Any house made of profiled timber as a construction project is very specific in terms of insulation and decoration. In order to choose the right materials, combine them and ensure reliable fastening of the facade pie, let’s consider the features of the insulation of wooden houses.
As you know, houses from a bar are characterized by the most severe shrinkage, which negatively affects the outer shell of the house. Due to the fact that wood has low thermal conductivity, house insulation can be postponed for a year or two. During this time, the peak of shrinkage will pass, and residents will be able to determine the required thickness of insulation in the most reliable way – experimentally.
Heat loss of a house from a bar
Although wood itself is a heat insulator, it is a misconception that thick wood walls alone will be enough to keep the heat inside. Modern building practice has shown that the best results can be achieved only by combining layers of thermal insulation.
In wooden houses, this is easier to do, since a wall made of timber is a fairly uniform layer and, in addition to its load-bearing function, partially prevents heat leakage. The profiled timber, due to the grooves, excludes the blowing of the walls and lengthens the cold bridges, it remains only to improve the heat-saving characteristics.
First, you need to get the initial data on heat loss, for which a thermal calculation is performed at home and scanned in the infrared spectrum. This information will help you choose the right thickness of additional insulation to reduce heat loss to the power level of the heating system.
In accordance with SNiP 23-02-2003, the coefficient of resistivity to heat transfer of the walls of residential buildings is in the range 4.2-4.9, for which the thickness of a dry wooden wall should be 40-50 cm. This is quite costly, besides, homogeneous wood does not perceive the temperature difference well and humidity from different sides. Therefore, the bearing layer of the wall is made thinner, for example, from a bar of 150×150 mm, and the insulation is carried out in a separate layer.
As wood is replaced by a material that is less thermally conductive, the thickness of the latter decreases in accordance with the difference in thermal conductivity. For example, to insulate a wall made of a profiled timber 150×150 mm, a 100 mm layer of extruded PPS or 120 mm of glass wool will be enough, which will also protect the tree from weathering.
Insulation layer device
A number of special requirements are imposed on the insulation of a log house. It must correspond to the operating environment, have an appropriate density and an optimal fastening method. In addition, the characteristics of the tree change with changes in temperature and humidity, so they need to be softened and stabilized, at the same time eliminating moisture migration.
To save internal space, the insulating layer is taken out, which also gives direct contact of the inhabited premises with the natural material of the walls. But this way the thickness of the insulation layer increases, and it can only be fixed inside the supporting system, because the thermal insulation of the house from the timber will be followed by the finishing of the facades, and these materials have an impressive dead weight.
If the outer walls will experience increased operational loads, some of them must be compensated by the insulation itself. A thin layer of EPS or polyurethane foam will cope well with this task, if you cover it with a hard shell (OSB, plywood, the facade itself), which has a through fastening to the bearing layer.
Glass wool and mineral wool at the same density are looser, therefore they are placed in the cavities of the cellular frame. To do this, horizontal beams of 50×50 mm are punched along the outer walls of the building and insulation is inserted between them. The next layer of lathing is fixed perpendicular to the previous one, achieving high strength and a minimum cross-section of cold bridges. When a new layer is added, the thickness of the insulation increases by 50 mm, while the outer surface remains strong enough for attaching the facade cladding.
Dew point question
When assembling the curtain wall cake, construction engineers often face the risk of condensation forming at the contact points of materials with different thermal conductivity. If the tree and adjacent mineral wool get wet, this will lead to the development of microorganisms and significantly reduce the service life.
During the construction of wooden houses, this phenomenon is rarely avoided, the increased humidity at the border of high and low temperatures almost always remains hidden from the eyes of the developer. Since it is guaranteed that condensation cannot be eliminated, the point of its formation is taken out into a layer that is practically insensitive to moisture oversaturation..
From the outside, the timber wall is covered with polyurethane plates with a thickness of 25 to 40 mm. During installation, the slabs are temporarily glued with polyurethane foam, then fixed with umbrellas and thoroughly foamed all joints. On the outside, the polyurethane layer is covered with a vapor barrier membrane with a capacity of not more than 1000 g / m2/ day Next, the first row of the crate is fastened and the insulation pie is installed.
To prevent moisture from retaining in the main insulation, a ventilation gap of 15–20 mm is left between it and the facade cladding for free air circulation and drying the mineral wool. The blowing of the insulation and the removal of its particles is eliminated due to windproof membranes placed between the rows of the crate or only on the outer side of the heat-insulating layer.
Choosing a facade system
Violation of the aesthetics of the facade is often mentioned as one of the arguments against the insulation of a house from natural timber. But we have already figured out that insulation is not a whim, but a necessary technological component of a comfortable and durable home. Therefore, it remains to return the building to an attractive appearance, for which there are several options.
The most interesting will be the facade systems that imitate the look of natural wood. To do this, you can use almost any siding with a wood texture, sheathe the house with overlapping edged boards or use wooden lining. Almost all modern facade systems are hinged and require a solid and reliable foundation.
The cross-batten system has sufficient strength, but the distance between the beams is chosen exclusively according to the size of the mats or insulation plates in order to exclude their trimming, that is, from 50 to 100 cm.This is too much for a confident and reliable fastening of the cladding, therefore, guides are nailed over the frame from the beams racks with a step of 40-60 cm and the facade is already attached to them.
Depending on the number of layers of insulation, the direction of the beams in the last row can be horizontal or vertical. Since the battening of the façade system also forms a convection gap, its guides should be vertical and not obstruct the air flow. In some cases, for this it is necessary to create two rows of battens in opposite directions. Well, for fastening thin and flexible materials, such as wooden lining, it is imperative to install a plywood substrate to prevent the cladding from being pushed through.