Construction stores today provide an extensive assortment of materials and systems of various price categories and purposes. One of them is aerated concrete. It does not apply to new developments, but the greatest prevalence has been observed in the last ten years. Due to the increase in popularity, more and more people are interested in the question of how to masonry aerated concrete with their own hands.
Specifications
Aerated concrete is based on artificial components pre-mixed in water, such as cement, lime, sand and gas-forming additives. The structure is characterized by the presence of many small cellular pores, which is why the blocks are characterized by a large void. The material is made in the process of exposure to high temperatures and pressure, followed by hardening in an autoclave. The cost of wall aerated concrete varies from 50 to 100 rubles apiece, depending on the size.
The blocks have a relatively small mass, so the use of special equipment is not required. It is also possible to cut out any necessary shapes using a standard hacksaw for wood.
disadvantages
This building material cannot be called universal, and many people prefer to use other methods of construction. This is due to the presence of a sufficient number of shortcomings, the main of which are the following:
- Fragility. If aerated concrete masonry will be carried out in an area with seismological activity, it is worth remembering that the movement of the soil can lead to dangerous cracks in the building. This cannot but affect the interior decoration of the premises. Given that the surface of the material is easily damaged with a screwdriver, it becomes clear the need to use special fasteners to carry the load while fixing the furniture on the wall structures and creating engineering systems.
- Hygroscopicity. Reducing this property is almost impossible, due to the presence of many pores, which contribute to the active absorption of moisture from the environment. This is especially noticeable in regions with cold winters and hot summers. Hygroscopicity leads to an increase in the humidity level in the structure, there is also the possibility of cracks on the surface of the walls, since the aerated concrete masonry absorbs water, which begins to freeze at low temperatures and expand, damaging the material.
The disadvantages indicated above, although quite serious, can be fought with. Suitable dowels for installation, external insulation and high-quality moisture insulation will reduce them to nothing.
Materials and Tools
Before starting work, you must prepare the following:
- cement mortar;
- special adhesive;
- level;
- trowel;
- fittings;
- rubber mallet;
- putty knife;
- sanding board.
Glue consumption
On the modern market, there are many compositions for working with materials characterized by a high level of moisture absorption, such as aerated concrete, the average size of which is 30x20x60 cm, and foam concrete. It is also possible to use solutions for processing and puttying of the obtained surfaces.
The use of glue does not cause any difficulties. All components are simply mixed in the specified proportions. The work can be greatly simplified using a special drill with a mixer nozzle.
When applying the material with a layer of 1 cm, about 1.5 kg of dry composition is required for 1 square meter of blocks. In the presence of roughness glue consumption increases. It is advisable to use the mixture on a fine-grained basis, thereby reducing the likelihood of the formation of “cold bridges”.
Advantages of the adhesive
Gas block glue has many advantages that cement mortar cannot boast of. The fractional sand and Portland cement contained in the composition provide the ability to distribute the mixture in a thin layer, which allows to reduce consumption without changing the quality of the connecting characteristics. Adhesive properties and uniform filling are achieved by adding polymer components to the composition. Moisture retention is provided by special modifying additives.
The hardening of the adhesive is characterized by the absence of shrinkage, it is also characterized by water resistance, ductility and a sufficient level of adhesion. When using this material, the installation of the block should be carried out within 10-20 minutes, about 5 minutes are allotted for correction. After cooking, the mixture must be consumed no later than three hours later. Under the condition of low temperatures, the time of use of the composition is reduced. During work in the winter, special attention is required to the thickness of the joints and the completeness of their filling.
Progress
The technology of laying aerated concrete includes the construction of the foundation of the building, which acts as the basis for the first row of blocks. The base should be at a distance of 60-80 cm from the ground surface. Mandatory installation of waterproofing between aerated concrete and the base of the building is required.
For the installation of the first row, a solution is used, distributed on the waterproofing layer. Walling of aerated concrete, regardless of the type of structure, is always done from the corner. To do this, a cord is pre-tensioned in each of them, with which the correct installation of all blocks is verified, while the building level is additionally used for verification. Rubber hammer allows you to change the location of the elements. It is worth noting that there is no need for a glue mixture when using blocks with a groove-comb system. The cost of aerated concrete of this type is about 100 rubles apiece. All irregularities must be removed after each row has been mounted, after which a sanding board is used for grouting.
Additional elements must be previously sawn. Due to their composition, work can be done using a conventional hacksaw. It is possible to use a band saw to ensure a more even cut. In this case, each time the accuracy should be measured using a square.
Installation of the next row is carried out after 2-3 hours from the moment of completion of the lower installation. Angular dressing of blocks is an integral part of the work for each row. The protruding elements are periodically adjusted with a rubber hammer.
Features
The laying of aerated concrete requires careful observance of the rules for pairing walls. In the inner partitions, every second row should have a connection with the main wall structure, it is formed using brackets or anchors on which a perforated galvanized strip is fixed. Also, do not forget about the hydro and sound insulation of interior partitions.
Planning floor slabs between floors should include support for the reinforced belt. It is performed on the last row of blocks and is a concrete belt with reinforcement in the form of reinforcing elements. It has many functions, including: uniform load sharing from the roof truss system, protection of wall structures from cracks. To connect the walls with the roof, a Mauerlat is used, which is fixed on the arm belt.
Structural reinforcement
Aerated concrete, the dimensions of which vary depending on the purpose and shape, for example, the dimensions of the direct block for creating partitions are 600x250x150 mm, is a rather fragile material and requires reinforcing work. The purpose of this process is to reduce the load exerted by the roof of a building or floors. Reinforcement of masonry provides additional structural strength and increases the service life.
Work must be carried out on the first row, as well as on every third. In addition, the belt located under the floor, window and door openings is being strengthened.
Girder grooves are cut along the perimeter of the wall masonry for mounting reinforcement. Most often, two strips with a width of not more than 4 cm are enough. They should be at a distance of 6-8 cm from each other. Any semi-liquid mortars for aerated concrete masonry are used for pouring; previously, the strobes are cleaned of dust. Reinforcing elements are completely immersed in the solution, the diameter of which should be about 10 mm. The solution that has gone beyond the surface is immediately removed. The laying of the following rows can be done immediately, without having to wait for the solution to dry.
Work in the cold season
It is desirable to carry out the laying of walls at a positive temperature, otherwise there are additional costs for heating the building material. The adhesive for the gas block contains a sufficient amount of water, because of which it quickly freezes in the cold and does not have time to fix the structure.
The creation of load-bearing walls at low temperatures can be carried out under the condition of an average daily level of at least -6 ° C, and there should be no prolonged freezing of the structure and precipitation. In this case, a solution containing antifrosty additives should be used . The finished mixture is consumed within 30 minutes, while heated water is used for cooking. Blocks are immediately laid on the applied adhesive layer, avoiding breaks. Otherwise, the mass will freeze and work on this site will become impossible. To cover the last row, a film is used.
Cost and Material Conservation
Blocks should be stored in suitable conditions to prevent the loss of technological properties and quality. If at least a month passes from the time of purchase to use, the factory packaging will not be removed from the material, which protects it from the negative effects of the environment. It must be removed a few days before the start of work, so that excess moisture can evaporate.
The cost of laying aerated concrete blocks is affected by the cost of transportation, the properties of the material itself and the cost of construction work. It is also worth remembering the volume of purchases and seasonality, which also have a significant impact.
The price of a cubic meter of material depends on the marking of the blocks, strength indicators and is in the range of 2000-4500 rubles. Additional factors, in addition to the acquired volume and season, are the availability of shares and the manufacturer.