Insulation between the block and the brick is needed. Insulation for brick walls: choosing, evaluating, installing. Multi-layer walls also have disadvantages.

Three-layer wall structure with brick cladding

V low-rise construction The design of an external three-layer wall is very popular: load-bearing wall - insulation-brick lining (120 mm), Fig. 1... Such a wall allows you to use effective for each layer materials.

Bearing wall made of bricks or concrete blocks, is power frame building.

Insulation layer... mounted on the wall, provides required level thermal insulation outer wall.

Wall cladding from facing brick protects the insulation from external influences and serves decorative coating walls.

Fig. 1. Three-layer wall.
1 - interior decoration; 2 - load-bearing wall; 3 - thermal insulation; 4 - ventilated gap; 5 - brick cladding; 6 - flexible connections

Multi-layer walls also have disadvantages:

limited durability of the insulation material in comparison with the material of the load-bearing wall and cladding;
the release of hazardous and harmful substances from the insulation, albeit within the permissible limits;
the need to use special measures to protect the wall from blowing and moisture - vapor-tight, windproof coverings and ventilated gaps;
flammability of polymer insulation;

Load-bearing wall in three-layer masonry

Insulation of the walls of the house with mineral wool slabs

Mineral wool slabs are fixed on the load-bearing wall with a ventilated air gap between the surface of the slabs and the brick cladding, or without a gap, Fig. 1.

The calculations of the humidity regime of the walls show that in three-layer walls condensation in the insulation falls in the cold season in almost all climatic zones of Russia.

The amount of condensate that falls out is different, but for most regions it fits into the norms established by SNiP 23-02-2003 " Thermal protection buildings ". Condensation does not accumulate in the wall structure during the year-round cycle due to drying in the warm season, which is also a requirement of the indicated SNiP.

As an example, the figures show graphs of the amount of condensate in the insulation based on the results of calculations for different options cladding of three-layer walls of a residential building in St. Petersburg.

Rice. 2. The result of calculating the humidity regime of the wall with mineral wool insulation as a middle layer (expanded clay concrete - 250 mm, insulation -100 mm, brick -120 mm). Facing - ceramic brick without ventilation gap.

Rice. 3. The result of calculating the moisture regime of a wall with mineral wool insulation with a plaster coating (expanded clay concrete - 250 mm, insulation - 120 mm, plaster coating -10 mm). Cladding - vapor permeable.

Rice. 4. The result of calculating the moisture regime of a wall insulated with mineral wool slabs with a ventilated gap and a "siding" -type coating (brick - 380 mm, insulation -120 mm, siding). Cladding - ventilated facade.

The graphs clearly show how the cladding barrier, which prevents ventilation of the outer surface of the mineral wool insulation, leads to an increase in the amount of condensate in the insulation. Although in the annual cycle, moisture does not accumulate in the insulation, but when facing with a brick without a ventilation gap, a significant amount of water condenses and freezes in the insulation annually in winter, Fig. 2... Moisture also accumulates in the layer of brick cladding adjacent to the insulation

Moistening the insulation reduces its heat-shielding properties, which increases heating costs building.

In addition, water annually, when freezing, destroys the insulation and the brickwork of the cladding. Moreover, the cycles of freezing and defrosting during the season can occur repeatedly. The insulation gradually crumbles, and the brickwork of the cladding collapses. I note that the frost resistance of ceramic bricks is only 50 - 75 cycles, and the frost resistance of the insulation is not standardized.

Replacing insulation, covered with brick cladding, is an expensive pleasure. More durable in these conditions are hydrophobized high-density mineral wool boards. But these plates also have a higher cost.

The amount of condensation is reduced or no condensation at all if you provide better ventilation of the insulation surface - fig. 3 and 4.

Another way to eliminate condensation is to increase the resistance to vapor permeation of the load-bearing wall. For this, the surface of the load-bearing wall is covered with a vapor barrier film or thermal insulation boards with vapor barrier applied to their surface are used. When mounted on a wall, the surface of the slabs covered with a vapor barrier must face the wall.

The device of a ventilated gap, sealing walls with vapor-tight coatings complicates and increases the cost of the wall structure. What does the moistening of the insulation in the walls in winter lead to is written above. So choose. For construction areas with harsh winter conditions, a ventilated gap can be economically justified.

In walls with a ventilated gap, mineral wool slabs with a density of at least 30-45 are used kg / m 3, glued on one side with a windproof coating. When using slabs without wind protection on the outer surface of the thermal insulation, windproof coverings should be provided, for example, vapor-permeable membranes, fiberglass, etc.

In walls without a ventilated gap, it is recommended to use mineral wool boards with a density of 35-75 kg / m 3... In a wall structure without a ventilated gap, thermal insulation boards are installed freely in a vertical position in the space between the main wall and the facing brick layer. The fasteners provided for fastening the brick cladding to the load-bearing wall - reinforcing mesh, flexible ties - serve as supporting elements for the insulation.

In a wall with a ventilation gap, insulation and a windproof covering are attached to the wall using special dowels at the rate of 8-12 dowels per 1 m 2 surface. The dowels must be buried in the thickness concrete walls at 35-50 mm, brick - by 50 mm, in the masonry of hollow bricks and lightweight concrete blocks - by 90 mm.

Wall insulation with expanded polystyrene or foam

Rigid foam boards are placed in the middle of a three-layer brick wall structure without a ventilated gap.

Polymer boards have a very high vapor permeability resistance. For example, a layer of wall insulation made of expanded polystyrene (EPS) plates has a resistance 15-20 times greater than that of a brick wall of the same thickness.

Insulation, when sealed, is a vapor barrier in a brick wall. Steam from the room simply does not get onto the outer surface of the insulation.

With the correct thickness of the insulation, the temperature of the inner surface of the insulation should be above the dew point. When this condition is met, steam condensation on the inner surface of the insulation does not occur.

Mineral insulation - low density cellular concrete

V Lately Another type of insulation is gaining popularity - products made of low-density aerated concrete. These are heat-insulating plates based on materials already known and used in construction - autoclaved aerated concrete, gas silicate.

Thermal insulation boards made of aerated concrete have a density of 100 - 200 kg / m 3 and the coefficient of thermal conductivity in a dry state 0.045 - 0.06 W / m about K... Mineral wool and expanded polystyrene insulation have approximately the same thermal conductivity. Slabs are produced with a thickness of 60 - 200 mm... Compressive strength class B1.0 (compressive strength not less than 10 kg / m 3.) Vapor permeability coefficient 0.28 mg / (m * year * Pa).

Aerated concrete thermal insulation boards are a good alternative to insulation made of mineral wool and expanded polystyrene.

Well-known trade marks on the construction market thermal insulation boards from cellular concrete: "Multipor", "AEROC Energy", "Betol".

Advantages of aerated concrete thermal insulation slabs:

The most important is higher durability. The material does not contain any organic matter - it is fake diamond... Has a fairly high vapor permeability, but less than mineral wool insulation.

Material structure contains a large number of open pores. The moisture that condenses in the insulation in winter dries quickly in the warm season. No moisture build-up occurs.

Thermal insulation does not burn, under the influence of fire it does not emit harmful gases. The insulation does not cake. Insulation plates are harder and mechanically more durable.

The cost of facade insulation with cellular concrete slabs, in any case, does not exceed the cost of thermal insulation with mineral wool insulation or expanded polystyrene.

When installing thermal insulation plates made of aerated concrete, the following rules are followed:

Thermal insulating slabs made of aerated concrete up to 100 mm fastened to the facade with glue and dowels, 1-2 dowels per slab.

From plates with a thickness of more than 100 mm a wall is laid out close to the wall to be insulated. The laying is carried out on glue with a seam thickness of 2-3 mm... WITH load-bearing wall masonry made of insulation plates is connected with anchors - flexible ties at the rate of five ties per 1 m 2 walls. A technological gap of 2-15 can be left between the load-bearing wall and the insulation. mm.

It is better to tie all layers of the wall and brick cladding with a masonry mesh. This will increase mechanical strength walls.

Wall insulation with foam glass

Three-layer wall of the house with foam glass insulation and brick cladding.

Another type of mineral insulation that has appeared on the construction market relatively recently is foam glass plates.

Unlike heat-insulating aerated concrete, foam glass has closed pores. Due to this, foam glass slabs poorly absorb water and have low vapor permeability. A ventilated gap between the insulation and the cladding is not required.

The foam glass insulation is durable, does not burn, is not afraid of moisture, is not damaged by rodents. Has a higher cost than all of the above types of insulation.

Installation of foam glass plates on the wall is carried out using glue and dowels.

The thickness of the insulation is chosen in two stages:

They are chosen based on the need to provide the required resistance to heat transfer of the outer wall.
Then a check is made for the absence of steam condensation in the thickness of the wall. If the check shows otherwise, then it is necessary to increase the thickness of the insulation. The thicker the insulation, the less the risk of steam condensation and moisture accumulation in the wall material. But, this leads to an increase in construction costs.

An especially large difference in the thickness of the insulation, selected according to the above two conditions, occurs when insulating walls with high vapor permeability and low thermal conductivity. To ensure energy saving, the thickness of the insulation is relatively small for such walls, and to avoid condensation, the thickness of the slabs must be unreasonably large.

When insulating aerated concrete walls (as well as from other materials with low resistance to vapor permeation and high resistance to heat transfer - for example, wooden, from coarse claydite concrete), the thickness of polymer thermal insulation, according to the calculation of moisture accumulation, turns out to be much greater than it is necessary according to the standards for energy saving.

To reduce the steam intake, it is recommended to arrange vapor barrier layer on the inner surface of the wall(from the side warm room), Rice. 6. For the device of a vapor barrier from the inside, materials with a high resistance to vapor permeation are chosen for finishing - a deep penetration primer is applied to the wall in several layers, cement plaster, vinyl wallpapers.

A vapor barrier device from the inside is mandatory for walls made of aerated concrete, gas silicate for any type of insulation and facade cladding.

It should be borne in mind that the masonry of the walls of a new house always contains a large amount of construction moisture. Therefore, it is better to allow the walls of the house to dry well outside. It is recommended to carry out work on the insulation of the facade after the interior decoration is completed, and not earlier than a year after the end of this work.

Facing the exterior walls of the house with bricks

The facing of the exterior walls of the house with bricks is durable and, when using a special colored facing facing brick and even better clinker brick... quite decorative. The disadvantages of cladding include the relatively large weight of the cladding, the high cost of special bricks, and the need to broaden the foundation.

It should be especially noted the complexity and high cost of dismantling the cladding to replace the insulation. The service life of mineral wool and polymer insulation does not exceed 30 - 50 years. At the end of its service life, the heat-saving properties of the wall are reduced by more than a third.

With brick cladding, use the most durable insulation, providing them with the conditions in the wall structure for the longest possible operation without replacing ( minimal amount condensation in the wall). It is recommended to choose high-density mineral wool insulation and polymer from extruded polystyrene foam, EPS.

In the walls with brick cladding, in It is most advantageous to use mineral insulation made of autoclaved aerated concrete or foam glass, with rock service which is much more than mineral wool and polymer.

Brick cladding is laid in half a brick, 120 mm. on ordinary masonry mortar.

A wall without a ventilated gap, insulated with slabs with high density(mineral wool - more than 50 kg / m 3, EPS), you can veneer with brickwork on the edge - 60 mm. This will reduce the overall thickness of the outer wall and base / plinth.

The masonry of the brick cladding is bonded to the masonry of the load-bearing wall with steel wire or reinforcing mesh, protected from corrosion, or special flexible connections (fiberglass, etc.). The grid or ties are placed vertically with a step of 500-600 mm.(height of the insulation plate), horizontally - 500 mm., while the number of bonds per 1 m 2 blank walls - at least 4 PC. At the corners of the building along the perimeter of the window and doorways 6-8 PC. by 1 m 2.

The masonry of the brick cladding is reinforced longitudinally with a masonry mesh with a vertical step of no more than 1000-1200 mm. The masonry mesh should fit into the masonry seams of the load-bearing wall.

For ventilation of the air gap in the lower row of the facing masonry, special air vents are arranged at the rate of 75 cm 2 for every 20 m 2 wall surface. For the bottom air vents, a slotted brick can be used, placed on the edge so that the outside air through the holes in the brick can penetrate into the air gap in the wall. The upper air vents are provided in the eaves of the wall.

Vents can also be made by partial filling cement mortar vertical joints between the bricks of the lower row of masonry.

Placing a window and a door in the thickness of a three-layer wall should ensure minimal heat loss through the wall at the installation site.

In a three-layer wall, insulated from the outside, a window or door frame installed in the same plane with a layer of insulation at the border of the heat-insulating layer- as it shown on the picture.

This arrangement of the window, door along the wall thickness will ensure minimal heat loss at the junction.

Watch the video tutorial on the topic: how to properly lay a three-layer wall of a house with brick cladding.

When facing walls with bricks, it is important to ensure the durability of the insulation layer. Longest term services will provide thermal insulation with slabs of aerated concrete of low density or foam glass.

It is also important to reduce the amount of moisture in the outer walls in winter period... The less moisture condenses in the insulation and cladding, the longer their service life and the higher their heat-shielding properties. To do this, it is necessary to take measures to reduce the vapor permeability of the bearing wall, and for vapor-permeable insulation it is recommended to arrange a ventilated gap on the border with the cladding.

To insulate a three-layer wall with mineral wool, it is better to use slabs with a density of at least 75 kg / m 3 with ventilated gap.

A wall insulated with mineral wool with a ventilated gap dries faster from construction moisture and does not accumulate moisture during operation. The insulation does not burn.

Hello!

When answering the question, I will use the information provided by you in the posts below, and in your question.

What is the thickness of the insulation needed. The calculation shows that to ensure resistance to heat transfer R = 2.4, the thickness of the foam is -25 mm. For R = 2.2, thickness 13 mm. If the obtained values of the thicknesses are rounded to those that are on the market, then these are, respectively, 30mm and 20mm of foam. You can take both regular foam and extruded polystyrene foam (EPS). In terms of durability (in such a design), no difference was noticed in practice. EPPS - it is better to take 35 kg / m3, the thicknesses for it are the same as for the foam. Polyfoam must be taken with a density of at least 25 kg / m3. The thickness of the foam (or EPS) obtained by calculation, 30mm and 20mm, is quite inconvenient when carrying out the work itself. Usually, external insulation (followed by plastering) is carried out when the thickness of the insulation is from 50mm and above. The fact is that a sheet of foam (and EPS), 30mm thick, and even more so 20mm, is quite fragile. But it needs not only to be glued to the wall, but also to be nailed with dowels (6 pieces per sheet).
As for the glue. A prerequisite is that there is a special glue for gluing polystyrene foam (or extruded polystyrene foam). Considering that all the same the glue is "duplicated" with dowels, then, in principle, it does not matter which company the glue is.
To strengthen the corners, there are special plastic corners with a reinforcing mesh.
As for the thermal seams. Here the situation is as follows: both polystyrene and EPS is with an even edge, and "with a quarter". That is, the sheets adjoin each other or evenly, or overlap one another. As far as I know, in thicknesses of 20 and 30 mm, only a flat edge is produced. When using insulation "with a quarter", the seams are cut by the installers themselves with a certain step of 2-3 m. When using insulation with a smooth edge, its joints are thermal seams, they do not need to be specially made.
On warm plaster, I recommend the article, it describes what you are asking about. As a conclusion, I can say that the insulation warm plaster more expensive than conventional insulation.

Conclusion for your home as a whole. Considering that you will insulate attic floor(through which there were the most significant heat losses), and the fact that the thickness of the missing wall insulation is only 20-30mm, then we can advise the following. Insulate the attic this year, and see how much more comfortable it will become during this summer and winter. If normal, then the walls, in principle, may not be touched. If it continues to be cold in winter (or hot in summer), then arrange facade work, and it is possible to take the thickness of the foam plastic 40mm, so that it is more convenient to mount it.

September 5, 2016
Specialization: facade decoration, interior decoration, construction of summer cottages, garages. The experience of an amateur gardener and gardener. He also has experience in repairing cars and motorcycles. Hobbies: playing guitar and much more, for which there is not enough time :)

Brick wall cladding is a reliable and durable facade finish that can transform appearance Houses. However, the brick itself does not insulate the walls very much, so if you want your home to become warm and energy-efficient, you need to place a heater between the main and facing walls. In this article, I will tell you in detail how to insulate the walls of a house under brick cladding.

Thermal insulation and wall cladding technology

The technique of cladding with a brick with insulation is quite complicated and includes several main stages:

Below we will get acquainted with the main nuances of work at each of these stages.

Selection and preparation of materials

Before starting work on wall insulation and its further decoration, it is necessary to decide on the type of insulation. Currently, there are quite a few heat-insulating materials, however, for the sounded purposes, the following heat insulators are most often used:

mineral mats are an environmentally friendly and durable material that is absolutely fireproof. The disadvantage of mats is high level moisture absorption and relatively high cost. In addition, keep in mind that the fibers of mineral mats getting on the skin, mucous membranes or in the respiratory tract cause irritation, therefore, when working with this material, you must use personal protective equipment;

expanded polystyrene is a lightweight material that has a much lower level of moisture absorption than mineral wool and at the same time is cheaper. However, keep in mind that expanded polystyrene is less durable, moreover, it supports the combustion process and is toxic in the event of a fire;
extruded polystyrene foam - is a type of ordinary foam, but it is more durable and durable, as well as zero level moisture absorption, therefore, in terms of performance, it is also excellent for a wall under facing brick... The disadvantage, in addition to toxicity and fire hazard, is the high cost.

The thickness of insulation for walls made of bricks or other materials depends on the climate in your area. If the temperature in winter often drops below 25 degrees Celsius, a 150 mm thick insulation should be used. If you live in a warmer climate, a 100 mm thick insulation is sufficient.

As you can see, all materials have their own advantages and disadvantages. Therefore, everyone must decide for themselves which better insulation use.

In addition to insulation, other materials must be prepared. You will need:

antiseptic primer for wall treatment (if the walls are wooden, you will need protective impregnation for wood;
vapor barrier film;
dowel umbrellas;
flexible ties (anchors that allow not only to fix the insulation, but also to tie load-bearing wall with facing);

Wall preparation

The next step is to prepare the walls. To do this, you need to do the following with your own hands:

start by removing all existing attachments. These can be antennas, all kinds of visors, ebb tides, window sills and other details that will interfere with the insulation and the facade;
if the facade has peeling and crumbling areas, they must be removed... To do this, you can use a chisel and a blade;
if the house is wooden, log or squared, it is necessary to insulate the slots between the joints. To do this, you can use tow, polyurethane foam, latex sealant or other suitable thermal insulation;
after that, the walls must be treated with a protective deep-penetrating compound or impregnation for wood. Instructions for the use of the formulations are always on the packaging.

If the house is recently built, you can start to insulate and clad it after completion interior decoration, i.e. after the walls are dry. Otherwise, the wall material will absorb moisture, which will lead to a series negative consequences, such as wetting of insulation, the appearance of mold, etc.

This completes the preparation of the facade.

The diagram shows the construction of a brick wall with insulation

Wall insulation

The next step is the installation of insulation. I must say that the insulation is often mounted on flexible connections during the construction of the facing wall. However, it is more convenient to first "grab" the plates with dowels, then erect the wall and install flexible connections.

Regardless of what type of insulation you will use for thermal insulation of walls, the instructions for its installation look like this:

first of all, you need to waterproof the blind area. To do this, you can miss it. bituminous mastic and then glue the roofing material to it. The latter should overlap about 10 cm, and the joints should also be smeared with bitumen mastic.
I must say that instead of roofing material, you can use other roll waterproofing materials however, roofing felt is the most budgetary solution;
now you need to fix the insulation on the wall. To do this, you should use special dowels, which are popularly called umbrellas or fungi. Installation of insulation should be started from the corner, and performed in rows.

During the installation process, make sure that there are no gaps between the insulation plates, as well as between the insulation and the waterproofed blind area.

To fix the thermal insulation, simply press it against the wall and drill holes for the dowels through the slabs. After that, insert the umbrellas into the holes and drive the expansion nails into them.

To begin with, in order to simply "grab" the thermal insulation, a pair of dowels for one plate is enough;

now fix on the insulation vapor barrier membrane overlapping it. For fastening the film, also use the dowels and umbrellas.
If you will be facing the walls with facing bricks, then the vapor barrier can be omitted, since this material has an almost zero moisture absorption coefficient.

People are often interested in forums - is a heater needed between gas silicate and brick? Despite the fact that gas silicate itself has a low coefficient of thermal conductivity, additional insulation will make housing even more comfortable and energy-saving.

It should be noted that according to this scheme, the installation of insulation is carried out only on monolithic, brick and wooden walls... If the walls are made of aerated concrete, the work is carried out a little differently:

first of all, you need to mark the location of flexible ties, taking into account the fact that they should be laid in horizontal joints between bricks. Therefore, count the height of the brick from the foundation.
Anchors should be located in increments of about 50 centimeters, both vertically and horizontally;
now you need to drill holes in the diameter and length of the tips (sleeves) of flexible ties;

after that it is necessary to screw the tips of the anchors into the holes using a special wrench. In this case, the liners must be completely immersed in aerated concrete;
further, insulation should be pinned onto the protruding flexible connections. Install it so that there are no gaps between the plates;
after that, on top of the insulation, fix the vapor barrier membrane, which is also pricked onto the anchor;
at the end of the work, fix the insulation and vapor barrier film clamps, which are put on the anchors and snap into place, thus pressing the steam and thermal insulation against the wall.

Vapor barrier in aerated concrete house it is necessary to install not only between the block and the brick, but also from the inside, i.e. from the side of the room.

After installing the insulation, you can start laying bricks.

The nuances of masonry facing wall

First of all, I note that facing wall has a fairly large weight, so it must be erected on a foundation... If the foundation of the house was not originally designed for the construction of a facing wall, an additional shallow strip foundation must be made around the perimeter of the house.

On our portal you can find detailed information on how it is done. The only thing, keep in mind that there should be a space of several centimeters between the insulation and the facing wall.

Before laying bricks, it is necessary to waterproof the foundation. To do this, lay several layers of roofing material on top of it. Further work is carried out in the following sequence:

work begins with laying the first row. In this case, beacons and building level, providing an even arrangement of the row;
if flexible connections were not installed in advance, a hole is drilled in the wall above the first row of bricks to the required depth and an anchor is driven into it. After that, a limiter is put on the anchor, which additionally holds the thermal insulation;

the end of the flexible connection is laid between the bricks to a depth of about 10 cm... To do this, a solution is placed directly on it;
in the second row, airflows are performed. To do this, leave a vertical seam unfilled with mortar every two bricks;

according to this principle, the entire facing wall is erected, taking into account the fact that flexible ties should be located with a step of 50 cm vertically and horizontally. In addition, they are installed along the perimeter of window and door openings;
in the top row of bricks, i.e. under the overhangs, air vents are carried out according to the scheme described above. This is necessary to ensure ventilation of the space between the wall and the insulation.

Here, in fact, is all the information on how walls are insulated under facing bricks. The only thing, finally, I note that the process of facing itself is quite complicated, requiring high qualifications from a bricklayer, so it is better to entrust this stage of work to specialists. True, the price of this service is also not small - on average, it starts from 800 rubles per square meter.

Exterior decoration of houses from aerated concrete blocks with bricks is very popular these days. A structure that is erected from this material, and then lined with brickwork, is much cheaper than completely brick building, while the view becomes modern, more aesthetic and status with the least investment. But is it only a matter of external attractiveness?

Advantages and disadvantages of facing an aerated concrete wall with bricks

Let us consider in detail the advantages and disadvantages of brick lining of aerated concrete.

Advantages

Soundproofing.
Visual aesthetics.
Strengthening the structure.
Extension of service life.

Flaws

Condensation may accumulate in the wall cavity if the laying is incorrect.
Additional construction and material costs.

An expenditure item is expected in any case when cladding a building, while aerated concrete blocks are one of the most inexpensive and stable structures. According to "Engineering and Construction Journal" No. 8 (2009), after serious tests for the strength and durability of aerated concrete wall with brick cladding in 2009 in St. Petersburg, it turned out that the life of such a wall varies from 60 to 110 years or more. A single climatic zone and material of the same quality.

A brick-lined aerated concrete house can have a service life that is almost twice as different.

Why is there such a difference in strength and wear resistance? It turned out that the matter is in the presence of a gap and ventilation between the base of aerated blocks and the brick cladding.

What are the ways of facing a gas block with a brick

A gas-block wall can be lined in several ways. This refers to the distance between the brick and aerated concrete block, as well as the presence of insulation, if there is a gap between the wall and the cladding. Let's consider each of them in detail.

Solid masonry without gaps and ventilation

The danger of early destruction appears when it is planned to use a heated room. That is, the difference in temperature inside and outside the house will significantly reduce the life of such a building. When the room is heated from the inside, water vapor will begin to move through the porous aerated concrete to the outside. In the absence of a gap or insulation, they will accumulate between the gas block and the brick, destroying both materials. In this case, condensate accumulates unevenly, which accelerates the process of decomposition and deformation of the structure of the gas block. The most cost-effective would be the use of external insulation in the form of mineral wool or wet plaster finishing. A similar finish of aerated concrete with bricks (without a gap) is applied only to unheated buildings.

Bricklaying at a distance from gas blocks without ventilation

In the rules of SP 23-101-2004 (Designing thermal protection of buildings) there is a prescription on the principle of the arrangement of layers between the wall and the surface of the cladding, which states that the closer to the outer layer of the wall, the lower the vapor permeability of the material should be. In accordance with paragraph 8.8, layers with a higher thermal conductivity and vapor permeability should be located closer to the outer surface of the wall. After conducting a series of studies, British specialists explained that it is necessary to arrange the layers so that the vapor conductivity to the outer layer increases with a difference of at least 5 times from inner wall... If this method of facing is chosen, then according to the rules of paragraph 8.13, the thickness of the unventilated gap must be at least 4 cm, while the layers are recommended to be separated with blind diaphragms from non-combustible material into zones of 3m.

Aerated concrete finishing with bricks with ventilated space

This cladding method is the most rational from the point of view technical characteristics materials and durability of the structure. However, the construction of such a structure should be carried out according to certain rules(SP 23-101-2004 clause 8.14).

Consider how to impose a brick house made of aerated concrete with a ventilated gap between the masonry according to all the rules. The airspace must be at least 6cm thick but not more than 15cm thick. Wherein the aerated concrete wall itself serves as thermal insulation... If the number of storeys of the building is higher than three, then perforated partitions are placed in the gaps (1 time per 3 floors) to cut the air flow. Masonry must have cross-cutting ventilation holes, total area which is determined according to the principle: on a 20sq.m area of 75sq.m of holes... In this case, the holes located at the bottom are made with a slight outward slope to drain condensate from the wall cavity.

In that case, if you plan to insulate aerated concrete wall additionally to the air gap, then for this purpose are used thermal insulation materials, the density of which is not less than 80-90 kg / m 3. The side of the insulation in contact with the air layer must have an air protective film on the surface (Izospan A, AS, Megaizol SD and others) or another air protective sheath (fiberglass, glass mesh, basalt wool). It is not recommended to use ecowool and glass wool as insulation, as these materials are too soft and not dense enough. It is also not allowed to use polystyrene and EPSP due to their flammability and vapor-permeable characteristics. When aerated concrete walls are clad with bricks with additional insulation on aerated blocks, soft, loose, combustible materials are not used. The vapor permeability of these materials must be sufficiently high to avoid condensation.

Summing up

So, what conclusions can be drawn about the methods of facing aerated concrete walls with bricks? For convenience, we will summarize the features of each cladding method in a table:

Specifications	Cladding without gap	Cladding with a gap, without ventilation	Vented Gap Cladding
Brickwork	+	+	+
Protection of aerated concrete walls from external influences	+	+	+
Thermal insulation	Insignificant increase	Increase (resistance brickwork), decrease (the moisture content of the aerated concrete wall increases)	No increase (ventilation of the space between the walls)
Terms of operation, destruction of the building	The useful life is reduced by 60%.	Reduction due to moisture and condensation.	No decrease or increase due to lack of condensation and controlled air circulation.
Construction costs	The costs of foundation, expansion (up to 15 cm), brick, mortar, flexible joints are increasing.	The costs of foundation, expansion (up to 19 cm), brick, mortar, flexible joints are increasing.	The costs of foundation, expansion (up to 21 cm), brick, mortar, flexible joints are increasing.
Profitability and feasibility	It is economically unprofitable due to a decrease in thermal insulation and service life.	Lack of particular benefit in most cases. It is advisable only in an even temperate climate that does not require heating the building from the inside.	Economically, it is not very profitable, but it is advisable if a brick cladding is required outside the heated buildings.

Thus, laying a brick around the aerated concrete wall, it will not be possible to significantly save on materials, and it will not be possible to increase the thermal insulation either. The only positive aspects are a respectable appearance and an increase in service life, but this is achieved under the condition correct organization construction processes, the use of materials and technologies recommended by SP 23-101-2004.