Classic three-layer brickwork. Three-layer masonry, device features, advantages and disadvantages Construction technology of a three-layer wall with facing bricks

How to make beautiful, strong, durable and warm exterior walls? What should be the design of the outer walls of the house? A few tips on building will help sort out this issue.

What structures are used

The placement of the insulation layer from the inside of the building is not considered, due to the many disadvantages inherent in this method, without any advantages.

Let's take a closer look at how the most expensive, three-layer walls are made. They are distinguished by good heat saving, durability, better appearance. They are usually built from small blocks. Continuous concrete casting in private construction is not so common due to the relatively high labor intensity when construction volumes are small.

How to make walls warm

The walls must have a resistance to heat transfer not lower than the standard. This value is suggested (and required) as economically viable. Those. building colder walls is unprofitable, not reasonable. Question - how to insulate a three-layer wall? In general, there are only two options - either stone fiber in the form of rigid slabs, or foamed plastics, also in the form of rigid slabs. In view of the various physical properties of these materials, and due to the special difference in resistance to steam movement, they are used according to various design schemes. If steam goes through plastic with difficulty (foam plastic, polyethylene) or does not go at all (extruded polystyrene foam), then it goes through fibrous cotton slabs as if there were no obstacles in the way at all. In both cases, special constructions must be used, which provide measures to prevent the wall from getting wet due to condensation.


If we talk about the three-layer wall structure, then two main distinctive features mineral wool boards. High-quality and dense (more than 50 kg/m3) basalt fiber slabs do not change their geometry over time, they are durable. They are not eaten by rodents, which is especially important. The used mineral wool boards must be impregnated with water-repellent preparations (hydrophobized), and their water absorption by volume should not exceed 1%. Since the insulation will be covered with a non-removable expensive facade layer, it is better to apply mineral plates High Quality as durable and resistant to external influences.

The thickness of the insulation layer is calculated in accordance with the standard, so that the total heat transfer resistance of the wall is not lower than the required values. More often, 10 cm of the thickness of the specified insulation is sufficient. In cold regions, 15 cm is likely to be required.

Features of a three-layer wall

The construction of a three-layer wall - between the bearing layer and the facade layer there is a layer of mineral wool insulation. A ventilation gap of 3–5 cm wide is left between the insulation and the facade layer, which is necessary for ventilation of the insulation. It is formed by plastic limiters put on ties, as a result of which the insulation always remains pressed against the wall and does not block the gap. At the bottom and top of the facade cladding, channels are made to supply air to the ventilation gap. The total area of ​​the supply channels must be at least 72 cm2. for 20 sq. walls, the same for the outlet ones (sometimes separate seams in the masonry are left empty for this). So that the fibers in the insulation do not erode, it is covered with a superdiffusion (vapour-permeable) membrane with a vapor permeability of at least 1700 g/m2 per day.

The carrier layer is usually made of solid or hollow bricks. The width of the layer depends on the design of the entire building, and on the purpose of a particular wall. More often, the layout is carried out in 1.5 hollow bricks (36 cm), sometimes in 1 brick (24 cm), but full-bodied. The strength characteristics of the layer, its width and the type of piece material are determined by the project.

The facade layer can be laid out of clinker bricks in brick floor or even 6 cm thick in 1/4 bricks.

It is important that there is a reliable connection between the carrier layer and the facade layer. Flexible (non-rigid) connections made of fiberglass or basalt-plastic rods are used. The coefficient of thermal conductivity of such bonds is not more than 0.5 W / m ° C, while a metal rod of a similar diameter is 50 W / m ° C, i.e. 100 times more. The density of laying bonds depends on the specific conditions and on the thickness of the insulation (than more thickness, the tighter it is pressed). Usually, the step of laying ties in the seams between the length of the wall is 0.5 - 1.0 m, and in height - 0.6 m. At the same time, they are inserted into the seams between the bricks to a depth of 7 - 9 cm.

Construction features

You should not use materials with low heat capacity for the inner carrier layer, as well as any materials that are afraid of water, for example, the same expanded clay concrete or foam concrete. The savings compared to brick will be small, and the problems if wet can be significant. Low internal heat capacity of the building - reduced comfort.


Note that in order not to add an extra cold bridge, all ceilings, beams go only into the load-bearing wall, and do not penetrate into the insulation layer. Thus, their ends are reliably protected from the cold by the same continuous layer of insulation.

It remains to pay attention to the "unobvious catch". The wall will be wet, cold and will rapidly collapse if the outflow of steam from it is disturbed. AT this description the design of a three-layer wall with ventilation of the insulating layer using the “ventilated facade” technology is shown. It is unacceptable to reduce the ventilation gap above the insulation, close ventilation holes. Or use a low-quality vapor diffusion membrane.

Another version of the design of a three-layer wall - with a dense bookmark inner space vapor-tight insulation (polystyrene foam, polyurethane foam) without a gap vent is also a popular option. In this case, the inner and outer layers are separated in pairs - each is in its own atmosphere. But due to the danger posed by the rodent, and also because of the slight, but still present, decrease in the natural outflow of moisture from the house, the lower durability of the material, it does not seem to be so preferable. However, it also has the right to life ...

In some new built buildings, insulation is placed centrally (in the middle) in the building envelope. With this option, the insulation is very well protected from mechanical damage and there are more opportunities for decorating facades. However, the risk of damage due to humidity is much higher than with external insulation, therefore, the layer structure must be carefully planned and executed without defects.

This design consists of three layers: load-bearing walls, walls made of facing material and insulation, which is located between them. The load-bearing and facing walls rest on the same foundation. The outer layer is most often made either from facing bricks, or from building bricks, followed by plastering, covering with artificial stone, clinker tiles, etc.

Advantages

• beautiful and respectable appearance when using expensive facing materials;
• high durability, subject to proper design and qualified installation of the structure.

disadvantages

• high labor intensity of construction;
• low breathability;
• the possibility of moisture condensation between the heterogeneous layers of such a wall.

It is very important that all layers of the structure are combined with each other in terms of vapor permeability.

Layered masonry

Compatibility is determined only by the calculation of the system as a whole.

Underestimating this circumstance can lead to the accumulation of moisture in the interior of the walls. This will create a favorable environment for the development of mold and mildew. The insulation from the possible formation of condensate will get wet, which will shorten the life of the material and significantly reduce it heat-shielding properties. The enclosing structure will begin to freeze, which will lead to inefficiency of insulation and may cause its premature destruction.

Types of structures

Typical solutions for layered masonry can be divided into two types: with and without air gap device.

The air gap device allows you to more effectively remove moisture from the structure, since excess moisture from the load-bearing wall and insulation will immediately go into the atmosphere. At the same time, the air gap increases the total thickness of the walls, and, consequently, the foundation.

Insulation inside masonry walls

To some extent, the problem of steam transfer is relevant for layered masonry with any type of insulation.

Thermal insulation of the structure with mineral wool is the most preferable.

In this case, it becomes possible to arrange an air gap between the insulation and the outer wall for better moisture removal from the load-bearing wall and insulation.

For layered masonry, use semi-rigid mineral wool insulation. This will allow, on the one hand, to fill in well all the defects in the masonry, to create a continuous layer of thermal insulation (the plates can be “squeezed” a little, avoiding cracks). On the other hand, such plates will maintain geometric integrity (do not shrink) throughout the entire service life.

Stone wool TECHNOBLOCK

Mineral cotton wool ISOVER Karkas-P34

Certain difficulties in the use of expanded polystyrene in layered masonry are caused by the low vapor permeability of this material.

Three-layer brickwork with insulation

1. Interior of a brick wall
2. Mineral wool
3. Exterior brick wall
4. Connections

The traditional material for the interior of the walls is solid red ceramic brick. Masonry is usually carried out on a cement-sand mortar of 1.5-2 bricks (380-510 mm). outer wall usually made of face brick 120 mm thick (in half a brick).

Products

In the case of a system device with air gap 2-5 cm wide for its ventilation, vents (holes) are arranged in the lower and upper parts walls through which vaporous moisture is removed to the outside. The size of such holes is taken at the rate of 75 cm 2 per 20 m 2 of the wall surface.

The upper ventilation ducts are located at the cornices, the lower ones - at the plinths. At the same time, the lower holes are intended not only for ventilation, but also for water drainage.

1. Air gap 2cm
2. Lower part of the building
3. Upper part of the building

To carry out ventilation of the layer, a slotted brick laid on the edge is installed in the lower part of the walls, or a brick is laid in the lower part of the walls not close to each other, and not at some distance from each other, and the resulting gap is not filled with masonry mortar.

Establishing links

The inner and outer parts of a three-layer brick wall are interconnected by special embedded parts - ties. They are made of fiberglass, basalt-reinforced plastic or steel reinforcement with a diameter of 4.5–6 mm. It is preferable to use fiberglass or basalt-reinforced plastic links due to the greater thermal conductivity of steel links.

These connections also perform the function of fixing the insulation boards (the insulation is simply
poke at them). They are installed in the process of laying in a load-bearing wall to a depth
6-9 cm in increments of 60 cm horizontally and 50 cm vertically, based on an average of 4 pins per
1 m 2.

To ensure a uniform ventilated gap over the entire area of ​​​​the insulation, fixing washers are attached to the rods.

Often, instead of special connections, bent reinforcing bars are used. In addition to connections, the outer and inner walls of the masonry can be connected with a steel reinforcing mesh laid every 60 cm vertically. In this case, additional mechanical fastening of the plates is used for the air gap device.

Insulation plates are installed with dressing of seams close to each other so that there are no cracks and gaps between individual plates. At the corners of the building, the plates are geared to avoid the formation of cold bridges.

Masonry technology with insulation

• Laying the facing layer to the level of connections
• Installation of a heat-insulating layer so that its top is 5-10 cm higher than the facing layer
• Laying the carrier layer to the next level of connections
• Installing ties by piercing them through the insulation

if the horizontal seams of the bearing and facing layers of the wall in which the ties are placed do not coincide by more than 2 cm in the bearing layer of brickwork, the ties are placed in a vertical seam

• Laying one row of bricks in the bearing part of the wall and the facing layer

Mounting sequence
(Alternative option)

Do I need to insulate a house made of bricks and foam blocks?

Do I need to insulate a stone house?

First, let's answer the question of why insulation of the external walls of the building is required. Insulation of the facade of the building is necessary to shift the dew point from the inside to the outside of the building wall. talking plain language, dew point is the point at which condensation forms due to the temperature difference between outdoors and indoors. Of course, the humidity of the air both indoors and outdoors plays an important role.

This phenomenon can be clearly seen in the picture below.

The presented picture also shows why the house is not insulated from the inside. In this case, you not only isolate the wall from heating, reducing its vapor-permeable and heat-insulating properties, but also often create favorable conditions for the formation of fungi, mold, the formation of efflorescence on interior decoration premises. Monolithic lintels and other concrete structures are subject to mandatory insulation.

Consider an example in the table below. Source of information: SP 23-101-2004, 2004-06-01

For example: the temperature inside the house is 23C, the humidity is 50% ( normal humidity), the dew point will form in areas where the surface temperature will be below 12.03C. Places of formation: door and window openings, areas of interface with the roof, chimney areas, corners of buildings, interfloor areas, etc.

What insulation is more preferable for facade insulation?

There are two main groups of heaters:

- polymeric,

- mineral.

Polymer heaters - heaters obtained as a result of thermal or machining materials based on chemically synthesized substances. The most common polymeric heaters are expanded polystyrene (EPS) and extruded polystyrene foam (EPS). PPS includes all types of foam, such as PSB, PSB-S, Neopor, etc.

Mineral insulation - fibrous materials obtained during heat treatment rocks, metallurgical slags and other mineral substances. Mineral heaters include basalt (stone, mineral) wool and fiberglass-based wool. For the production of glass wool, the same materials are used as for the production of glass, as well as waste from glass production. These include heaters with markings: P_, PZH_, PSZH_, MW-EN_, etc.

Consider their characteristics in the table below.

In addition, it should be noted that:

- mineral heaters, have good soundproofing characteristics but are afraid of moisture. Those. when wet by more than 2-3% of their mass, the thermal insulation properties of the material are reduced by more than 50%. Moreover, the fibers themselves do not absorb moisture, the air contained between the fibers is saturated with moisture. Structures where moisture can penetrate into the insulation layer must be protected by vapor barrier membrane films.

- polymer insulation, do not cope well with the function of sound insulation, but unlike mineral insulation, have great thermal insulation properties with a smaller thickness. It is believed that this species insulation is flammable and emits harmful phenol.

Air in the foundation (basement)

XPS made according to modern technologies, has a flammability class G1 and a residual styrene content of 0.01-0.03%, which meets all environmental requirements.

In addition, phenol is released from any polymeric substances only when heated. This type of insulation is used only in the "closed" insulation of the facade.

There are three main types of facade insulation:

- Insulation inside the well masonry,

- Warming " hinged facade»,

- Insulation with the application of a plaster layer on the insulation (wet plaster).

Insulation inside the well masonry.

In this case, the insulation is located between the facing and the main bearing wall. Both polymer and mineral insulation is used. For walls made of gas silicate block it is recommended to use a mineral insulation with a density of at least 50 kg / m 3 using waterproofing films. For areas with high atmospheric humidity (forest areas, areas near water bodies), it is possible to use polymer insulation with certain changes in the technology during installation.

Insulation of the "Hinged facade".

The insulation is attached to the load-bearing wall using fasteners or in pre-prepared niches in the frame of the structure. It is recommended to use mineral insulation with a density of 35-50 kg/m 3 in combination with superdiffusion windproof membranes. Materials for facing ventilated facades: porcelain stoneware, aluminum panels, polymer siding for various types of installation. It is necessary to leave a ventilation gap between the insulation and the front material.

Insulation with the application of a plaster layer on the insulation (wet plaster).

With this option of facade insulation, a heater is first attached to the load-bearing wall, then a decorative plaster layer. The use of mineral insulation with a density of 140-150 kg/m 3 is recommended. Plaster material is also recommended to be used with good vapor permeable characteristics.

Insulation is a prerequisite not only because it helps to reduce the energy consumption of the house, making it warmer, but also protects the main structures (walls, monolithic beams, lintels) from freezing, extending the life useful operation building.

With insufficient insulation of the walls, about 60% of the heat used to heat the home is lost through them. However, the heat saving standards in force since 2000 required builders to use modern highly efficient insulating materials, significantly increasing the heat-shielding properties of the walls

To the question of what to build a house from - wood, brick, concrete, or their numerous and varied combinations, everyone answers in their own way. The choice depends on many factors, among which personal preferences often play a much more significant role than practical considerations. We will try to focus on practical aspects and will proceed from the fact that it was decided to build a brick house. Main advantage brick building- its undoubted strength and unlimited service life, of course, subject to proper construction and competent operation.

Thicker doesn't mean warmer

The thickness of the main brick walls is always (well, or almost always) a multiple of the size of half a brick, but at the same time it cannot be less than 25 cm, that is, one of its lengths. It is well known from the richest construction practice that even a wall of one brick is capable of carrying any uniformly distributed load that occurs in one, two-storey houses from above structures. Thermal engineering calculations show that at a temperature "overboard" -30 ° С, namely, such a temperature is not uncommon in winter in most regions of the central part of Russia, to keep warm in the house, the thickness of its outer walls (with continuous masonry without voids and on cement-sand solution) should be at least 160 cm. Walls made of silicate brick will be even thicker.

Ordinary red brick is corpulent and hollow. For external walls, it is better to use a hollow one, the air sinuses of which significantly improve the heat-shielding characteristics of the structure. In addition, the masonry itself must be carried out with the formation of voids, wells, widened joints filled with heat-insulating material, the use of effective modern heaters and the so-called warm masonry mortars. An equal or even more serious effect can be achieved using different kind insulation, masonry with the formation of voids, porous bricks.

The trick of laying brick walls is the use of warm masonry mortars containing slag, expanded clay, tuff, perlite, etc. as a filler. Ordinary cement-sand masonry mortar has a thermal conductivity close to the thermal conductivity of a solid brick, and for a mixture with such fillers it turns out to be approximately 10-15% lower. It also quite significantly increases the heat-shielding properties of the walls, because the total area of ​​\u200b\u200bthe joints in the masonry is almost 10%.

Where does the heat go?

An important question that interests many potential customers is something like this: "Where should the insulation be located on the walls - inside the room, outside or in the body of the masonry?"

The greatest heat losses in houses, including individual ones, accounted for windows 20 years ago. With double glazing, which was so common until recently, the specific heat flux through windows is 4-6 times higher than the heat flux through walls. And this despite the fact that the window area is rarely more than a fifth of total area enclosing structures. Let us make a reservation right away that the use of multi-chamber PVC profiles with three- or four-chamber double-glazed windows significantly reduces heat loss. 9-10% of the heat leaves the house through the roof and the same goes into the ground through basements. And 60% of losses are accounted for by non-insulated walls.

The location of the dew point depending on the type of wall insulation

Consider three options for wall construction: solid without insulation; with a heater from the side of the room; with external insulation. The temperature in the house, according to the current standards that determine the level of comfortable living, should be + 20 ° С. Measurements carried out by specialists show that at a street temperature of -15 ° C, the temperature inner surface for an uninsulated wall is approximately 12-14°C, for an external one - about -12°C. The dew point (the point at which the temperature corresponds to the beginning of moisture condensation) is located inside the wall. Considering that part of the building envelope has a negative temperature, the wall freezes through.

In the presence of thermal insulation located on the walls inside the room, the picture changes significantly. The temperature of the inner surface of the wall (more precisely, inner sides s insulation) in this design is approximately + 17 ° С. At the same time, the temperature of the masonry inside the building turns out to be about zero, and outside it is slightly lower than the temperature of the street air - about -14 ° C. A house with such internal thermal insulation can be warmed up quite quickly, but brick walls do not accumulate heat, and when turned off heating appliances the room is rapidly cooling down. But something else is worse: the dew point is between the wall and the thermal insulation layer, as a result, moisture accumulates here, mold and fungus may appear, the wall still freezes through. However, heat losses are somewhat reduced compared to an uninsulated structure.

Finally, the third option is external thermal insulation. The temperature of the wall surface inside the house becomes slightly higher: 17-17.5 ° C, and outside it rises sharply - up to a level of 2-3 ° C. As a result, the dew point moves inside the insulation layer, while the wall itself acquires the ability to accumulate heat, and heat losses from the room through the building envelope are significantly reduced.

External thermal insulation of walls helps to solve several problems at once. First of all, if done correctly, such insulation allows you to achieve high level energy savings – building heating costs are reduced by 50-60%

Layered masonry

The easiest way to increase the thermal insulation properties of brick walls is to leave cavities in them, because air is an ideal natural heat insulator. Therefore, for a long time, closed air gaps 5-7 cm wide have been made in the body of a wall of solid brick. On the one hand, this reduces the consumption of bricks by almost 20%, and on the other hand, it reduces the thermal conductivity of the wall by 10-15%. This type of masonry is called well. Air, of course, is an excellent insulation, however, with a strong wind, such walls can be blown through the vertical seams of the masonry. To prevent this from happening, the facades are plastered on the outside, and various heaters. Now a variety of well masonry is widely used, called layered: Brick wall, then the insulation and the outer layer of facing bricks.

Options for wall insulation with a bond of two layers of brick masonry (a) and metal embedded elements (b)

Thermal insulation in laminated masonry, as a rule, is slabs of mineral wool (based on stone fiber or staple fiberglass) or expanded polystyrene, less often - from extruded polystyrene foam (due to its high price). All materials have similar thermal conductivity coefficients, so the thickness of the insulating layer in the wall will be the same, regardless of the type of insulation chosen (the thickness of the layer is determined not only by the characteristics of the thermal insulation, but also climate zone where construction is taking place). However, fibrous materials are non-combustible, which is fundamentally different from polystyrene foam, which is combustible. In addition, unlike polystyrene foam boards, fiber boards are elastic, so that during installation it is easier to press them tightly against the wall. Certain difficulties in the use of expanded polystyrene in layered masonry are also caused by the low vapor permeability of this material. At the same time, expanded polystyrene is about four times cheaper than mineral wool, and for many customers this advantage compensates for its disadvantages. We add that, according to SP 23-101-2004 "Design of thermal protection of buildings", when using combustible heaters in the building envelope, it is necessary to frame window and other openings around the perimeter with strips of non-combustible mineral wool.

A snug fit of the insulation is a guarantee of its efficiency, since if air pockets are allowed in the structure, heat leakage from the building can occur through them.

The device of any type of insulation system requires a thoughtful calculation of its vapor permeability: each subsequent layer (from inside to outside) must pass water vapor better than the previous one. After all, if steam has an obstacle on its way, then its condensation in the thickness of the building envelope is inevitable. Meanwhile, in the case of a popular solution - a wall of foam blocks, fibrous insulation, facing bricks - the vapor permeability of foam blocks is quite high, for a heater it is even higher, and the vapor permeability of facing bricks is less than that of a heater and foam blocks. As a result, steam condenses - most often on the inner surface of the face brick wall (since it is in the zone of negative temperatures in winter), which entails Negative consequences. Moisture accumulates in the lower part of the masonry, eventually causing the destruction of the brick of the lower rows. The insulation will get wet over its entire thickness, and, as a result, the service life of the material will be reduced and its heat-shielding properties will significantly decrease. The enclosing structure will begin to freeze, which will lead, in particular, to a decrease in the effect of using the insulation system, to deformation of the room finish, to a gradual displacement of the condensate zone into the thickness of the load-bearing wall, which can cause its premature destruction.

To some extent, the problem of steam transfer is relevant for layered masonry with any type of insulation. In order to avoid wetting of thermal insulation, it is recommended to provide two points. Firstly, it is necessary to create an air gap of at least 2 cm between the insulation and outer wall, and also leave a series of holes about 1 cm in size (a seam not filled with mortar) in the lower and upper parts of the masonry in order to achieve air inflow and exhaust to remove steam from the insulation. However, this is not a full-fledged ventilation of the structure (in comparison, for example, with a ventilated facade system), therefore, secondly, it makes sense to make special holes for condensate drainage from the layered masonry in its lower part.

An important feature of layered masonry is the use thermal insulation materials with sufficient rigidity and their reliable fixation - so that they do not settle over time. For additional fastening Insulation and conjugation of the outer and inner brick layers are used with flexible connections. Usually they are made of steel reinforcement.

Replacement of steel flexible connections on fiberglass allows (due to the thermal uniformity of the wall structure) to reduce the estimated thickness of mineral wool by 5-10%

In recent years, in individual construction for the construction of walls, porous large-format ceramic stones. During their manufacture, organic and mineral materials are added to the composition of ceramics, which contribute to the formation of closed pores during the brick firing process. As a result, such stones become 35-47% lighter than solid bricks of the same size, and due to the porous structure, their thermal conductivity coefficient reaches 0.16-0.22 W / (m ° C), which is 3-4 times more than solid clay bricks. Accordingly, the walls of porous stone can be much less thick - only 51 cm.

Due to the high heat capacity of the material, brickwork has significant thermal inertia - the walls warm up for a long time and cool down just as slowly. For houses permanent residence this quality is certainly positive, since the temperature in the rooms usually does not have large fluctuations. But for cottages, in which the owners visit periodically, with long breaks, the thermal inertia of brick walls already plays a negative role, because their heating requires considerable fuel and time. The construction of walls of a multilayer structure, consisting of layers of different thermal conductivity and thermal inertia, will help to remove the severity of the problem.

External insulation

Today, the most widespread systems of external insulation. These include ventilated façades with an air gap and "wet" façades with thin plaster layer(a slightly less popular option with a thick plaster layer). In facades with "thin" plaster, the number of heat-conducting inclusions is minimized. In this they differ from ventilated facades, where there are more heat-conducting inclusions and, accordingly, the insulation should be thicker, which affects the cost of the structure - for ventilated facades, it turns out to be twice as high on average.

Scheme of external insulation

The name "wet" facade is associated with the use in insulation systems plaster solutions. This explains the main and, perhaps, the only limitation on their arrangement - the seasonality of work. Since the technology provides for the presence of "wet" processes, the installation of the system can only be carried out at positive temperatures.

The composition of such "wet" systems includes many various components(insulation, mesh, mineral glue, plaster mixes, dowels, profiles and a number of accessories), but there are only three main layers: insulation, reinforcing and protective and decorative layers. As a heater, plates made of rigid heat-insulating material with a low coefficient of thermal conductivity are used. These can be mineral or glass wool boards with an average density (not lower than 145 kg/m³) or sheets of extruded non-shrinking self-extinguishing polystyrene foam with a density of at least 25 kg/m³. At the same time, the thermal insulation properties of a 6 cm thick expanded polystyrene layer correspond to approximately 120 cm of brickwork. The insulation is fixed on the wall using special glue and fasteners. A reinforcing layer of alkali-resistant mesh and a special adhesive solution is applied to the thermal insulation, which fastens it to the insulation plate. And only then form the outer layer, consisting of a primer and a decorative finish.

The main advantage of a “wet” facade is the possibility of obtaining a wall with any required degree of insulation, moreover, such an insulation system is less expensive than layered masonry, while the appearance of the facade, where high-quality plasters are used, will be attractive for a long time. The costs for the construction of the foundation will also be reduced, since the load on it from the insulation layer will be insignificant. The use of such systems makes it possible to reduce heat losses through building envelopes by a factor of three and save up to 40% of funds spent on heating.

Three-layer brickwork has become more common due to the rising cost of energy resources.

Thermal insulation materials are used as the third layer, which saves thermal energy in the premises. An ordinary brick, solid and slotted, retains thermal energy, but below the established norms. To do this, in the projects of houses using such bricks, a layer of thermal insulation of the outer walls should be provided.

For thermal insulation, widely used materials are used:

• mineral wool;
• expanded polystyrene.

Polystyrene is most often used if the masonry is made of concrete or aerated concrete blocks. This is due to the coefficient of vapor permeability. Failure to comply with the principle of vapor permeability can lead to active condensation, which means that the humidity of the structure will increase. Humidity, in turn, leads to the destruction construction materials, the formation of fungus on the inside of the walls and the deterioration of heat saving, the masonry is destroyed at the seams.

To maintain the rate of vapor permeability, it is necessary to provide a ventilation gap in a three-layer masonry.

In order for the vapor permeability characteristic to be within the normal range, three-layer masonry designed with ventilation gaps. The gap is made between the surface of the facing brick and the insulation. For air circulation in the air gap, when laying the front brick, embroidered vertical seams are left. The number of seams is determined by the area of ​​the wall. For 3 sq. m clear one seam. In the absence of a gap, the heat-insulating material will retain moisture, the properties of thermal insulation will decrease, the material, having lost its properties, will become unusable, and the energy consumption for space heating will increase. The heat-insulating material, having absorbed a lot of moisture during freezing, expands and can squeeze out the facing brickwork. Masonry seams are destroyed from high humidity. Fungus can form on the inner surface of the outer wall.

Advantages and disadvantages

Three-layer masonry with an air gap has both advantages and disadvantages. However, with high-quality masonry, all disadvantages can be minimized.

The main advantage of this type of masonry is compliance with the requirements of SNiP "Thermal Protection". The disadvantages include the complexity of the design, as well as the short service life of the facade due to the fragility of the thermal insulation layer, which is approximately 25 years.

However indicated deficiencies do not outweigh the benefits of keeping your home warm. When choosing this method of laying, one should be attentive to the control of the work if they are performed by a team of developers.

Lightweight three-layer masonry can be built with your own hands. Masonry is a wall, which consists of a bearing base, a layer of insulation and a facing part. Bearing brick wall is in progress solid brick with a masonry width of 38 cm. Three-layer masonry is performed with a layer of insulation 5-10 cm thick. The facing wall is masonry in half a brick. Do not forget about the air cushion between the insulation and the facing wall, which should be about 2-3 cm. Of course, there will be difficulties in creating such a gap, but this should not be neglected.

The facing brick wall cannot be suspended when creating an air gap, it rests on the floors.

Masonry thermal insulation

The strength of a brick wall can be increased by installing reinforcing masonry meshes every five rows of bricks.

Do not save on insulation, use mineral wool boards that have high density. Placement of plates along the wall is carried out with a snug fit to each other.

Certified materials intended for facade work should be used. It is necessary to use this particular type of insulation due to the fact that the facing brick wall more performs the function of decorating and protecting against atmospheric influences, but not climatic ones. The density of layered mineral wool made from basalt rocks should be 140 kg per cubic meter. Styrofoam is used only foamed with a density of at least 16 kg per cubic meter.

For thermal insulation of masonry, you should not save on materials: choose only certified heaters intended for facade work.

Using cheap materials of lower density, you create a low-quality layer of thermal insulation, which in a year or two will turn into dust and fall down. It is not recommended to use penoizol, as it is harmful to the human body. In his chemical composition includes reagents that, when wet and then dry, evaporate into the environment.

Great attention is paid to the system of connecting the outer and inner walls, because with a three-layer construction, these walls are separated by a layer of thermal insulation and an air gap. If a brick is used for connection, “cold bridges” are formed, which will worsen the heat saving in the premises. To reduce this effect, stainless steel can be used as a binder, but even with its smaller area, it will lead to heat loss. The most effective way to increase heat saving is the use of special fiberglass. Losses during its use are approximately 2%. Fiberglass has low thermal conductivity, is a high-strength material, does not corrode and does not deform. At this material very high prospect of distribution in the market.

• if the foam acts as a heater, it is recommended to foam all joints with mounting foam;
• the laying of the lower rows (basement) is carried out using clay red bricks, in no case silicate;
• chimneys and walls of wet rooms are laid out using red brick;
• the strength of the wall can be increased using reinforcing masonry meshes, which are installed every five rows of bricks;
• if the walls from the outer and inner sides are plastered, then the seams are not completely laid. This is done in order to better hold the plaster;
• control the horizontal lines of the masonry perimeter;
• floor slabs are laid on a row of pokes, that is, in the room under the slab we observe brick pokes;
• when used for metal jumpers, it is necessary to paint it to reduce the effect of corrosion;
• unused insulation must be covered from rain and monitored for dryness.

According to formal features, only walls without finishing are considered single-layer, affecting the heat saving and performance of the main material of a self-supporting or load-bearing wall. That is, a finish that increases the thermal properties of a wall is formally considered a wall layer.

All walls made of a homogeneous base material that determines the strength of the wall and one or more additional layers, each of which contributes to the thermophysical characteristics of the wall, are multilayer.

The well-known company in the Russian Federation - "Ksella-Aeroblock-Center" in its catalog only from aerated concrete gives more than a dozen options for multilayer walls.

Taking into account other materials that provide the main load on the wall, there will be several dozen structural options for multilayer walls.

One of the attempts to classify multilayer wall structures gave the following result - in the Russian Federation, four main types of multilayer walls are most often used:

• well masonry;
• internal thermal insulation (from inside the room);
• ventilated facade;
• external thermal insulation of "wet type".

The first well masonry was started by Russian masons under the guidance of Russian engineer A.I. Gerard in 1829. On this basis, about a dozen variants of three-layer wall structures were developed.

When are sandwich walls needed?

Traditional single-layer walls came under great attention of heating specialists around the world with the onset of the energy crisis in the 70s of the twentieth century. In the USSR, and then in the CIS, this process has shifted by 10-15 years. But the most serious shifts in this direction took place in the 2000s. In Russia, the norms for the thermal efficiency of buildings have been tightened several times.

According to the new standards, in order to achieve the required thermal insulation characteristics a single-layer wall should be of the following thickness:

• from ceramic brick(thermal conductivity coefficient - 0.8 W / (m ° C)) - from 1.1 to 4.5 m;
• from silicate (0.87) - from 1.2 to 4.8 m;
• from ceramic hollow (0.5) - from 0.7 to 2.9 m;
• foam blocks, at a density of 800 kg / cu. m. (0.37) - from 0.5 to 2 m, at a density of 400 (0.15) - from 0.2 to 0.8 m;
• clayditeboton 1 800 (0.9) - from 1.25 to 5 m;
• it is at a density of 500 (0.23) - from 0.3 to 1.2 m;
• reinforced concrete (1.8 - 2.1) - from 2.2 to 11.5 m.

It turns out that only from foam concrete with a density of less than 500 kg / cu. m. you can get a "digestible" wall thickness.

If the thermotechnical calculation of the wall shows that the wall of aerated concrete should be more than 0.4 m, and for hollow ceramics with micropores - more than 0.45 m, then it is cheaper to build houses with two-layer walls.

In addition, single-layer walls have the following disadvantages:

• high humidity material, i.e., the heat resistance of the wall is lower than the design one, and it is colder in the house;
• irrational consumption of materials, since the thickness of the wall is much greater than that required for its strength.

Therefore, to meet the thermal requirements of the walls, you need to use two, three or more layers, one of which will give the wall strength, the second will protect the house from the cold, the third will ensure the wall dries quickly after construction, the fourth will protect from bad weather, UV radiation or just make the wall beautiful.

Layered walls are not needed:

• in regions with a mild climate and frosty winter;
• when materials make it possible to build a heat-saving wall of the required strength and acceptable thickness.

In this case, you can use:

• porous materials: porous bricks, aerated concrete, gas silicate, expanded clay blocks, foam blocks, etc.;
• hollow: hollow brick, ceramic, sand-concrete, cinder-concrete and expanded clay hollow blocks, etc.;
• large blocks:

  a) concrete blocks;
  b) composite blocks: wood concrete, sawdust concrete, polystyrene foam concrete, etc.

Advantages and disadvantages of multilayer walls

In double-layer walls, the heat-insulating layer is usually installed on the cold side, outside.

In three-layer structures, a thermal insulation layer is installed between two layers of load-bearing material of the same thickness. That is, the wall is divided in half and a layer of thermal insulation is arranged between the halves. The halves of the walls are “tied up” among themselves repeating through 5 - 8 rows:

• one or two rows of solid brickwork;
• steel galvanized reinforcing ties or meshes;
• solid reinforced concrete belts- vertical and horizontal.

But more often the outer layer is made in 0.5 bricks from special facing bricks.

There are other ways, but they are used less frequently.

Advantages of multilayer walls:

• the wall is lighter, because strength is provided by a relatively small amount of material, and thermal insulation, by definition, weighs little;
• highly efficient insulation provides thermal parameters with a margin, and facing (outer layer) - appearance;
• fire resistance;
• simple materials;
• You can build all year and in winter too, etc.

Disadvantages of multilayer walls:

• heterogeneity medium density wall material (cold bridges from bonds, concrete diaphragms, etc.), which gives different thermal efficiency of the wall in different places;
• high qualification of performers is needed;
• ceilings facing outer surface walls, give up to 20% of heat loss; *
• load from temperature changes - the concrete of the floors is always warm, and face masonry in the freezing / thawing zone; **
• minor repairs are almost impossible;
• possible accidental unintentional damage to thin layers;
• large volumes hidden works and defects are possible: incorrect or incomplete installation of insulation, incorrect installation of vapor barrier, and more. others;
• high labor intensity;
• the cost of the house is more than with two-layer walls, and even more so with single-layer ones.

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* When interfloor floor slabs exit on any type of wall, their end faces onto the outer wall steel reinforcement conducts heat much better than dense concrete, although concrete also has a high thermal conductivity. Internal voids, with a diameter of 130 to 250 mm, filled with air, also participate in this process.

To reduce heat loss:

• the ends of the slabs are covered with standard (design) thermal insulation and outer cladding;
• the cavities of the slabs are filled with thermal insulation or foam-aerocrete inserts (at least 0.5 - 1 m). Concrete concrete plants can do this on request during the production of slabs.

** With temperature fluctuations, the concrete of the floors, protected from them by thermal insulation, has small changes in size, while the facing masonry is entirely under the influence of these fluctuations. In the zone of their contact, crumbling of materials and gradual destruction are possible.

Materials used in the construction of sandwich walls

For the construction of a load-bearing and self-supporting wall, providing a load from its own weight, ceilings and all overlying floors, use:

• full-bodied ceramic brick, hollow, porous;
• silicate full-bodied 3, 11 and 14-hollow, etc.

With a small number of storeys up to 3, sometimes 5 floors:

• ceramic blocks - warm hollow-porous;
• arbolite and brisolite blocks, twin blocks;
• foam, gas, slag, polystyrene, sawdust, expanded clay concrete and other types of large-format blocks,

Highly efficient heaters are used as heat-insulating materials:

A. Foams:

• EPPS - extruded polystyrene foam;
• other foamed plastics - polyethylene foam, foam propylene, polyurethane foam, etc.;
• foam glass, expanded clay and other foamed materials;

B. Mineral wool - basalt, fiberglass, gabbro-basalt, marl, etc.

B. Natural organic materials:

• ecowool - crushed cellulose impregnated with flame retardants etc.;
• shredded waste wood, bark, branches, etc.;
• crushed fibers and stems of plants, etc.

Features of the construction technology of multilayer walls

There are several ways to build multilayer walls:

• at the same time they lay the outer and inner walls and install soft or hard insulation boards;
• layered construction: they completely lay the inner wall, strengthen the insulation on it and lay the outer wall:

  a) at a distance - a fixed distance from the wall, leaving a ventilation gap with molded rails or profiles between the thermal insulation and the outer wall;
  b) on the main wall through the insulation layer with special anchors or dowels.

A crate is installed on the inner wall, between the elements of which a slab mineral wool or expanded polystyrene plates are fixed with recessing relative to the crate. With the help of horizontal ties, after 4-6 rows of masonry and after 0.5-0.6 m in a row, using the crate as a means of maintaining the width of the gap, a facing layer is laid. The ventilation gap is formed between the outer wall and the thermal insulation. Between inner wall and there is no thermal insulation.

Simultaneous construction of a three-layer wall

Consider the process of simultaneous construction of a brick three-layer wall with internal insulation:

1. Thickness interior masonry determined by calculating the strength of the wall, but cannot be less than 250 mm - “in 1 brick”.
   The thickness of the thermal insulation layer is determined by thermal engineering calculation and is at least 0.5 bricks.
   The thickness of the outer masonry - "facing" is not more than 0.5 bricks, but in 1 - 2 storey building maybe less.
2. The laying is carried out simultaneously with the inner and outer layers, leaving a gap of 120 mm, which is filled with mineral wool boards. After 5 - 8 rows, ligation is made with stainless steel steel ties (a mesh of 2 longitudinal and 2 transverse wires), horizontally - about 600 mm. You can use glass or carbon fiber reinforcement, placing it at an angle of 45 degrees. The segments are laid alternately at an angle of 45 and 135 degrees (approximately). This reinforcement does not bend, and its segments are laid at an angle with respect to the axis of the wall. It is either very difficult to bend them (for small diameters) or impossible at all.

Collapse analysis facing walls in Moscow over the past 10 years has shown that the "black" metal corrodes to complete destruction in 3 - 5 years.

The transition in the overlap zone is made in accordance with the project with mandatory thermal insulation of the end of the floor slab.

With a separate method of erecting a wall, the insulation is installed in two ways:

• wet lightweight - the insulation is glued to the wall with glue and steel or high-strength is strengthened on its outer surface plastic mesh on which plastering is carried out;
• in dry way finished wall with a crate of profiles or wooden bars mounted on the wall heat-insulating layer, on top of which a brick cladding is attached, artificial stone etc.

When building multilayer walls using fixed formwork, ready-made blocks are used in the form of box-shaped reinforced structures made of expanded polystyrene, wood concrete (chip concrete), porous ceramics, glass foam, etc.

These blocks, like the Lego constructor, are installed with dressing and form a wall. In the cavity of the blocks in vertical position(if necessary and horizontally) steel or composite plastic reinforcement is installed and poured with concrete. You can use ordinary concrete, or concrete with heat-insulating fillers, or foaming concrete.

Can be used slabs from the most different kinds insulation. They are attached to the reinforcing cage of the future wall and the concrete is poured layer by layer.

A horizontal reinforcing cage is mounted on the upper part of the wall and poured with dense concrete. monolithic belt along the entire perimeter of the building and internal load-bearing walls. After the concrete has gained strength, floor slabs are installed.

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