Aerated concrete is a durable and lightweight material that has been used everywhere in construction for more than a decade. Its main advantages are high thermal insulation rates. So, a wall with a thickness of 30 cm. by this indicator corresponds to a brick wall 60 cm wide. Despite these characteristics, thermal insulation of a house from aerated concrete is a common practice.
When is it necessary to carry out such work and what materials are used for this?
There is no urgent need to insulate houses from aerated concrete, especially when it comes to heat-efficient brands of building material. This is due to the cellular structure of the building material, consisting of sand, cement, lime, water and aluminum powder. The components are mixed and placed in an autoclave. There they are foamed due to the corrosion of the aluminum powder. The reaction proceeds with the release of oxygen, which forms porosity in the concrete.
But still most often in the harsh conditions of the Russian climate without such finishing is indispensable. The factors that make the work necessary include:
Living in regions with a harsh climate is also a condition for insulating walls made of aerated concrete. An additional layer of thermal insulation will help to reduce the thickness of the walls and the load on the foundation, and will reduce the cost of building the building.
Several materials are used to insulate a house made of aerated concrete.
Each of them has its own advantages and disadvantages. The insulation technology is also different.
A house is most often insulated when it has served for some time, and it turned out that it has thermal conductivity higher than expected. But often such work is carried out at the construction stage.
Then they do not immediately insulate. First, they completely line up the entire box. Then they wait from 2 to 5 months for the walls to dry out and to remove excess moisture from the blocks.
Insulation of buildings is carried out inside and outside.
Positive aspects of insulation:
The benefit of such insulation is that the dew point moves outward. As a result, the effect of "cold bridges" is minimized. They usually occur at floor slabs, lintels, armature belts. Thermal insulation on the inside of the wall prevents condensation.
When insulating a house, the main thing is to correctly calculate the thickness of the insulation.
This can be done using special calculators, which contain all the necessary parameters, including the region of residence.
Wall insulation from the inside is less important and often even harmful to structural elements. Usually the work is to level the walls. Plasterboard sheets are often used for this. Internal insulation is inconvenient, since the area of the room is lost due to the installation of an insulating structure.
This method of thermal insulation is allowed in the following cases:
Therefore, external insulation is still preferred.
Mineral cotton wool is one of the most famous and popular heaters. It can be of several types:
Mineral wool is resistant to heat and chemical attack.
The thermal conductivity of the material is about 0.035 W / m * ° C . This indicator depends mainly on the density of the material. Over time, its ability to conserve heat decreases due to moisture penetration.
Advantages of mineral wool insulation:
Of the shortcomings, experts note hygroscopicity, or the ability to absorb moisture. So, when humidified by 2% , 10% of thermal insulation characteristics are lost.
Important! When insulating buildings with mineral wool, acrylic plasters should not be used. This will provoke condensation.
When choosing cotton wool, pay attention to rigidity.
The higher this indicator, the better the leaf keeps its shape. Another important factor is the geometry and direction of the fibers. It is preferable to choose materials with a random fiber direction.
The disadvantage of mineral wool is that the cost of insulation will cost about a third more than when using foam and penoplex. In addition, the layer of insulation will be large.
The builders also point out that the danger of this material to health is not excluded. The insulation contains formaldehyde. This substance is harmful to the body and is considered a carcinogen.
Therefore, when working with mineral wool, it is necessary to wear a respirator that will protect the respiratory system from the smallest dust particles entering the body. But with proper handling of the heat insulator, there will be no harm to health.
Rodents can settle in the layers of insulation. Then the insulating properties of the finish will quickly become unusable. To protect the structure from pests, a metal cornice is installed at the bottom of the crate, in the basement of the building. This is recommended when using other materials.
Step-by-step instructions for mineral wool insulation:
The wall is cleaned of dirt, the seams are rubbed with cement, the surface is leveled. If the damage is significant, plaster is used. Otherwise, the insulation will not fit tightly, which will increase heat loss.
Step 2. Install a metal shim at the bottom along the perimeter building.
Wooden beams are fixed on the wall. The distance between them should be 1-2 centimeters less than the width of the cotton wool sheet. The sheets should fit fairly tightly.
Step 3. Attach the rock wool to the wall on glue-foam or glue dowel-umbrellas.
Plates are placed between the beams, shifting them in relation to the bottom row, to get a "checkerboard" pattern.
Step 4. Cover the insulation with a vapor barrier film, which fastened to staples, again covered with glue solution.
Step 5. The corners are reinforced with perforated corners.
Upon completion of the installation work with mineral wool, a ventilated facade is installed.
Mineral wool is usually used only for ventilated facades. The insulation does not have sufficient rigidity to be used under plaster.
When insulating the outer walls of the house with mineral wool, vapor barrier films must be used. The coating shields moisture and condensation.
At the same time, air penetrates through it, so the walls "breathe".
The attitude to expanded polystyrene as an insulating agent for aerated concrete walls is ambiguous among builders.
On the one hand, it is a popular heat-insulating material in Russia, which is 98% formed from air. In Europe, more than 60% of the polystyrene produced is used for thermal insulation of various buildings.
The following advantages of insulation are distinguished:
The disadvantages of expanded polystyrene include interaction with certain chemical substances - organic solvents, alcohols, oil products. The panel may dissolve on contact with these products. In addition, expanded polystyrene is subject to combustion.
Table 1. Thermal insulation properties of expanded polystyrene (PSB-S) 12 cm thick in comparison with building materials:
|Material name||Wall thickness, cm|
|Expanded clay concrete||90|
On the other hand, the material has opponents who do not recommend its use on aerated concrete houses.
They substantiate their opinion by the fact that expanded polystyrene has a low level of vapor permeability.
Experts note the following. The building codes indicate that when designing multilayer insulation, the layers must be positioned so that warmer and more vapor-permeable materials are outside, and cold and deaf ones are inside. Otherwise, the outer layer of aerated concrete will not have time to dry out over the summer. As a result, moisture gradually accumulates in it, as a result of which the bearing capacity of the wall is gradually lost.
Accordingly, the thermal conductivity of the material also increases. Gradually, the dew point moves inward, and probably to the inner wall. Condensation, fungus, etc. will appear on its surface.
The listed problems do not arise immediately after insulation, but after a few years.
For this reason, the use of expanded polystyrene is recommended only in exceptional cases. Opponents of this building material believe that rock wool is a more suitable material.
In view of the listed disadvantages, when insulating a house with foam, it is especially important to correctly calculate the thickness of the insulating layer. You also need to take care of normal ventilation of the premises.
Before the walls are insulated with foam plastic, the surface is prepared, as when working with mineral wool.
Then the surface of the blocks is treated with antiseptic solutions to prevent the formation of mold and mildew. After drying, cover the facade with a primer.
Installation begins from the bottom, and is performed in this order:
Walls in the room itself are insulated in the same order as and outside.
The dowels used for fixing the panels must be made of plastic and not contain metal parts.
During operation, metal is capable of creating additional "cold bridges". Each sheet will require at least 5 dowels.
When laying, pay attention to the connection of the slabs at the corners of the building. So, in one row the panel protrudes, and the opposite one rests against it, in the other - on the contrary.
Adhesives for working with expanded polystyrene should not include ingredients that can damage the structure of expanded polystyrene - they were mentioned above. For fastening use:
Work should be carried out in dry weather at an air temperature of 7 ° C.
For internal work, take the appropriate products, which are usually cheaper.
Penoplex is extruded polystyrene foam.
The material successfully competes with mineral wool and foam. It is as light as polystyrene, but denser, and is capable of storing heat as well as mineral wool.
Insulation has the following characteristics:
Among the shortcomings, builders note its low ability to adhesion. Since it has a high density, it does not react well with adhesives.
For this reason, the material is often used inside buildings, even when using fasteners. Since the slabs are thin (5-30 mm), the loss of living space (sometimes already small) with such insulation is insignificant.
For the installation of foam boards it is better to use FastFix type glue-foams. You will also need:
Deep penetration primer
Important! For external work, take plates with a thickness of 50 mm or more.
But builders recommend laying the slabs in 2 layers, which will give 100 mm of foam.
Thermal insulation of the facade is carried out as follows:
For decorative coating, you first need to make the surface of the slabs rough ... To do this, use a grater or sandpaper.
Then the facade is treated with an adhesion-promoting primer, also in two layers. The gaps between the slabs are filled with foam that was used for the walls. The outer corners of the house and the slopes are formed with perforated corners. The surface is reinforced with a mesh. Then decorative trim is done.
Another way to insulate facades is by spraying polyurethane foam. For aerated concrete blocks, it is recommended to use rigid polyurethane foam with closed cells.
The main advantage is that when spraying, there are no gaps between the wall and the insulation, therefore, no cold bridges are formed, no condensate settles. After application of the product, a seamless coating forms, which improves the quality of the thermal insulation coating.
Economically, this method is less profitable, since the cost of thermal insulation increases at least 1.
2 times in comparison with other materials. But at the same time, it is easier to work with, since no fasteners are required. The service life of such a heater is about 30 years.
The most popular method of spraying. Although sheets with tongue-and-groove locks and thermal panels with tiles are also used for insulation.
Polyurethane is obtained by mixing polyol and polyisocyanate in special installations. If spraying on the facade is planned, then the components are mixed in the spray chamber. Foaming takes only 10-60 seconds.
Each of the listed materials has its own advantages and disadvantages. Therefore, before using this or that material, it is necessary to conduct careful calculations, to study the characteristics of the materials. After all, making rash decisions will shorten the life of the building and lead to additional energy costs.
Posted By: Work Style |06, Nov 2020
Posted By: Work Style |12, Nov 2020
Posted By: Work Style |04, Nov 2020
Posted By: Work Style |05, Nov 2020
Posted By: Work Style |05, Nov 2020