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External walls for a private house - choosing a reliable design solution. Panel walls and their design solutions. Wall joints Structural solutions for walls

Walls are the main load-bearing and enclosing structures of a building. They must be strong, rigid and stable, have the required fire resistance and durability, be low thermal conductivity, heat resistant, sufficiently air and soundproof, and also economical.
Basically, external influences on buildings are perceived by roofs and walls (Fig. 2.13).

The wall has three parts: the lower one is the plinth, the middle one is the main field, the upper one is the entablature (cornice).

Figure 2.13 External impacts on the building: 1 - permanent and temporary vertical force impacts; 2 - wind; 3 - special force impacts (seismic or others); 4- vibrations; 5 - lateral soil pressure; 6- ground pressure (resistance); 7 - ground moisture; 8 - noise; 9 - solar radiation; 10 - precipitation; 11 - state of the atmosphere (variable temperature and humidity, presence of chemical impurities)

By the nature of perception and transmission of loads walls (external and internal) are divided into load-bearing, self-supporting and curtain walls (with a load-bearing frame) (Fig. 2.14). Load-bearing walls must ensure the strength, rigidity and stability of the building from the effects of wind loads, as well as loads on floors and coverings, transferring the resulting forces through the foundations to the base. Self-supporting walls must maintain their strength, rigidity and stability when exposed to loads from wind, their own weight and the overlying part of the wall. Curtain walls, intended only to protect premises from atmospheric influences (cold, noise), are constructed using highly effective lightweight multilayer thermal insulation materials. They usually transfer the load (wind) within one panel and from their own mass to the elements of the supporting frame of the building.

By the nature of placement in the building a distinction is made between external walls, i.e. enclosing the building, and internal walls - separating rooms.

By type of materials used the walls can be wooden (logs, paving stones, frame-panel, etc.), made of stone materials, concrete, reinforced concrete, as well as multilayer (using highly effective heat-insulating materials as a heat-insulating layer).

The main parts of external walls are plinths, openings, piers, lintels, pilasters, buttresses, pediment, cornices and parapets (Fig. 2.14). Basement - the lower part of the wall adjacent to the foundation. The walls have openings for windows, doors and gates. The sections of walls between the openings are called piers, and those above the openings are called lintels. The crown cornice is the upper protruding part of the wall. Parapet is part of the wall enclosing the roof in buildings with internal drainage.

Figure 2.14 Wall structures: a - load-bearing in a frameless building; b - the same in a building with an incomplete frame; c - self-supporting; g - mounted; d - main parts of the walls; 1- foundation; 2 - wall; 3 - overlap; 4 - crossbar; 5 - column; 6 - foundation beam; 7 - strapping beam; 8 - base; 9 - opening; 10 - cornice; 1 - pier; 12 - jumper

In frame one-story industrial buildings with large openings, significant height and length of walls, to ensure their stability, half-timbering is used, which is reinforced concrete or steel frame, which supports the walls and also absorbs the wind load and transfers it to the main frame of the building.

According to the design solution, the walls can be solid, or layered.

Walls are the most expensive structures. The cost of external and internal walls is up to 35% of the cost of the building. Consequently, the effectiveness of the structural design of the walls significantly affects the technical and economic indicators of the entire building.

When selecting and designing the wall structure of civil buildings, it is necessary to:

• reduce material consumption, labor intensity, estimated cost and cost;
• apply the most efficient materials and wall products;
• reduce the mass of walls;
• make the most of physical and mechanical properties materials;
• use materials with high construction and performance qualities, ensuring the durability of the walls.

In terms of thermal engineering, the enclosing parts of buildings must meet the following requirements:

• provide the necessary resistance to the passage of heat through them;
• not have a temperature on the inner surface that is significantly different from the indoor air temperature so that cold is not felt near the fences and condensation does not form on the surface;
• possessing sufficient heat resistance (thermal inertia) so that fluctuations in external and internal temperatures are less reflected in fluctuations in the temperature of the internal surface.
• maintain normal humidity conditions, as humidification reduces the heat-protective properties of the fence.

Brick walls. The materials for masonry are bricks: ordinary clay, silicate, hollow plastic pressed; hollow brick semi-dry pressed. (Fig. 2.15) When making a stack of bricks, their thickness can be different, depending on the climatic zone. So, in the conditions of Almaty, the wall thickness is 510 mm (2 bricks), and for internal load-bearing walls - 380 mm (one and a half bricks) and even 250 mm. Ceramic hollow stones and small concrete blocks (eg 490x340x388) can be used. Brick grades 50 - 150.

Ordinary clay brick is manufactured in dimensions 250x120x65 mm (88 mm) and has a volumetric mass of 1700 - 1900 kg/m 3.
Effective clay bricks are produced hollow and lightweight. The volumetric mass of hollow brick is 1300 - 1450 kg/m 3, lightweight brick is 700 - 1000 kg/m 3 or more.

Sand-lime brick has a volumetric mass of 1800 - 2000 kg/m 3 ; dimensions 250x120x65 (88 mm).

Slag brick has a volumetric mass of 1200 -1400 kg/m 3.
Hollow ceramic stones differ from hollow bricks in their height dimensions (138, 188, 298 mm), shape and location of voids. Ceramic stones of plastic pressing with 7 and 18 voids and have dimensions 250x120x138 mm, volumetric mass 1400 kg/m 3

Lightweight concrete stones there are solid and hollow volumetric mass 1100 - 1600 kg/m3.

The dimensions of stones with slot-like blind voids are 190x390x188 and 90x390x188, three-hollow ones - 120x250x138 mm.

Stones with slot-like voids have the best thermal performance.

Facing bricks and stones are divided into profile and ordinary (solid and hollow).

Shaped ceramic slabs are either embedded or leaned.

In addition to ceramic products, concrete and other non-fired slabs and stones can be used for wall cladding. Natural stones and slabs from: natural stone is used for laying foundations and walls, for cladding (in the form of facing slabs - sawn, chipped, hewn, polished). Natural stone is also used to make floors, window sills and stair steps. Solid masonry made from ordinary brick and heavy stone materials is used to a limited extent - where increased strength is required, as well as in rooms with high humidity. In other cases it is recommended; use lightweight masonry.
The masonry is carried out using heavy (sand) or light (slag) mortars of grade 10; 25 - 50 and 100.

Continuous masonry is carried out using a multi-row (spoon) or single-row (chain) suture ligation system, masonry of narrow walls (no more than 1.0 m wide) is the same as masonry brick pillars, is carried out according to a three-row system. The thickness of horizontal seams is assumed to be 12 mm, vertical 10 mm. For lightness and insulation, wells filled with lightweight concrete are left in the wall.

Figure 2.15 Walls made of brick and ceramic stones: a- single-row; b- multi-row; c - systems L.I. Onishchika; g - brick and concrete; d-well; e- with an air gap; g - with slab insulation; 1- poke; 2 spoons; 3-light concrete; 4-air gap; 5-plaster; 6- slab insulation; 7-grout.

Walls made of large blocks. Buildings from large blocks are constructed without frames and with frames (Fig. 2.16.). According to their purpose, large blocks are divided into blocks for external and internal walls, for walls of basements and plinths, and special blocks (eaves, for bathrooms, etc.). The material for large blocks is lightweight concrete with a class of at least B5 (slag concrete, expanded clay concrete, cellular concrete large-porous concrete, concrete on porous crushed stones) volumetric weight 1000; 1400 and 1600 kg/m3.
Concrete blocks for external walls they have a thickness of 300; 400 and 500 mm, for internal walls 300 mm. Outer surface blocks are textured with decorative concrete or facing tiles, and the inner surface is prepared for finishing.

Walls made of large panels. According to their design, the panels are divided into single-layer and multi-layer (Fig. 2.17). Single-layer panels are made from lightweight concrete with a volumetric weight of up to 1200 kg/m 3, which has the required frost resistance and heat-insulating qualities.

Multilayer panels (two-layer and three-layer) consist of a load-bearing shell that absorbs all loads and insulation. The outer surface of the panels can be textured with a 20mm thick decorative layer of white and colored cement, lined with ceramic tiles, etc. The inner surface of the panels must have a finishing layer 10mm thick.

The transmission of vertical forces in horizontal joints between panels represents the most difficult task large-panel construction.

Figure 2.16.Large-block walls of civil buildings: a - two-, three- and four-row cutting of external load-bearing walls; b-main types of wall blocks; c - double-row cutting self-supporting walls; I, II, III, IV - rows of blocks; d - diagrams of the arrangement of blocks in axonometry; blocks: 1- wall; 2 - jumper; 3 - window sill; 4-belt.

Figure 2.17 Panel walls of civil buildings: Cutting of external walls: a- single-row with panels per room; b- the same for two rooms; c- double-row cutting of the panel structure; g-single-layer concrete; d - two-layer reinforced concrete; e - the same three-layer; g - from rolled slabs; 1- panel with an opening; 2- ribbon panel; 3- wall panel; 4 - reinforcement frame; 5 - lightweight concrete; 6 - decorative concrete; 7 - insulation; 8 - heating panel; 9 - reinforced concrete slab; 10 - rolled plate.

Four main types of connections have been used in practice (Fig. 2.18):

• platform joint, the peculiarity of which is that the floors are supported by half the thickness of the transverse wall panels, i.e. stepwise transmission of forces, in which forces are transmitted from panel to panel through the supporting parts of the floor slabs;
• serrated joint, representing a modification of a platform-type joint, provides deeper support for floor slabs, which, like a “dovetail”, rest on the entire width of the wall panel, but forces are transferred from panel to panel not directly, but through the supporting parts of the floor slabs;
• contact joint with the ceilings supported on remote consoles and direct transfer of forces from panel to panel;
• contact-socket the joint with the support of the panels is also based on the principle of direct transfer of forces from panel to panel and the support of the floors through consoles or ribs (“fingers”) protruding from the slabs themselves and placed in specially placed slots in the transverse panels.

Platform junction applied for all types of nine-story buildings, and also, as an experiment, in 17-story and 25-story buildings with a narrow pitch of transverse load-bearing walls.

Figure 2.18 Types of horizontal joints between load-bearing panels: a-platform; b-toothed; c- contact on remote consoles; g-contact-socket

General requirements and classification

One of the most important and difficult structural elements the building is outer wall (4.1).

External walls are subject to numerous and varied force and non-force impacts (Fig. 4.1). They perceive their own weight, permanent and temporary loads from floors and roofs, the effects of wind, uneven deformations of the base, seismic forces, etc. From the outside, external walls are exposed to solar radiation, precipitation, variable temperatures and humidity of the outside air, external noise, and from the inside - the effects of heat flow, water vapor flow, noise.

Fig.4.1. Loads and impacts on the structure outer wall.

Performing the functions of an external enclosing structure and a composite element of facades, and often a load-bearing structure, the external wall must meet the requirements of strength, durability and fire resistance corresponding to the capital class of the building, protect the premises from adverse external influences, ensure the necessary temperature and humidity conditions of the enclosed premises, have decorative qualities. At the same time, the design of the external wall must satisfy industrial requirements, as well as economic requirements for minimum material consumption and cost, since external walls are the most expensive structure (20 - 25% of the cost of all building structures).

In the external walls there are usually window openings for lighting the premises and doorways for entrance and exit to balconies and loggias. The complex of wall structures includes filling of window openings, entrance and balcony doors, open space structures. These elements and their connections to the wall must meet the requirements listed above. Since the static functions of walls and their insulating properties are achieved through interaction with internal load-bearing structures, the development of external wall structures includes the solution of interfaces and joints with floors, internal walls or frames.

Expansion joints

External walls, and with them the rest of the building structures, if necessary and depending on the natural-climatic and engineering-geological conditions of construction, as well as taking into account the features of space-planning solutions, are cut vertically expansion joints (4.2) various types: temperature-shrinkage, sedimentary, anti-seismic, etc. (Fig. 4.2).

Fig.4.2. Expansion joints: a – temperature-shrinkable; b – sedimentary type I; c – sedimentary type II; d – antiseismic.

Temperature shrinkage seams arranged to avoid the formation of cracks and distortions in the walls caused by the concentration of forces from the effects of variable temperatures and shrinkage of the material (masonry, monolithic or prefabricated concrete structures etc.). Temperature-shrinkage joints cut through the structures of only the ground part of the building. The distances between temperature-shrinkable seams are assigned in accordance with climatic conditions and physical and mechanical properties of wall materials. So, for example, for external walls made of clay brick on mortar grade M50 or more, the distance between temperature-shrinkage joints of 40 - 100 m is taken according to SNiP II-22-81 “Stone and reinforced masonry structures”. In this case, the shortest distance refers to the most severe climatic conditions.

In buildings with longitudinal load-bearing walls, seams are arranged in the area adjacent to transverse walls or partitions; in buildings with transverse load-bearing walls, seams are often arranged in the form of two paired walls. The smallest seam width is 20 mm. Seams must be protected from blowing, freezing and through leaks using metal expansion joints, sealing, and insulating liners. Examples of design solutions for temperature-shrinkage joints in brick and panel walls are given in Fig. 4.3.

Fig.4.3. Device details expansion joints in brick and panel buildings: a – with longitudinal load-bearing walls (in the area of ​​the transverse stiffness diaphragm); b – with transverse walls with paired internal walls; c – in panel buildings with transverse walls; 1 – outer wall; 2 – internal wall; 3 – insulating liner wrapped in roofing felt; 4 – caulk; 5 – solution; 6 – cover plate; 7 – floor slab; 8 – outer wall panel; 9 – the same, internal.

Sedimentary seams should be provided in places where there are sharp differences in the number of storeys of the building (sedimentary joints of the first type), as well as in case of significant unevenness of deformations of the base along the length of the building, caused by the specific geological structure of the base (sedimentary joints of the second type). Settlement seams of the first type are prescribed to compensate for differences in vertical deformations of ground structures of the high and low parts of the building, and therefore they are arranged similarly to temperature-shrinkable ones only in ground structures. The design of the seam in frameless buildings provides for the installation of a sliding seam in the zone of support of the floor of the low-rise part of the building on the walls of the multi-story; in frame buildings, the hinged support of the crossbars of the low-rise part on the columns of the high-rise part. Sedimentary joints of the second type cut the building to its entire height - from the ridge to the base of the foundation. Such seams in frameless buildings are constructed in the form of paired frames. The nominal width of settlement joints of the first and second types is 20 mm.

Wall classification

External wall structures are classified according to the following criteria:

The static function of the wall, determined by its role in structural system buildings;

Material and construction technology determined construction system buildings;

Constructive solution - in the form of a single-layer or layered enclosing structure.

By static function distinguish (Fig. 4.4) load-bearing walls (4.3), self-supporting walls(4.4) and curtain walls (4.5).

Fig.4.4. Classification of external walls by bearing capacity: a – load-bearing; b – self-supporting; c - non-load-bearing

Non-load-bearing walls are supported floor by floor on adjacent internal structures of the building (floors, walls, frame).

Load-bearing and self-supporting walls perceive horizontal loads along with vertical ones, being vertical elements of rigidity of structures. In buildings with non-load-bearing external walls, the functions of vertical stiffeners are performed by the frame, internal walls, diaphragms or stiffening trunks.

Load-bearing and non-load-bearing external walls can be used in buildings of any number of floors. The height of self-supporting walls is limited in order to prevent operationally unfavorable mutual displacements of self-supporting and internal load-bearing structures, accompanied by local damage to the finishing of the premises and the appearance of cracks. IN panel houses, for example, it is permissible to use self-supporting walls with a building height of no more than 4 floors. The stability of self-supporting walls is ensured by flexible connections with internal structures.

Load-bearing external walls are used in buildings of various heights. The maximum number of storeys of a load-bearing wall depends on the load-bearing capacity and deformability of its material, design, the nature of the relationships with internal structures, as well as on economic considerations. For example, the use of lightweight concrete panel walls is advisable in buildings up to 9–12 floors high, load-bearing brick exterior walls in mid-rise buildings, and steel lattice shell walls in 70–100 storey buildings.

Based on the material, there are four main types of wall structures: concrete, stone, non-concrete materials and wood. In accordance with the construction system, each type of wall contains several types of structures: concrete walls - made of monolithic concrete, large blocks or panels; stone walls - brick or small blocks, walls made of large stone blocks and panels; wooden walls - chopped, frame-panel, panel and panel.

External walls can be of single-layer or layered construction. Single-layer walls are erected from panels, concrete or stone blocks, monolithic concrete, stone, brick, wooden logs or beams. IN layered walls various functions are entrusted to various materials. Strength functions are provided by concrete, stone, wood; durability functions - concrete, stone, wood or sheet material (aluminum alloys, enameled steel, asbestos cement, etc.); thermal insulation functions - effective insulation materials (mineral wool boards, fiberboard, expanded polystyrene, etc.); vapor barrier functions – roll materials(pasting roofing felt, foil, etc.), dense concrete or mastics; decorative functions - various facing materials. An air gap may be included in the number of layers of such a building envelope. Closed - to increase its resistance to heat transfer, ventilated - to protect the room from radiation overheating or to reduce deformations of the outer cladding layer of the wall.

Question 4.1. Can walls be called load-bearing if they bear the load not only from their own weight, but also from other elements of the building?

4.1. answer: yes

4.1. answer: NO

Design solutions walls

The thickness of the external walls is selected according to the largest of the values ​​obtained as a result of static and thermal calculations, and is assigned in accordance with the design and thermal characteristics of the enclosing structure.

In prefabricated concrete housing construction, the calculated thickness of the outer wall is linked to the nearest larger value from the unified series of outer wall thicknesses adopted in the centralized production of molding equipment: 250, 300, 350, 400 mm for panel buildings and 300, 400, 500 mm for large-block buildings.

The calculated thickness of stone walls is coordinated with the dimensions of the brick or stone and is taken equal to the nearest greater structural thickness obtained during masonry. With brick sizes of 250×120×65 or 250×120×88 mm (modular brick), the thickness of the solid masonry walls is 1; 1.5; 2; 2.5 and 3 bricks (including 10 mm vertical joints between individual stones) are 250, 380, 510, 640, and 770 mm.

The structural thickness of a wall made of sawn stone or light concrete small blocks, the standardized dimensions of which are 390 × 190 × 188 mm, when laid in one stone is 390 and 1.5 - 490 mm.

The design of walls is based on the comprehensive use of the properties of the materials used and solves the problem of creating the required level of strength, stability, durability, insulation and architectural and decorative qualities.

According to modern requirements economical use of materials when designing low-rise residential buildings with stone walls, they try to use the maximum amount of local building materials. For example, in areas remote from transport routes, small locally produced stones or monolithic concrete are used to build walls in combination with local insulation and local aggregates, which require only imported cement. In villages located near industrial centers, houses are designed with walls made of large blocks or panels manufactured at enterprises in this region. Currently, more and more wide application Stone materials are obtained during the construction of houses on garden plots.

When designing low-rise buildings Typically, two design schemes for external walls are used - solid walls made of homogeneous material and lightweight multilayer walls made of materials of different densities. For the construction of internal walls, only solid masonry is used. When designing external walls using a solid masonry scheme, preference is given to less dense materials. This technique allows you to achieve a minimum wall thickness in terms of thermal conductivity and more fully use the load-bearing capacity of the material. Construction materials high density is advantageous to use in combination with low-density materials (lightweight walls). The principle of constructing lightweight walls is based on the fact that the load-bearing functions are performed by a layer (layers) of high-density materials (γ > 1600 kg/m3), and the heat insulator is a low-density material. For example, instead of a solid outer wall made of clay brick 64 cm thick, you can use a lightweight wall structure made from a layer of the same brick 24 cm thick, with fiberboard insulation 10 cm thick. Such a replacement leads to a reduction in the weight of the wall by 2.3 times.

Artificial and natural small stones are used to make walls of low-rise buildings. Currently, artificial firing stones (solid clay bricks, hollow bricks, porous bricks and ceramic blocks) are used in construction; unfired stones (sand-lime brick, hollow blocks of heavy concrete and solid blocks of light concrete); natural small stones - torn rubble, sawn stones (tuff, pumice, limestone, sandstone, shell rock, etc.).

The size and weight of the stones are designed in accordance with hand-laying technology and taking into account maximum mechanization of work. The walls are laid out from stones with the gap between them filled with mortar. Cement-sand mortars are most often used. For laying internal walls, ordinary sand is used, and for external walls, low-density sand (perlite, etc.). Wall laying is carried out with mandatory compliance suture dressings(4.6) in rows.

As already noted, the width of the wall masonry is always a multiple of the number of brick halves. The rows facing the façade surface of the masonry are called front mile, and those facing the inside – inner mile. The rows of masonry between the inner and front versts are called forgettable. Bricks laid with the long side along the wall form spoon row, and the walls laid across - splice row. Masonry system(4.7) is formed by a certain arrangement of stones in the wall.

The row of masonry is determined by the number of spoon and butt rows. With uniform alternation of spoon and butt rows, a two-row (chain) masonry system is obtained (Fig. 4.5b). A less labor-intensive multi-row masonry system, in which one interlocking row of bricks binds five rows of spoons (Fig. 4.5a). In walls made of small blocks, erected using a multi-row system, one tying row ties two tread rows of masonry (Fig. 4.5c).

Fig.4.5. Types of hand-made walls: a) – multi-row brickwork; b) – chain brickwork; c) – multi-row masonry; d) – chain masonry

Solid masonry of high-density stones is used only for the construction of internal walls and pillars and external walls unheated premises(Fig. 4.6a-g). In some cases, this masonry is used for the construction of external walls using a multi-row system (Fig. 4.6a-c, e). The double-row stone laying system is used only in necessary cases. For example, in ceramic stones It is recommended to place void gaps across the heat flow in order to reduce the thermal conductivity of the wall. This is achieved using a chain laying system.

Lightweight external walls are designed in two types - with insulation between two solid masonry walls or with an air gap (Fig. 4.6i-m) and with insulation lining the solid masonry wall (Fig. 4.6n, o). In the first case, there are three main structural options for walls - walls with horizontal releases of anchor stones, walls with vertical diaphragms made of stones (well masonry) and walls with horizontal diaphragms. The first option is used only in cases where lightweight concrete is used as insulation, which embeds anchor stones. The second option is acceptable for insulation in the form of pouring lightweight concrete and laying thermal liners (Fig. 4.6k). The third option is used for insulation made from bulk materials (Fig. 4.6l) or from lightweight concrete stones. Solid masonry walls with an air gap (Fig. 4.6m) also belong to the category of lightweight walls, since the closed air gap acts as an insulation layer. It is advisable to take the thickness of the layers equal to 2 cm. Increasing the layer practically does not increase its thermal resistance, and reducing it sharply reduces the effectiveness of such thermal insulation. More often, an air gap is used in combination with insulation boards (Fig. 4.6k, o).

Fig. 4.6, Options for manual masonry of walls of low-rise residential buildings: a), b) - solid external walls made of brick; c) – solid internal brick wall; e), g) – solid external walls made of stones; d), f) – solid internal walls made of stones; i)-m) – lightweight walls with internal insulation; n), o) – lightweight walls with external insulation; 1 – brick; 2 – plaster or sheet cladding; 3 – artificial stone; 4 – slab insulation; 5 – air gap; 6 – vapor barrier; 7 – wooden antiseptic strip; 8 – backfill; 9 – solution diaphragm; 10 – lightweight concrete; 11 – natural frost-resistant stone

To insulate stone walls on the street side, rigid slab insulation made of lightweight concrete, foam glass, fiberboard in combination with weather-resistant and durable cladding (asbestos cement sheets, boards, etc.) is used. The option of insulating walls from the outside is effective only if there is no access of cold air to the contact area of ​​the load-bearing layer with the insulation layer. To insulate the external walls on the room side, semi-rigid slab insulation (reed, straw, mineral wool, etc.) is used, located close to the surface of the first or with the formation of an air gap, 16 - 25 mm thick - “at the distance”. The slabs are attached to the wall with metal zigzag brackets or nailed to antiseptic wooden slats. The open surface of the insulation layer is covered with sheets of dry plaster. Between them and the insulation layer, a layer of glassine vapor barrier must be placed, polyethylene film, metal foil, etc.

Study and analyze the above material and answer the proposed question.

Question 4.2. Can rows of bricks laid with the long side along the wall be called bonded rows?

4.2. answer: yes

The structures of external walls of civil and industrial buildings are classified according to the following criteria:

1) by static function:

a) load-bearing;

b) self-supporting;

c) non-load-bearing (mounted).

Load-bearing external walls perceive and transfer to the foundations their own weight and loads from adjacent building structures: floors, partitions, roofs, etc. (at the same time they perform load-bearing and enclosing functions).

Self-supporting external walls take vertical load only from their own weight (including the load from balconies, bay windows, parapets and other wall elements) and transfer them to the foundations through intermediate load-bearing structures - foundation beams, grillages or plinth panels(simultaneously perform load-bearing and enclosing functions).

Non-load-bearing (curtain) external walls, floor by floor (or across several floors), rest on adjacent load-bearing structures of the building - floors, frames or walls. Thus, curtain walls perform only an enclosing function.

Load-bearing and non-load-bearing external walls are used in buildings of any number of floors. Self-supporting walls rest on their own foundation, so their height is limited due to the possibility of mutual deformations of the external walls and internal structures of the building. The higher the building, the greater the difference in vertical deformations, therefore, for example, in panel houses, the use of self-supporting walls is allowed when the building height is no more than 5 floors.

The stability of self-supporting external walls is ensured by flexible connections with the internal structures of the building.

2) According to the material:

a) stone walls are built from bricks (clay or silicate) or stones (concrete or natural) and are used in buildings of any number of floors. Stone blocks are made from natural stone (limestone, tuff, etc.) or artificial (concrete, lightweight concrete).

b) Concrete walls made of heavy concrete of class B15 and higher with a density of 1600 ÷ 2000 kg/m3 (load-bearing parts of the walls) or light concrete of classes B5 ÷ B15 with a density of 1200 ÷ 1600 kg/m3 (for thermal insulation parts of the walls).

For the production of lightweight concrete, artificial porous aggregates (expanded clay, perlite, shungizite, agloporite, etc.) or natural lightweight aggregates (crushed stone from pumice, slag, tuff) are used.

When constructing non-load-bearing external walls, cellular concrete (foam concrete, aerated concrete, etc.) of classes B2 ÷ B5 with a density of 600 ÷ 1600 kg/m3 is also used. Concrete walls are used in buildings of any number of floors.

V) Wooden walls used in low-rise buildings. For their construction, pine logs with a diameter of 180 ÷ 240 mm or beams with a section of 150x150 mm or 180x180 mm are used, as well as board or glue-plywood panels and panels with a thickness of 150 ÷ ​​200 mm.

d) walls made of non-concrete materials are mainly used in the construction of industrial buildings or low-rise civil buildings. Structurally, they consist of outer and inner cladding made of sheet material(steel, aluminum alloys, plastic, asbestos cement, etc.) and insulation (sandwich panels). Walls of this type are designed as load-bearing only for one-story buildings, and for larger storeys - only as non-load-bearing.

3) according to a constructive solution:

a) single-layer;

b) two-layer;

c) three-layer.

The number of layers of the building’s external walls is determined based on the results of thermal engineering calculations. To comply with modern standards for heat transfer resistance in most regions of Russia, it is necessary to design three-layer external wall structures with effective insulation.

4) according to construction technology:

a) by traditional technology Hand-laid stone walls are being erected. In this case, bricks or stones are laid in rows in layers cement-sand mortar. The strength of stone walls is ensured by the strength of the stone and mortar, as well as the mutual bandaging of vertical seams. To further increase the load-bearing capacity of masonry (for example, for narrow walls), horizontal reinforcement with welded mesh is used every 2 ÷ 5 rows.

The required thickness of stone walls is determined by thermal engineering calculation and linked with standard sizes bricks or stones. Apply brick walls 1 thick; 1.5; 2; 2.5 and 3 bricks (250, 380, 510, 640 and 770 mm, respectively). Walls made of concrete or natural stones when laying 1 and 1.5 stones, the thickness is 390 and 490 mm, respectively.

5) according to the location of window openings:

From the consideration of these options, it can be seen that the functional purpose of the building (residential, public or industrial) determines the constructive solution of its external walls and appearance generally.

One of the main requirements for external walls is the necessary fire resistance. According to the requirements of fire safety standards, load-bearing external walls must be made of fireproof materials with a fire resistance limit of at least 2 hours (stone, concrete). The use of fire-resistant load-bearing walls (for example, wooden plastered walls) with a fire resistance limit of at least 0.5 hours is allowed only in one- and two-story houses.

A study of the old residential buildings of Moscow, St. Petersburg, Kaliningrad, Kaluga and other Russian cities showed that within the long-established central part of the city the main objects overhaul and reconstructions are two- to five-story residential buildings built at the beginning of the last century. The variety of structural forms of objects of the old stock is distinguished by a relatively small assortment: material - rubble stone, brick, wood; construction technology - manual labor.

Constructive solutions for old houses

Foundations at ordinary soils, as a rule, were erected in strips from torn rubble stone, less often - from burnt iron bricks with a complex mortar. On weak, unevenly compressed soils, for example, in St. Petersburg, foundations were often built on an artificial foundation - on wooden piles or beds.

Load-bearing walls of residential buildings were laid out on heavy cement and lime mortars made of solid red brick of the highest (by today's standards) quality. As a result, they have been preserved much better than other types of structures. The thickness of the walls ranges from 2.5 to 4 bricks. The rigid connection of the longitudinal and transverse stone walls of the buildings was ensured by installing hidden connections made of the strongest wrought iron. In general, civil buildings built before the revolution are characterized by a wide variety of design solutions and the presence of a significant number of transverse walls that provide high spatial rigidity of the load-bearing frame. The vertical load in these buildings is usually carried by external and internal longitudinal walls. Occasionally there are load-bearing wooden half-timbered partitions. Interior partitions They were made of wood (plastered on both sides with shingles) or brick.

The main type of floors in old stone buildings is the floor wooden beams with a roll of plates or boards. The pitch of load-bearing beams according to the pre-revolutionary “standard position” was usually assigned to 1-1.5 m. The floors in the living area are wooden, parquet or linoleum. In wet rooms and in the area of ​​staircases and elevators - from metlakh tiles, or cement with iron reinforcement.

Rafter system pitched roofs were built from layered logs and hanging type. Most staircase designs stone buildings designed in the form of stone or concrete steps laid on steel stringers. In staircases with one stringer per flight, one end of the steps was embedded in the masonry of the walls.

Typification of design solutions of the old foundation

A number of research organizations are engaged in research and typification of design solutions in the field of major repairs and reconstruction of old residential buildings. The research results are summarized in unified system and sorted into groups and categories according to a variety of classification criteria.

In Fig. 1. a schematic plan and section of a residential building is presented, indicating the structural elements and technical and economic parameters that are of greatest interest to designers and builders working in the field of reconstruction of old buildings.

Fig.1. Schematic plan and section of an old residential building with the designation of the main typification parameters

Analysis of the data accumulated by engineers and builders during the research process allows us to draw the following conclusions:

1. The most common two-bay scheme of residential buildings (from the 1st internal wall), less often - three-span (with 2 internal walls). The share of these schemes accounts for 53-54%, i.e. more than half of all houses.

2. The “clear” distance between load-bearing walls is:

• in Moscow from 4 to 7 m - 51%; from 7 or more - 46.9%;
• in St. Petersburg from 4 to 7 m - 77.1%; from 7 or more - 16.7%.

3. The most common distances between the axes of external walls:

• in Moscow from 2 to 2.5 m - 80.5%;
• in St. Petersburg from 1.75 to 2.75 m - 87.9%.

4. External walls in their upper part, at the level attic floor, have a thickness of 60 to 90 cm, and internal walls - from 40 to 80 cm.

5. The thickness of the ceilings and floors ranges from 33 to 40 cm (89.6%).

6. Floor heights also vary widely. However, in Moscow, buildings with floor heights from 3 to 4 m are 93.1%, and in St. Petersburg - 84.3%.

The considered design characteristics of old residential buildings should form the basis for the development of industrial engineering solutions.

Modern building codes require additional insulation of stone walls, since otherwise their thickness would be too large. But, if when laying a thick wall there is no technical issues, then the multilayer structure, which contains insulation, raises these questions, and quite acutely. Mistakes made during insulation can be very expensive, and in order to avoid them, it is necessary to thoroughly study the theoretical part.

Frankly speaking, the issue of insulation is one of the most difficult in construction. Main problem, which has long haunted heating engineers, is the moistening of insulation. As you know, the more the insulation is moistened, the worse it copes with its function.

The technology for insulating the building envelope depends on the materials from which they are built. In this article we will look at the main options for insulating stone walls, i.e. made up of various building stones, in particular, ceramic and silicate bricks, cellular concrete blocks, porous ceramics; as well as from monolithic concrete.

There are three main ways to insulate stone walls:

• outside the building envelope;
• in the thickness of the enclosing structure;
• from inside the enclosing structure.

Of these, internal insulation is considered the worst option, since the masonry in this case is not protected from external influences. In addition, with internal insulation, high-performance ventilation of the premises is necessary, otherwise condensation will form on the walls. The savings in internal insulation are only apparent, but in reality they are not at all, if you take into account operational factors.

In cottage construction, external and layered (in the thickness of the wall) insulation is most often used. But they also have a number of disadvantages that must be, if not eliminated, then minimized. Multilayer walls, in which the insulation is located between the supporting structure and the outer brick layer, are a very common solution. Such walls give the house a solid appearance and are not expected to require periodic renovation of the façade.

Used as insulation mineral wool or ordinary polystyrene foam, less often extruded, due to its high cost. In layered walls, mineral wool, subject to a number of technological requirements for its installation, works better than other insulation materials. Its main advantage is vapor permeability, which polystyrene foam, especially extruded polystyrene, lacks. However, this advantage can work against vata itself and wall structure in general, if you do not take into account the fact of waterlogging of the insulation.

It is very important to understand that the best option insulation of residential buildings is one in which each subsequent layer is more vapor-permeable than the previous one in the direction of diffusion of water vapor - from the inside to the outside. If mineral wool is sandwiched between two layers of brickwork, it will quickly become moist and lose its insulation properties. Water vapor directed from inside the premises to the outside, passing through the insulation, will hit the cold outer masonry and begin to be absorbed by the cotton wool. It is possible and necessary to combat this phenomenon. To do this, a ventilated gap of 2 cm is left between the wool and the outer layer, and ventilation holes are made in the form of unfilled vertical seams in the lower and upper rows of the masonry. This scheme is not a full-fledged ventilated facade, but significantly reduces the degree of moisture content of the fiber insulation. Condensation falls on the inner surface of the outer layer, but does not come into contact with the cotton wool, but flows down and is partially discharged through the ventilation holes.

For correct execution layered masonry with mineral wool insulation, it is necessary to use embedded parts that will connect both layers of the wall. These can be special flexible connections made of steel with an anti-corrosion coating, fiberglass or basalt plastic. They are installed in increments of 60 cm horizontally and 50 cm vertically. The connections also perform the function of fastening the insulation.

Expanded polystyrene is four times cheaper than mineral wool and is not inferior to it in heat transfer resistance. It is the low cost of polystyrene foam that makes it the most common insulation material in layered walls. However, the problem associated with its low vapor permeability does not allow this material to be called ideal for use in layered masonry. Obviously, the issue of vapor diffusion is not the easiest to understand for non-specialists, and therefore many customers choose expanded polystyrene, especially since builders do not strongly dissuade them from this. The consequences of low vapor permeability of insulation do not appear immediately, but when the problems become obvious, it will be quite difficult to make a claim. And the consequences are as follows: the load-bearing layer of the wall may become waterlogged; in a room where there is no enhanced ventilation, a characteristic smell of mold may appear, the interior decoration may be damaged, etc.

Expanded polystyrene is a flammable material, and therefore cannot be left open and, of course, no ventilated gaps can be used. In addition, according to the requirements of SP 23-101-2004 “Design of Thermal Protection of Buildings”, when using foam plastics for insulation, window and other openings must be framed around the perimeter with strips of mineral wool.

As we can see, both expanded polystyrene and mineral wool in the structure of layered walls have disadvantages. Cotton wool gets wet, but polystyrene foam does not allow steam to pass through. If you vapor-proof mineral wool insulation from the inside, then the vapors will not penetrate into its thickness, but to remove them you will need forced ventilation. The problem of cotton wool moistening is eliminated if you leave it ventilation gap between it and the façade layer. In the case of expanded polystyrene, only intensive ventilation of the premises can help.

It should be noted that the efficiency of heat insulators in layered masonry and the durability of the layered enclosing structure as a whole largely depends on the quality of installation. If mistakes have been made, they can no longer be corrected in the future.

External insulation with a plaster layer

This method of insulation is better known as “ wet facade"or "facade insulation". External insulation is less expensive than layered insulation; In addition, an indirect reduction in cost occurs due to a less powerful foundation, which is not loaded with a stone façade layer. The load-bearing part of the wall is completely protected from all external factors that could shorten its service life. In addition, external insulation does not allow water vapor to condense in the thickness of the wall, so it does not become damp. True, this only happens with high-quality execution of all technological layers; with their correct calculation and location.

In external insulation systems, both mineral wool and facade polystyrene foam (grade 25F) are used. Plaster layers that form external finishing, can be thin-layer (7-9 mm) and thick-layer (30-40 mm). Thin plaster on a warm facade is the most common. Regardless of the type of insulation, its slabs are mounted to the wall using glue and disc dowels (5 pcs/m²), and the main load-bearing function lies with the glue, and the dowels help cope with wind loads.

The standard facade insulation system, starting from the wall, consists of:

• penetrating primer;
• adhesive layer;
• thermal insulation (calculated based on the missing heat transfer resistance);
• alkali-resistant fiberglass mesh enclosed in a layer adhesive solution;
• quartz primer;
• plaster layer.

At the ground floor level, the plaster layer is made twice as thick to withstand possible impact loads.

The insulation of a cottage from the outside is usually carried out by a hired team, since it is quite difficult to cope with a large amount of work on your own, and most importantly, it takes a long time. And when mineral wool slabs are used as insulation, it is necessary to finish them as quickly as possible so that rain does not wet them. Expanded polystyrene is also not recommended to be left unfinished for a long time, because... it is quickly destroyed by solar ultraviolet radiation.

It is best to use branded facade insulation systems, because... this eliminates errors in the selection of materials. If you select it yourself, there is a risk that some technological layers will begin to conflict with each other, which will lead to their peeling up to the collapse of the facade.

Warm facades using flammable insulation, in particular polystyrene foam, require fire-resistant cuts - separation by 15-centimeter strips stone wool on the floors and framing the same stripes of window openings, as well as the location of balconies and loggias throughout the entire area.

The durability of external facade insulation systems can be calculated in decades, but only if the technology is carefully followed. So, when using mineral wool for insulation, it is important to use vapor-permeable plaster, otherwise the fibrous insulation will accumulate moisture that diffuses from the premises and rests against the pane-proof layer of acrylic plaster.