering of the building's facade, the choice of architecture. Usually, companies specializing in the sale of materials for construction, offer services for the creation of house designs, so you can turn to them for help. You can also find a suitable plan on the Internet, but this is not always the best option.
• Creating a working version of the project. Designers take into account all your wishes and draw a diagram of all necessary for the construction of products. A working project can be performed for free. But this will happen only in the event that you sign a contract with the firm on a contract for construction. In the case where you want to prepare all the necessary documentation, rather than a full-fledged construction, the service will cost about 400 rubles / m ² (in Moscow).
• Preparation of parts for timber house kits. This is one of the most difficult and requiring special attention stages of building houses on the technology of "double beams". Reviews builders say that the production of a house with a total area of more than 100 m2 ^on average takes 1 month, not taking into account the complexity of its architecture.
• Construction of the structure. This is the final stage at which the assembly of the product takes place. No nails or glue are used on it, but only "adjust" all the nodes and connections. Lock joints provide high strength and durability of the structure.

Cost

The houses built using the "double timber" technology are more expensive than log houses made of solid wood. The average price of 1 m ^{2 of} insulated wall will cost 5 500 rubles. The cost of a solid timber thickness of 150 mm will cost cheaper - 3,500 rubles. But it is important to understand that a bar of thickness of even 20 cm requires warming.

The technology of double insulated wall provides a ready design that does not need additional work and, therefore, costs.

For comparison, we will compile a simplified estimate on a wall from a profiled beam. As already noted, the average cost of a "bare" wall 15 cm thick is 3,500 rubles / m ² . Insulation, for example, 20 cm ekovata, costs 800 rubles / m ² . The work on the installation of the frame, as well as the lining of the lining - an additional 600 rubles / m ² . That is, additional work on the insulation of the frame from the timber will cost approximately 1 400 / m ² . As a result, 4 900 rubles / m ² - the price, which will have to lay out on the m ^{2 of} the house from a double beam. Reviews at the same time convince us that a relatively small difference in price is not so significant, since the technology has a large number of advantages.