Aerated concrete blocks, the pros and cons of which will be considered in the article, differ from traditional concrete in that their thermal conductivity is quite low. This quality is achieved due to the fact that among the ingredients there is aluminum powder. Hydrogen bubbles are distributed throughout the hardening process; therefore, aerated concrete transfers heat much worse than ordinary concrete. However, this advantage also entails a decrease in strength, which is relevant compared to conventional concrete. Therefore, when calculating the wall thickness, it is necessary to take into account the required level of thermal insulation and wall strength. Itβs important to keep up with the budget.
Choosing a type of aerated concrete block for different walls
Depending on what the purpose of the room is and what are the requirements for thermal insulation of walls and their strength, aerated concrete blocks can be designed for the construction of:
- garages;
- auxiliary premises;
- summer cottages intended for living in the summer;
- residential buildings.
For the first three categories, the heat-insulating qualities of the walls do not play such an important role, therefore, choosing the thickness, it is necessary to focus on strength. With increasing density, the strength increases and the thermal conductivity of the blocks increases.
Block classes
Having familiarized yourself with the assortment of the market, you can understand that aerated concrete can belong to one of the following classes:
- B3.5 is a material which is intended for the bearing walls of houses in 5 floors;
- B2.5 are used as material for load-bearing walls, if the height of the house is not higher than 3 floors;
- V2.0 is aerated concrete, which is used for the construction of load-bearing walls with a height of no more than 2 floors.
Depending on the density, the blocks can be attributed to the brand within the range of D300 to D1200. The number next to the letter indicates the density in kg / m 3 . High density indicates that you have structural blocks that can undergo a heavy load. Blocks with a lower density can be used as a self-supporting insulation.
Regulatory requirements
Construction using cellular concrete is regulated by STO 501-52-01-2007. Recommendations for the use of aerated concrete blocks suggest the need to determine the permissible wall height. If autoclaved cellular blocks are used in construction, the bearing walls can have a height of up to 5 floors or 20 m. Self-supporting walls can have a height of 30 m or 9 floors.
In the standards, you can find the strength of the blocks depending on the number of storeys. For the construction of internal and external walls of a five-story building, it is necessary to use products whose strength corresponds to indicator B3.5. The brand of the solution should be equal to M100 and above. The class of aerated concrete in three-story buildings should be B2.5; the class of solution in this case corresponds to the value of M75. For the construction of self-supporting walls, it is necessary to use blocks of class B2.5. The norms mentioned above take into account only the strength of the issue; as for thermal insulation, this side is not lit.
Wall thickness selection
If you are thinking about how to calculate the wall thickness of aerated concrete, you should know that you will need to take into account the thermal performance and strength. However, it is quite difficult to cope with such a task on your own. In this case, you can focus on approximate values ββof thickness and strength, which will depend on the purpose. If we compare with other materials, the aerated concrete wall will have a smaller thickness with equal energy efficiency.
Having familiarized yourself with Russian building codes, you will find out that the wall thickness of aerated concrete should be 44 cm, while a brick wall will have a thickness of 51-64 cm. For expanded clay concrete and wood, these values ββare 90 cm and 53 cm, respectively. Walls with this thickness will equally prevent heat loss. These recommendations are average in nature; they are based on statistics.
If you wondered about how thick the walls should be made of aerated concrete, then you should pay attention to the experience of some developers. For the construction of one-story houses, garages and summer kitchens in a warm climate, aerated concrete is sometimes used, the thickness of which is 200 mm. However, this value cannot be called recommended. Even for non-residential premises, aerated concrete with a thickness of 300 mm is used.
Additional recommendations for determining wall thickness
For the walls of basement floors and basements, D600 grade material should be used, while the thickness of the block can be equal to a limit of 300 to 400 mm. If you have to erect inter-apartment partitions, their thickness can be from 200 to 300 mm, while you should use blocks B2.5, which correspond to brands within the range of D500 - D600. Aerated concrete internal walls, the thickness of which varies from 100 to 150 mm, are constructed from B2.5 blocks, while their brand corresponds to the limit from D500 to D600. When partitions are being built in an existing room, it is best to prefer aerated concrete grade D300. In this case, sound insulation is of great importance, not strength.
The recommended wall thickness of aerated concrete should be taken into account in the construction of non-residential premises as summer kitchens and garages. During the work, aerated concrete of the D500 brand should be used, the thickness of which starts from 200 mm. The final value will depend on the load.
Wall thickness calculation
The thickness of the outer walls of aerated concrete can be calculated independently. To do this, you need to know the normalized value of heat transfer resistance for a certain region (Rreq, m2 Γ Β° / W), as well as the thermal conductivity of the blocks (Ξ», W / (m β Β° ). The thickness is calculated by multiplying these values. hygienic comfort, the heat transfer resistance should be equal to or greater than the normalized value, which is determined by the following formula Rreq = coefficient a * Dd + coefficient b. In it Dd is the degree-day of the heating period.This value is determined by the method of multiplying quantities and days by degrees for a specific locality, coefficient a is 0,00035, while the second coefficient is 1.4, all of these values ββare given in sanitary norms and rules 23-02-2003.
When determining the thickness of the bearing walls of aerated concrete, the coefficient of thermal conductivity of the material, which depends on the density, is necessarily taken into account. The denser the aerated concrete, the higher the level of its thermal conductivity. The most common in cottage construction are aerated concrete blocks of the M500 brand. They are structurally heat-insulating.
M600 brand blocks are very durable, they have high thermal conductivity, which indicates that they will pass a large amount of heat from the room. For thermal insulation, it is better to use M400 blocks, because they have a large number of pores, the volume of which in the total mass exceeds 75%. This suggests that the material retains heat well, but has a low level of strength.
Pluses of aerated concrete blocks
When the thickness of the walls of aerated concrete is calculated, you should definitely ask what advantages and disadvantages the material you use has. Among other advantages, a high level of thermal insulation should be highlighted. It is on it that consumers and suppliers make the main emphasis. Aerated concrete wall has a lower cost compared to that built of brick, but the thermal insulation properties of these structures can be equal.
The thickness of the walls of aerated concrete should not be calculated by you yourself. For this, you can use the standard values. Additional advantages of the described material are high accuracy and impressive product dimensions. All this allows you to build walls with high speed and with minimal deviations. The cost of external decoration will be reduced, and the use of products with grooves will eliminate the formation of cracks and cold bridges.
Another important advantage is the possibility of eliminating the use of cement mortar for masonry. The material is very fire resistant, light in weight and fairly easy to process. It is environmentally friendly, characterized by biological resistance and frost resistance.
Cons of aerated concrete blocks
The thickness of the walls of aerated concrete is a rather important minus of the described material. The minimum value for the Moscow region is 535 mm. It is important to take into account the cold bridges, which will give an additional 10% reduction in protection. The wall will definitely have to have reinforced belts and jumpers to strengthen the openings, this also reduces the level of thermal insulation by 10-30%. As a result, you will need to build a wall whose thickness is 65 cm.
Aerated concrete blocks, the pros and cons of which you must consider before starting construction, are often used today for the construction of residential buildings and structures for various purposes. But you must remember that the material is highly hygroscopic. This minus can be called one of the main.
Conclusion
Having familiarized yourself with regulatory documents, you will be able to understand that in the central regions of Russia you can build single-layer aerated concrete walls. As for Siberia and the northern regions, two-layer and three-layer structures are usually built there. Now you know how thick the walls of aerated concrete should be. But before purchasing this material, you should definitely familiarize yourself with its pros and cons, the latter of which quite often make consumers incline their choice towards other materials.