Insulation between the wall with facing bricks. Brick insulation - the secrets and nuances of the right finish

We continue our traditional series of articles from Yuri Voedilo (professional builder-repairman). Yuri writes:

V Lately heating prices are rising tremendously, so many people pay great attention to external wall insulation. Therefore, I decided to pay attention to this topic. This article will focus on the insulation of external walls. brick house facing brick. Next, we will talk about the tricks of laying the brick itself and the need for loose insulation. Also, in the article we will give examples of laying out the arch.

The house lined with ceramic bricks has a very pleasant and tidy appearance. But only on condition that the brick is laid correctly, that is, the seams must be even and clean, and the brick itself is not stained with mortar and does not have cracks.

Stage 1. Mortar for laying facing bricks

To work, we need the following tools:

Construction trowel;
Building level;
Thread or fishing line
Twig 8-12 mm (square section);
Bulgarian with a circle on concrete;
Cement, sand;
Polyfoam in loose form.

First, let's prepare the solution. All by standard scheme one part cement grade 400 and three parts sand, preferably not river sand, since the solution on river sand sets very quickly. But if you don’t have any other sand, then add a plasticizer to the solution, you can buy it at any hardware store. The density of the mortar should be such that it can be easily picked up with a trowel and applied to the brick. More and more often, in the solution on which the bricklaying will be carried out, they add different kind pigments (special dyes). Therefore, a little advice: before buying a brick, consider the combination of the color of the brick with the color of the seam itself. In our case, the client wanted a classic seam color, i.e. gray.

Stage 2. Laying ceramic (facing) bricks

There is a lot of information on the Internet about how a brick is laid, so I think it’s not worth writing about the basic principles. But about the features of masonry ceramic brick not so much, because high-quality insulation of the house with brick requires special attention.

Work will begin with laying out the corners. Facing brickwork should only be laid on waterproofing. To do this, use roofing material or a thick plastic film. In our case, the waterproofing was built into the foundation itself, so we started laying the masonry directly on top of the foundation. Stepping back from the main wall 4-5 centimeters, we will produce masonry. We retreat these 4-5 cm for the air gap, I will explain why later. It is necessary to lay ceramics in the same way as ordinary bricks, but only under a metal twig with a section of 8 by 8 or 10 by 10, 12 by 12 millimeters.

And the way it is done: a metal twig lies directly on the masonry itself along the front edge of the brick, and a solution is applied near it. In such a way that the thickness of the applied solution near the twig itself should not be higher than the twig itself. And on the back side, the solution was ten millimeters higher. This effect is easy to achieve if the mortar is cut along a twig with a construction trowel, while holding the trowel at an angle.

A vertical seam is applied in the same way, only the twig is placed vertically to the end side of the brick (poke). The twig itself will not stand, so you have to hold it while applying the solution.

Note: after about 2-3 hours of work, you need to wipe the seams with a small brush. At the same time, if there are holes or scuffs in the seams, then be sure to cover them! Otherwise, when the temperature drops +/- degrees, water will get there and, when frozen, it will tear the seam, and after a while the brick itself. All drops of the solution from the wall must also be wiped with a rag, as it will be much harder to wipe after drying. By the way, after a while, white spots may appear on the wall. This is the salt that was in the sand. There is nothing terrible here, it is easily wiped with a rag, well, or you need to wait until the rain washes it off.

Laying facing bricks is a painstaking process that requires accuracy. Therefore, be patient.

Stage 3. Making a frame for a brick arch

In order to lay out an arch from a brick, we first need to make a frame under it. We don't need beauty here. The main thing is strength and even bending. We take a USB sheet 10 mm thick and cut out two half-moon strips with a width of at least 6 centimeters using a jigsaw. The length and bend of the crescents is individual for each window.

Next, these crescents need to be twisted together, as shown in the photo below. We use old bars for this, their thickness can be different, but the width is the same from 10 to 12 centimeters. And the length is equal to the height of our windows.

We insert the bars between two crescents and twist them with self-tapping screws 45 mm long, after which the frame is ready for use.

Stage 4. Making an arch

Having installed the frame on the place where the arched window will be, we begin to overlay the frame with a brick on top.

Only now we will lay the brick not horizontally, but vertically with the bond side on the face of the masonry. But since the length of the brick is 25 cm, and the width of our masonry is 17 cm (brick width 12.5 cm + air gap 4-5 cm), then the brick will have to be cut to length. For cutting bricks, we will use a grinder with a diamond wheel for concrete.

The adjoining bricks of the main wall will also need to be cut at an angle. The arch should be in relation to the main wall along the plane at the same level or protrude outward by 2-4 cm, here it is a matter of the client's taste. After a day, three arch frame can be safely disassembled. The arch is ready.

Stage 5. Insulation of the brick walls of the house with foam plastic from the outside

We will still fill the air gap that we left between the main wall and the ceramic brick. This is an integral part of lining the house with facing bricks with insulation. The next question is: what should be the insulation between brick wall and facing bricks? To do this, we decided to use loose foam, which is sold in bags. Why exactly him, and not sheet foam?

Here's why. The first advantage: if the walls of the building were not even for some reason, then the loose foam plastic will not react during backfilling. But with the sheet will have to suffer. The second advantage: mice can get into the foam sheet and make a lot of moves and holes for themselves. In loose foam, it is impossible to make moves, since mice do not have the opportunity to climb on it. Raking with their paws, they sharpen like a truck in the mud, staying in place.

Before pouring foam into the wall, you need to close the gaps around the perimeter of windows and doors with mineral wool or sheet foam. Moreover, the latter is better, since when puttying the slopes on the foam, it will be easier to apply the putty.

Note: in order to insulate the walls of a brick house without excesses outside in windy weather, I do not advise you to fill up the foam. All the foam will scatter around your yard at best, and at worst even sweep your neighbors.

Attention! We received a review that with such insulation during the year, the foam filled in this way can sink at three meters of the height of the house about 60-70 cm. There was an experience of dismantling such walls. As experience shows, the insulation of voids gives a small effect. In this material, the photo showed that they had the opportunity to attach ordinary foam to the walls, even with glue-foam. And then lay the masonry. The difference in the price of materials is not significant.
This can be corrected by blowing perlite into the voids formed in the upper part of the masonry.

Yuri, the author of the article answers: To provide for shrinkage, we rammed foam plastic through every meter of height. In addition, for backfilling in two or three years, it is enough to remove the hemming and make topping up. And yet, the difference in price is not significant, but there are two but ... 1. In such a foam, mice start up three times less often and not for long, since it is not convenient for them to make moves there and they simply fall down. 2. When using sheet foam, a more or less even surface is needed, for bulk it is useless.

Stage 6. Final work

Tip: few builders know such a secret, when all the work on insulating the house with bricks is completed, do not spare the money and buy a couple of canisters of liquid silicone in a building supermarket. And carefully paint all the brickwork, especially the seams, they can be poured at all. After drying, a barely noticeable transparent film will remain on the wall. Thanks to her, your house will look like new for 5-10 years longer. If there is not enough money for liquid silicone, then replace it with a deep penetration primer, just remember that there are no streaks on the brick, otherwise after drying it will not wait for you very much. a pleasant surprise. And so, all the work on laying facing bricks and insulating a brick house is completed. Although this insulation is a bit expensive, it will serve you for many years.

We also recommend you:

Construction of a three-layer wall with brick cladding

In low-rise construction, the construction of an external three-layer wall is very popular: the load-bearing wall is a brick insulation-cladding (120 mm), Fig.1. This wall allows effective for each layer materials.

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

insulation layer. fixed on the wall, provides the necessary level of thermal insulation of the outer wall.

wall cladding from a facing brick protects a heater from external influences and serves as a decorative covering of a wall.

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

Multilayer walls also have disadvantages:

limited durability of the insulation material compared to the material bearing wall and facings;
identification of dangerous and harmful substances from a heater, albeit within acceptable limits;
the need to use special measures to protect the wall from blowing and moistening - vapor-proof, windproof coatings and ventilated gaps;
combustibility of polymeric heaters;

Bearing wall in three-layer masonry

Insulation of the walls of the house with mineral wool boards

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

Carried out calculations humidity regime walls show that in three-layer walls condensate in the insulation falls during the cold season in almost all climatic zones of Russia.

The amount of condensate falling out is different, but for most regions it fits into the norms established by SNiP 23-02-2003 "Thermal protection of buildings". There is no accumulation of condensate in the wall structure during the year-round cycle due to drying in the warm season, which is also a requirement of these SNiP.

As an example, the figures show graphs of the amount of condensate in the insulation according to the results of calculations for various options for facing the three-layer walls of a residential building in St. Petersburg.

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

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

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

From the above graphs it is clearly seen how the lining 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 of moisture accumulation in the insulation does not occur, but when facing with bricks without a ventilation gap, a significant amount of water condenses and freezes in the insulation every year in winter, Fig.2. Moisture also accumulates in the layer of brick cladding adjacent to the insulation.

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

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

Replacement of insulation covered with brick cladding, expensive pleasure. Hydrophobized high-density mineral wool boards are more durable under these conditions. But these plates have a higher cost.

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

Another way to eliminate condensation is to increase the vapor permeability resistance of the load-bearing wall. To do this, the surface of the bearing wall is closed vapor barrier film or use heat-insulating boards with a vapor barrier applied to their surface. When mounting on a wall, the surface of the boards covered with a vapor barrier must face the wall.

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

In walls with a ventilated gap, mineral wool boards with a density of at least 30-45 kg / m 3, pasted over on one side with a windproof coating. When using plates without wind protection on the outer surface of the thermal insulation, wind protection coatings 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, heat-insulating boards are installed freely in a vertical position in the space between the main wall and the facing layer of bricks. As supporting elements for insulation, fasteners are used, provided for fastening brick cladding to a load-bearing wall - reinforcing mesh, flexible connections.

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

Wall insulation with polystyrene foam or polystyrene foam

Rigid slabs of foamed polymers are placed in the middle of a three-layer brick wall structure without a ventilated gap.

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

Insulation with hermetic laying is a vapor-tight barrier in a brick wall. Steam from the room simply does not get to the outer surface of the insulation.

With the right thickness of the insulation, the temperature of the inner surface of the insulation must 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

Recently, another type of insulation is gaining popularity - products from low-density cellular concrete. These are heat-insulating slabs based on materials already known and used in construction - autoclaved aerated concrete, gas silicate.

Thermal insulation slabs made of cellular concrete have a density of 100 - 200 kg / m 3 and dry thermal conductivity coefficient 0.045 - 0.06 W/m o K. Mineral wool and polystyrene foam heaters have approximately the same thermal conductivity. Plates are produced with a thickness of 60 - 200 mm. Compressive strength class B1.0 (compressive strength not less than 10 kg / m 3.) Vapor penetration coefficient 0.28 mg/(m*year*Pa).

Heat-insulating slabs made of cellular concrete are a good alternative to mineral wool and polystyrene foam insulation.

Trademarks of heat-insulating slabs made of cellular concrete well-known in the construction market: Multipor, AEROC Energy, Betol.

Advantages of cellular concrete thermal insulation slabs:

The most important one is higher durability. The material does not contain any organic matter - it is an artificial stone. It has a fairly high vapor permeability, but less than mineral wool insulation.

The structure of the material contains a large number of open pores. Moisture that condenses in the insulation in winter dries quickly in the warm season. There is no accumulation of moisture.

Thermal insulation does not burn, under the influence of fire does not emit harmful gases. The heater does not stick. Insulation boards are harder and mechanically stronger.

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 heat-insulating plates made of aerated concrete, the following rules are followed:

Heat-insulating slabs of aerated concrete up to 100 thick mm fastened to the facade with glue and dowels, 1-2 dowels per plate.

From plates with a thickness of more than 100 mm close to the insulated wall lay out the wall. Laying is carried out on glue with a seam thickness of 2-3 mm. WITH bearing wall the masonry of the insulation boards is connected with anchors - flexible connections at the rate of five connections per 1 m 2 walls. Between the bearing wall and the insulation, you can leave a technological gap of 2-15 mm.

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

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 slabs.

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

Foam glass insulation is durable, does not burn, is not afraid of moisture, and is not damaged by rodents. It has a higher cost than all of the above types of heaters.

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 check for the absence of steam condensation in the thickness of the wall. If the test shows otherwise, then it is necessary to increase the thickness of the insulation. The thicker the insulation, the lower the risk of steam condensation and moisture accumulation in the wall material. But, this leads to an increase in construction costs.

A particularly 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. The thickness of the insulation to ensure energy saving is relatively small for such walls, and to avoid condensation - the thickness of the plates should 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, wood, from large-pore expanded clay concrete), the thickness of polymer thermal insulation, according to the calculation of moisture accumulation, turns out to be much larger than it is necessary according to the standards for energy saving.

To reduce the flow of steam, 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 vapor barrier from the inside for finishing, materials with high resistance to vapor permeability are chosen - a deep penetration primer is applied to the wall in several layers, cement plaster, vinyl wallpaper.

A vapor barrier 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 building moisture. Therefore, it is better to let the walls of the house dry well outside. It is recommended to perform facade insulation works after the interior decoration is completed, and not earlier than one year after the completion of these works.

Facing the exterior walls of the house with bricks

Facing the exterior walls of the house with brick is durable and, when using a special colored facing facing brick, and even better clinker brick. quite decorative. The disadvantages of the 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 the 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 conditions in the wall structure for maximum long-term operation without replacement (minimum amount of condensate in the wall). It is recommended to choose high-density mineral wool insulation and polymer from extruded polystyrene foam, XPS.

In brick-lined walls, it is most advantageous to use mineral heaters made of autoclaved aerated concrete or foam glass, with the service life of which is much longer than mineral wool and polymer.

Brick cladding is done in half a brick, 120 mm. on conventional masonry mortar.

A wall without a ventilated gap, insulated with high-density slabs (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 plinth.

Masonry brick cladding is connected with the masonry of the load-bearing wall steel wire or reinforcing mesh, protected from corrosion, or special flexible connections (fiberglass, etc.). Vertically, the grid or connections are arranged in increments of 500-600 mm.(height of the insulation plate), horizontally - 500 mm., while the number of bonds per 1 m 2 blank wall - at least 4 PC. At the corners of the building along the perimeter of window and door openings 6-8 PC. for 1 m 2.

The laying of brick cladding is longitudinally reinforced with masonry mesh with a vertical step of not more than 1000-1200 mm. The masonry mesh should go into the seams of the masonry of the bearing wall.

To ventilate the air gap in the bottom row of facing masonry, special vents are arranged at the rate of 75 cm 2 for every 20 m 2 wall surface. For lower ventilation, you can use a slotted brick, placed on the edge so that the outside air through the holes in the brick has the opportunity to penetrate into the air gap in the wall. Upper vents are provided in the eaves of the wall.

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

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

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

Such an arrangement of the window, door along the thickness of the wall 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 a brick lining.

When facing walls with bricks, it is important to ensure the durability of the insulation layer. The longest service life will be provided by thermal insulation with low-density cellular concrete or foam glass slabs.

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 lining, the longer their service life and the higher the heat-shielding properties. To do this, it is necessary to take measures to reduce the vapor permeability of the bearing wall, and for a vapor-permeable insulation, it is recommended to arrange a ventilated gap at the border with the cladding.

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

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

Hello!

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

What thickness of insulation is 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 we round the obtained thicknesses to those that are on the market, then these are, respectively, 30mm and 20mm foam. You can take both ordinary foam and extruded polystyrene foam (EPS). In terms of durability (in this 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 polystyrene. Styrofoam must be taken with a density of at least 25 kg / m3. The thickness of the foam (or EPPS), obtained by calculation, 30mm and 20mm, is quite inconvenient during the work itself. Usually, external insulation (with subsequent plastering) is carried out when the thickness of the insulation is from 50 mm and above. The fact is that a sheet of foam (and EPPS), 30 mm thick, and even more so 20 mm, is quite fragile. But it must not only be glued to the wall, but also nailed with dowels (6 pieces per sheet).
As for the glue. A prerequisite is that the glue is special 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 what brand the glue is.
To strengthen the corners there are special plastic corners with reinforcing mesh.
As for the thermals. Here the situation is as follows: both polystyrene and EPPS come with a smooth edge, and "with a quarter". That is, the sheets adjoin each other either exactly, or go one on top of the other. As far as I know, in thicknesses of 20 and 30 mm, only a smooth 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.
I recommend an article on warm plaster, it describes what you are asking about. As a conclusion, I can say that insulation with warm plaster is 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 20-30 mm, we can advise the following. Insulate the attic this year, and see how much more comfortable it becomes 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 a foam plastic thickness of 40 mm to make it more convenient to mount it.

Exterior decoration of houses made of aerated concrete blocks with bricks is very popular these days. A building that is built from this material, and then lined with brickwork, is much cheaper than a 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 a brick

Let us consider in detail the advantages and disadvantages that facing aerated concrete with bricks has.

Advantages

Soundproofing.
visual aesthetics.
Strengthening the building.
Service life extension.

Flaws

If the masonry is not installed correctly, condensation may accumulate in the wall cavity.
Additional costs for construction and materials.

A consumable article is expected in any case when laying 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 conducting serious tests for the strength and durability of an 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 was considered.

A house made of aerated concrete lined with bricks can have a service life that differs by almost half.

Why such a difference in strength and wear resistance? It turned out that the matter was the presence of a gap and ventilation between the base of the gas blocks and the brick lining.

What are the ways of facing a gas block with bricks

The 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 heaters, if there is a gap between the wall and the cladding. Let's consider each of them in detail.

Dense masonry without gaps and ventilation

The danger of early destruction appears when it is planned to use a heated room. That is, the temperature difference 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, the condensate accumulates unevenly, which accelerates the process of decomposition and deformation of the structure of the gas block. The most cost-effective will be the use of external insulation in the form of mineral wool or wet plaster finish. A similar finishing of aerated concrete with bricks (without a gap) applies only to unheated buildings.

Brick laying at a distance from gas blocks without ventilation

In the rules of SP 23-101-2004 (Design of thermal protection of buildings) there is a prescription on the principle of arranging 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 greater thermal conductivity and vapor permeability should be located closer to the outer surface of the wall. British experts after a series of studies 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 the inner wall. If this cladding method is chosen, then according to the rules of paragraph 8.13, the thickness of the non-ventilated gap must be at least 4 cm, while it is recommended that the layers be separated by blind diaphragms of non-combustible material into zones of 3 m each.

Finishing aerated concrete with bricks with a ventilated space

This method of cladding is the most rational in terms of specifications materials and building durability. 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 overlay a house made of aerated concrete with a brick with a ventilated gap between the masonry in accordance with all the rules. The air space must be at least 6 cm thick, but not more than 15 cm 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. V brickwork should be through ventilation holes, total area which is determined according to the principle: per 20sq.m area 75sq.cm holes. At the same time, the holes located below are made with a slight slope outward to drain condensate from the wall cavity.

In that case, if you plan to insulate the aerated concrete wall additionally to the air gap, then for this purpose heat-insulating materials are used, the density of which is not less than 80-90 kg / m 3. The side of the insulation that comes into 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 shell (fiberglass, glass mesh, basalt wool). It is not recommended to use ecowool and glass wool as a heater, as these materials are too soft and not dense enough. It is also not allowed to use foam and XPS due to their flammability and vapor barrier characteristics. When facing walls made of aerated concrete with bricks with additional insulation on gas blocks, soft, loose, combustible materials are not used. The vapor conductivity of these materials must be sufficiently high to avoid the formation of condensate.

Summing up

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

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

Thus, by lining an aerated concrete wall with bricks, it will not be possible to significantly save on materials, and it will also not work to increase thermal insulation. The only positive aspects - respectable appearance and an increase in service life, but this is achieved subject to the proper organization of construction processes, the use of materials and technologies recommended by SP 23-101-2004.

Video: how to properly brick aerated concrete wall

Brick is the most common material for the construction of load-bearing walls. It is successfully used both in high-rise industrial construction and in private low-rise buildings. The only drawback of a brick is its low thermal insulation qualities. To solve this problem, additional wall insulation is made. Brickwork with insulation inside makes it possible to build warm house with a minimum investment of time and money.

Cons of masonry without insulation

More recently, the issue of thermal insulation of brick buildings was solved in a simple way- increase in wall thickness. Yes, for middle lane the usual wall thickness was 3-3.5 bricks, and in the northern regions it could reach 1-1.5 m. This is due to the high coefficient of thermal conductivity of the brick, which causes large heat losses.

Such a thickness was a forced measure in the absence of effective and inexpensive heat-insulating materials. Another factor contributing to the use of "thick wall" technology in the Soviet era was the relative cheapness of bricks. This made it possible to simplify the masonry technology by refusing to use heat-insulating materials.

However, recently this approach has become too wasteful from a financial point of view: in addition to the cost of bricks, the cost of arranging reinforced foundations is increasing.

Another problem that can be encountered when laying brickwork without thermal insulation is the displacement of the dew point inside the premises.

In construction, the dew point is the point inside or outside the street walls of a building where the cooled vapor contained in the air begins to condense. The transformation of steam into dew occurs when warm air comes into contact with cold surfaces.

The most preferred option is to find the dew point outside the building, in which case the condensed moisture will simply evaporate under the influence of wind and sun. It is much worse if the dew point is shifted inside the premises. Dampness, which forms on the inner surfaces of the walls, negatively affects the microclimate in the house, becoming a source of high humidity and causes mold and mildew.

Not insulated walls in winter frosts are cooled to their entire thickness, as a result, steam condensation occurs on their internal surfaces.

In areas where sub-zero temperatures are set in the cold season, the brick laying technology with insulation is the only acceptable one.

Three-layer masonry

One type of insulated wall is a three-layer brickwork. Its structure looks like this:

Inner wall made of bricks, cinder blocks, aerated concrete, etc. Carries out the bearing function for interfloor overlappings and a roof of the building.
. The insulation is placed in the internal cavities-wells between the outer and inner walls. Protects the inner wall from freezing during the cold season.
Exterior wall with brick cladding. Performs decorative functions, giving the facade additional aesthetics.

On the image:

No. 1 - interior decoration.

No. 2 - the bearing wall of the building.

No. 3 - insulation between brickwork.

No. 4 - ventilation gap between the internal insulation and the facing wall.

№5 - outer wall with brick cladding.

№6 - internal reinforcement connecting the inner and outer wall.

Brickwork with insulation inside, like other building technologies, has its pros and cons. Its positive qualities include:

Smaller masonry volume, which reduces the estimated cost due to savings on the amount of building material.
Less weight of the building, which makes it possible to use lighter and more inexpensive foundations.
High thermal insulation performance, allowing you to keep warm in winter time.
Improved sound insulation. The thermal insulation layer can significantly reduce the noise level, which is especially important if the building is located on a central street with heavy traffic.
External walls lined decorative brick, do not need additional decorative finishing.

Among the disadvantages of multilayer walls, you can specify:

Greater labor intensity associated with insulation, compared with brickwork in 3 - 3.5 bricks.
Three-layer walls do not allow periodic replacement of insulation, while its service life is always shorter than the service life of brick walls.

The choice of insulation

As a heat-insulating material, a wide range of heaters can be used that meet the recommendations of SNiP.

Firstly, the thermal conductivity of the material must be such as to ensure the protection of the interior at the maximum negative values typical for this region.

You can get acquainted with the heat-insulating performance of the insulation in the instructions from the manufacturer on its packaging or in the tables of technical characteristics of SNiP. By comparing these figures with the winter minimum temperatures, you can calculate the required thickness of the insulation layer.

Secondly, the insulation must have sufficient vapor permeability. Otherwise, moisture will accumulate inside it, which will lead to the loss of thermal insulation qualities.

And, thirdly, the internal insulation must be fire resistant. Due to its incombustibility, it will not only not support combustion, but will also create a fire-retardant layer inside the masonry.

Mineral wool

A large family of heaters based on mineral fibers have excellent heat-saving characteristics. They are made by whipping molten minerals in a centrifuge: glass, basalt, slag, etc. Low level heat transfer in this case is achieved due to the high porosity of the material - air gaps do not allow cold to penetrate through the mineral wool.

Absolutely not combustible, but very afraid of dampness. When wet, it almost completely loses its heat-saving properties, therefore, when laying it, it is necessary to take care of an effective waterproofing device.

Styrofoam

Foamed - another often used in three-layer masonry thermal insulation material.

It is produced by saturating liquid polystyrene with air, which, after solidification, takes the form of porous round granules. To fill wells in the wall, it can be used in the form of sheets or as bulk material. It is much less afraid of damp than mineral wool, but unlike it, it is combustible, so walls insulated with polystyrene foam should be protected from open fire. Even if the fire does not damage the brickwork, it will burn out and melt the Styrofoam inside it. To replace the insulation, you will have to carry out time-consuming and expensive work to dismantle the facing part of the wall.

Bulk insulation

In private construction, sometimes three-layer masonry is made with backfilling of internal wells with various mineral fillers: slag, expanded clay, etc. This technique is somewhat cheaper and easier than laying a mini-slab or expanded polystyrene sheets, but its effectiveness is much lower. This is due to the lower thermal protection of slag and expanded clay.

The slag is very hygroscopic - it tends to absorb and retain moisture, which can cause an increase in its thermal conductivity and premature destruction of the adjacent layers of brick.

Masonry of three-layer walls

Wall laying with insulation is carried out in several stages.

Interior wall masonry. It is produced using the same technologies as the laying of a conventional load-bearing wall made of solid bricks or building blocks. Depending on the minimum winter temperatures, it can be 1 or 1.5 bricks thick.
Exterior wall masonry with cladding. It is carried out in such a way that between it and inner wall there was a gap necessary for laying or filling the insulation - a well. Between themselves, 2 walls can be connected either by ties of anchor bolts and reinforcement, or by brick dressing, carried out at certain intervals.
is needed to protect the insulation from moisture, since it is impossible to completely prevent the flow of moisture through the brick.
Filling the wells with filling insulation is carried out when the walls reach a height of 0.8 - 1 m. Sheet and roll insulation is attached to the inner wall using dowels-mushrooms with a wide plastic cap, after which it is closed with external facing masonry.

For the construction of a waterproofing layer, it is not recommended to use "deaf" materials, such as roofing material. This eliminates the possibility of free gas exchange between external environment and the interior of the house. Ventilation products should be left in the outer wall every 0.5 - 1 m - vertical seams between the bricks not filled with mortar.

Three-layer brickwork allows you to solve many problems that arise during the operation of housing in the winter. The process of building such walls is shown in the video below..