Monolithic belt for brickwork snip. Stone and reinforced masonry structures

On the foundation and walls of a building built on soft soils, cracks appear over time. The formation of defects is associated with the ability of soils to deform under the weight of the structure during periods of precipitation (wetting), freezing and thawing. In this case, the subsidence of the building may be uneven. How to protect the walls and its foundation from the appearance of cracks due to soil deformation under the influence of adverse phenomena? An experienced builder will answer that you need a reliable monolithic belt in the formwork: what it is, why it is used, and how it is organized.

If self-manufacturing of the formwork structure causes difficulties, its assembly and installation in Moscow can be ordered from our company. We offer affordable prices and a wide range of systems from leading manufacturers.

What is a formwork belt?

A monolithic belt is a beam made of reinforced concrete, which is organized above the foundation and on masonry walls. The solidity of the element is guaranteed by the installation of a temporary formwork system - a structure of panels and fixing elements for pouring liquid concrete in which it hardens. The formwork makes it possible to produce a beam that is solid and closed along its entire length without connecting seams. This feature of the belt in the formwork is extremely important to improve the performance of the structure, and therefore a lot of attention and effort is paid to the organization of a monolithic beam.

A one-piece monolithic belt is formed in the formwork from the following building materials:

• liquid concrete: sand, water, additives, cement, etc.;
• building reinforcement - it is recommended to use steel bars with a wrapping diameter of 12 mm;
• wire for knitting reinforcement - the technology for knitting rods for reinforced concrete products must be strictly observed.

A monolithic reinforced concrete belt is organized under the load-bearing elements of the building. If we are talking about a small private house, then the beam is organized around the perimeter of the outer walls. But if the project provides for internal partitions that will serve as a support for floor slabs, then a one-piece monolithic beam is laid for them.

What is the purpose of the belt?

• combining the load-bearing parts of the building into a single structure;
• uniform distribution of loads on load-bearing elements;
• alignment of the walls horizontally, which facilitates and improves the quality of further installation and construction work;
• foundation for future floors (necessarily used in multi-storey buildings);
• gives the building monolithic strength and durability.

The formation of a closed monolith-belt is mandatory if the walls are built from hollow building materials, for example, cinder block, shell rock, foam concrete or aerated concrete. According to building GOSTs and SNiP standards, it is also necessary when building a house in an area with increased seismic activity. Also, multi-storey residential buildings are not erected without a monolithic beam.

Characteristics of a monolithic closed belt

It is extremely difficult to perform the installation of belts without formwork in accordance with the standards, since it is necessary to maintain the following parameters at the stage of pouring concrete:

• the height of the reinforced concrete element is not less than 20 cm;
• the width is strictly equal to the width of the foundation, wall;
• evenness and smoothness of the surfaces of the reinforced concrete belt;
• horizontal evenness of the element;
• absence of seams and defects on surfaces.

The formwork system must be stable and not deform under the pressure of concrete. There should not be large gaps between its components. Building codes allow gaps of no more than 2 mm. The forming temporary structure must be rigid and resistant to external loads. Therefore, for its organization, materials are selected that can withstand weather and climatic, mechanical loads for a long time. But the most important thing is moisture. The quality with which the formwork for the monolithic belt was assembled and installed determines the physical and technical characteristics of the reinforced concrete element.

Recommended building materials for installation of reinforced concrete belt formwork

In private housing construction, pine or coniferous boards 40 mm thick are used to equip formwork systems. But when assembling the forming system for a monolithic beam, you need to take care of the evenness of the external and internal surfaces of the reinforced concrete element. Therefore, it is more competent to make a formwork for a belt from sheets of laminated plywood - they are moisture resistant, do not delaminate, and can then be used on the farm. An alternative option would be chipboard with a polished surface. It is profitable to buy sheets with dimensions of 2.5 m × 1.25 m - cutting in half, we get two even formwork panels with dimensions of 2.5 m × 0.62 m with perfectly smooth surfaces.

To assemble the system forming a monolithic belt, you will also need:

• rails and stops measuring 50 mm × 50 mm;
• self-tapping screws and drill;
• connecting elements for opposite panels - reinforcement or a steel bar of at least 12 mm in diameter (the length is 1.5-2 cm more than the width of the formwork);
• reinforcement frame (you can use a welded sect - an analogue of a knitted one);
• concrete grade M250.

The pouring of the liquid solution is correctly carried out using a deep vibrator. It will ensure the compaction of the mixture, which means the quality of the reinforced concrete monolith. With a belt thickness of 300 mm or more, the steel bars tightening the shields are laid in two tiers - the lower one is strictly under the upper one. If slabs 2.5 m long are chosen to organize the walls of the shield, then at least 6 tightening rods will need to be installed. When using conventional chipboard or boards, we recommend additional waterproofing. Coat the building material (including rails and props) with, for example, used motor oil. This will guarantee the stability of the formwork elements to weather loads.

In order for a house built on its own to be durable and serve without problems for many years, it is necessary to ensure structural rigidity and high-quality bonding of walls. To do this, it is necessary to erect an armored belt under the floor slabs.

For the construction of a high-quality reinforced belt, it is important that the circular casting process be continuous and one-time.

This important part of the load-bearing structure is a solid band of metal-reinforced concrete, which is laid along the perimeter of the house under the ceiling.

A monolithic reinforced belt evenly distributes pressure along the entire perimeter of the wall and provides a flat surface for subsequent overlapping.

A monolithic belt is erected along the perimeter of the walls of each floor under construction, on the last floor it plays the role of a base for the roof and. At the same time, window and door lintels can be made of a minimum size with a small amount of reinforcement, since the main load is assumed and evenly distributed by the belt.

How necessary is an armored belt?

Most often, a monolithic belt is a construction necessity, but in some cases such strengthening of the structure is not required.

You can do without an armored belt if:

• the foundation is poured below the freezing level of the soil;
• the walls of the house are made of bricks.

But even if these conditions are met, it is necessary that the floor slab extends at least 12 cm on both sides of the wall, and the building itself is located in a seismically safe area.

An armored belt is necessary if:

If the walls are made of gas silicate blocks, then the armored belt is necessary, regardless of the purpose of the room on the second floor.

• The house is multi-storey. In this case, the presence of monolithic belts is prescribed by the norms;
• The walls are built of porous materials, such as cinder blocks or aerated concrete. Under the uneven pressure of the floor slab, these materials begin to wrinkle and quickly collapse;
• The building is built on soft ground. In this case, there is a danger of subsidence of the house and, as a result, the formation of cracks in the walls. The monolithic belt will act as a screed and prevent cracks. Inspect the old buildings in the neighboring areas. If they are covered with cracks going down from the roof and up from the ground and the corners of the windows, then the construction of a reinforced belt is definitely necessary;
• The foundation of the building is made of prefabricated blocks or shallow. The armored belt will evenly distribute the pressure of the plates around the entire perimeter of the foundation;
• The house is located in a seismically active zone.

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How to build a reinforced belt?

A monolithic belt is a structurally simple element. A formwork is built along the perimeter of the wall, into which metal reinforcement is mounted. Then the structure is poured with concrete and insulated.

For the construction of a monolithic armored belt, the following materials are required:

For a 2-storey house, an armopoyas is made after the walls of the first floor are erected, before laying the floor slabs and after the second floor is erected, before the roof is installed.

• Plywood/boards;
• Fast installation;
• self-tapping screws;
• Nails;
• Ribbed metal rods;
• bricks/stones;
• Concrete / sand, cement, crushed stone;
• Cellophane film;
• Insulation (polystyrene);
• knitting wire.

And tools:

• Welding machine;
• Screwdriver;
• Perforator;
• Concrete mixer;
• Building level;
• A hammer.

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The first stage: the construction of formwork

Most often, the formwork is assembled on the basis that the armored belt will be approximately 15-30 cm in height, and in width it will either be narrower than the wall or the same size as it. In the second case, the formwork moves deeper into the wall, which makes it possible to fill the resulting gap with insulation in the future.

The optimal materials for formwork are plywood, OSB boards, boards. The formwork must be mounted so that its upper part is in a perfectly horizontal plane. This can be achieved by adjusting the installation using the building level.

There are several ways to install formwork:

If, when installing the formwork, step back 2-3 cm inward, and after pouring the "niche" fill with heat-insulating material, heat loss through the armored belt will decrease.

• Fastening by electric welding. In this case, the anchors are passed through the formwork walls, and the plugs are welded;
• Fastening with quick mounting. This method is much faster and easier to perform, but it requires some preliminary preparation. Installation practically does not hold in materials such as aerated concrete or cinder block. If the main part of the building was built from such materials, then the last rows under the proposed belt must be laid out of brick.

Holes are drilled through the board attached to the wall at a distance of 700 mm from each other. A fungus is inserted into the holes and secured with a screw. Quick installation is better to take 6x100 mm, and a 6 mm drill. When removing the drill from the resulting hole, it must be slightly swung in different directions. The hole will increase slightly and the wood fibers will not interfere with the installation of the fungus.

We fix self-tapping screws at a distance of 1 m on the upper edge of the board, and nails are similarly driven into the front brickwork. Self-tapping screws are pulled together in pairs with nails using a knitting wire.

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The second stage: the manufacture of fittings

The frame is prepared on the wall in a gutter from a removable formwork, since it is very heavy when finished.

For the manufacture of the reinforcing cage, it is necessary to use only ribbed rods. The concrete mortar is attached to the uneven surface of the ribs and thus provides greater load-bearing capacity and tensile strength.

The rods should be 12 mm in diameter and 6 m long. For transverse fastening, rods with a diameter of 10 mm are required. The transverse frame must be welded along the edges and along the central part, the remaining transverse rods are not welded, but connected with wire. In the process of assembling the frame, it is necessary to minimize welding work. The fact is that the welded seam becomes less durable due to overheating, and this is unacceptable when erecting a reinforced belt. Most of the parts should be assembled with a tie wire.

The wire can be taken of the smallest thickness, its function is to maintain the integrity of the frame shape during concrete pouring. From the use of thick wire, the frame will not become stronger, and the installation of such a structure will require much more money and effort.

When the two parts of the frame are ready, they are stacked, forming a small space between them. Then they are welded in the center and along the edges, forming a finished frame, which in cross section has the shape of a square or rectangle. It is best to do this directly in the formwork, since the resulting part has a fairly large weight.

Between the reinforcement and each side of the structure there must be a distance of at least 5 cm. To raise the reinforcement above the horizontal surface, bricks or stones are placed under the frame.

When assembling parts into a solid reinforced belt, there is no need to use welding, you can simply overlap 0.2 - 0.3 m between adjacent parts of the frame. The structure must lie flat inside the formwork; to achieve this condition, it is necessary to use the building level.

A monolithic belt is a reinforced concrete beam, which is made mainly under the ceiling in masonry walls.

At first glance, the purpose of such a belt is not clear: after all, it is possible to lean the ceiling directly onto the masonry and not arrange any belts. As they say, "cheap and cheerful." Let's analyze the reasons for the construction of a monolithic belt.
1. If the masonry material of the walls does not bear the load from the ceiling. In a brick wall made of solid brick, for example, a monolithic belt is not needed, but in a cinder block wall, when supporting the ceiling of a large span, such a belt is necessary.

In the place where the slab is supported, a significant load is concentrated (from the floor, floors, people and furniture), and all of it does not fall evenly on the wall, but increases towards the slab support. Some masonry materials (cinder block, foam and aerated concrete, shell rock, etc.) do not work well for the impact of such a concentrated load, and may simply begin to collapse. This type of destruction is called collapse. A special masonry calculation can be performed to determine if a distribution monolithic belt is needed. But in some cases (when using cinder block, foam concrete), a monolithic belt must be made for design reasons, due to experience in building from these materials.

2. If the building is being built on weak soils (for example, subsiding). Such soils tend to deform significantly after some time, during soaking or other adverse factors - to shrink under the weight of the building. At the same time, part of the house can sag, as a result, cracks form in the walls and foundation. One of the measures that protect against the adverse effects of subsidence is the installation of a continuous monolithic belt under the floors. It serves as a screed for the house and, with little rainfall, can prevent the formation of cracks. If you are going to build a house, first of all inspect the houses on the neighboring plots (preferably those that were built a long time ago). If there are slanting cracks in the walls going from the ground up, from the roof down or from the corners of the windows up, then this is the first sign that a monolithic belt will not be superfluous in your house.

3. If the house is being built in a seismic region, the installation of monolithic belts is mandatory.

4. In multi-storey buildings, the installation of monolithic belts is also required according to the norms.
Prefabricated floor or monolith?

It's time to decide on the type of flooring for your home. Here, as elsewhere, there are options that, first of all, depend on the number of storeys.

If the house is one-story, and only an attic is planned above, a lightweight option is possible - wooden flooring on metal or wooden beams.

For a house with an attic or a full-fledged second floor, a more reliable floor is needed. There are two traditional options here: a prefabricated floor made of hollow-core slabs or a monolithic floor. And to help you finally decide on the choice of the type of overlap, we will consider in detail the features of each of them.

So, prefabricated floor. If there is a factory of reinforced concrete structures in your city or neighborhood, then it is quite possible to stop at this option. The advantages of a prefabricated ceiling are the speed of installation, reliability, guaranteed good quality. This overlap is in most cases cheaper than a monolithic one.

What should you pay attention to? Typical slabs are produced in predetermined sizes (here are some slab lengths: 2.4; 3.0; 3.6; 4.5; 6.0; 7.2; 9.0 m) and require load-bearing walls for support. The layout of your house should clearly correspond to the dimensions of the selected slabs. At the same time, it is worth asking the supplier or manufacturer in advance what sizes of slabs they can deliver. If you have 3 m long slabs at your disposal, the clear distance between the walls on which they rest should be no more than 2.8 m (the minimum slab support on the wall is 10 cm). Round walls and other frills will also have to be partially refrained from.

The slabs should be supported by opposite short sides on the bearing walls. Leaning against walls on three sides is undesirable. But the arrangement of the balcony with the help of the departure of the floor slab beyond the outer wall is simply unacceptable. Firstly, floor slabs are designed so that their support zone is along the edge, but not somewhere in the span. And most importantly, with a load on such a balcony, a collapse can simply occur. And another big drawback of such improvisation is that in winter part of the plate will freeze through. As a result, winter will make its way straight into the house along the so-called "cold bridge". The result - if it doesn’t collapse, it will simply freeze, or even “cry” - from the temperature difference, the overlap may well be moistened, overgrown with fungus, mold and other delights.

Where the plates cannot be placed (due to cramped dimensions or in places of ventilation shafts from the kitchen and bathroom), it is necessary to make monolithic sections. Let's say we have a distance between the walls of 3.15 m, and the plates are available with a width of 1.0 m. In this case, there is a gap of 15 cm between the two plates, which needs to be filled with something. Here it is necessary to substitute the formwork from below, lay the reinforcement and perform concreting (see the figure - a monolithic section 150 mm wide). Such a monolithic section is reinforced with rods with a diameter of 6 mm in increments of 200 mm. Concrete is used class B15 (M200). Be sure to support the ceiling (200 × 30 mm in size) with the introduction of reinforcement bends onto the slab. Sometimes there is a need for large-width monolithic sections (up to 1 m) if it is necessary to organize a hole in the ceiling (for example, for ventilation shaft ducts). Please note - the wider the monolithic section, the larger the diameter of the reinforcement resting on the ceiling (see the figure - a monolithic section with a width of 980 mm). More information about all types of monolithic sections in prefabricated floors can be found here.
When choosing a prefabricated floor, you should carefully consider the material of the load-bearing walls. So, if it is a brick, then the thickness of the brick wall should be at least 24 cm. If you use a cinder block when building a house, you need to take into account its not very good bearing properties - in this case, you need to make a so-called monolithic belt under the ceiling - a reinforced concrete reinforced layer with a height 20-30 cm (see picture).
Now consider the option with a monolithic overlap. Of course, it is multivariate and allows you to embody almost any fantasy on the layout of your home. Walls or columns can be placed without the rigid restrictions dictated by the precast floor. It's not worth playing though. The optimal distance between the supports in monolithic reinforced concrete is 6 m. A larger distance, of course, is permissible, but such an overlap must be calculated by a specialist. And here it is just necessary to take into account the importance of the issue and include the calculation of the overlap in the expense item. An experienced specialist will help you not only ensure the reliability of the structure, but also save on material consumption - after all, the thickness of the ceiling can be from 140 to 200 mm, and according to the calculation, reinforcement should be used in different diameters - from 8 to 16 mm (and for large spans and more ), and these are quite different costs. You can, of course, take everything by eye and with a margin, but such savings will cost more.

Materials for the slab: concrete of a strength class of at least B15, hot-rolled rebar. The slab is reinforced with meshes in two planes (in the lower and upper zones of the slab). Grids can be welded (welded by resistance spot welding; welding of reinforcement crosshairs with electrodes is not allowed due to the high probability of burning through the reinforcing bar) or assembled from individual rods. In the latter case, at each intersection of the reinforcement, the rods must be connected with a special wire. The optimal step for laying reinforcing bars is 200 mm. At the same time, it is necessary to provide a protective layer of concrete for the working reinforcement (the distance from the reinforcing bar to the concrete surface) is at least 20 mm. The protective layer not only ensures the safety of the reinforcement (if it is small, the metal corrodes and rusty stripes appear on the concrete), but also increases the fire resistance of the ceiling. The minimum amount of support of a monolithic ceiling on the wall is taken on the basis that the working reinforcement must be brought to the support by at least 10 diameters (i.e., when reinforcing with rods with a diameter of 12 mm, the introduction to the support will be 120 mm; add a protective layer of 20 mm and get the minimum support of the plate on the wall 140 mm).

Theory considered, let's move on to practice. For the installation of the floor, you will need scaffolding (a system of racks that support the floor until it has gained sufficient strength), formwork (metal or wooden panels on which concrete is laid), reinforcement and concrete, and most importantly, experienced builders. Another point - concrete after laying must be subjected to vibration. If your hired builders haul concrete in wheelbarrows and lay without compaction, relying on gravity, drive them in the neck. A prerequisite for a high-quality reinforced concrete structure is vibration compaction - it is then that the concrete reaches the desired density and works with the reinforcement as a whole. Concreting at an air temperature below 5 ° C is not allowed (there may be exceptions, but a number of measures must be taken - concrete heating, the use of special additives). Concrete reaches its strength within 27 days. All this time, a positive air temperature must be maintained and loads on the still fragile floor must be excluded.

Armopoyas - a structural element of the building, arranged at the level of the top of the walls, under the floor slabs. The purpose of the armored belt is to ensure the joint operation of building structures with uneven deformations of wall materials. Also, the reinforcing belt provides a reliable connection between the walls of the building. Ensuring such a connection is necessary, because brickwork is an anisotropic material (the same can be said about laying from gas blocks, foam blocks, expanded clay blocks, etc.), which cannot work equally in compression and tension.

It is necessary to clearly distinguish between the concepts of armo-belt (armosh), armo-brick belt, monolithic belt. Armoshov is reinforcing bars arranged in one row, protected by a layer of c. n. solution. The thickness of such armoshva (armopoyas) usually reaches 30 mm. Such a structural element is laid on top of the walls, under the support of floor slabs. This type of armo-belt should be provided on the first and last floor of the building, as well as through five floors throughout the entire height of the building.

Reinforced brick belt - a constructive inclusion in brickwork from monolithic reinforced concrete. The characteristic features of the reinforced brick belt are as follows: it is located at the ends of the floor slabs and not over the entire width of the wall. Between the ends of the floor slabs and along the perimeter of the building, reinforcing cages are installed and concreted.

Monolithic reinforced concrete belt. This structural element in configuration and location resembles an armored belt (armosh), but, unlike it, it is reinforced not with one row of reinforcing bars, but with several rows, as a rule, with two, and has a height of 15 cm or more. The functional advantage of a monolithic belt lies in the distribution of the load from the floor slabs on the walls of the building, i.e. the load-bearing and non-bearing walls become approximately equally loaded and, due to this, give an approximately equal load on the foundation, and also have a smaller difference in deformations under load than walls without a monolithic belt. It is very important to arrange a monolithic belt when building a house from aerated concrete blocks. In low-rise construction, a truss roof Mauerlat is installed on a monolithic belt. Also, in addition to evenly distributing the load between different walls, the monolithic belt protects the walls from the effects of local compression under the supports of floor slabs (collapse), which is very important when building a house from aerated concrete and wood concrete blocks.

A fairly common design solution is the use of a monolithic belt as a lintel over a window or doorway. In this case, the monolithic belt is calculated as a beam on two supports (an ordinary armored belt cannot work as a jumper). The beam, in the general case, appears to be rigidly clamped at the ends, however, the decisions made in the design scheme still need to be provided constructively. If the opening is located in the middle of an extended wall along which a monolithic belt runs, then the design scheme of a rigidly clamped beam will be provided. However, if the opening is located too close to the edge of the wall, and has a large width (approximately 10-15 * H, where H is the height of the monolithic belt), then in this case it is worth calculating it as a hinged beam. Of course, it is possible to rigidly fix a monolithic belt in masonry, but this will require a number of structural calculations and constructive measures during construction, so it is better to install metal channels along its edges over the opening to strengthen the monolithic belt, which, by the way, will also serve as fixed formwork.

In the general case, the calculation of the armo-belt is performed on the action of loads from uneven settlements of the building. The reinforcing belt should prevent the rotation of one part of the building relative to the other or its parallel displacement during uneven precipitation.

When installing reinforcing and monolithic belts on brick walls, the question arises about the installation of ventilation ducts that will cross the armored belt through and through. Such solutions are very common in design practice, so that while maintaining the integrity of the working reinforcement (or part of the longitudinal rods) at the location of the ventilation duct, the operation of the reinforcing belt will not be disturbed.

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The main types of unloading belts

Depending on the location of the armored belt, it can have different names and take on certain functions:

1. Rostverk - is laid between the columnar or pile foundation of the house and the walls. However, it is not built of brick - too important a site.
2. The basement is already the second level of unloading and reinforcement, which is used in the construction of houses on a foundation of concrete blocks. It provides the base with greater rigidity on moving soils and is also made of reinforced concrete. Although a fairly common option is brickwork, which acts as a fixed formwork for subsequent pouring.
3. Unloading is an intermediate armored belt for floor slabs, which not only takes on their weight, but also ensures the rigidity of the building above one floor at each level. When building from lightweight concrete blocks, you can’t do without it, and here brick is the best way.
4. Support under the Mauerlat is an indispensable element of a house made of aerated concrete or other porous blocks that do not perceive well point and multidirectional loads. In addition, the fastening of the timber itself with the help of studs in such walls turns out to be unreliable even when chemical engineering is used. Here, the reinforced belt for walls made of aerated concrete turns into a kind of bundle between the blocks with which it is connected with mortar and the roof truss, reinforced through a Mauerlat beam.

Features of laying on aerated concrete

As a rule, a brick belt is made 4-7 rows high and the width of the wall being reinforced. Reinforcement is necessarily carried out in each horizontal seam using a steel mesh with a cell of 3-4 cm or a hard wire with a thickness of at least 5 mm. Installation is carried out in the same way as in the case of ordinary brick walls:

• with a seam offset of 1/3 of the length;
• with tychkovy dressing in every third row.

If the armored belt for aerated concrete made of brick serves as a support for the Mauerlat, vertical pins can be immured into the masonry - metal threaded studs with a diameter of 12-16 mm. They are installed in increments of 1-1.5 m, and the depth of their embedding will depend on the thickness of the beam - it should be twice as long as the free end for mounting the Mauerlat. However, many builders advise immediately immuring trimmings to the entire height of the armored belt.

After the mortar has set, a roofing material or two layers of roofing felts are spread on the surface of the masonry. This is a waterproofing that will protect the beam itself and the brick superstructure from the accumulation of condensing moisture. Further, the mauerlat is planned and drilled at the right points, strung on the stud outlets and fixed on the reinforcement belt with nuts for wide washers.

Since ceramics has a higher thermal conductivity than the main wall material, it turns into a kind of cold bridge (although monolithic reinforced concrete in this case performs even worse). So that during the further operation of the building in the winter there are no problems, you can try to “close” the contour of the cellular blocks in parallel with the laying of bricks. To do this, a thin partition from the GB is removed from the side of the premises, as if hiding the armored belt inside the aerated concrete wall. If a gap has formed between the surfaces, experts recommend additional thermal insulation.

Stages of erecting a belt under the ceiling

If a rigid contour under the roof plays the role of unloading and reliable support for the Mauerlat beam, it is enough to lay it out around the perimeter of the house box. However, the use of slabs for interfloor or attic floors will force the middle load-bearing wall to be closed with rows of bricks. Here, aerated concrete can also experience loads, so a rigid layer for its reinforcement is simply necessary.

No matter how light the floor slabs are, it is impossible to rest them directly on cellular or expanded clay concrete blocks. The masonry will be able to support their weight, but when the direction of the applied force changes, it will begin to collapse. The belt in this case serves as a kind of buffer, which distributes the pressure of the slab over the entire area of ​​​​the walls, preventing the supporting structure from being forced through. It is possible to refuse a powerful layer of solid bricks only when the floor is made of wood - here they get by with a substrate for beams in one or two blocks.

Otherwise, the armored belt for hollow-core slabs is built according to all the rules. Main stages of work:

• The first row is planted directly on aerated concrete using a solution. If the thickness of the main wall is standard (30 cm), the laying is done in two bricks, filling the gaps with "checks".
• Installation of reinforcing mesh along the entire line of the belt.
• Laying the second row in the same way, followed by reinforcement.
• The third row of bricks is tychkovy. Here you need to focus on the inner plane of the wall. The gap remaining outside is filled either with quarters or pieces of mineral wool, if an insulated ventilated facade is being erected at the same time.

Under the upper row of aerated concrete, on which the belt is placed under the floor slabs, reinforcement must be laid in the strobes. This will add rigidity to the entire structure and provide the walls with additional protection against cracks. Otherwise, once they appear, they will crawl lower.

According to the above scheme, the armored belt is laid out to the entire required height, after which floor slabs can be fearlessly mounted on it. Anchoring is carried out in the standard way for brick walls - using L-shaped metal brackets. Fasteners for protection against corrosion are closed with a layer of cement mortar.

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Introduction

Aerated concrete is an excellent alternative to brick. However, unfortunately, the value of the strength index of aerated concrete blocks is much lower. The material does not hold fasteners on its surface well.

Masonry of aerated concrete blocks has its own characteristics:

1. The construction of walls must be carried out on a solid foundation.
2. In the process of work, it is necessary to regularly check the evenness of the structure.
3. Along the entire perimeter of the building, the walls should be strengthened with a reinforced belt made of reinforced concrete.

When conducting construction work in violation of technological rules, cracking of blocks may occur under the influence of roof pressure.

The meaning of the armored belt

A reinforced belt is a monolithic structure located around the entire perimeter of the building. Armopoyas protects the walls of the house from destruction and deformation under the influence of loads. The technology of strengthening the wall surface of an object involves laying a relief belt between the ceilings of each floor and at the place of roofing.

To ensure the functionality of the armored belt, its structure must be:

1. continuous.
2. Ring style.
3. closed.

The main components of the armored belt:

• Armature frame.
• Concrete mix.
• Formwork or blocks.

The purpose of the design is:

• In the distribution of the bearing load from additional floors or roofing on the walls in order to give them strength.
• In protecting the foundation and walls from cracks.
• In increasing the spatial rigidity of the building.

The design ensures the strength and reliability of load-bearing walls, increases the resistance of the structure to the effects of wind, temperature changes, seismic vibrations, shrinkage of the soil and the construction site itself.

Armo-belt dimensions

The dimensions of the armored belt depend on the design features of the building material to which it is necessary to attach it. The wall can be internal or external. For each category, builders consider their specific requirements regarding the size of the structure.

1. The internal structure is reinforced with an armored belt with a width value corresponding to the thickness of the wall.
2. When strengthening the house from the outside, the width of the protective belt should correspond to the width of the wall, excluding insulation and formwork.
3. The minimum value of the height of the structure corresponds to one hundred and fifty millimeters. This indicator cannot be greater than the width of the wall.

Options for creating an armored belt

It is possible to install an unloading belt for walls made of aerated concrete blocks in several ways:

1. With the help of wooden formwork.
2. Using extension blocks.

When comparing these two methods, it can be noted that it is technologically more difficult to equip walls with armored belts using wooden formwork. The second method, using additional blocks, is much simpler, but you will have to invest more money in it due to the use of expensive building material.

The unloading belt is not laid:

• Under a solid reinforced concrete structure.
• Under wooden floors, based on blocks.

In the case of using wooden floors, it is enough to pour concrete pads five centimeters thick under the beams, playing a supporting role, which will reliably protect the building blocks from punching.

Creating an armored belt using formwork

The formwork for the unloading belt is a wooden frame. It is made from scraps of boards fastened together on the outside.

After the complete assembly of the formwork, its lower part is attached to the wall with self-tapping screws, and the upper part - with transverse board ties with an interval of eighty to one hundred centimeters. The screed is necessary to give the structure reliability, otherwise, when pouring concrete, it can be deformed or crushed.

Prior to the construction of the structure, you should take care of acquiring the necessary building materials:

1. Edged boards, with a minimum thickness of three centimeters and timber 40x40 for the manufacture of formwork.
2. Nails for fastening the board structure to the wall.
3. Flexible wire to stiffen the structure.
4. Reinforcing bars with a diameter of twelve millimeters.
5. Expanded polystyrene for insulation.

Construction tools used:

1. Drill.
2. Hacksaw.

Formwork construction technology

The technological process involves the performance of work in several stages:

1. Preparation of wooden shields.
2. Laying a layer of polystyrene between the wall of the house and a wooden shield for insulation purposes.
3. Fastening the structure to the wall with self-tapping screws or long nails.
4. Additional fastening of elements of a wooden structure using self-tapping screws and wire.
5. Reinforcing cage assembly. Initially, the reinforcing pins should be laid inside the wooden shields. A flexible wire is used to connect to the reinforcement frame. It is not recommended to fasten the reinforcement to each other by welding due to the rusting of the material inside the concrete.
6. Filling with cement mortar.

Reinforcement

Reinforcement is made from reinforcement bars with a diameter of eight to twelve millimeters.

The principle of the process is:

1. In horizontal laying of rods.
2. In fastening them, they are overlapped with a flexible knitting wire around the entire perimeter of the wall.
3. In tying joints with rings of wire with a diameter of six millimeters.

Reinforcing bars should be knitted directly in the formwork. In finished form, the reinforcing cage is heavy. With a separate assembly of the structure, it will be difficult to lift and place it. Between the aerated concrete blocks and the frame of the unloading belt, it is recommended to lay a layer of stones or bricks.

1. Pouring concrete

When purchasing a dry concrete mix, it is necessary to use a material marking of at least M200.

In the absence of products of the required characteristics in the store, you can cook it yourself, using the following proportions in the ratio of components:

• Crushed stone - 4.8 parts.
• Cement - 1 part.
• Sand - 2.8 parts.

To increase the density of the composition, crushed stone can be replaced with gravel. After mixing the dry elements, water should be added in small portions, the amount of which should correspond to twenty percent of the total amount of the mixture.

The concrete pouring technology provides for work performance standards that, in order to obtain the desired functional result, should be performed:

1. Pouring must be carried out in one cycle without interruptions, preventing partial drying of the concrete layer.
2. It should be avoided in the solution for pouring bubbles with emptiness, which in the future, when the mixture dries, will reduce the strength characteristics of the structure.
3. After pouring, it is recommended to compact the concrete using a perforator with a special nozzle. Also, to eliminate voids in the solution, a vibrating machine is used, and in its absence, air bubbles will have to be removed by baying the solution with fittings.

2. Construction of the unloading belt using blocks

Formwork can be not wooden structures, but U-shaped aerated concrete blocks. A prerequisite for such a building material is the presence of an internal cavity, which is necessary for laying the frame of reinforcement and pouring concrete.

Tray type blocks are stacked the same width as the walls. It is convenient to arrange such a belt to the outer walls due to its additional insulating function, while excluding the formation of "bridges" of cold.

3. What will be required

The method is simple and requires the prior purchase of building material - additional blocks ten centimeters thick. Before buying, you should calculate the required amount of material based on the planned height of the structure and the perimeter of the object.

The process of manufacturing the construction of the armored belt using additional blocks

1. Installation of additional blocks on the wall in the usual manner.
2. Reinforcement of the central part of the building material.
3. Pouring with cement mortar of the resulting structure.

Brick armored belt

The loading belt can be constructed using brickwork reinforced with reinforcing mesh. It is less reliable than concrete and is applicable only for small outbuildings. To increase the strength indicators of a brick structure, the use of reinforcement or welded metal mesh is recommended.

Features of the building:

1. When using a reinforcing mesh with a cross-sectional diameter of five millimeters, it is recommended to lay it through four rows of bricks.
2. The width of the structure must correspond to the thickness of the wall of the building being processed.
3. The height of the structure depends on the type of building material of the walls of the house and on the type of roof. The average construction size for a wall of aerated concrete blocks is forty centimeters.

Strengthening walls with bricks with built-in reinforcing mesh cannot fully replace giving reliability to structural elements using a reinforced concrete counterpart.

The most important feature of aerated concrete is its low thermal conductivity, which ensures the absence of a freezing factor for a structure built from it, even at the lowest ambient temperature. Therefore, when constructing a reinforcing structure, it is important that it does not violate the thermal insulation properties of the house.

In the cold season, as well as during periods of sharp temperature changes, condensation may occur on the reinforced belt. In order to avoid this phenomenon, it is recommended to carry out work on the insulation of the structure.

Expanded polystyrene, polystyrene and mineral wool can be used as insulating heat-insulating elements. In some cases, aerated concrete blocks with partitions are used. When using mineral wool, a small ventilation gap should be left between the insulation and the facing surface.

Tips for organizational work on the insulation of the object:

1. When constructing a structure for the purpose of its subsequent insulation, it should be performed with an indent from the outer edge of the wall, and not over its entire width.
2. The minimum width of the unloading belt should be twenty centimeters when using monolithic concrete and twenty-five centimeters when using bricks.
3. The resulting free space after pouring the armored belt should be filled with insulation and closed with a foam block, pre-cut in accordance with the desired dimensions.

1. When pouring with a cement composition, care should be taken that the elements of the reinforced mesh do not touch the walls of the formwork.
2. To increase the functionality of the armored belt, the reinforcement frame is installed on the surface using a level.
3. The strength of concrete after it is poured is facilitated by its periodic moistening, especially in hot weather. It is recommended to moisten the structure every day for five days. The best effect is achieved when the moistened surface is covered with a plastic film.
4. It is possible to remove the formwork in a week, however, it will function as intended only after two weeks, when the cement mixture has completely solidified.
5. If you plan to insulate the unloading belt, then you should not do it flush with the wall. Experts recommend moving the formwork inward with the further goal of filling the resulting niche with insulating heat-insulating material.
6. There is no need to spend money on a reinforced belt if there is a solid soil not saturated with water under the foundation, brick walls, and also when building a one-story house with wooden beams rather than reinforced concrete panels.

orcmaster.com

Formwork for armored belt. Types and methods of device

Armopoyas is a monolithic reinforced concrete structure. The belt has an annular contour, sits on the walls, and has no gaps (gaps) in its body. The solution to the question: how to properly make an armored belt begins with a formwork device. The most accessible formwork material is board. The formwork for the armored belt is made either from separate boards or from ready-made wooden panels interconnected from the outside with wooden trimmings. From below, the boards are attached to the wall with self-tapping screws. On top, the opposite walls of the formwork are connected with wooden screeds (on nails). Tie spacing - 80 cm, but not more than 100 cm.

Do-it-yourself armored belt

When making an armored belt with your own hands, you can use another option for creating it, in which the formwork is not wooden structures, but U-shaped blocks of aerated concrete. Tray blocks are laid the same width as the wall, and have a cavity inside for laying the associated reinforcing cage and concrete. A belt with such a "formwork" is especially advantageous to arrange along the outer walls, because the side walls of the U-shaped blocks act as a heater and exclude the formation of "bridges" of cold. The disadvantage of tray blocks is the high price.

Height of armored belt

The geometric and technical characteristics of a monolithic structure are determined by calculation. Usually the width of the belt is equal to the width of the wall, 30-50cm. Since the support of a prefabricated or monolithic ceiling on the walls is only 120 cm (in practice - 150-200 cm), then on this basis, the width of the belt can be taken smaller. The recommended height of the armored belt is 30cm.

In cottages where it is planned to create light ceilings, it is allowed to install a flat frame in the belt. The ladder frame is prepared directly on the wall, directly in the formwork. It consists of 2 rods (for a wide wall 3 rods) of a periodic profile (calculated diameter), interconnected by transverse rods. The pitch of the rods is 50 cm. The armored belt under the floor slabs carries higher loads. Therefore, the frame is made three-dimensional from 4 or 6 longitudinal reinforcing bars and tied with transverse wire clamps.

Armopoyas for aerated concrete

The frame on all sides must have a protective layer of concrete 4-5cm. From below, it is laid on supports made of brick or concrete chips. It should be noted that an armored belt is arranged on aerated concrete not only along the outer walls, but also along the bearing inner walls. And if along the length of the wall the transverse rods and clamps can be connected with a knitting wire, then at the corners of the building and in the places where the frame forks into internal load-bearing walls, the connection of the longitudinal reinforcement and transverse elements is carried out by welding. The frame is leveled strictly horizontally.

When constructing a roof truss structure, its lower row - Mauerlat, is attached to the load-bearing wall with special anchors and studs. The rafter system itself creates a bursting load, which can lead to deformation of the walls. Armopoyas under the roof provides the strength of the wall, stable rigidity of the roofing system. It will be performed similarly to the procedure for installing a monolithic belt under the ceiling. The armored belt under the Mauerlat serves both to distribute the load on the entire surface of the wall, and to lay fasteners in it for the Mauerlat itself.

How to fill in an armored belt

Task: how to fill in the armored belt is decided at the final stage of the monolithic structure. For pouring, you can use ready-made purchased concrete mix grade M200 (B15). Another option is the production of concrete at the construction site. Cement M400, sand and gravel, are taken in a ratio of 1:3:5. All components are loaded into a concrete mixer, water is added to the desired consistency and mixed. It is important that concrete is poured into the formwork continuously, and not in parts. To remove air bubbles from the mixture, after pouring the concrete mixture, vibrate or intensively pierce the concrete along the entire length of the belt with a piece of reinforcement.

Armopoyas for aerated concrete made of bricks

In practice, as an option for strengthening wall structures, sometimes an armored belt for aerated concrete is made of bricks. It is an ordinary solid brick masonry, reinforced with reinforcement. Reinforcement is carried out with masonry wire mesh: 4-5 mm through each row of masonry in height. The solution is used cement-sand in a ratio of 1:4. The height of the brick belt is taken from 20 cm to 40 cm. The width of the belt can correspond to the width of the wall, but maybe narrower. Of course, a brick armored belt cannot be called equivalent in terms of strength characteristics to a reinforced concrete belt. However, it is reliable when building houses in areas with low seismic activity or for the construction of auxiliary facilities and outbuildings.

So that the reinforced belt does not become a "bridge" of cold and in order to avoid the formation of condensate on it, it is necessary to insulate the armored belt. Therefore, a monolithic or brick belt, most often, is performed not over the entire width of the wall, but with an indent from its outer edge. It is important to maintain the minimum width of the reinforced belt, which is 20 cm for concrete and 25 cm for brick. The resulting longitudinal niches are filled with heat-insulating material, which are partition aerated concrete blocks laid on a spoon (10 cm), expanded polystyrene plates and other materials.

A reinforced monolithic or brick belt gives the building structures of the house from aerated concrete blocks increased strength. And for all household members, he becomes the guarantor of safe, long and happy living in a new house.

of-stroy.ru

How necessary is an armored belt?

Most often, a monolithic belt is a construction necessity, but in some cases such strengthening of the structure is not required.

You can do without an armored belt if:

• the foundation is poured below the freezing level of the soil;
• the walls of the house are made of bricks.

But even if these conditions are met, it is necessary that the floor slab extends at least 12 cm on both sides of the wall, and the building itself is located in a seismically safe area.

An armored belt is necessary if:

• The house is multi-storey. In this case, the presence of monolithic belts is prescribed by the norms;
• The walls are built of porous materials, such as cinder blocks or aerated concrete. Under the uneven pressure of the floor slab, these materials begin to wrinkle and quickly collapse;
• The building is built on soft ground. In this case, there is a danger of subsidence of the house and, as a result, the formation of cracks in the walls. The monolithic belt will act as a screed and prevent cracks. Inspect the old buildings in the neighboring areas. If they are covered with cracks going down from the roof and up from the ground and the corners of the windows, then the construction of a reinforced belt is definitely necessary;
• The foundation of the building is made of prefabricated blocks or shallow. The armored belt will evenly distribute the pressure of the plates around the entire perimeter of the foundation;
• The house is located in a seismically active zone.

How to build a reinforced belt?

A monolithic belt is a structurally simple element. A formwork is built along the perimeter of the wall, into which metal reinforcement is mounted. Then the structure is poured with concrete and insulated.

For the construction of a monolithic armored belt, the following materials are required:

• Plywood/boards;
• Fast installation;
• self-tapping screws;
• Nails;
• Ribbed metal rods;
• bricks/stones;
• Concrete / sand, cement, crushed stone;
• Cellophane film;
• Insulation (polystyrene);
• knitting wire.

And tools:

• Welding machine;
• Screwdriver;
• Perforator;
• Concrete mixer;
• Building level;
• A hammer.

The first stage: the construction of formwork

Most often, the formwork is assembled on the basis that the armored belt will be approximately 15-30 cm in height, and in width it will either be narrower than the wall or the same size as it. In the second case, the formwork moves deeper into the wall, which makes it possible to fill the resulting gap with insulation in the future.

The optimal materials for formwork are plywood, OSB boards, boards. The formwork must be mounted so that its upper part is in a perfectly horizontal plane. This can be achieved by adjusting the installation using the building level.

There are several ways to install formwork:

• Fastening by electric welding. In this case, the anchors are passed through the formwork walls, and the plugs are welded;
• Fastening with quick mounting. This method is much faster and easier to perform, but it requires some preliminary preparation. Installation practically does not hold in materials such as aerated concrete or cinder block. If the main part of the building was built from such materials, then the last rows under the proposed belt must be laid out of brick.

Holes are drilled through the board attached to the wall at a distance of 700 mm from each other. A fungus is inserted into the holes and secured with a screw. Quick installation is better to take 6x100 mm, and a 6 mm drill. When removing the drill from the resulting hole, it must be slightly swung in different directions. The hole will increase slightly and the wood fibers will not interfere with the installation of the fungus.

We fix self-tapping screws at a distance of 1 m on the upper edge of the board, and nails are similarly driven into the front brickwork. Self-tapping screws are pulled together in pairs with nails using a knitting wire.

The second stage: the manufacture of fittings

For the manufacture of the reinforcing cage, it is necessary to use only ribbed rods. The concrete mortar is attached to the uneven surface of the ribs and thus provides greater load-bearing capacity and tensile strength.

The rods should be 12 mm in diameter and 6 m long. For transverse fastening, rods with a diameter of 10 mm are required. The transverse frame must be welded along the edges and along the central part, the remaining transverse rods are not welded, but connected with wire. In the process of assembling the frame, it is necessary to minimize welding work. The fact is that the welded seam becomes less durable due to overheating, and this is unacceptable when erecting a reinforced belt. Most of the parts should be assembled with a tie wire.

The wire can be taken of the smallest thickness, its function is to maintain the integrity of the frame shape during concrete pouring. From the use of thick wire, the frame will not become stronger, and the installation of such a structure will require much more money and effort.

When the two parts of the frame are ready, they are stacked, forming a small space between them. Then they are welded in the center and along the edges, forming a finished frame, which in cross section has the shape of a square or rectangle. It is best to do this directly in the formwork, since the resulting part has a fairly large weight.

Between the reinforcement and each side of the structure there must be a distance of at least 5 cm. To raise the reinforcement above the horizontal surface, bricks or stones are placed under the frame.

When assembling parts into a solid reinforced belt, there is no need to use welding, you can simply overlap 0.2 - 0.3 m between adjacent parts of the frame. The structure must lie flat inside the formwork; to achieve this condition, it is necessary to use the building level.

Third stage: pouring concrete

Concrete for pouring a monolithic belt must be strong, since the weight of the floor slabs will fall on it. If ready-made concrete is used, then it must be grade 200 and higher.

If the mixture is prepared independently, then you need to thoroughly follow the technology and it is advisable to use a concrete mixer. Take 1 part of cement, 3 parts of sand and 5 parts of crushed stone. The resulting mixture must be mixed well and, gradually adding water, bring to the desired consistency.

In no case can concrete be poured in several layers. If it is not possible to pour the entire belt at once, it is necessary to make temporary vertical jumpers from aerated concrete or boards. Before pouring the next portion of concrete, the jumper must be removed, and the junction should be well watered.

When pouring a monolithic belt, it is necessary to constantly check the horizontality of the resulting structure with a building level and eliminate drops as much as possible. In the future, it will be much easier to install floor slabs on a carefully leveled surface.

When the concrete is already poured, it is necessary to pierce it with a special tool or just a piece of reinforcement. These simple actions will release air from the concrete and prevent possible voids.

The poured concrete needs to create conditions for hardening and curing. To do this, it is covered with a film so that the moisture does not evaporate too quickly, and in hot weather it is pre-watered.

The formwork can be removed after about 3 days - the period depends on weather conditions. This is done with a crowbar or a nail puller.

Fourth stage: warming

The monolithic belt, becoming part of the wall, plays the role of a heat conductor, and if measures are not taken to insulate it, “cold bridges” may appear. Before finishing work, it is necessary to lay insulation in the recesses left after the removal of the formwork. Styrofoam of the right size is perfect.

A monolithic reinforced belt will protect the house from destruction caused by many external causes. This element of the building frame is not difficult to calculate and mount, it can be done by anyone who has at least once encountered construction. When manufacturing a reinforced belt, you cannot save on materials. Quality and well-made, it will justify its cost. In many cases, a strong armored belt is a guarantee of strength and durability of the entire building.

1popotolku.ru

Armopoyas for the walls of a house made of aerated concrete

Often inexperienced, novice builders do not even know why they should be poured onto the walls of a one-story house concrete reinforced belt. And the need for its device lies in the following reasons:

Dimensions of the armored belt

Monolithic is poured along the perimeter of the entire building, and its dimensions are tied to the width of the outer and inner walls.

In height, it can be poured along the upper level of the gas block or lower, but it is not recommended to raise it above 300 mm - it will be easy unjustified waste of material and increasing the load on the walls of the house.

The width of the armored belt for aerated concrete is made according to the width of the wall, but maybe a little narrower.

Reinforcement of the concrete belt

For reinforcement, reinforcement made of metal or fiberglass is used. Usually its cross section does not exceed 12 mm. Most often, the reinforcing cage consists of four long rods, which stacked along the wall of the house. Of these, with the help of brackets from reinforcement of a smaller section, a square or rectangular frame is formed. Long reinforcing bars, every 300 - 600 mm, are attached to the staples with a knitting wire. It is not recommended to use welding to connect them in the frame because the metal is weakened at the point of penetration, and at the same time, corrosion may occur at this point.

Do not allow the frame to come into contact with aerated concrete blocks. For this, special plastic linings about 30 mm high are placed under it. In extreme cases, you can put individual pebbles from crushed stone.

Attention. In order to properly fabricate a frame for a reinforced belt, it is recommended to use reinforcement only with a ribbed surface, which provides a rigid grip on concrete.

When you can do without an armored belt belt

It does not always make sense to pour a reinforced belt to reinforce walls. Therefore, in order not to spend extra capital on the purchase of materials, you should know in which cases you can do without a reinforced concrete belt:

• The foundation is located on solid rock.
• The walls of the house are built of brick.

It is also not necessary to pour a concrete belt over aerated concrete blocks if a wooden floor is supported on them. To unload the floor, under the load-bearing beams of the floor, it will be enough to pour concrete into small supporting concrete pads with a thickness of about 60 mm.

In other cases, when construction is carried out on peat bogs, clay, and other weak soils, it is necessary to make an armored belt. It is especially impossible to do without it when building walls from aerated concrete, expanded clay and other large-mesh blocks, which are fragile materials.

Gas blocks are practically incapable bear point loads and are covered with cracks at the slightest subsidence of the foundation or when the soil shifts.

How to fill the armored belt with concrete correctly

When filling, the following rules must be observed:

1. Concrete placement must be completed in one continuous duty cycle. For a high-quality reinforced concrete belt, partially dried layers of concrete mass are unacceptable.
2. Air bubbles should not be allowed to remain in the concrete mass, which form pores, and thereby reduce the strength of the hardened concrete.

To prevent this from happening, freshly poured concrete must be compacted using a deep vibrator or a special nozzle using a perforator. In extreme cases, it can be sealed with a rammer or a metal pin.

Types of belts and their functions

Reinforced concrete belts are poured to reinforce structures such as:

Sometimes when building small outbuildings, it is used reinforced brick belt on aerated concrete walls. To do this, on the walls, for its entire width, 4 or 5 rows of building bricks are laid out. Between the rows, in the armored belt made of bricks on the walls of aerated concrete, in the process of work, a metal mesh is laid on the solution, welded from a wire 4–5 mm thick with cells of 30–40 mm. Floor beams or wooden Mauerlat can be laid on top for fixing the roof.

Reinforced armored belt on aerated concrete

For a reinforced belt, which is poured into blocks of aerated concrete, a concrete solution of the M 200 brand is used. The supporting reinforcement, with a cross section of 12 mm, is fastened in a frame with transverse square or rectangular clamps with a knitting wire. Clamps are made of smooth reinforcement with a diameter of not more than 4-6 mm. The load-bearing reinforcement is overlapped with each other with an overlap of at least 150 mm and is connected to each other with a soft knitting wire.

The belt can be made without a three-dimensional frame of 4 reinforcing bars. Sometimes a flat frame of two rods is enough, which is assembled in almost the same way as a bulk one. Only in this case, not clamps are used for transverse dressing, but individual reinforcing bars.

The connected frame can be laid in a wooden formwork, which is made from boards. It can also be used as a formwork, aerated concrete blocks of the upper row. But first you need to cut out the inside of them so that something like a box without end walls comes out of the block. The blocks are stacked with the resulting shelves up, after which the frame is laid in them.

When laying the frame, make sure that there is a small space of about 20 - 30 mm between the reinforcement and the formwork walls, as well as the lower blocks.

After bookmarking in reinforcement cage formwork, you can additionally make and fix the necessary embedded parts to it, which will be needed to fix the Mauerlat or other elements from the house structure.

A separate reinforced belt for a monolithic floor slab is not made. The plate itself evenly distributes almost all vertical loads on the walls, and at the same time it is the main stiffener for the house and connects almost all the walls of the building, combining them into one spatial structure.

It would be ideal if it occupies the entire width of the wall. But this is usually done if from the side of the facade heater will be installed bridging the cold bridge that can form through the concrete. But in the case when only a plaster finish is supposed to be outside, its thickness will need to be reduced within 40 - 50 mm to lay foam or other insulation.

To insulate the belt, you can also use thin (100 mm) partition blocks, which are installed and temporarily unfastened along the edge of the wall. A frame is laid between them and everything is poured with concrete. At the same time, partition blocks play the role of formwork and at the same time a heater.

Reinforced belt under a wooden Mauerlat

Since aerated concrete blocks have a fragile porous structure, it will not be possible to firmly attach the roof truss system to them. Under the influence of wind, the fasteners simply loosen over time and roof may warp. And with a strong gusty wind, it can simply be demolished.

In addition, when the roof is loosened, when its fasteners loosen, the upper rows of block masonry will also collapse over time. Therefore, a reinforced concrete belt for a strong connection of the roof with walls made of aerated concrete blocks is simply necessary.

The reinforced belt for mounting the Mauerlat can be smaller in width than its counterparts for the ceiling and foundation, since the vertical load on it is the smallest. Therefore, for its reinforcement, often for economy, a frame with two reinforcing bars is used.

For reliable fastening of the Mauerlat in the belt, vertical anchors are installed even before it is poured. bolts with external thread, which together with the frame are poured with concrete. In this case, the thread rises above the concrete by about 200 - 250 mm.

For a strong fixation of the Mauerlat, through holes are drilled in it, through which it is put on anchors, after which it is firmly pressed against the concrete with nuts.

Eventually- a properly made reinforced concrete belt can provide a house built from aerated concrete blocks with high strength and durable operation. At the same time, it will be able to protect the walls from deformation, the appearance of cracks, maintain the strength of the roof and extend the life of the house by 3-4 times.

Reinforced belt (armopoyas) is a closed reinforced structure that repeats the outline of the walls of the building and blocks their deformation as a result of the redistribution of loads. That is, the armored belt allows you to avoid the effects of adverse weather conditions, when the house shrinks, soil subsidence, etc. Reinforcement can be made of reinforced concrete or brick. The armopoyas acquires particular relevance in the construction of houses from building materials that are not resistant to deformation.

- this is the usual masonry, reinforced with reinforcement. At first glance, this approach is simpler than pouring a full-fledged monolithic armored belt made of concrete with reinforcement. However, is this approach sufficient? Will such reinforced masonry replace a full-fledged armored belt? To begin with, let's figure out what types of armored belts are and what functions are assigned to them.

The main functions of the armored belt

• strengthening the walls;
• ensures uniform distribution of loads;
• prevents the formation of cracks;
• helps to level the brickwork;
• maintaining the integrity of the structure during shrinkage of the house.

Types of reinforced belts

It is customary to distinguish 4 types of reinforced belts.

Grillage.

Grillage- this is the lower, sub-foundation armored belt, which is the key to the strength of the entire building. In addition, it can connect piles of columnar and pile foundations. The height of the grillage is from 30 to 50 cm, the width is 70 - 120 cm. For the manufacture, reinforcement with a thickness of 12 - 14 mm is used. For greater reliability and durability, concrete should cover the reinforcement cage by 5 cm on each side.

Socle armored belt

It is laid around the entire perimeter of the outer walls. In the event that slabs serve as an overlap, it is recommended to do it on all load-bearing walls. The main function of the socle armored belt is the distribution of loads on the foundation. Mesh reinforcement with a height of 20 - 40 cm is used;

Interfloor (unloading) belt

It is built to strengthen and tighten the walls, as well as to prevent the formation of cracks. In addition, it perceives and distributes the load of the entire structure. Lay on all load-bearing walls;

Armor belt under Mauerlat

The armo-belt under the Mauerlat - performs a number of useful functions: it allows you to securely fix the Mauerlat itself, distributes the load from the roof, gables, truss system, aligns the horizontal of the entire structure under construction. It is mounted along the perimeter of the outer walls, in some cases (with inclined rafters) - on the middle load-bearing wall. When creating a reinforcing cage, the studs are brought out above it. A thread is made at the end of the rods, and corresponding holes are made in the Mauerlat. After the poured concrete hardens and gains strength, a Mauerlat is installed on the studs and fixed with bolts.

In the manufacture of armored belts, special requirements are placed on the quality of concrete. It is recommended to use cement grade not lower than M200. The concrete mixture is poured at once, which will allow it to solidify evenly and set well. For higher strength, concrete is periodically moistened.

Is it worth making an armored belt out of brick?

So is it worth the risk and instead of a full-fledged armored belt made of concrete and reinforcement, make an armored belt made of bricks? In our opinion, no! Brickwork is only slightly stronger than blockwork, even if reinforced. Two or three rows of bricks will not be able to evenly distribute the entire load on the walls. This will lead to the fact that some fragments and sections of the brickwork will experience increased pressure compared to the rest of the wall, and this is dangerous for the appearance of cracks and even complete destruction of the wall. Therefore, it would be right not to take risks, and make a full-fledged reinforcement with an armored belt made of reinforced concrete.

A monolithic belt is a reinforced concrete beam, which is made mainly under the ceiling in masonry walls.

At first glance, the purpose of such a belt is not clear: after all, it is possible to lean the ceiling directly onto the masonry and not arrange any belts. As they say, "cheap and cheerful." Let's analyze the reasons for the construction of a monolithic belt.

1. If the masonry material of the walls does not bear the load from the ceiling. In a brick wall made of solid brick, for example, a monolithic belt is not needed, but in a cinder block wall, when supporting the ceiling of a large span, such a belt is necessary.

In the place where the slab is supported, a significant load is concentrated (from the floor, floors, people and furniture), and all of it does not fall evenly on the wall, but increases towards the slab support. Some masonry materials (cinder block, foam and aerated concrete, shell rock, etc.) do not work well for the impact of such a concentrated load, and may simply begin to collapse. This type of destruction is called collapse. A special masonry calculation can be performed to determine if a distribution monolithic belt is needed. But in some cases (when using cinder block, foam concrete), a monolithic belt must be made for design reasons, due to experience in building from these materials.

2. If the building is being built on weak soils (for example, subsiding). Such soils tend to deform significantly after some time, during soaking or other adverse factors - to shrink under the weight of the building. At the same time, part of the house can sag, as a result, cracks form in the walls and foundation. One of the measures that protect against the adverse effects of subsidence is the installation of a continuous monolithic belt under the floors. It serves as a screed for the house and, with little rainfall, can prevent the formation of cracks. If you are going to build a house, first of all inspect the houses on the neighboring plots (preferably those that were built a long time ago). If there are slanting cracks in the walls going from the ground up, from the roof down or from the corners of the windows up, then this is the first sign that a monolithic belt will not be superfluous in your house.

3. If a house is being built in a seismic region (in Ukraine it is Crimea), the installation of monolithic belts is mandatory.

4. In multi-storey buildings, the installation of monolithic belts is also required according to the norms.

How to make a monolithic belt - see topic "Prefabricated floor or monolith" .

Attention! For the convenience of answering your questions, a new section "FREE CONSULTATION" has been created.

Comments

0 #61 Irina 06.05.2013 19:00

Quoting Angelina Wat:

I want as much as I need, because every builder thinks and speaks in his own way

In order to find out how much you need, you need to know what is available: the layout of the house, the presence of load-bearing walls or columns, the distance between them, the load on the top floor from the floors, partitions - this is the necessary minimum.

Hello! The foundation is not buried. Partly - self-construction, but the construction path was determined by a person who has been engaged in foundations for more than 50 years, a professor at our University, an honored builder of the Republic of Karelia (and so on. regalia).
With normal soil, crushed stone of a large fraction was brought, in a very large amount, backfilled with a height of about 50-70 cm above the ground level, and in area protruding beyond the perimeter of the future foundation for a couple of meters on each side. Aligned. Then a large construction vibratory roller was found (it worked half a kilometer at the facility), which drove this rubble for a couple of hours. To be honest, only the first "passages" of the vibratory roller apparently squandered rubble to the eye. After that, to level the level of the horizon, a thin layer on top of the rubble is sand. Further, waterproofing on the top, formwork and reinforcement. I knitted armature for the first time, myself. 14th reinforcement, along the perimeter and in the area of ​​\u200b\u200bbearing walls (under the wall and a meter to the right and left) every 10 centimeters, the rest - 15 cm. Two planes at a distance of 30 centimeters from each other. It was recommended to knit reinforcement less often, and a thickness of 30 centimeters is enough. It took 5 tons of reinforcement for a foundation 12 by 12 meters, and with a thickness of 42 cm - 66 cubes of concrete grade 250. I understand that it is possible that I relaid the foundation a little, but that year I was looking for people for foundation work. They asked for work from 200 thousand rubles. and higher. I decided that it would be better to invest this money in the foundation than in improving the well-being of other people. For two weeks of vacation, slowly, with the help of my father, they tied the armature. I was sure in every node. They poured it in 5 hours with imported concrete using a concrete pump at the base of the Isuzu car. I plan to start laying the walls as soon as the snow melts, the brick is already on the site. I will reinforce the walls to the conscience. Now I'm looking for normal masons. It hurts too much requests they have now. They ask for rough masonry for 2800 rubles. per cube, and even additional payments for each movement of the hand and turn of the head.
They are pressed under the plates to make an armored belt 5 cm thick, with two thin reinforcements inside. It is clear that this, like an armored belt, is of little use. Just a leveling screed. The screed is understandable to do and so it will have to be done, but is it worth bothering with a full-fledged armo-belt 30-40 centimeters thick and the corresponding reinforcement - THIS IS THE QUESTION! I would be grateful for any constructive advice. The fact is that for aerated concrete - and there would be no questions, I would do it unambiguously. And with a brick - it is not clear yet. It seems that brick, as a material for load-bearing walls in private housing construction, has generally gone out of fashion. All are built exclusively from aerated concrete.

After you have finished concrete block foundation or laid it out of rubble stone, must be completed. Some inexperienced developers, not understanding the meaning of a monolithic belt, do not make it, trying to save money on it. And this is an unforgivable mistake! The monolithic reinforced concrete belt of your home is a kind of strong and reliable belt on your trousers, which, no matter how and where you tear your trousers, tear off a button or “zipper”, will keep them on you in any situation! (For some reason, such an association came to my mind! 🙂 The main task of such a belt is to ensure the strength of the foundation in case of local soil subsidence under it. In addition, such a belt connects the entire foundation into one, which gives it additional spatial rigidity.

The minimum height of a monolithic reinforced concrete belt is 200 mm. As a rule, it is carried out over the entire width of the foundation, because it is much easier and easier to install. formwork for monolithic belt. The quality of the monolithic belt directly depends on the quality of the formwork. Previously, the formwork for a monolithic reinforced concrete belt was made of edged boards with a thickness of 40 mm. The material is not bad, in principle, it may be enough to build one house. And yet the quality of the front surface of the belt with such formwork is low. It is best to use moisture-resistant plywood or chipboard for formwork. For several years now, we have been manufacturing formwork for a monolithic belt from moisture-resistant chipboard. Having cut the sheet, which has dimensions of 2500x1250mm, lengthwise into two equal parts, it is necessary to strengthen the resulting blanks with a size of 2500x620mm with a wooden lath with a section of 40x40 or 50x50mm, fixing it around the perimeter with 3.5x55mm self-tapping screws. Also, in order for the middle of the formwork panels not to sag over time from high humidity, it is necessary to strengthen it with several short slats of the same section. Before installing such formwork panels, they must be opened every time with any water-repellent compound. The easiest option is to use used engine oil.

We install these formwork panels via
metal studs with a diameter of 12-16mm. The length of such studs should exceed not only the width of the future belt, but also the thickness of the formwork. It is necessary to add another 40-50mm to the resulting size - for nuts and washers. With the help of such a pin, we tighten two shields together, and in order to accurately maintain the required width of the monolithic belt and easily remove the pin after the concrete has set, we use liners from the cheapest water plastic pipe with a diameter of 16-20mm. In the photo, everything that I am trying to explain in words, you can consider and understand the principle of installing formwork for a monolithic belt in this way. Install the studs in

two tiers: the lower tier is laid directly on the foundation, under the lower reinforcement of the frame, while the plastic tube serves as a kind of guarantor of the obligatory 20 mm protective layer of concrete for the reinforcement. The top tier of studs sits directly above the bottom tier. Depending on the height of the belt, for the upper studs, if they are higher than concrete, tube liners can be omitted.

For a shield with a length of 2500 mm, six of these studs are needed. Holes for studs are best made in vertical reinforcement rails.

formwork panels. In this case, the shields will serve you much longer. I write “hairpin”, although in fact a metal rod of the required diameter with a thread of 50 mm long cut on each side is suitable for such a fastening. Alternatively, you can make a stud with a thread on only one side, securing a plug of any material on the other side.

This method of formwork installation is very convenient because it does not require a large amount of additional wooden fasteners to secure the panels. Depending on the height of the chord, only a few braces are required to keep the formwork vertical. Reinforcing cages and grids It is best to tie with a tie wire, but can also be crafted with a welding machine. The height of the frame should be less than the height of the belt by 40mm. The frame of a monolithic reinforced concrete belt is made of reinforcement A-III with a diameter of 10-14 mm, which is placed in two tiers. For a wall with a width of 400 mm, three rebars in two tiers are enough. As mounting fittings, you can use wire VR-I with a diameter of 4-6 mm.

First, reinforcing cages are laid on the wall, after which the formwork is installed. It is possible to mark the top of the belt concrete on the formwork using a level, hydraulic level or conventional

level, although the latter can be used only with a small length of the belt. The standard grade of concrete for a monolithic reinforced concrete belt is M250. It is best to lay it in the formwork using a deep vibrator, the use of which guarantees the high quality of the finished belt. By the way, the use of such studs will definitely not allow the concrete to push the formwork apart. If you are going to pour monolithic reinforced concrete belt small width, these studs can also be used, regardless of their length, by inserting additional inserts on the outside of the stud so that the nut can press the outer insert against the formwork.

After you remove the formwork, only the end of the tube with a hole will be visible on its surface. Having filled it with mounting foam or just with a mortar, the device of a monolithic reinforced concrete belt can be considered complete.