The thickness of the walls of aerated concrete: regulations,

How thick the wall of aerated concrete should be depends on several parameters and, first of all, these are the requirements that the project places on the thermal insulation characteristics of the building, as well as on the size of the blocks themselves. In addition, the wall can be a carrier, self-supporting or just a partition, which also determees the thickness, in addition, there is a way of laying or a geometric position in which the block will be in the construction of the structure. All of this will be discussed below, and as additional material you can watch the video in this article on this topic.

Aerated concrete blocks

Note. Aerated concrete blocks are a kind of artificial stone made of lightweight cellular concrete, in the mass of which pores with a diameter of 1-3 mm are evenly distributed. Although the material is a type of stone foam, it should not be confused with foam concrete, as it has other technical characteristics.

Specifications and scope

• The complexity of the processing of aerated concrete blocks can be compared with a tree - it is easy to cut it to drill and nail.
• Compared with foam concrete, it has higher thermal insulation and durability.besides, less cement is consumed for its manufacture.

Table of sizes and volumes of aerated concrete blocks UDK

Table of parameters of AEROC aerated concrete blocks (CLASSIC)

• For the manufacture of aerated concrete blocks use quartz sand, special specific blowing agents and, of course, cement, and in addition, there may be added lime or gypsum, as well as industrial waste in the form of ash and slag blast furnaces. Gas bubbles occur as a result of the interaction of finely dispersed aluminum metal with lime mortar or high-alkaline cement with a blowing agent — this leads to the formation of gaseous hydrogen foaming the whole mass. In the production, as a rule, aluminum pastes and suspensions are used, because powdered aluminum is impractical to create a solution - it is very dusty.
• It is noteworthy that the natural radioactivity of aerated concrete is much lower than that of ordinary heavy concrete. - this is explained by the fact that there are no crushed stone and mica in its composition - and one and the other is an integral part of natural granite, which has an increased natural radioactivity.
• The popularity of such material is so high that according to statistics for 2014, 50 countries were engaged in its production at 240 factories and produced a total of 60,000,000 m³.

Thickness guidelines

Currently, cellular concrete has gained great popularity, and the thickness of the supporting walls of aerated concrete in one block allows you to make construction of both one-story and low-rise (up to 5 floors) buildings. But when determining the height of the structure, one should pay attention to the strength class of concrete, since the load that blocks will have to withstand will depend on the height of the building. The need for thermal insulation also plays an important role, and naturally, the thicker the walls, the warmer they are.

*

Explanation. The value of the number after the letter F denotes the number of freezing / thawing cycles of the material. According to SNiP II-22-81, the F25 values ​​are enough for 50 years to operate buildings with high humidity, and if there is normal humidity in the rooms, the instruction indicates that their minimum life is 100 years.

The table, which is located at the top, is just a list of numbers, which in most cases are understandable only to designers, but in practice it will look like this: the minimum thickness of aerated concrete wall for load-bearing walls and columns is 600 mm, and for self-supporting ones - 300 mm.

This means that blocks with a thickness of 200 mm or more will be used. But in this case only mechanical requirements are considered and we are not talking about residential buildings at all, where certain insulating properties are required from the wall.

But the thickness of the aerated concrete wall for a residential building is determined by SNiP 23-02-2003 - here thermal protection is already taken into account. In addition, in such cases, a reduction in the rated thermal resistance of the structure is applicable, depending on the climate of the region and the specific fuel consumption inside the building. For example, for Moscow and the Moscow region, the heat transfer value of external walls should be R_req= 3.13 m²t ° C / W, but at the same time it can be reduced to R_me= 1.97 m²t ° C / Вт (R_me=0,63*R_req= 0.63 * 3.13 m²t°C/Вт= 1.97 m²t ° C / W), but this is only if the building is sufficiently heated, that is, the norms of temperature difference between the external state of temperature and the internal surface of the walls are observed (section 5, 13 SP 23-02-2013).

Block masonry technology

The laying of aerated concrete blocks is usually provided on the base of the strip foundation, on the slab base, and also on the grillage of a columnar or pile foundation - in any case, the basis should be a tape, the width of which is not less than the thickness of the wall being built on it. Before installation, installation of a shut-off waterproofing is provided (sometimes with insulation, as in the photo above) in order to minimize the influence of moisture and temperature characteristics of the soil on the building.

But such precaution is necessary only in those cases when waterproofing and insulation of the foundation itself were not performed, however, some duplicate this procedure and this cannot be superfluous.

As a cut-off waterproofing, you can use ordinary roofing material, laying it on a layer of mortar, or more modern materials, such as waterproofing or rubemast, as well as a dense packing cellophane film.

Mineral wool is used as a heater (not more than 20 mm thick, so that the pillow is not too soft) and it is waterproofed again - only slag wool should not be used, as it contains iron ore particles, which rust when the moisture interacts with oxygen.

The first row is usually placed not on glue, but on a cement-sand mortar not less than 20 mm thick - this allows leveling out the overall level in case of an error on the base or hiding the drops of the waterproofing layer. The first block lies on the corner and laying in two directions begins, but not along the entire perimeter, but only a few blocks up and to the sides in order to create a lock joint.

Все последующие ряды лучше всего класть на специальный раствор типа «YTONG» или обычный плиточный клей - тогда толщина шва при кладке газобетона получится не более 5 мм.

Regardless of what the thickness of the wall at the moment, GOST 5781-82 and GOST 10884-94 recommend to produce transverse masonry reinforcement to provide the entire structure with the necessary tensile strength and fracture.

For maximum protection of the building against the resistance of such mechanical loads, reinforcement is carried out in the first and then in every fourth row of the wall being erected, but without fail in the lower and upper parts of the window and door openings. In the construction of single-storey buildings with a height of up to 3m, reinforcement should be carried out on at least two levels of the wall being erected, if there are no openings in it.

During the construction of load-bearing walls, it is best to use chute (U-shaped) blocks - there is already a finished route for fittings - we sell such a stone from the manufacturer AEROC. But in those cases, when you lay the usual block type UDK, then you will have to make such grooves with your own hands - this is done quite easily, as cellular concrete is well treatable.

For reinforcement, a rod of type AIII is usually used with a cross section of 8-10 mm or wire rod, but in any case its thickness should not be less than 6 mm. At the corners of the building (locks) it is best to make smooth bends of the grooves, as shown in the top photo - so you can increase the structural strength of the box.

The size of the grooves must slightly exceed the cross section of the reinforcement, so that the adhesive solution is also placed in the groove, and no oxygen sinuses remain in the metal zone - this will prevent the material from rusting.

If the construction of a house you have maintained the recommended thickness of aerated concrete, it does not mean that you will be warm there, especially if you live in the northern regions of Russia - after all, 60 cm, this is just a strength parameter for the supporting wall. Consequently, you will have to insulate the building from the outside or from the inside, although the first option is much better and more convenient from a technical point of view.

Three types of materials are commonly used for thermal insulation - mineral wool, polystyrene foam or extruded polystyrene foam.

Usually, any type of insulation is fixed with impact fungi-dowels at the rate of 4-5 pieces per square meter, but if it is polystyrene or extruded polystyrene foam under decorative plaster, then it is additionally fixed with tile glue, spreading it around the perimeter and center of the panel.

In addition, thermal insulation can fit both directly on the wall, and between the batten profiles - it all depends on the type of cladding material with which you will finish the building. For example, if it is siding, then the insulation can be simply impaled on the brackets for the frame profiles and only in some places for fixing fix with dowels.

Note. It should be noted that cutting of reinforced concrete with diamond circles and diamond drilling of holes in concrete have nothing in common with aerated concrete, since the latter is easily processed with conventional tools.

Conclusion

In conclusion, it should be said that, despite the fact that the price of aerated concrete is moderate enough, you still should not lay masonry of such thickness to fully meet the needs of thermal insulation of the room. It is much easier and more efficient to resort to the installation of additional insulation of the building, followed by lining.