What should be the walls of aerated concrete. Thermotechnical calculation of the optimal thickness of the walls of a house made of aerated concrete Foam block wall 20 cm

Due to its low weight compared to silicate or red brick, good heat and soundproofing properties, frost and fire resistance, simplicity machining and installation, aerated concrete blocks used in construction load-bearing elements and partitions residential buildings, garages, country cottages. Many people make the wrong thickness of the aerated concrete wall, which, with its low power, does not prevent the penetration of cold and requires additional installation insulation, and with a large one leads to an inappropriate waste of excess material, and therefore money. In order to avoid such a situation, it is necessary to understand what affects this indicator and what it should be according to the standards and depending on external factors.

• D300-D500.

Lightweight blocks with low density and excellent thermal insulation properties. They are mainly used as a heater.

• D500-D900.

Unlike the previous ones, they have sufficient strength, weigh more and conduct heat a little better. Perfectly suited as the main material for the construction of walls.

• D1000-D1200.

Heavy gas blocks with the most high density for the construction of buildings requiring structural strength.

How thick should a concrete wall be?

The power value is calculated depending on the following factors:

According to the requirements of such a standard as SNiP 23-02-2003, the minimum thickness (H) is calculated using the following formula: H = R req × λ, where:

• R req is the resistance of the structure to heat transfer, calculated for each region;
• λ – coefficient of thermal conductivity of gas blocks, (W/m∙°C) depends on the grade and humidity.

The lower the value of λ, the better its thermal insulation properties - respectively, the most best indicator have walls made of aerated concrete grade D300, and the worst - D1000. In wet material, due to the presence of water in the cavities, the conductivity of heat is higher than in dry material.

The value of R req characterizes the resistance of the material to the passage through it of the total amount of heat accumulated inside the room, and is equal to the product of degree-days (D) heating period to the correction factor a and adding the constant b to the result: R req = (D×a)+b.

The value of D is equal to the product of the temperature difference inside the room during the heating period and the average daily outdoor temperature by its duration in days: D=(tin.room-tout)×Pfrom.period.

So, for example, for Moscow, this figure for 214 days with an average air temperature outside and inside the room of -3.1 and +20 ° C is 4943 degree-days; the southern regions have the lowest D value, for example, in Rostov region it is only 3523 ° C * day, and in the northern ones - Siberia, Magadan, the Urals - the highest. The values ​​of variables a and b depend on the type of building used and for the walls of residential buildings, garages and cottages, they are 0.00035 and 1.4, respectively.

Using from the reference materials the value of the degree-days of the heating period, the above coefficients and the thermal conductivity of the block grades, it is possible to calculate what thickness, according to the standards, should be at the walls of aerated concrete in the most major cities various parts of Russia and adjacent areas.

Calculation of the power of structures from cellular concrete for various zones of the Russian Federation:

thickness chart wall structures depending on the region and brand of gas silicate blocks:

The best thermal insulation properties are characterized by walls made of aerated concrete grades D300-D400. Their thickness ranges from 20 to 40-45 cm, despite this, these materials contain a lot of pores with air and little load-bearing solidified solution. The highest strength, but at the same time, the large wall thickness (up to 100 or more cm), necessary to preserve heat inside the room, is distinguished by gas blocks of the D800, D1000 brands. Most often they are used in construction. public buildings, trade pavilions and other structures with a heavy load and additional insulation.

The "golden mean" and the most optimal ratio of strength-thermal conductivity are characterized by blocks D500-D600, most often used in the construction of residential buildings and cottages, as well as other buildings.

What to consider when choosing the power of wall structures?

In addition to the calculated values, several more factors are also distinguished, on which the thickness depends.

1. Duration of stay in the building under construction during the calendar year. For country house, an outbuilding, an aerated concrete garage, heated for a short time, you can use thin walls no more than 20 cm thick that can withstand the weight of the roof and provide protection from the cold in the spring and autumn. The opposite situation in residential buildings permanent residence- in order for the heat not to leave the premises, walls with a design capacity of 30-40 cm are needed.

2. View - load-bearing structures should have a thickness of 10-15 cm more than the partitions inside the room.

3. The number and location of floors - with an increase in the height of the building, gas blocks with greater strength are used. Wall thickness one-story building should be at least 25 cm, two or more - 30-40 cm.

4. Climatic conditions outside - duration of the cold period and average temperature indicators directly affect the strength of the building fences. The walls in Siberia are made thicker than in the southern regions.

5. The presence or absence of a layer of insulation (polystyrene foam with the obligatory application of a layer on top of it facade plaster) – application heat-insulating materials allows the use of thinner blocks. A wall without insulation, in addition to having an unsightly aesthetic appearance, absorbs moisture faster due to the open porous structure, which increases the thermal conductivity of the structure.

Results

• Cellular concrete in modern construction is one of the most acceptable both in terms of price and quality of materials for the construction of various buildings.
• The walls of the house made of aerated concrete blocks have high strength, relative durability and good heat-insulating properties.
• Using the formulas given in the regulations, it is possible to calculate the optimal power of enclosing structures, taking into account the conditions of a particular region, allowing you to save material and make the wall thickness in the Moscow region less than in the northern ones.
• The use of insulation for lining masonry from gas blocks increases their service life and reduces consumption.

Aerated concrete belongs to the category of cellular concrete and their use in the construction industry is strictly regulated. The main recommendations to determine the necessary indicators of the strength of the walls being built, the following:

• it is necessary to calculate the allowable indicators of the height of the erected walls of the structure;
• height restrictions bearing walls, erected from aerated concrete blocks, are four to five floors;
• the strength indicators of blocks for the construction of five-story buildings are B-3.5, and for three-story buildings B-2.5;
• for the erection of buildings self-supporting walls it is recommended to use, depending on the number of storeys, blocks B-2.0 or B-2.5.

Regulatory documents in the context of private housing construction are currently purely advisory in nature, and therefore may not be taken into account in low-rise construction, as well as in the construction of any outbuildings or garages.

This means that there is no need to rent housing to any commissions. You built it yourself, live it yourself. No one will check the strength of structures, their compliance with thermal conductivity standards and other parameters. However, if the goal is to build a house for yourself well and for a long time, then you need to focus on these recommendations.

What wall thickness is enough for a summer home

Before building any building strength calculations are required. Do it yourself such calculations are not always possible, therefore it is allowed to proceed from examples that take into account the values ​​​​of strength classes, in accordance with which the wall thickness is selected. An important factor is also the purpose of the building being erected.

In low-rise construction of houses for summer living, it is advisable to adhere to the basic simple recommendations:

• one storey houses in warm climatic conditions, country and garage buildings require the use of aerated concrete with a thickness of at least 200 mm;
• two- or more-story houses require the use of gas silicate with a thickness of 300 mm or more;
• construction basements or ground floors involves the use of blocks with a thickness of 300-400 mm (here it should be remembered that gas silicate is afraid of moisture, therefore, at the risk of its presence, it is better to choose other materials);
• inter-apartment and interior partitions are performed with aerated concrete with a thickness of 200-300 mm and 150 mm, respectively.

You can go to the official website of any block manufacturer and see the list of sizes of manufactured products.

Here we will see that the blocks are divided into wall (for building walls) and partition (for interior partitions).

If on suburban area it is supposed to carry out the construction of non-residential premises or a house for summer use, it is recommended to give preference to aerated concrete with a minimum thickness of 200 mm.

Thermal conductivity of walls

When building houses for permanent residence, strength alone is no longer enough. Here also the thermal conductivity of the materials used must be taken into account. In accordance with the calculations, either the required thickness of the blocks for your climate zone, or the thickness remains as for summer buildings, but a heater is additionally used.


And in this case, you need to consider the money, which will be cheaper - an increase in the thickness of the wall due to aerated concrete or insulation.

When calculating the cost of insulation, it is worth adding the price of fasteners and the payment for the work of builders.

As I wrote at the very beginning, it was decided to do without a heater. Therefore, further calculations will be carried out for "bare" walls.

In accordance with GOST, which regulates the main technical specifications, as well as the composite characteristics and dimensions of absolutely all cellular blocks, the thermal conductivity of such a building material is 4 times lower than similar indicators solid brick, which makes it possible to build structures with narrower walls.

The thermal conductivity of a material is the ability to conduct heat. The calculated indicator of the amount of heat passing through 1 m 3 of a material sample in 1 hour at a temperature difference of 1 °C on opposite surfaces.

The higher this indicator, the worse the thermal insulation properties.

I will give a detailed comparison with a solid brick. The thermal conductivity of aerated concrete is approximately equal to 0.10-0.15 W / (m * ° C). For bricks, this figure is higher - 0.35-0.5 W / (m * ° C).

Thus, to ensure the normal thermal efficiency of a residential building for the Moscow region (where the air temperature rarely drops below -30 degrees in winter) Brick wall must be at least 640 mm thick. And when used in construction aerated concrete blocks D400 with a thermal conductivity of 0.10 W/(m*°C) walls can have a thickness of 375 mm and conduct the same amount of heat energy. For D500 blocks with a thermal conductivity of 0.12 W / (m * ° C), this figure will be in the range from 400 to 500 mm. Detailed calculations will be below.

Thermal conductivity indicators depending on the wall thickness:

Between the coefficient of thermal conductivity and the thermal insulation of the walls there is inverse proportionality which must be taken into account when performing independent calculations.

Load-bearing walls without insulation for permanent residence

Cellular concretes have excellent thermal characteristics, therefore, subject to the calculation rules, there is no need to use heaters even when erecting buildings intended for year-round use.

To perform independent thermotechnical calculations you need to know the reference tabular values ​​​​of indicators such as heat transfer resistance R req m 2 °C / W and heat conductivity of aerated concrete.

Calculation depending on the region of residence

Heat transfer data for some regions are shown in the table. Choose locality appropriate for your climate zone.

Thermal conductivity

For this value, I will again go to the website of the manufacturer of the wall material that I am going to buy, and I will find the following sign there:


Now let's see the real reference data.

We see that the manufacturer indicates the characteristics for dry material. If the walls contain moisture, which is acceptable, then these characteristics will be slightly worse.

As you know, the blocks that came off the conveyor have a moisture content of up to 30%. During normal use, this excess moisture goes away in about 3 years.

Continuous heating running in the house accelerates this process.

On the Internet, you can find reviews of developers complaining about cold walls in aerated concrete house. It turns out that the house was built during the summer-autumn. And in the winter the family settled in it. The walls of the house are damp, not yet dry properly. Water - good conductor heat.

Residents are starting to think about the insulation of their homes. But you just have to wait until next winter. Moisture from the walls will go away, and reside in winter period will become more comfortable.

An example of calculating the required wall thickness for the Moscow region

In the capital and the region, most often they choose between D400 blocks with a width of 375 mm and D500 with a width of 400 mm. It is on these test subjects that we will make calculations.

Minimum thickness values aerated concrete walls are determined using the standard multiplication of such parameters as the average heat transfer resistance R and the conductivity of aerated concrete blocks without the use of heaters. These parameters are shown in the tables above.

For Moscow R=3.29 m2×°C/W.

Let's make a calculation for blocks D400

For a dry state, the thermal conductivity coefficient is 0.096.

3.29 * 0.096 = 0.316 (m)

At a moisture content of 4%, the coefficient is 0.113.

3.29 * 0.113 = 0.372 (m)

Based on the calculations, it can be seen that for a perfectly dry material, a wall thickness of 316 mm is sufficient for the D400 grade.

However, manufacturers in commercials tell us that for Middle lane Russia has enough block thickness of 375 mm for the D400 brand and produces this size. From which we can indirectly conclude that the calculation includes a coefficient for humidity of 4%.

Now let's calculate block D500

For a dry state, the thermal conductivity coefficient is 0.12.

3.29*0.12=0.395 (m)

At a moisture content of 4%, the coefficient is 0.141.

3.29 * 0.141 = 0.464 (m)

So, the manufactured blocks D500 with a width of 400 mm will fit the characteristics for the ideal case. There is nothing perfect in the world. But to approach the ideal, it is necessary to avoid external wetting of the walls from precipitation by lining the house with a brick with a ventilation gap. You can also install siding or other panels.

Even housing must be constantly heated. And when severe frosts above -20 degrees, which is recent times in the Moscow region it happens extremely rarely to be prepared for short-term increased heating bills.

Obviously, in terms of thermal conductivity, the D400 block with a width of 375 mm outperforms its fellow D500 with a width of 400 mm. But if only it were that simple. You also need to look at the safety factor B. A few years ago wall material D400 was produced with a deliberately lower strength, which stopped developers from choosing such a building stone. Now leading manufacturers guarantee the strength of B-2.5 for the D400 grade.

If construction is planned alone, then an important criterion for choosing will be, which depends on the size and density.

Thus, the desired parameters directly depend on the brand (density) aerated concrete building material. For some regions, these values ​​are calculated and collected in a table.

Useful video

In this story, there are some clever thoughts on calculating the thickness of the walls:

Internal partitions made of aerated concrete

The thickness of the aerated concrete partition must be selected in accordance with several factors, including calculation bearing capacity and height.

When choosing blocks for the construction of non-bearing partitions, you need to pay attention to the height:

• the height of the structure being erected does not exceed three meters - the building material is 10 cm thick;
• the height of the internal partition varies from three to five meters - the building material is 20 cm thick.

If it is necessary to obtain the most accurate data without performing independent calculations, you can use standard tabular information that takes into account the interface with the upper floor and the length of the structure being erected. It is also necessary to give special meaning the following recommendations choice of building material:

• determination of operational loads on internal partitions allows you to choose the optimal material;
• erect non-bearing interior walls best of all from products of the D500 or D600 brand, having a length of 625 mm and a width of 75-200 mm, which creates a strength of 150 kg;
• installation is not load-bearing structures allows the use of products with a density of D350 or D400, which helps to obtain standard sound insulation up to 52 dB;
• sound insulation parameters directly depend not only on the thickness of the building blocks, but also on the density of the material, therefore, the higher the density, the better soundproofing properties aerated concrete.

With a partition structure length of eight meters or more, as well as a height exceeding four meters, in order to increase the strength characteristics, it is necessary to strengthen the frame with the help of load-bearing reinforced concrete structures. The required strength of the partition is also achieved due to the adhesive layer that holds the block elements together.

Affordable cost, manufacturability and excellent quality characteristics made aerated concrete blocks popular and in demand in the market of modern building materials. Properly calculated thickness of the wall of aerated concrete allows you to provide buildings under construction high level strength, as well as maximum resistance to almost any static load or shock factors.

Any owner who decides to build Vacation home, wants it to be warm, cozy, and living in it - comfortable. perfect building material for the construction of a private dwelling, cellular concrete, in particular foam blocks, has recently been deservedly recognized.

In the article we will talk about what should be the thickness of the walls of foam blocks for load-bearing walls and partitions, so that the building is strong, reliable and durable.

Comparative characteristics of masonry materials

So, for clarity, we will compile a table of the main indicators of cellular concrete in comparison with other analogues.

Let's take the most popular materials for the construction of residential buildings: brick, expanded clay and aerated concrete:

Based on the table, we draw conclusions on the advantages of foam concrete:

• By weight foam blocks are equal only to aerated concrete (see), low weight facilitates transportation and carrying. And given the significant size of the blocks, then laying and reducing construction time.

• By thermal conductivity foam and gas blocks are unparalleled, which means that a house made of these materials is more ergonomic, it will always be warm and comfortable in it at low heating costs.

• water absorption foam concrete has much less than other analogues, which means that the risk of moisture penetration into the room is reduced, and, accordingly, dampening of the walls, the formation of fungus, mold, and so on.

Important! Humidity in the room should be no more than 60%, but in any case, the waterproofing of wall surfaces is done with all responsibility, since the moisture absorption of the foam block, although small, is still present.

• Number of freeze and defrost cycles foam blocks have more than, for example, bricks, so the service life of the building increases. By the way, experts say that over the years the foam block is only gaining strength, but the brick, on the contrary, is subject to destruction.

• Foam concrete works in compression a little worse than brick or aerated concrete, but this indicator depends on the brand of foam blocks - the higher it is, the stronger the wall. You can increase this parameter.

Especially it should be said about the cost of this material, the price of foam blocks is 2-3 times lower than for other building materials.

Types and brands of foam blocks

We digressed a little from the topic, promised to talk about how thick the wall of foam blocks should be. And it depends just on the type of foam concrete and brand, so we give a table of existing designations for blocks of cellular concrete.

I must say that all foam blocks are also divided by appearance, they are:

• Thermal insulation.

They are used to insulate the contour of the walls of buildings and the installation of internal self-supporting partitions.

• Structural and thermal insulation.

They are used for both additional insulation, and for the construction of partitions and walls of low-rise buildings.

• Structural.

They serve for the construction of responsible, load-bearing structures (foundations (see), plinths, walls).

Important! The brand of the foam block is indicated by the letter D, for example, the D 800 block has a density of 800 kg / m3. With an increase in density, the thermal insulation qualities of the blocks deteriorate, therefore structural types additional insulation is recommended.

About unique features quite a lot has been said about foam concrete, we will not analyze its pros and cons in detail, we will finally move on to choosing the thickness of the walls.

Features of determining the thickness of the walls

To clearly show the advantage thermal insulation properties foam concrete, take a wall of foam blocks of 60 cm, and now let's see what the wall thickness of other materials should be equal to, which has the same thermal conductivity:

• Beam - 52 cm.
• Expanded clay concrete - 101 cm.
• Brick - 230 cm.
• Concrete - 450 cm.

In terms of heat retention, foam concrete is only equal to wood, all other materials will require additional insulation, otherwise there will be a huge overrun and incredible wall thickness.

The choice of thickness is influenced by the following parameters:

If the building is one-story, the floor is wooden, the roof is not heavy, then grades D600–D800 are usually taken for load-bearing walls. With a house with several floors and reinforced concrete floors apply more high marks D900-D1200. For partitions, blocks D200–D400 are used.

1. Dimensions and thickness of foam blocks.

In areas with a temperate climate, houses are built with a wall thickness of 30 cm, for this they take a foam block measuring 30x30x60 (width, height, length) and lay it along.

For cold regions, walls are erected with a thickness of 60 cm, the same block is laid in two rows.

A foam block wall thickness of 20 cm is made mainly for internal load-bearing partitions, both interior and separating the living space from the veranda, as well as for garages and outbuildings. Self-supporting partitions in bathrooms or pantries are mounted from semi-blocks 10 (15) x20 (30) x60.

1. Soundproofing of rooms.

If you need to isolate the room from the penetration of noise from next room or from the street, it is better to take wider blocks. For example, foam blocks with a thickness of 30 cm will more reliably reduce the noise level than with a width of 20 or 15 cm. A thickness of 10-15 cm will require additional sound insulation.

1. Warming.

When external insulation of surfaces is planned, the thickness of the foam blocks is taken at a maximum of 30 cm, bricks, thin semi-blocks (10x20 (30) x60) or other facing materials are used for decoration. Due to the insulation layer placed between the main wall and the sheathing, the thermal insulation of the room increases significantly.

If the house is being built without additional insulation (for example, foam blocks with a finished facade are used), then the instruction recommends increasing the wall thickness to 60 cm.

Now insulated foam blocks are being produced, which immediately contain insulation and facing material. In this case, a wall of foam blocks (thickness 20 cm + 8–10 cm foam + facade tiles) will withstand even severe frosts.

Important! It must be remembered that the higher the density, the worse the sound and heat insulation. For example, the thermal conductivity of a wall made of foam blocks D600 with a thickness of 45 cm is equal to a wall made of D800, but with a thickness of 68 cm!

The same goes for interior layout. For partitions, the thickness of the D200 foam block of 10-15 cm better soundproofs the room than D300 or D400 of the same thickness.

Accurately calculate all parameters for wall thickness, quantity required material, the brand of foam blocks can be found on the calculator available on any construction site. If you want to calculate the wall thickness yourself, then refer to SNIP II-3-79. It contains the values ​​​​of all the necessary indicators for calculating the heat transfer of any wall composition and various foam block densities.

Conclusion

As we found out, the thickness of the foam block for partitions and walls of the building is calculated quite simply. In addition to the parameters presented, it also depends on the area of ​​\u200b\u200bthe premises, the desires and financial capabilities of the owners.

All the same, somewhere in something you will have to adapt to the size of the site or the type of foundation. But it is still desirable to adhere to the basic rules. Additional information is contained in the presented video in this article, we hope that the photos will also help you quickly decide on this issue.