Installation of an armored belt in a house made of aerated concrete: types, application, installation stages, photos. Reinforced belt on aerated concrete: we build with our own hands Interfloor reinforced belt
The reinforcement in the reinforced belt consists of working reinforcement (10-12mm), and structural reinforcement of a smaller diameter (frame - 6mm). Often, reinforcement is made of 4 or 6 rods. In this article we will describe in detail and show reinforcement schemes, methods of bending reinforcement and other nuances of the reinforced belt.
The reinforcement frame is needed in order to fix the working reinforcement in the correct position. That is, two or three bars of reinforcement at the bottom of the reinforced belt, and two bars at the top.
For a frame, fittings with a diameter of 6 mm are quite suitable; you can even use thick wire.
The size of the frame should correspond to the thickness of your wall, taking into account the insulation and protective layer of concrete. Extruded polystyrene foam with a thickness of 30 to 50 mm is best suited as insulation.
Often the frame has edge dimensions of approximately 120-200 mm.
Such square frames can be easily made in the following way.
We take a board (20-50 mm thick. 200 mm wide), draw a square, for example, 150 by 150 mm, drill a hole in the corners of the square.
The holes should be about 9mm so that the 10mm reinforcement fits tightly. The reinforcing bars themselves should be about half a meter long.
Place the board on the ground, hammer four reinforcing bars through the holes of the board into the ground. The template for bending the frames is ready. It is more convenient to bend the reinforcement along the frame using a pipe. For such a frame, the reinforcement blanks should be about 600 mm long.
Working fittings of the armored belt
The working reinforcement is a thick ribbed wire with a diameter of 10 mm, preferably 12 mm. The working reinforcement in the armored belt works in bending, creating high rigidity of the structure. The reinforcement must be continuous (circular) and pass over all load-bearing walls. If the building has very long openings, then the places of the reinforced belt above the openings need to be reinforced with an additional lower reinforcement bar.
The working fittings must be inside the frame, and are tied to the frames with ordinary binding wire; welding is not needed here.
- The height of the armored belt is made from 200 to 300 mm.
- The distance between frames should be from 200 to 400mm.
- The overlap of the reinforcing bars should be 500 mm.
- To reduce the consumption of reinforcement, it is better to use longer rods to reduce the number of overlaps.
- Do not forget about the protective layer of concrete, which should be 40 mm on all sides.
At the corners, be sure to bend the working reinforcement and use additional reinforcement clamps, see the diagram below. It is convenient to bend the reinforcement using a long pipe.
Reinforcement schemes for armored belts
It is also worth noting that it is better to install the reinforcement cage at the place where it is poured, since when assembled it will weigh a lot.
The formwork must be strong enough to withstand the pressure of the concrete. Pay special attention to leveling the formwork along all planes.
If you don’t have a professional tool for vibrating concrete, you can use the following method: take a hammer drill and hit the reinforcement in hammer mode, the concrete is compacted and air bubbles come out.
Modern technologies are being introduced and new materials are being used in the construction industry. At the same time, the requirements for the sustainability of buildings, as well as increasing their service life, are increasing. Buildings are affected by natural factors caused by wind loads, soil reaction and precipitation. To strengthen the building, an armored belt is made. A strong reinforced belt along the load-bearing walls is a concrete edging reinforced with reinforcement, poured along the contour of the building. Let's look at the design features, figure out what an armored belt is and why it is used.
What is a reinforced belt on load-bearing walls?
Many have heard the term seismic belt used by professional builders, but not everyone knows what it is. Novice developers are interested in what an armored belt is and why it is used in the construction of residential buildings and industrial facilities. To prevent deformation of buildings, it is important to know how to make a seismic belt in compliance with all building codes. We will try to answer each question in order.
An armored belt is a reinforced concrete structure that is designed to strengthen the walls of a house.So, the reinforced belt along the load-bearing walls represents a solid load-bearing structure with increased strength.
It is made from the following materials:
- concrete grade M400. It is poured into collapsible or stationary formwork with reinforcement, forming after hardening a strong contour of a closed shape. A standard concrete mortar based on cement and sand and gravel mixture, mixed in a ratio of 1:4, is used. It is important to pour concrete in one go, and also thoroughly compact it using a special vibrator. This helps prevent the formation of air inclusions, which increases the strength of the concrete monolith;
- reinforcing bars with a diameter of 8-10 mm. They are connected into a load-bearing frame, ensuring the integrity of the concrete under load. To increase the strength of the seismic belt, steel rods are combined into a spatial frame consisting of four longitudinal elements. Transverse jumpers with a cross section of 6 mm combine the rods into a spatial frame that looks like a square or rectangle. Tying wire is used to connect the rods.
The following can be used as formwork:
- wood. The collapsible structure is made of planed boards combined into panels;
- polystyrene It is an element of stationary formwork and increases the thermal insulation of the building.
It is important to think through the design features of the formwork and ensure its integrity when pouring concrete mortar. To increase rigidity, spacer elements are installed, and the panels are tightened with steel wire. Reliable edging increases the rigidity of the structure, making it difficult for cracks to appear on the walls of the building. A reinforced belt along load-bearing walls is a special element of building reinforcement that compensates for the resulting forces and prevents deformation of the structure.
In order for the reinforced belt to be of high quality, and therefore the house to be reliable, you need to know how to properly make a reinforced mesh/frame
Is a reinforcing belt needed - the purpose of the reinforcement circuit
Let's figure out what the seismic belt is intended for. An armored belt for the walls of any building is a responsible structure that can be constructed at various levels.
It performs a number of serious tasks:
- forms a solid foundation to ensure horizontal laying of building blocks;
- dampens support loads that are created by elements of the building's rafter structure;
- prevents the formation of cracks on the main walls of a building as a result of deformation processes;
- evenly distributes the acting forces over the entire supporting surface of the main walls;
- reduces the likelihood of deformation of the building frame as a result of the influence of increased loads;
- reduces the influence of sudden wind loads acting on the main walls of the building;
- ensures the stability of residential and industrial buildings erected on an inclined soil surface;
- preserves the integrity of buildings erected in areas with increased seismic activity;
- provides strength characteristics of building structures exposed to frost heaving forces.
The absence of a reinforcement contour on the main walls of a building negatively affects its integrity. Knowing how to make an armored belt, you can independently build a structure that increases the rigidity of the building.
We figured out what an armored belt is and why it is being built.
The rods are fastened to fix the reinforcement in the required position when pouring concrete
When deciding on the construction of a seismic belt, it is important to analyze the factors that negatively affect the strength of the structure:
- fastening elements of the roof structure transmit point forces from the rafters to the surface. In the area where fixing anchors are installed, deep cracks may form, which negatively affect the strength of the main walls;
- the sloped roof acts through the rafters and causes thrust forces that deform the main walls of the building. The belt, reinforced with steel reinforcement, evenly distributes forces across the upper level;
- The concrete edging reinforced with a reinforcement frame prevents deformation processes in the main walls. The load-bearing structures of a building with openings for doors and windows unevenly perceive various force impacts.
The relevance of strengthening the walls along the perimeter is caused by the characteristics of the materials used during construction activities. Having figured out how to make a seismic belt, taking into account the characteristics of the building materials used, you can significantly increase the strength characteristics and stability of building structures.
Armored belt for a building - scope of application
The area of use of reinforced belts is quite extensive. It is impossible to imagine modern buildings without it.
Installation and fastening of formwork is carried out using several methods
The seismic belt is performed during the construction of objects for various purposes:
- residential buildings;
- industrial buildings;
- shopping centers;
- sports facilities.
At the same time, a variety of building materials can be used for the construction of load-bearing walls:
- brick (hollow, solid, silicate);
- foam concrete blocks;
- cellular blocks of aerated concrete.
Blocks made from cellular types of concrete have reduced strength characteristics and require additional strengthening. That is why it is important to prevent cracking of aerated concrete and foam concrete blocks in problem areas that require special reinforcement with a seismic belt. Regardless of the type of building material used, it is important to understand what an armored belt is and why it is formed at different levels during the construction of main walls.
How to make a reinforced belt - design features
Strengthening problem areas located at different heights from the zero level is carried out with a concrete belt. It is additionally reinforced with reinforcing bars.
Interfloor armored belt allows you to save on door/window lintels
When thinking about how to make an armored belt, you need to understand the types of unloading belts:
- The first reinforcing contour, called a grillage, is formed above the foundation of the building. It is concreted at the stage of construction of the strip base, reproducing the configuration of future load-bearing walls. The power edging of the base is made up to 40 cm high, which allows you to evenly transfer forces from the mass of the building and compensate for the reaction of the soil;
- sections of masonry located at intervals of four levels of concrete blocks are necessarily reinforced with steel mesh or reinforcement. Reinforcement elements are cemented with a binder solution, forming power tiers. This makes it possible to increase strength and distribute loads occurring at masonry levels in proportion to the area of the supporting surface;
- the next unloading tier is located under the floor slabs. A monolithic concrete structure, reinforced with reinforcement, ensures the stability of the load-bearing elements, preventing the formation of cracks. The belt evenly distributes the forces that are created by the floor slabs and act on the contour of the building;
- the final seismic belt is located on the topmost tier under the roof of the building. It forms a reliable base for the Mauerlat. The rafter elements, which are a system of beams, are fixed with anchor bolts. A one-piece seismic belt made of reinforced concrete dampens loads from roof elements, as well as snow cover, wind and precipitation.
To ensure the necessary safety margin, you should figure out how to make an armored belt on your own. This is a doable task if you carefully study the technology and prepare everything necessary.
If an armored belt is installed on walls made of poorly load-bearing material, the load from the floor slabs will be distributed evenly
Materials and tools for making a seismic belt
Having an idea of how to make a seismic belt, it is easy to determine the list of materials and prepare the necessary tools to complete the work.
You will need:
- concrete solution based on sand-crushed stone mixture and cement;
- steel reinforcement of various diameters for frame assembly;
- concrete mixer for mixing;
- grinder with cutting wheel for cutting workpieces;
- steel wire for tying frame elements.
To knit the frame, it is advisable to purchase a special crochet hook. When using rods of increased diameter, it is advisable to use special equipment for bending rods.
Sequence of work - how to make a seismic belt on your own
- Cut blanks for making formwork.
- Assemble formwork from plywood, polystyrene or wood.
- Cut the reinforcement into pieces of the required sizes.
- Assemble the frame by tying the rods together with tying wire.
- Mix the ingredients and prepare the concrete mixture.
- Fill the formwork with concrete continuously.
- Perform vibration compaction.
- Cover the concrete with polyethylene and moisten it periodically.
- Disassemble the formwork after final strength gain.
So we figured out how to make a seismic belt. This work is easy to do on your own, having studied the technological process and promptly prepared everything necessary for the work.
To build a house, various materials are used, which have their own functional characteristics. One of the building material options is aerated concrete blocks. The material has enough advantages, but at certain stages and places of installation it needs strengthening. An auxiliary element in the process is the construction of a reinforced concrete belt.
What is an armored belt?
- This is a closed structural element of a building made of monolithic reinforced concrete, which exactly follows the contours of the building along the entire perimeter. Can be used for both load-bearing walls and interior walls. The reinforcing belt has other names such as seismic and unloading.
What is it needed for?
- Increases the level of resistance of building walls from harmful atmospheric influences.
- Aerated concrete blocks under the pressure of the roof can be subject to some degree of deformation from strong pressure on them, and the armored belt gives rigidity to the entire structure.
- If a house is built on a site with loose soil or in a seismic zone, the walls may crack due to uneven shrinkage of the foundation. The unloading belt promotes uniform shrinkage.
- The blocks have a fragile structure and it is not recommended to attach beams to them with anchors when installing the roof, because the point load exceeds the stability indicators. A high-quality basis for this is an armored belt.
What does it represent?
The structural element of the building, the armored belt, is a metal frame (in the shape of various geometric shapes - parallelepiped, square), filled with concrete or an adhesive mixture. After the concrete has completely hardened, the structure becomes a monolithic formation with a base (aerated concrete blocks) and allows further construction work to be carried out.
Methods for constructing an armored belt
- The most common way to construct a reinforcing belt is to attach it directly to the walls of the building.
- The formwork for a reinforced concrete belt can be special U-shaped aerated concrete forms, in which the process of constructing a frame and pouring concrete is no different from the method using wooden boards. On the one hand, it is fast and convenient, but on the other, it is very expensive.
- The reinforcing belt can also be made using, but using as a rigid fastening, a reinforcing mesh.
Types of armored belt
For each stage of building construction, there is its own type of reinforcing belt - it all depends on the need for their use:
- Foundation belt ().
- Base belt (seismic).
- Interfloor belt.
- The main belt for roof construction, for fastening.
Required materials and tools
Tools:
- Concrete mixer.
- Wooden boards and nails.
- Shovel – bayonet and “worm”.
- Hand saw or electric jigsaw.
- Hammer.
- Welding machine and electrodes.
- Pliers.
- Building level.
Materials:
- Sand.
- Cement grade M400-500.
- Dropout
- Metal rods with a diameter of 10-12mm.
- Wire for knitting (elastic).
Installation of armored belt on aerated concrete
The construction of a reinforcing belt is not a simple process at all and requires certain skills. All parameters should be taken into account and the materials selected correctly. It consists of several stages:
- Construction of formwork.
- Manufacturing and installation of reinforcement cage.
- Pouring concrete.
Detailed step-by-step guide
Construction of formwork
- To construct wooden formwork, you will need wooden boards of various widths, but with a thickness of at least 20mm, in order to prevent the possible effect of bursting in knotty places. If possible, you can use wooden shields.
- The lower part of the boards is attached directly to the aerated concrete blocks. You can drive long nails (150-180mm) through the boards or tighten self-tapping screws.
- The following boards are fastened to the original base by connecting them together with an edged board from the outside along the length (perpendicularly).
- Identical board connections occur on the outer and inner sides of the walls along the entire perimeter.
- During the construction of formwork, it is necessary to constantly check the level of the upper plane of the boards, because this is the boundary for the future concrete mixture. Differences in the plane relative to the zero level from the level threaten additional construction work.
- To prevent the parallel planes of wooden formwork from spreading in different directions due to concrete pressure during the concrete pouring process, jumpers are installed between them. The jumpers should have a pitch of 800-1000mm.
Manufacturing and installation of reinforcement cage
- It should be noted that the construction of a metal frame occurs directly in the formwork, because it is impossible to place the assembled frame due to partitions and the significant weight of the structure itself.
- To ensure that the frame is in a “suspended” state and its elements are not adjacent to the aerated concrete blocks, the remains of bricks or other construction debris are placed under it.
- Calculation of the side elements of the metal frame (stiffening rods) assumes a 50mm distance from the formwork on each side.
- To begin the process, two long metal rods are laid parallel to the bottom of the formwork, and constrictions (connectors) are welded between them. If a welding machine is not used, the joints are tied together with dressing wire.
- Rods are welded or tied perpendicularly to the created “ladder” base. To create a full-fledged reinforcement “cage”, the upper part is attached to the rods in a similar way to the lower version.
- Along the entire length of the frame and especially at the corners of the building, the reinforcement should be strengthened with additional adjacent rods. The more jumpers and additional elements in the frame, the better.
Pouring concrete onto a metal frame
Before you start pouring the constructed frame, you need to make sure that the capabilities of the concrete mixer and the amount of materials for concrete are sufficient so that there are no gaps. After all, the main condition for creating a high-quality belt is the continuity of supply (pouring) of concrete. If the process complies with the technology, cracks will never appear in the armored belt and the integrity of the structure is guaranteed.
Components of concrete:
- Cement M400-500.
- Sand.
- Fractional screening (5×6 or 5×7mm).
- The proportions are 1:3:5 plus water in the required quantity.
The prepared solution is gradually poured into the formwork and to prevent the formation of “air cushions” on the surface it is necessary to walk with a hand tool - a vibrating plate. With its help, the concrete mixture will penetrate into all areas of the formwork.
Formwork filled with concrete cannot be dismantled in the first two days (natural bonding of the mixture). After the deadline has passed, dismantling is necessary, but further work cannot be started, because the final strength of the reinforced belt is achieved 15-20 days after pouring.
Current prices
- 1 linear meter of rod (12mm) – 80-100 rubles.
- Dressing wire (100m) – 250-300 rubles.
- Sand (1000kg) – 800 rubles.
- Elimination (1000kg) – 1700 rubles.
- Cement (50kg) – 450-500 rubles.
In accordance with current ruble exchange rates, prices may vary and prices are relative. It is also necessary to take into account that if the work is carried out by hiring specialized workers, you should add + 45-50% to their wages in the overall estimate for the purchase of materials.
Dimensions/thickness of armored belt
In accordance with established standards, the thickness of the belt corresponds to the width of the wall of the building being constructed (30-60cm). The height of the belt may vary, but master builders recommend 25-35cm.
Changes in overall dimensions are quite acceptable, because buildings have different characteristics, and the strength of the walls can only be guaranteed by an armored belt.
Aerated concrete without armored belt
In 95% of cases, it is not recommended to erect buildings without strengthening their walls with a reinforcing belt, because the service life is reduced significantly. At the slightest vibrations caused by soil shrinkage or natural phenomena, the buildings are slightly deformed and cracks appear in the walls (this is a draft).
What to replace it with?
Considering the fact that a reinforced concrete structure (reinforced belt) is a rather expensive structural element when building a house, it can be replaced with a less cheap one - brick. As a rule, it is used which performs two functions during the masonry process - giving an aesthetic appearance and reinforcing aerated concrete blocks.
How to replace?
Instead of a reinforced concrete structure, you can use brickwork. In this process, the quality of the brick does not matter at all, because in the future its surface will be refined - plastered.
The armored belt is made like a regular one, but with one addition - a metal mesh (0.5-07mm) is placed between the rows. In this way, the possibility of the slightest movement (deformation) between the bricks is prevented. This method may be 70% equivalent to a real armored belt, but it will give you confidence.
- It is not recommended to carry out pouring a concrete layer at temperatures below -5-10°C.
- All work must be carried out by master builders, and not by “shabashniks”.
- It is necessary to monitor the quality of materials and their compliance with GOST (standards provided by the manufacturer).
Conclusion
Construction of a house from aerated concrete blocks must ALWAYS be equipped with an armored belt, and in some cases more than one. This belt will preserve the integrity of the building for a long time.
The armored belt is a monolithic reinforced concrete structure that runs along the perimeter of the entire building to increase the structure’s resistance to external and internal loads. This could be shrinkage of the house, natural phenomena, interior decoration and much more that causes deformation of the walls. An armored belt for aerated concrete is usually installed between floors under the floor beams and directly under the roof; this is necessary so that the walls can withstand the weight of the roof and cracks do not form.
It is considered mandatory when building a house from aerated concrete blocks, for several reasons:
- During the construction of the roof truss structure, anchors and studs are used to attach the Mauerlat to the wall. This creates a point load that aerated concrete cannot withstand.
- If you lay the beams of the rafter system directly on aerated concrete, without creating a reinforced belt, this can lead to many problems. If there is the slightest deviation in the roof level, cracks will appear.
- The seismic belt is a rigid frame that also distributes the load evenly across the entire house. This is important when hanging rafters are used in the rafter system.
In order for the structure to be strong and durable, the unloading belt must be done consistently, while observing many rules.
Materials, tools, sequence of work
To create such a device you will need the following materials:
- Water.
- Gas blocks, for example.
- Boards.
- Fittings.
- Stone.
- Concrete mixture.
- Net.
- Brick fragments or rubble.
- Insulation.
- Wall chasers, electric and manual.
- Diameters.
- Equipment for aerated concrete.
The following tools will also be needed:
- Roulette.
- Self-tapping screws.
- Mallet.
- Anchor bolts or studs.
- Vibrating machine.
- Concrete mixer.
- Notched trowel.
- Level.
- Spacers, fasteners.
First you need to make an accurate calculation. Typically, the thickness of the seismic belt is equal to or narrower than the wall, and the height is 30 cm. Depending on the size of the house and the load, the diameter of the reinforcement and its required quantity are calculated.
Formwork
To fill a structure with concrete, removable formwork must be made; most often it is made from boards, the thickness of which is 2 cm or more. U-blocks and brick are also suitable, but we will focus on the classic version.
Reinforcement is placed and fastened into the formwork, which is filled with concrete mortar; it is easy to prepare it yourself using a concrete mixer, because a large amount of mortar will be needed.
To arrange the formwork, they usually use knitting wire and spacers, which are made of wood 15 cm long. The simplest formwork option is considered to be a frame made of boards. They are spliced together from the outside with pieces of wood. The top of the box must be secured with transverse ties so that it can withstand pouring concrete and not collapse. The lower part of the entire wooden structure must be screwed to the wall with self-tapping screws. As a result of all the work, a niche should remain, which is filled with insulation. This is necessary so that heat loss through the unloading belt is minimal.
Reinforcement cage
The frame is equipped in several ways: a couple of rods or four (then in cross-section it will look like a square). This can be calculated based on what the load will be. If the building does not have heavy concrete floor blocks, then two rods may be sufficient. It is not recommended to use welding to fasten reinforcement. It is best to tie it using a special wire directly in the formwork. You can do this in advance, but lifting such a structure once assembled will be problematic. The frame must be placed level, this is checked using a level. It is important that the reinforcement is at least 5 cm away from the formwork walls.
Correct filling of the unloading belt is of great importance; it is monolithic, so it must be filled at one time. Many people order ready-made concrete, but it must have a grade of at least M200. When making the solution yourself, you need to mix crushed stone, sand and cement in a ratio of 5:3:1, and bring the solution to the desired consistency by adding water; it is best to rent a concrete mixer.
The most important thing is that concrete is poured only once; multiple layers cannot be poured. If it is not possible to prepare the required amount of solution immediately, then vertical cutoffs are installed. When the next portion is ready for pouring, the partition is removed, and the joint must be thoroughly wetted with water.
To remove voids that could form inside the mixture in the formwork, the bayonet method is usually used - pierce the solution several times with a piece of reinforcement. When everything is done, you need to wait 3-4 days and dismantle the formwork.
To quickly and efficiently create an armored belt, the main thing is to understand how to reinforce it correctly. Everything can be completed within a few days, to a large extent it depends on the professionalism and number of workers. Reinforcement of walls made of aerated concrete blocks is sometimes mandatory; without a monolithic belt, the structure can quickly collapse.
The reinforced belt in a house made of aerated concrete, brick (other block materials) during construction serves as additional protection for walls and other load-bearing structures from deformation and movement. In other words, this belt is nothing more than a reinforced concrete structure designed to strengthen the walls and foundations of a house from various loads that arise under the influence of both external and internal factors. External factors include the impact of wind, soil movement, terrain features of the site and, of course, seismic activity of the earth. Internal factors include redistribution of load from load-bearing elements, connection of columnar elements (foundation), installation of additional fasteners and structures.
To study the issue in more detail, let’s consider the process of installing an armored belt using the example of a house made of aerated concrete. However, this technology is also applicable to other types of houses, where the walls can be made of brick, expanded clay blocks and any other block materials. But, first of all, let’s determine the factors acting on the walls and figure out why an armored belt is needed in this or that case.
Why do you need an armored belt in the house?
To understand the principle of operation of a reinforcing protective structure, let’s consider it within the framework of building a house. Any stone or block material works better in compression than in tension. Tensile and torsional loads can arise both due to settlement of the building, heaving of the soil at the foundation, and for other reasons. This may also be caused by incorrect calculation of bearing capacity, as a result of which walls in different areas will receive both compressive and more critical tensile loads. These masonry areas may not be structurally ready for them. As a result, the walls will crack. By adding reinforcement with concrete at the top of the masonry between floors, we will additionally protect the walls from destruction.
Let’s take a house made of aerated concrete as an example and look at the diagram. In the lower part it is almost always performed, which is still the same protective belt. A properly executed warping copes well with loads, so there should be no problems at this level. Using an interfloor armored belt, we add reinforcement to the structure that copes with stress. At the same time, the wall itself becomes more rigid and conditionally works like an I-beam. The monolithic belt also resists lateral loads from the wind and bursting loads from the roof much better. The sum of all these properties increases the seismic resistance of the house, which is a mandatory requirement for any residential building in earthquake-prone areas. We looked at a multi-story scheme, but the armored belt is also applicable in a one-story house with or without an attic. In this case, a belt under the Mauerlat is used in conjunction with the foundation.
The armored belt also redistributes point loads well. This is especially important for materials that are not ready to work with local point loads - these are gas silicate blocks and other similar materials. Therefore, in a house made of aerated concrete, it is necessary to perform reinforcement under reinforced concrete floor slabs. A similar principle of load redistribution applies to the wooden base for rafter legs. But, at the same time, in order to properly secure the Mauerlat to a structurally weak wall, an armored belt is needed. The under-roof belt will increase the structural rigidity of the walls and will also resolve issues regarding the fastening of roof structures.
Calculation of reinforced belt
Armopoyas - main stages of manufacturing
Rebar frame
Assembling the frame begins with installing reinforcement on the top of the wall. When laying it, it is necessary that it is subsequently recessed in concrete at least 40 mm from the outer boundaries of the monolithic belt. When working with aerated concrete, for convenience, you can drive control sections of reinforcement into it. And attach the frame to the segments with a given distance from the top of the masonry. To tie the reinforcement together, you will need a soft binding wire. To set the dimensions of the frame, it is recommended to create a square of four pins or bend it from a solid rod (transverse clamp). These clamps are primarily attached to sections driven into the wall at a certain interval - usually 250-300 millimeters. If you do not drive in the control pins, you will need special pads - clamps to raise the frame itself. Therefore, consider the feasibility of one method or another. Having completed this work, we move on to fastening the reinforcement.
The lower row of longitudinal reinforcement is inserted into frames - clamps and connected with wire. The top row is fastened in the same way (the longitudinal reinforcement should be inside the clamp). As discussed above, the required minimum is two reinforcements on the bottom and two on top. For additional rigidity, the amount of reinforcement and frame configuration can be changed. Naturally, this will affect material costs. But if this is necessary, you should not neglect the calculation. We also note that the length of segments or solid squares (transverse clamps) is related to the thickness of the armored belt. For example, the thickness of the belt is 300 millimeters, then the dimensions of the transverse clamps are 220X220 millimeters (taking into account that the height of the belt is also 300 millimeters). That is, we leave indentations from the edges of at least 40 millimeters.
Formwork
Let's consider the formwork. What options for installing a monolithic belt in a private house may be:
- Using factory-made or home-made U-blocks as formwork.
- Formwork from.
U-blocks made of aerated concrete are used as permanent formwork for the installation of reinforced monolithic lintels covering openings in walls and partitions, as well as for the installation of monolithic reinforced strapping belts that impart spatial rigidity to the entire building and redistribute the load from the floors. U-shaped blocks are elements of permanent formwork for reinforced concrete. The diameter of the reinforcement and the class of concrete for filling the U-block are selected by calculation, depending on the perceived load. When choosing these elements as formwork, consider how to insulate the concrete strip. It is advisable to insulate the block from the outside, but if this is impossible in certain cases, put insulation inside (given the internal factory dimensions, this is not the best option).
With a possible thickness of the outer wall of 375-400 millimeters, it can have the following structure:
- Outside - a block 100-150 mm thick.
- Next in order, we insulate the armored belt to cut off the cold bridge. Instead of extruded polystyrene foam with a thickness of 50-100 mm, you can use high-density mineral wool, which is used in “wet facade” technology.
- Reinforcement frame.
- On the inside of the wall, blocks 50-100 millimeters thick are used as permanent formwork. The remaining space is filled with concrete.
The advantages of this type of formwork include the speed of its installation. To strengthen the structure, you can use additional ties made of bars or reinforcement connecting the internal and external blocks.
Performs several functions: it gives shape to concrete, protects it from spreading and subsequently serves as an excellent insulator.
The advantages of this formwork method:
- Easy to assemble formwork. Ready-made blocks are produced, including corner and joints.
- High installation speed.
- The installation of reinforcement is made easier because there are special grooves for it.
- It is easier to control the dimensions of the concrete tape.
- The concrete will harden in the formwork, which will protect it from rapid drying and sudden temperature changes.
- Extruded polystyrene foam is a waterproofing material.
This technology may seem very expensive. But if you take into account the cost of insulation, the cost of assembling and dismantling conventional wooden formwork, then the difference becomes insignificant. Alternatively, you can make this formwork not from factory blocks, but yourself from expanded polystyrene. But this will be a more labor-intensive option.
For an armored belt in an aerated concrete house, it is the most labor-intensive to manufacture. At the first stage, you need to make shields from boards. To do this, put them together and connect them together using wooden blocks and nails.
At the second stage, ready-made panels are installed around the perimeter of the future reinforced belt. The concrete solution will create pressure on the walls of the formwork, so in order to prevent the formwork from moving apart, it is necessary to secure the entire structure with clamps.
Pouring concrete
In general, this stage should not cause difficulties. The only inconvenience is the delivery of concrete to the very top of the wall. The quality of concrete should not be lower. When making your own mortar using M-500 cement, the following proportion will help: a bucket of cement / three buckets of sand / five buckets of crushed stone. It is recommended to use thick concrete - this way it does not put too much pressure on the formwork. It should not be forgotten that the concrete must be properly compacted. After pouring the concrete, cover it with film. This way you will reduce moisture evaporation. As a rule, it takes about two days for the concrete to completely set, after which the formwork can be removed (provided that it is collapsible).
Video: armored belt in a house made of aerated concrete
This video demonstrates the installation of a Mauerlat reinforced belt on aerated concrete walls. The formwork in this case is made of plank panels. When viewing, pay special attention to the reinforcement connections at the corners. It is better to additionally connect the studs for fastening the roof to the frame reinforcement and not waste energy on useless reinforcement in a fragile gas silicate block.
To conclude, we note that the reinforced belt in a house made of aerated concrete and any other block material is waterproofed before further stages of work. Whether this is advisable or not is up to you to decide. Naturally, when considering the foundation belt, it must be covered with insulation in any case, since there is moist soil nearby. With belts above the foundation, with proper construction of the walls, there should be no moisture in the concrete. But still, it would not be amiss to separate the Mauerlat belt with waterproofing from the wooden structures of the rafter system.
Aerated concrete is a warm, inexpensive and easy-to-install material. That is why it is considered a very good alternative to brick. However, in terms of strength, blocks made from this material are, unfortunately, significantly inferior to the latter. Therefore, laying walls from this material has some nuances. Firstly, it must be carried out on a very reliable foundation, and secondly, during construction the evenness of the structure should be carefully checked. The third condition for the reliability of aerated concrete walls is the installation of a reinforced concrete armored belt on top along the entire perimeter. We'll talk about it in this article.
Purpose of the design
An armored belt for aerated concrete is poured specifically to prevent cracking of the walls under the pressure of the roof. In addition, this design is used for more reliable fastening of the Mauerlat. One of the disadvantages of aerated concrete is that it does not hold fasteners very well. Of course, the armored belt should be constructed strictly adhering to the prescribed technology.
Device methods
You can make an armored belt for aerated concrete walls correctly and with your own hands in two ways - using wooden formwork or special additional blocks. The first filling option is technologically more difficult. Constructing a structure using blocks is a very simple procedure, but will cost more.
How to make an armored belt using formwork?
With this method of constructing a reinforcing structure, you will need to prepare the following materials:
Material | Characteristics | What is it needed for |
Edged board | Minimum 2.5cm thick | Manufacturing of formwork |
timber | 40x40mm | Manufacturing of formwork |
Nails | Attaching boards to the wall | |
Wire | Flexible | To add rigidity to the formwork structure |
Expanded polystyrene | 20mm | Insulation of armored belt |
Tools you will need are a drill and a hacksaw
The height of the armored belt is usually 40 cm. Therefore, each side of the formwork will have to be knocked down from two boards 20 cm wide. Instead of boards, you can use thick plywood.
Important: The formwork must be installed immediately along the entire perimeter of the wall. There should be no horizontal joints in concrete.
They fasten the formwork panels to the walls with self-tapping screws, or simply nail the elements with long nails. Spacers from 40x40 timber are installed on top between the shields, spacers are cut out to the same length, equal to the width of the armored belt. They are installed between the shields in 1.5 meter increments. In order for the reinforced belt on aerated concrete to be absolutely even, the structure should be given rigidity. To do this, the opposite beams holding the shields together (they should protrude about 20 cm above the surface) are intercepted with wire and twisted with an iron rod, tightly pressing the walls against the spacers.
Tip: On the inside of the house, the formwork panel (from the inside) can be lined with sheets of expanded polystyrene. Concrete has a much higher degree of thermal conductivity than aerated concrete and therefore, without insulation, the reinforced belt will become a cold bridge, which will worsen the operational characteristics of the building. After pouring the armored belt and removing the formwork panel, the polystyrene foam can be secured to the concrete with “fungi” dowels or in some other way.
Fill
An armored belt is installed for a building made of aerated concrete with mandatory reinforcement. To make the structure more reliable, a 12mm rod is used. The frame is tied together using knitting wire. Welding is not allowed, as the metal inside the concrete will quickly begin to rust.
The frame is installed inside the formwork on 30mm blocks or special plastic stands. The filling itself must be done at one time. If this cannot be done, first pour a layer around the entire perimeter of the formwork without interruptions. The next one will need to be filled no later than 12 hours later.
Construction of an armored belt using blocks
With this installation of the armored belt, everything is extremely simple. The blocks are installed on the walls in the usual manner. Next, their central empty part is reinforced and also filled with concrete.
Well, we hope now you understand how to make an armored belt for aerated concrete. This design is mandatory for houses of this type. Filling it, as you can see, is not difficult, but the walls will be much more reliable and durable.
Video on the topic “How to make an armored belt for aerated concrete with your own hands”:
Remove the steel hoops from a wooden barrel and it will fall apart. Remove the reinforced belt from the house and the building will not stand for long. This is a simplified but very clear explanation of the need to strengthen walls. Anyone who is going to build a durable house will benefit from information about the purpose, types and design of armored belts.
What is this structure and what functions does it perform? Armopoyas is a tape made of monolithic reinforced concrete, which is laid on several levels of a building under construction.
The reinforced belt is poured in the foundation, under the floor slabs and under the mauerlats (supporting beams of the rafters).
This amplification method performs four important functions:
- Increases the spatial rigidity of the building.
- Protects the foundation and walls from cracks caused by uneven settlement and frost heaving of the soil.
- Prevents heavy floor slabs from pushing through fragile gas and foam concrete.
- Reliably connects the roof truss system with walls made of light blocks.
Reinforced concrete has been and remains the main material for increasing the rigidity of walls. For small outbuildings, you can use a less powerful brick armored belt. It consists of 4-5 rows of brickwork, the width of which is equal to the width of the load-bearing wall. In the seam of each row, a mesh with a cell of 30-40 mm made of steel wire with a diameter of 4-5 mm is placed on the mortar.
In what cases is an armored belt needed?
For walls
Reinforcing walls with a reinforced belt is not always required. Therefore, there is no need to waste money on its device in the following cases:
- under the base of the foundation lies a strong soil (rocky, coarse clastic or coarse sand, not saturated with water);
- the walls are built of brick;
- a one-story house is being built, which is covered with wooden beams rather than reinforced concrete panels.
If the site contains weak soils (pulverized sand, loam, clay, loess, peat), then the answer to the question of whether a reinforcing belt is needed is obvious. You cannot do without it even when the walls are built from expanded clay concrete or cellular blocks (foam or aerated concrete).
These are fragile materials. They cannot withstand ground movements and point loads from interfloor floor slabs. The armored belt eliminates the risk of wall deformation and evenly distributes the load from the slabs onto the blocks.
For (the wall thickness is not less than 30 cm, and the strength grade is not lower than B2.5), an armored belt is not needed.
For Mauerlat
The wooden beam on which the rafters rest is called the Mauerlat. It cannot push through the foam block, so someone may think that an armored belt is not needed under it. However, the correct answer to this question depends on the material from which the house is built. Fastening the Mauerlat without an armored belt is allowed for brick walls. They securely hold the anchors with which the Mauerlat is attached to them.
If we are dealing with light blocks, then the armored belt will have to be filled. B, and the anchors cannot be securely fixed. Therefore, a very strong wind can tear the Mauerlat from the wall along with the roof.
For the foundation
Here the approach to the amplification problem does not change. If the foundation is assembled from FBS blocks, then an armored belt is definitely necessary. Moreover, it must be done at two levels: at the level of the sole (base) of the foundation and at its upper cut. This solution will protect the structure from intense loads arising during the rise and settlement of the soil.
Rubble concrete strip foundations also require reinforcement with a reinforced belt, at least at the level of the sole. Rubble concrete is an economical material, but not resistant to soil movements, so it needs reinforcement. But a monolithic “tape” does not need an armored belt, since its basis is a steel three-dimensional frame.
There is no need for this design for a solid foundation slab, which is poured under buildings on soft soils.
What types of interfloor ceilings require an armored belt?
Under panels that rest on expanded clay concrete blocks, gas or foam concrete, a reinforced belt must be made.
It does not need to be poured under a monolithic reinforced concrete floor, since it evenly transfers the load to the walls and firmly connects them into a single spatial structure.
An armored belt for a wooden floor that rests on light blocks (aerated concrete, expanded clay, foam concrete) is not required. In this case, it will be enough to pour concrete support platforms 4-6 cm thick under the beams to eliminate the risk of pushing through the blocks.
Someone may object to us, pointing out a number of cases when the reinforced belt is poured under the wooden floor of the floor. However, in this case, reinforcement is required not because wooden beams on concrete pads are capable of pushing through the masonry, but to increase the spatial rigidity of the building frame.
How to make an armored belt correctly?
The technology for constructing a reinforced stiffening belt is no different from the method of pouring a monolithic foundation.
In general, it consists of three operations:
- Manufacturing of reinforcement frame;
- Installation of formwork;
- Pouring concrete.
Certain subtleties and nuances in the work appear depending on the area where the armored belt is located.
Reinforced belt for the foundation
Answering the question of how to make a reinforced belt under the foundation (level 1), let’s say that its width should be 30-40 cm greater than the width of the supporting part of the main concrete “ribbon”. This will significantly reduce the pressure of the building on the ground. Depending on the number of storeys of the house, the thickness of such a stiffening belt can be from 40 to 50 cm.
The reinforced belt of the first level is made for all load-bearing walls of the building, and not just for the external ones. The frame for it is made by knitting reinforcement clamps. Welding is used only for preliminary connection (tack welding) of the main reinforcement into a common spatial structure.
Armoyas of the second level (on the foundation)
This structure is essentially a continuation of the strip foundation (rubber concrete, block). To reinforce it, it is enough to use 4 rods with a diameter of 14-18 mm, tying them with clamps with a diameter of 6-8 mm.
If the main foundation is , then there are no problems with installing the formwork under the reinforced belt. To do this, you need to leave free space in it (20-30 cm) for installing the reinforcement cage, taking into account the protective layer of concrete (3-4 cm).
The situation is more complicated, since formwork is not installed for them. In this case, wooden spacers should be used, which support the formwork panels from below. Before installation, cut boards are stuffed onto the boards, which protrude 20-30 cm beyond the dimensions of the formwork and prevent the structure from moving to the right or left. To connect the formwork panels, short crossbars are nailed to the top of the boards.
The fastening system can be simplified by using threaded rods. They are placed in pairs in the formwork panels at a distance of 50-60 cm. By tightening the studs with nuts, we get a sufficiently strong and stable structure for pouring concrete without wooden supports and crossbars.
This system is also suitable for formwork, which requires an armored belt for floor slabs.
The studs that will be filled with concrete need to be wrapped in glassine or a little machine oil applied to them. This will make it easier to remove them from the concrete after it has hardened.
Armobelt for floor slabs
Ideally, its width should be equal to the width of the wall. This can be done in the case when the facade is completely lined with slab insulation. If it is decided to use only plaster mortar for decoration, then the width of the armored belt will have to be reduced by 4-5 centimeters in order to leave room for foam plastic or mineral wool. Otherwise, a through cold bridge of very substantial dimensions will appear in the area where the stiffening belt is laid.
When making an armored belt on aerated concrete, you can use another solution. It consists of installing two thin blocks along the edges of the masonry. A steel frame is placed in the space between them and concrete is poured. The blocks act as formwork and insulate the belt.
If the thickness of the aerated concrete wall is 40 cm, then partition blocks 10 cm thick can be used for this purpose.
If the wall thickness is smaller, you can cut out a cavity for an armored belt in a standard masonry block with your own hands or buy a ready-made aerated concrete U-block.
Reinforced belt under the Mauerlat
The main feature in which the armored belt under the Mauerlat differs from other types of reinforcement is the presence of anchor pins in it. With their help, the beam is firmly fixed to the wall without the risk of tearing off or shifting under the influence of wind loads.
The width and height of the reinforcement frame must be such that after embedding the structure between the metal and the outer surface of the belt, at least 3-4 cm of a protective layer of concrete remains on all sides.
Correct, competent installation of floors is a guarantee of a reliable, long-term service life of buildings. For buildings made of blocks (aerated concrete), additional support is required - reinforcement. An armored belt in a house made of aerated concrete is a special additional structure that is required when installing floor beams and roofs. The production of reinforced belts for houses made of cellular concrete, the installation of floors is regulated by SNiP. Here are the brands and characteristics of the beams, the necessary parameters for supporting them on the walls, what they are made of and how they are made. Compliance with these standards is directly related to the structural stability of building structures.
Armored belt is a mandatory element when building a house
Why is an armored belt needed?
A structure made of aerated concrete material will not be able to withstand high loads (shrinkage of the building, settlement of the soil underneath, daily temperature changes, seasonal changes). As a result, the blocks crack and collapse. To avoid various types of deformations, monolithic reinforced concrete devices are installed. The reinforced belt takes on these loads, distributes them evenly, ensuring the reliability of the structure, and connects the walls into one whole.
It is also needed to distribute the vertical load. Giving the structure rigidity, it prevents movement of the floor (aerated concrete blocks expand with the movement of moisture and steam). For this, it also received the name - unloading, seismic belt. Another purpose of armored belts is to protect the edges of the upper blocks from destruction (installation of interfloor ceilings). Remove the point load of timber beam frames when constructing the roof. Taking these qualities into account, an armored belt is required for beams and floor slabs of the second (subsequent, roof) floors in a house made of aerated concrete blocks.
An armored belt is needed to evenly distribute the load on the foundation and walls
When constructing one-story buildings, the question often arises whether an armored belt is needed for a one-story house made of aerated concrete. This element is simply necessary if:
support beams (mauerlat) are installed on which the roof rafters are attached, this is especially true for projects of one-story houses with an attic;
the foundation is made on unstable soil to connect the entire structure into one (load-bearing) system.
A prerequisite for houses made of aerated concrete blocks is a complete loop of the belt. The outline of the structure must be without breaks. If you refuse to use an armored belt, the appearance of cracks is inevitable. Even despite light wooden floors and masonry reinforcement made of aerated concrete blocks.
Unlike brick structures, for a house made of aerated concrete, the reinforcing belt must be made as a single ring
Interfloor reinforced belt
This type of construction is made for slab or beam floors. The main purposes of floors include the perception and transfer of the load of its own weight, the interior, people onto the walls, the division of the internal space of buildings into floors, and the overlap of spans. This is a load-bearing structure supported by external and internal walls along the entire perimeter.
The basis for pouring the armored belt is the supporting surface of the load-bearing walls, which absorbs the entire mass of the building. General requirements:
installation is carried out along the entire perimeter of the future building, taking into account the internal walls;
for external load-bearing walls, blocks with a density of at least D-500 are used;
height, made according to the height of aerated concrete, or less is allowed (200-400 mm);
belt width – 500 mm (possibly reduced by 100-150 mm);
the reinforcement frame is placed on supports (brick, pieces of blocks, plastic fasteners) 3 cm high so that it does not touch the walls, thus creating a so-called protective concrete layer;
For pouring, concrete of at least grade B-15 is used.
Formwork for pouring concrete mortar with reinforcing mesh
On our website you can find contacts of construction companies that offer foundation repair services. You can communicate directly with representatives by visiting the “Low-Rise Country” exhibition of houses.
Reinforced belt for aerated concrete under floor beams, poured into pre-prepared formwork. This frame is made from:
-
Aerated concrete blocks.
Plastic.
Aluminum.
This type of formwork is used most often. This is the cheapest and most popular option. When installing a double-sided removable wooden frame (wood panels), it is secured with self-tapping screws on both sides of the wall (to aerated concrete blocks). The upper part is tightened with wooden jumpers (step 800-1000mm). This is necessary so that when pouring concrete the structure does not move apart.
Wood formwork is the most common option due to its availability.
The reinforcement frame (reinforcement diameter 8-14 mm), made in the form of a “ladder” (connected by jumpers in increments of 5-7 cm), is placed in the prepared space. The rods are knitted together using knitting wire (every half a meter), forming a square shape. It is not recommended to use welding, due to rusting of the welds in the concrete. For beam floors (with not a high load), a frame of two rods, with a monolith height of 30 cm, is sufficient. For covering with slabs, an armored belt with increased reliability is used (4 rods and a monolith - 40 cm).
After removing the formwork, the outer wall is insulated along with an armored belt. If, during finishing, the outer walls are only plastered, then to remove the “cold bridge”, the formwork is moved deeper into the wall. And then insulation is installed in the resulting niche.
You can use one-sided removable formwork. In this case, the external function is performed by aerated concrete blocks (10 cm thick). They are laid on the bottom row using glue. A wooden frame is attached to the inside. After that, insulation (5 cm) and fittings are laid. The top is also tightened with jumpers.
Video description
How to make wooden formwork for an armored belt:
Belt using blocks
The production of such formwork requires additional additional blocks or ready-made U-shaped aerated concrete products. In this case, internal (5 cm thick) and external (10 cm) or U-blocks (with walls 5 and 10 cm) are installed on glue (on top of the previous row). In the internal space, fittings and insulation are placed (to the outer wall). Afterwards, concrete is poured. For openings (doors, windows), at the level of the top of the previous row of masonry, wooden lintels are installed. They are secured with vertical supports.
This formwork option is relatively easy and quick to install. But it is not very popular due to the need to purchase additional material, and as a result, increased construction costs.
An armored belt using concrete blocks will be more expensive, but with their help the place of reinforcement will not be noticeable
Belt for Mauerlat
This armored belt is installed from the bottom of the attic space, both for one-story and two or more storey buildings. It is necessary for installing fasteners under the Mauerlat, and takes the main load from the rafter system (vertical, tensile forces) and the load from snow and wind. Installed fasteners for timber simply in aerated concrete will not withstand these loads. They will become loose (due to the low strength of the blocks) and the Mauerlat will move from its place, which will inevitably lead to negative consequences. It also plays the role of additional strengthening of the walls, preventing them from cracking.
Such a belt can be made of reduced dimensions due to its thickness (by correctly calculating the load) and two reinforcing rods can be used for the frame. A distinctive feature of this armored belt is the vertical studs with nuts. They are installed together with the reinforcement cage, before pouring concrete. It is on these fastenings that the Mauerlat will be installed, secured on top with nuts. This is the basis for the roof rafter system.
In the same way, you can make an armored belt in a house made of aerated concrete and under wooden floors. Pre-prepared fasteners for wooden structures will avoid subsequent drilling of concrete to install anchors.
Pouring concrete
To fill the belt, after all preparatory work has been completed, ready-made concrete (M200) is used or produced on site in a 3-5-1 ratio from:
-
cement (M400).
Filling is carried out not in parts, but completely around the entire perimeter. If such a process is impossible, the necessary jumpers are made in advance. Before pouring the next batch of concrete, the temporary lintels are removed, the joints are moistened with water and filled with concrete. The solution is compacted with an iron pin, removing air bubbles from it. During the hardening process (about 5 days), the concrete is watered to increase strength.
Video description
Preparation of solution for filling armored belt:
Conclusion
A reinforced concrete monolithic belt made in accordance with all the necessary parameters and rules will give a house made of aerated concrete blocks the necessary strength and durability. It will protect walls from premature cracks and allow you to make a reliable roof.
04.06.2018Question: What is a reinforced reinforcing belt and its structure?
Nowadays, all construction technologies are primarily aimed at ensuring maximum stability of erected buildings and increasing the service life. After all, construction sites are exposed to enormous influence of natural factors. Therefore, building structures must be properly strengthened. One of these fortifications is the armored belt.
Armopoyas - what is it?
An armored belt is a monolithic reinforced concrete contour that is placed on all the main walls of the building, connecting them into a single frame.
The main task of the armored belt is to distribute a uniform load on the load-bearing walls of the building and on the foundation.
The reinforced belt is laid at several levels of the building under construction, in the foundation, under the floor slabs and under the mauerlat (beam on which the roof rafters rest).
What functions does the armored belt perform?
There are several reasons that determine the need for an armored belt when building a house:
- Increased spatial rigidity - the reinforced belt connects the building structure into one whole and serves as a rigid frame, thanks to which the building receives additional resistance to negative factors, wind loads, ground movements, and earthquakes;
- Uniform distribution of loads - a monolithic belt protects the foundation and walls from cracks and prevents heavy attic and interfloor slabs from pushing through fragile aerated concrete and foam concrete;
- Implementation of openings - a reinforced concrete belt allows you to make openings of any width in the walls for doors and windows without the use of special jumpers;
- Connection of the roof truss system with the walls - a monolithic armored belt provides a rigid and reliable fastening for the installation of the roof truss system, especially important when the walls of the building are made of light blocks.
Is an armored belt always necessary?
Strengthening your home is not always necessary. Let's consider situations in which the construction of an armored belt can be neglected:
- the foundation is located on solid soil: rocky soil, coarse and coarse sand, soil not saturated with water;
- the walls of the house will be made of brick;
- the walls of the house will be built from wood concrete blocks, with a thickness of at least 30 cm and a strength of at least B2.5;
- A one-story house is being built, the floors of which will be made of wooden beams rather than concrete slabs.
If the soil on the site is weak and not very stable, for example, dusty sand, loess, clay, loam or peat, then the construction of an armored belt is mandatory.
The same is true if the walls of a house are built from light and fragile expanded clay concrete, foam concrete or aerated concrete blocks - the answer is obvious, an armored belt is needed! This is because these blocks are not designed for ground movements and point loads coming from the floor slabs.
Armored belt construction technology
The technique for constructing a monolithic reinforced belt is similar to the technology for pouring a conventional monolithic foundation:
- The reinforcement frame is knitted and installed;
- Formwork is installed;
- Concrete is poured.
Some additional nuances, subtleties and minor changes in technology depend on the location of the reinforced concrete belt.
Types of armored belt or location zone
Basic unloading armored belt or Base (1st level - under the foundation) - this structure bears a lot of effort from the entire mass of the building and the reaction of the soil. The base is reinforced with a reinforcement frame, repeats the location of the main walls and is concreted when forming a strip foundation.
Base armored belt (2nd level - above the foundation) - the width of this belt should correspond to the thickness of the walls and proportionally distribute the forces acting on the base.
Armobelt between floors for floor slabs - this solid reinforced concrete belt is located between the upper level of the walls of the house and the concrete floor slabs located between the floors. Its task is to ensure the immobility of load-bearing walls and prevent cracks from appearing in them. It distributes the loads from the interfloor slabs onto the building contour and reduces the likelihood of openings being deformed.
Armobelt of the last floor under the Mauerlat - this reinforced belt is poured after the construction of the last floor and serves as the basis for the Mauerlat. It compensates for the load from the roof itself and additionally from precipitation, snow and wind.
Armobelt of the first level (under the foundation)
In order to significantly reduce the pressure of the house on the ground, the armored belt under the foundation should be made 30-40 cm wider than the main concrete strip of the foundation. And its thickness, depending on the number of floors, can vary from 40 cm to 50 cm.
The armored belt of the first level is made for all load-bearing walls of the building, and not just along the perimeter of the external walls. The reinforcement frame for it is made exclusively by knitting, and no welding. Welding can only be used when preliminary connecting the main reinforcement into a common spatial structure.
The diameter of the main reinforcement is 16-20 mm. The diameter of the transverse clamps is from 8 to 10 mm. Step - no more than 20 cm.
It is very important that when pouring concrete into the foundation, the reinforcement cage does not come into contact with the base. The fittings must be recessed in the middle. This can be achieved by placing pebbles or halves of bricks under the frame. This will save the metal frame from the corrosion process (rust).
Pouring the reinforced belt with concrete must be done in one go. This is necessary in order to avoid joints that reduce the strength of the structure.
Second level armored belt (on the foundation)
Before you begin to build walls on the foundation, you need to fill in the base reinforced belt. At its core, it is a continuation of the main foundation and serves as an additional strengthening of the building.
If to knit the frame for the first level of the reinforced belt, 8 rods of the main reinforcement were needed, then to knit the frame for the reinforced belt of the second level, it will be enough to use 4 rods of reinforcement with a diameter of 14 to 18 mm and clamps with a diameter of 6 to 8 mm.
The structure is poured along the perimeter of the building along the external walls. The average height is from 20 to 40 cm. Concrete for pouring the base reinforced belt - M200 or higher.
The reinforced belt of the first level is the basis of the house, and the basement belt is a complement and strengthening of the load-bearing capabilities of the reinforced belt for the foundation. Therefore, if the armored belt of the first level was filled with high quality, then the belt of the second level (basement) can be made not so strong.
In general, we can say that a combination of high-quality armored belts of the first and second levels is a guarantee of the reliability and durability of the foundation on any soil.
Armobelt for floor slabs
If a multi-storey building is being built, the floor slabs place heavy loads on the walls. In order to reduce this load, at the junction height, between the wall and the floor slabs, it is also necessary to install a reinforced belt. It is poured along the perimeter of the external walls and has a height of approximately 20 to 40 cm. As for the width of the armored belt, it should preferably be equal to the width of the wall.
The distance between the slab and the belt should not exceed the width of 1-2 bricks. The ideal distance would be 10 to 15 cm.
The reinforcement frame for the interfloor belt is knitted in the form of a mesh of two-core reinforcing rods with a thickness of 10 to 12 mm.
If the masonry of the building walls is made of aerated concrete blocks, then two thin blocks can be placed at the edges as formwork and a reinforcement frame can be installed between them and concrete can be poured.
For walls 40 cm thick, 10 cm partition blocks can be used as formwork.
If the wall thickness is less than 40 cm, then in a standard aerated concrete block you can cut out a gutter yourself to lay a reinforced belt in it. Or buy a special aerated concrete U-block with a ready-made gutter in advance.
Armobelt under the Mauerlat
The reinforced belt, which is installed under the roof, allows for strong fastening of the roof (mauerlat + rafters) and installation of wooden and concrete floors between the attic and the top floor.
The armored belt for the Mauerlat, compared to other belts, is the smallest in width. This is acceptable since the vertical load that falls on this belt is minimal.
The Mauerlat is attached to the reinforced belt using threaded anchor pins, the diameter of which should be from 10 to 16 mm. Depending on the shape of the bolts, they are welded to the reinforcement frame or simply inserted into the concrete and held in it due to their curvature.
In order not to encounter difficulties later, the location of the anchor studs and the distance between them must be calculated in advance, so that in the future they end up in the middle between the rafter structures. The main thing is that the rafter legs do not then coincide with the studs. After pouring concrete, the length of the studs should be sufficient to install the Mauerlat on them and secure it with two nuts and a washer; this is approximately the height of the Mauerlat + 4 cm.
Also, when making a reinforcement frame, you need to take into account its width and height so that when the concrete is poured, there is at least 3-5 cm between the frame and the outer surface of the concrete.
Reinforced brick belt
In the construction of large houses, especially several storey ones, it is mandatory to make the reinforcing belt strictly from reinforced concrete, but for small outbuildings, where powerful reinforcement is not required, the belt is laid out of brick.
The design of the reinforced brick belt consists of 3 to 5 rows of brickwork, reinforced with reinforcing mesh. A steel mesh of wire with a diameter of 4-5 mm, with a cell size of approximately 3-4 cm, is placed on the mortar in the seams of each row of bricks.
The width of the brick belt should be equal to the width of the load-bearing wall.
Sometimes, in order to enhance the strength of the structure, bricks are placed not horizontally, but vertically at the ends.
Is it necessary to insulate the armored belt?
In terms of thermal insulation, the reinforcing belt does not perform very well and some amount of heat is lost through it in the winter season. Because of this, condensation can form on the inside, which leads to the formation of mold.
To avoid this, when constructing an armored belt, it must be insulated from the outside using heat-insulating materials.
“What to insulate the armored belt with,” you ask. There are several possible answers to this question. The most common material is polystyrene foam, but polystyrene foam and aerated concrete can also be used.
The main thing is that before knitting the reinforcement frame and pouring concrete, you need to take into account and remember to leave space (from the outer edge of the wall) for laying insulation.
What grade of concrete is needed for an armored belt?
For the manufacture of reinforced belts for interfloor ceilings and rafter systems, the minimum requirement is to use concrete grade M200 or M250, and possibly higher. The required concrete can be purchased ready-made or mixed yourself using M400 cement.
In order to make concrete yourself, it is important to know the proportions of the components.
The amount of water in concrete should be minimal, and to impart plasticity, a plasticizer is used - an additive that increases the mobility and fluidity of concrete.As for the water-cement ratio. It should be in the range from 0.5 to 0.7 per unit of cement, in other words, for 10 parts of cement there should be from 5 to 7 parts of water.
Excessive amounts of water in concrete negatively affect its performance and make it less durable.
The cost of filling an armored belt
The cost of the armored belt is always calculated individually for all specific projects. The main parameters of the structure and the materials from which the house will be built are taken into account.
First of all, depending on what the walls of the building are made of, the technology for manufacturing armored belts for the foundation, for the floor (roof) and if the building has several floors, then for interfloor ceilings is determined.
As a rule, reinforcement belts are required when building a house from lightweight materials, such as aerated concrete, slag concrete, foam concrete, polystyrene concrete, expanded clay concrete and wood concrete concrete. This is because blocks made from these materials do not have high strength and are afraid of high seismic activity, unstable soils and point pressure from the roof.
Calculating the cost of filling an armored belt is a simple task, since houses are almost always different and in each project there are many factors that will influence the final price.
If you seek the services of a private foreman Mikhail Dolgikh, he will help determine and calculate all the work on installing an armored belt for your home.
The cost of filling a reinforced belt will be 250 rubles. per linear meter.
Trust in professionals
Only professional builders should trust the installation of the harness.
When choosing performers of work, pay attention only to highly specialized professionals who have been working in their field for many years and are well familiar with the installation features of this type of structure.
The cost of the work must include payment for the crew, all the machinery and equipment necessary for construction.
With a qualified construction team, you will be able to make a reliable home structure, and an experienced foreman will help you minimize the time and costs of the estimate.
To find out the price of an armored belt in your home project, contact our specialist using the contacts listed on the website.