• Repair
• Repair
• Interior Design
• About everything
• About plumbing

Blocks for walls pros and cons. Gas silicate blocks - disadvantages and dubious qualities. Gas silicate block D500 building material characteristics

Gas silicate was invented as an alternative to concrete and brick. The main goal of the developers of the new building material was to reduce the cost of erecting buildings without losing the strength characteristics of the bearing and not load-bearing structures. Manufacturers of gas silicate blocks position them as one of the best building materials for low-rise buildings. However, the practice of its application shows that the gas silicate block has its pros and cons.

What is a gas silicate block

The gas silicate block is a building stone intended for laying walls, supports and partitions. It is made of cellular gas silicate concrete, a feature of which is the absence of cement in the composition. The binder function is performed by a mixture of lime and quartz sand in a ratio of 0.62:0.24.

The production technology is simple:

1. Measure the required amount of lime and sand.
2. Sifted on a vibrating sieve.
3. Joint fine grinding of the listed ingredients is carried out in a ball mill.
4. Add water.
5. Aluminum powder is introduced, which acts as a blowing agent.
6. The resulting mixture is poured into molds, filling each of them by ½ volume.
7. For two hours kept at a temperature of +40°C, waiting for completion chemical reaction which produces hydrogen.
8. The blocks are placed in an autoclave, where they are kept for 12 hours at a pressure of 0.8–1.3 MPa and a temperature of up to +200°C.
9. The blocks are removed by a divider crane and they are laid for further hardening and gaining brand strength.

The resulting material is a porous stone with the following technical characteristics:

• dimensions of voids (cells) - 1–3 mm;
• density - 200–1200 kg / m 3 (corresponds to the brand: D200-D1200);
• thermal conductivity - 0.11–0.16 W / ° С * m 2.

Frost resistance deserves special attention. For blocks of grades D200-D400, this indicator is not standardized. Building stones with a density of 500–600 kg/m 3 can withstand up to 35 freeze-thaw cycles without loss of strength and other characteristics. Frost resistance of blocks of higher grades (D700-D1200) corresponds to F50-F75.

Outstanding technical indicators due to the porous structure of the material

Application area

Residential and non-residential buildings are erected from gas silicate blocks. Construction technology involves the use of stones of different densities for certain purposes:

• D200-D350 - construction insulation.
• D400-D600 - masonry material for the construction of load-bearing and non-bearing walls in low-rise construction.
• D700-D1200 - masonry material for the construction of high-rise buildings, subject to reinforcement in every fourth row.

Gas silicate allows you to significantly save on space heating

Difference from aerated concrete

Gas silicate and aerated concrete blocks - materials of the class of cellular concrete. They have much in common in properties and specifications Ah, they are used for the same purposes. All this confuses the classification of these materials, and due to the external similarity, even experts cannot accurately determine which block is in front of them: gas silicate or aerated concrete.

For internal partitions, a structural and heat-insulating type of material is suitable

But there are significant differences between them. First of all, it is the composition and method of production. There are other differences, which can be found in the table.

Differences between gas silicate and aerated concrete

The dimensions of gas silicate blocks are standardized by GOST 31360–2007. All enterprises specializing in the production of cellular concrete adhere to the accepted recommendations. But this does not exclude the possibility of making building stones according to individual sizes customer.

Generic Block Parameters

The choice of objects for construction is carried out based on the pros and cons of gas silicate blocks.

pros

The indisputable advantage of gas silicate is its low thermal conductivity. This property is due to the porosity of the material. It consists of a large number hollow cells filled with air and having an irregular spherical shape. They are the best heat accumulator. The principle of insulation of buildings and communications with fibrous materials (mineral wool in rolls and slabs) is based on this property of air.

Gas silicate has other advantages:

• High accuracy of geometric parameters of products. According to GOST 21520 89, there are three categories of accuracy, each of which allows small deviations: in height - 1–5 mm, in thickness and length - 2–6 mm. The use of even stones of the same size in masonry allows you to save on the binder: cement-sand mortar or glue.
• High rates of vapor and air permeability, corresponding to similar parameters of most types of wood. In this regard, gas silicate can be called a "breathing" material.
• Environmental safety due to the absence of components harmful to human and animal health.
• Fire resistance, allowing the use of gas silicate blocks for the construction of fire barriers. In a building made of this material, the fire spread limit is 0.
• A light weight. The mass of a block depends on its density and geometric dimensions. The weight of a standard stone 625x300x250 with a density of 400 kg / m 3 - 17 kg; with a density of 1200 kg / m 3 - 28 kg. A low-rise building made of gas silicate blocks does not require a powerful foundation. In most cases, private developers choose between shallow tape (MZLF) or slab. But with the foundation device, not everything is so simple, which will be discussed below.
• Flexibility in processing. Blocks of cellular concrete can be sawn with a conventional hacksaw for wood. Nails are easily hammered into them and self-tapping screws are screwed in. All this greatly facilitates the implementation of construction and finishing work.
• Do not attract rodents and insects, are not damaged by them.

Has the least weight heat-insulating look gas silicate blocks

Minuses

Private developers often express a negative opinion about gas silicate and aerated concrete, report on their experience in building and operating houses from these materials. Based on the reviews, we can draw conclusions about the inherent shortcomings of these blocks.

Hygroscopicity

Gas silicate has one significant disadvantage that can minimize and cross out all the advantages of this material: a high degree of hygroscopicity. It defines many problems that arise in the construction and operation of houses.

Moisture permeability of porous stones is due to the presence of air in them. It is able to penetrate into the smallest cracks and fill them. The moisture contained in it is absorbed by a mixture of sand and lime (components of the gas silicate composition). Aerated concrete is also exposed to the same danger, since the presence of cement in it is not an obstacle to the penetration of water into the structure of the block.

We draw conclusions: a wet block is a cold block. Therefore, the thermal characteristics of the material declared by the manufacturer correspond to the conditions of its operation: at low or normal humidity air.

In reality, this cannot be achieved, since the natural a natural phenomenon- precipitation in the form of rain and snow will always increase the humidity level surrounding house atmosphere. In addition, this indicator is inevitably affected by the proximity of water bodies: rivers, ponds, pools.

In confirmation of the information presented, one of the recommendations regarding cellular concrete can be cited.

According to clause 1.7 of the "Handbook to SN and P for engineering and technical workers of scientific research and design organizations» cellular concretes, including gas silicate blocks, are categorized as non-moisture resistant and non-biologically resistant materials not recommended for building walls in rooms with wet and wet conditions.

Beams can be used to protect external walls

fragility

With all its advantages, gas silicate has a low bending strength. This causes the fragility of the blocks and the appearance of cracks in the walls and partitions. The lack of elasticity makes gas silicate structures responsive to the slightest deformations.

Practice shows that houses above three floors are not built from this material. For the construction of high-rise buildings, blocks of high density are required: from D700, which have lower thermal insulation characteristics. The cost of construction increases significantly, as the cost of purchasing more expensive blocks, heat and waterproofing materials.

But even for a three-story building, a high-quality foundation made of heavy concrete is required. Moreover, it is important that the base of the house has a high bearing capacity and has a perfectly flat, horizontal surface. In this case, the risk of shrinkage deformation of the walls and the formation of cracks in them is minimal.

The experience of builders suggests that without a reliable foundation, it makes no sense to deal with cellular concrete. When choosing an MZL or a shallow slab as the base, experts recommend building a brick basement. And only after that proceed to the laying of gas blocks.

Poorly laid out foundation leads to cracking of gas silicate

Low mechanical strength

To fix massive structures, heat and waterproofing materials on walls made of gas silicate, special fasteners will be needed. Ordinary, in the form of dish-shaped dowels, will not work. Aerated concrete blocks have a fairly loose structure, so they require special screw-in dowels or chemical anchors. The price for these fasteners is 5-6 times higher than for dish-shaped ones.

On average, the cost of insulation, waterproofing or finishing 1 m 2 only due to the use of specialized fasteners increases by 250–300 rubles. The total area of ​​the facade of a private house is at least 300 m 2, so this feature of gas silicate blocks leads to a significant increase in the cost of construction estimates.

The structural type of gas silicate has low thermal insulation

The use of material for the construction of a bath

The bath from the gas-block differs in an optimum ratio of the price and quality. Adherents of log cabins will find many negative aspects in the construction of cellular concrete, but not every owner has the means to purchase expensive wood. In this situation, affordable materials help out: gas silicate and aerated concrete. They have a number of characteristics that can be regarded as positive for the construction of a bath:

• Fast erection. Due to its light weight and correct geometric shape blocks, masonry can be done independently, without involving specialists. Big sizes building stones provide high speed building walls.
• Low thermal conductivity. With the same wall thickness, a gas-block bath will be warmer than a brick one.
• Small load on the foundation. A small-sized one-story building can be erected on a strip or column base. Recently, the foundation of Semykin, patented by the author, has been gaining popularity. Such a foundation is built from, filled with sand, car tires. It is great for building a bath from gas blocks.
• Walls made of cellular concrete hold well and give off heat for a long time.

The negative aspects of building a bath from gas silicate blocks:

• high-quality hydro- and thermal insulation of walls is required;
• installation of a warm floor is desirable, which will ensure quick drying of the building;
• important to observe increased requirements for storage, transportation and laying of the gas block, preventing the appearance of chips and cracks.

A bath made of this material is an advantageous structure in all respects. It is only required to properly protect it from moisture and veneer.

Gas silicate can be easily cut into pieces of the desired size

The construction of the walls of the house from blocks

For the construction of a private house, a gas block is not the best material. If there is no other way out, it can be used, but you need to be prepared for additional costs for insulation and waterproofing of walls and ceilings. Required Special attention to the quality of the construction of the foundation: it must be reliable and even.

An important point in building a house from gas silicate blocks is the thickness of the walls. Manufacturers claim that 380 mm is enough for Moscow and the Moscow region, but this does not meet accepted standards.

When calculating in accordance with SNiP 23–01–99 “Construction Climatology” and SNiP II-3–79 “Construction Heat Engineering”, it turns out that the minimum wall thickness for Moscow and the Moscow Region (when using gas silicate and excluding seams) is 535 mm, the maximum - 662 mm. Taking into account the seams - 588–827 mm, respectively. It is irrational to build such walls, so you will have to make high-quality expensive insulation.

Facing gas silicate blocks will protect them from destruction and extend the life of the material

Video: gas silicate house

How to choose

When choosing gas blocks, they are primarily determined by their type: wall or partition. The first are necessary for the construction of load-bearing structures, the second - for non-bearing. The market offers a wide range of blocks different brands. For building a house the best choice will be the following:

• D400 B2.5 - suitable for the construction of buildings up to three floors;
• D500 B3.5 - used for the same purposes, more dense and durable, but the thermal conductivity is higher than that of D400 B2.5;
• D600 B3.5–5 - high-strength stones recommended for the construction of basement floors, houses with a ventilated facade and suspended structures.

A visual inspection of the blocks is also important, which will give an idea of ​​the state of the building material of the entire purchase batch. High-quality stones are even, with clear edges and without cavities. The autoclaved gas block is much lighter than the one that gained brand strength through natural drying.

The high density of the material reduces its thermal insulation qualities

Among the large number of wall building materials offered domestic producers and representatives of foreign companies, there are many discussions about the properties, characteristics and conditions for the use of blocks from lightweight concrete . In particular, gas silicate blocks, the disadvantages and advantages of these products are considered in detail from all sides. Moreover, to what extent some actively position these blocks as ideal means for obtaining durable, warm and durable walls , so others diligently prove inapplicability of European developments for the Russian climate.

Given the prevalence and availability of gas silicate blocks, it is advisable to calmly and in detail consider all the pros and cons of this material.

What blocks can be called gas silicate

First of all, it makes sense to decide which building blocks belong to gas silicate, since in discussions this category includes almost all types of products made of lightweight concrete, with the exception of expanded clay and cinder blocks. In accordance with an international patent received in 1924 for this material, blocks can be called gas silicate:

1. which, in addition to the filler (quartz sand with a limited content of impurities, water with regulated hardness), as a binder includes lime- cement mortar with weight content ground quicklime about 75%, A as blowing agent - aluminum pastes or powders containing at least 90% metal fraction from 20 to 45 microns;
2. in which pore formation occurs due to the occurrence in the process of mixing a liquid mixture of hydrogen, which saturates the finished mass with bubbles; as a result, the hardened material has many small, evenly distributed pores of the same size and regular shape;
3. hardening of which is carried out in autoclaves at a pressure of 8 to 12 atmospheres and at a temperature of about 200ºС, which allows you to completely bind active aluminum, eliminating the possibility of its influence on environment, as well as to achieve the stability of the thermal characteristics of the material due to the hydrophobization of the cement stone.

In order to determine the reasonableness of the cost of, the disadvantages and advantages of these products should be compared with materials of the same purpose and with similar properties.

Disadvantages are known in comparison

The most correct comparison for gas silicate blocks are building blocks made of foam concrete. In this case, blocks should be analogous autoclaved, since foam concrete blocks of natural hardening, manufactured under conditions construction site or adapted premises:

• due to the need to fill in metal molds, they have a limited size range;
• need a certain time to gain the necessary strength;
• have non-uniform physical characteristics by volume due to unstable mixing of the mixture;
• may have significant deviations from the geometric dimensions, which leads to an increase in the thickness of the seams and, accordingly, to the appearance of "cold bridges".

Deviations are due to production in separate forms, while autoclaved blocks are made by sawing a single volume of concrete into blocks of the required dimensions.

That's why it is advisable to compare the main indicators of gas silicate and foam concrete blocks manufactured in accordance with GOST 31360-2007 (“Wall products, unreinforced, from autoclaved cellular concrete”)from autoclaved cellular concrete in accordance with GOST 31359-2007(“Autoclaved cellular concrete”).

Based on the analysis of the given technical characteristics, it is possible to makefollowing conclusions:

• with equal strength, the density of gas silicate blocks is lower than that of foam concrete, which indicates their lower thermal conductivity and, accordingly, the smaller wall thickness required in specific climatic conditions;
• at the same density and thermal conductivity, the strength of gas silicate blocks will be higher.

The indicators of each of the materials vary depending on the manufacturer, the parameters of the materials used, the differences in technology, so the table shows average values.

Gas silicate blocks: disadvantages and advantages - what more?

However, gas silicate blocks are not only characterized by advantages, they also have disadvantages. The negative properties of this material include:

1. high water absorption, which limits the use of gas silicate concrete blocks in rooms with humidity above 60%. Therefore, for the installation of gas silicate blocks of external walls in areas with a humid climate, partitions in sanitary facilities, a special finish is required;
2. relatively low heat resistance of gas silicate blocks, which cannot be used at temperatures above 400ºС;
3. the impossibility of obtaining gas silicate concrete in construction conditions for its use for thermal insulation of building structures.

And if the second and third shortcomings do not matter to the vast majority of potential buyers, then high water absorption can seriously limit the scope of application of gas silicate blocks.

This limitation can be removed by special plaster mixtures , with high vapor permeability, water-repellent properties, good adhesion to the base, strength and frost resistance. This plaster is applied with a layer of 7 - 9 mm thick on the outer surface of primed gas silicate blocks with a mesh of alkali-resistant fiberglass fixed on it. The plaster is being painted vapor-permeable paints and covered with a layer of water repellent. This technology makes it possible to ensure the durability of external walls made of gas silicate blocks, regardless of climatic conditions.

Conclusion: each block is good in its own system

Summarizing all the above, we can say that gas silicate and foam concrete autoclave blocks are almost equivalent. However, on the domestic market, mainly blocks of naturally hardened foam concrete are presented, the properties and characteristics of which are much lower. As for gas silicate blocks, disadvantages they are connected with the fact that in the Western European countries, from where this material came to us, blocks as an independent structural material rarely applied. Basically, in the construction, primarily of individual residential buildings, complex compatible wall and finishing materials, allowing to level the negative properties, like high water absorption, highlighting the positive- low thermal conductivity, smooth surfaces, excellent geometry.

Hence the conclusion: having certain knowledge of the rules for using autoclaved gas silicate blocks and following them, you can build a light, strong and durable house with beautiful facades.

Every year for construction market there are more and more new types of building materials that are used in the construction of cottages and garages, cottages and skyscrapers. But the materials used in the construction of residential buildings are gaining great popularity. Still, many people dream of living in their own home, away from the bustle of the city, noise and poisoned air.

One of these materials is a gas silicate block. Due to their price and ease of installation, they have gained popularity among developers. At first glance, this material is simply ideal for the construction of private cottages. But before buying material and starting construction, you should find out which gas silicate blocks have pros and cons. First, let's talk about the advantages.

In contact with

Classmates

gas silicate blocks

This material has gained considerable popularity not only in the construction of residential buildings, but also outbuildings - from chicken coops to garages. This became possible due to the following advantages:

• low cost when comparing gas silicate blocks with bricks;
• low weight is guaranteed by low density - from 300 kg / m 3 to 600 kg / m 3. That is, it is comparable to most types of wood used in construction;
• excellent thermal insulation characteristics. The thermal conductivity of a wall made of gas silicate blocks is 8 times less than that of a brick. This advantage has brought popularity to the blocks, in countries with a harsh climate;
• high rate of thermal accumulation significantly reduces the cost of heating the house. Even if a country house was empty during the winter months, it can be heated in a matter of hours, burning a minimum of fuel;
• incombustibility - even direct contact with open fire does not harm the material;
• good sound insulation- according to this indicator, the material exceeds the brick by 10 times;
• excellent vapor permeability creates a healthy atmosphere in the house - it is pleasant and comfortable to be in such houses;
• environmental friendliness.

As you can see, gas silicate blocks have many significant advantages. But it is not enough to know only about them - to be aware of the shortcomings of the material is even more important.

What are the disadvantages of these blocks?

Crack on the gas silicate block

The main disadvantage of gas silicate sides is strength. Unfortunately, these blocks do not withstand both bending and tensile loads, and compressive loads. Therefore, build multi-story houses it is impossible from it - the walls will collapse under their own weight. Often they are damaged during transportation and installation. In order not to have to interrupt work due to a lack of material, it is advisable to purchase it with a margin, the number of additional blocks depends on the amount of work. Yes, it will increase financial costs. But the blocks are guaranteed to be enough to complete the construction.

Another important disadvantage is moisture absorption. This leads to a whole range of problems. Firstly, mold may appear on a block soaked with moisture - both from the outside and from the inside. Secondly, significant moisture absorption is the cause of low frost resistance. If the blocks are saturated with water, then when it freezes, it will destroy its pores, reducing the already not very high strength of the material.

The disadvantages can also include external attractiveness of gas silicate blocks. Light gray walls with streaks of dark gray mortar will hardly please even the most undemanding owner. That's why aesthetic appeal can not be included in the list of advantages of the material. Such shortcomings significantly narrow the scope of application of gas silicate blocks.

Is it possible to get rid of the cons?

Properly selected blocks guarantee strong walls

As you can see, gas silicate blocks have pros and cons, like any other building material. Let's figure it out - is it possible to get rid of the shortcomings in order to get a dream home?

With low strength, alas, nothing can be done. It is necessary to choose the right material, based on the future load on the walls. As mentioned above, the density of blocks can vary from 300 to 600 kg per cubic meter. Of course, the greater the weight, the higher the cost, but the strength also increases. When building walls one-story house it is desirable to use a material with a density of 400 or 500 kg / m 3(depending on the thickness of the walls and future loads on them). They are able to withstand significant loads without harm to themselves. If you decide to build two-storey house, it is better to purchase blocks with a density of 600 kg / m 3 - they are stronger. Alas, the construction of tall houses will have to be abandoned - the material simply cannot withstand the load.

Another disadvantage is moisture absorption. The only way troubleshooting, this reliable protection. Plastering and painting in this case will not achieve the desired result. As practice shows, plaster does not stay on the surface of gas silicate blocks for too long. The house inevitably shrinks, which causes the plaster to become covered with a web of cracks, and sometimes simply crumble, leaving the blocks defenseless against moisture. A layer of paint disrupts gas exchange, leading to the fact that the material loses one of its main advantages.

Wall decoration from gas silicate blocks with siding

That's why best solution in this situation is siding. The walls are sheathed with a special membrane material that allows for effective removal of moisture from the premises, and at the same time, to protect the walls from rain, snow and other atmospheric precipitation. Siding not only makes the house attractive, saving it from another important drawback, but also protects it from mechanical stress.

Satisfied with the popular way of finishing walls from gas silicate blocks - mineral wool insulation. fasteners mineral wool to the wall, is made with special dowels, as a result, its delamination from the wall is excluded. After the mineral wool is reinforced with a mesh, it will be pressed into the glue layer. After complete drying, putty is applied to the adhesive in two layers, rubbed, primed and painted.

We must not forget about the waterproofing of the walls from below. Before laying the first row of blocks, 2 layers of building polyethylene or roofing material are placed on the foundation. If you need to protect the walls from moisture after they are laid, you can use mastic - it covers several lower rows, which allows you to protect the blocks from moisture, and at the same time, almost does not disturb gas exchange.

With this approach, you can completely rid the material of all the most important shortcomings.

Now you know all the pros and cons inherent in a house made of gas silicate blocks, and you also have an idea of ​​\u200b\u200bhow to eliminate the latter. So, you have a great opportunity to acquire a cozy, reliable, beautiful and warm home.

In contact with

Gas silicate is not a new material, and it is well known to professionals. But in recent years, interest in it has only grown. The boom in suburban construction, coupled with the desire to save on heating as much as possible, brought cellular concrete to the market leaders. The price of autoclave blocks is significantly higher than that of analogues manufactured using a simpler technology.

The porous structure largely determined the high technical specifications. On the one hand, the finished blocks are really light and warm, on the other hand, the cellular matrix of aerated concrete is much less durable than a monolith. Read about the difference between gas silicate and aerated concrete blocks.

The density of the produced gas silicate varies from 300 to 800 kg / m3, it is divided into three groups:

1. Thermal insulation - the most lightweight material weighing up to 400 kg/m3, not particularly durable, but with the best energy saving performance. Only 2.5-3.5 MPa can withstand compression, but their thermal conductivity barely reaches 0.1 W / m ° C.

2. Structural and heat-insulating (500-600 kg / m3) - it can be used for the construction of self-supporting and lightly loaded walls. This internal partitions from blocks and a box of houses 1-2 floors high. Their strength ranges from 2.5-5 MPa, and the thermal conductivity is 0.118-0.15 W / m ° C.

3. Structural - a full-fledged building material with a density of 700 to 800 kg / m3 and resistance to compressive loads of 5-7 MPa and above. Thermal insulation characteristics leave much to be desired (0.165-0.215 W / m ° C), but they also exceed the corresponding indicators of more traditional options like brick or monolithic concrete.

All blocks are non-combustible (NG group) and at the same time have good vapor permeability, which also depends on specific gravity. The lighter the autoclaved concrete, the better it “breathes”, passing through its pores from 0.14 to 0.23 mg/m h Pa.

Feedback on the use of blocks

“I liked working with gas silicate. Moreover, I decided to buy options with tongue-and-groove edges and handles on the butt side - the price is the same. I had to build the walls myself, so the light weight and ease of installation turned out to be serious pluses for me. For glue, the consumption turned out to be one and a half times more than the manufacturer promised. But the seams I (far from being an expert in construction) still came out neat and straight. The only negative is that these blocks absorb water very quickly. I had to hastily impregnate them with Aquasol so that they would last until the start of finishing.

Sergey, Voronezh.

“For me, all the advantages of the gas silicate block are obvious, but the products are very demanding in terms of construction technology. At one time I had to quarrel with the foreman, who did not want to make an armored belt around the perimeter under the attic floor - well, the guys at work enlightened me in time. As a result, I brought a couple more stacks of bricks and the team laid out a hard edging for me. So now I have a warm, and most importantly, a strong house outside the city. No cracks have appeared in three years.”

Roman, Nizhny Novgorod.

“The fact that aerated concrete is perfectly sawn, drilled and nailed is definitely a plus. But it is very fragile and at first I was even a little scared that my house would collapse. When piles of supposedly Hebel gas silicate local spill were brought to the site, I was horrified. Despite the pallets, corner binding and several layers of film, some of the blocks arrived with chips on the sides. In general, I would advise everyone to purchase this material with a margin of not 10%, like other piece products, but all 20%, because in the process of work they will still be beaten a lot.

Nikolay, Moscow.

“And I liked the result. Masonry from autoclave blocks turns out to be smooth, neat, plaster requires a minimum. But you can’t leave the walls completely without it - the experts’ reviews of gas silicate say correctly. Three years earlier, I had a garage built from it: on cement mortar and without any cladding. So after a couple of winters, the lower rows were covered with small cracks, began to crumble, and a musty smell appeared inside.

Valery, St. Petersburg.

“I saw a house made of gas silicate with my brother in another city. Everything is as it should be: plastered and painted. But when you tap the walls, you can hear that there is a serious peeling of the finish. In one place they knocked it down themselves, and under the plaster, crumbling blocks and White sand. It turns out that the builders did not bother to make a vapor barrier from inside the premises and fix at least some kind of insulation on the facade. They shifted the dew point exactly into the thickness of the wall, where moisture safely accumulated, and in winter it froze there, not finding a way out through the plaster.

Let's summarize the pros and cons

The main advantages of autoclaved aerated concrete:

• Light weight with large dimensions of stones, which allows you to quickly build a box at home, even alone.
• Excellent geometry - blocks are cut to size, which allows you to get correct form and perfectly flat edges. And this is the minimum thickness of the seams and a small consumption of the adhesive mixture.
• Low thermal conductivity, comparable only to solid wood, makes it possible to build walls of small thickness and spend at a minimum on additional insulation.

The main advantage of gas silicate is that with it the construction of a house has become more affordable for people who do not have enough funds for the services of contractors, but who want to get really comfortable housing. In terms of energy efficiency and environmental friendliness, such material can be compared with wooden beam. The only difference is that it is easier to install and the price of the blocks is 30-40% savings.

On the one hand, cutting additional elements and laying strobes for reinforcement do not cause any difficulties. On the other hand, to attach heavy hinged structures will be problematic.

They do a good job of warming the house, they pass air well, regulating the microclimate in the room, but they also easily absorb moisture, which gradually destroys the blocks from the inside. Without quality impregnations and protective finish it is undesirable to leave them for a long time. This also explains the low frost resistance, which even in very dense variants does not exceed 35-50 cycles.

When should you choose gas silicate?

Building from autoclaved concrete makes sense in the southern and central regions of Russia, provided it is not too humid climate. In this case, it will be possible to get by with a relatively small wall thickness and a minimum amount of insulation. And when the construction of the house has already been completed, but there is a need to reduce energy losses, light gas silicates with a density of up to 400 kg / m3 can be used to create a warm circuit.

Porous concrete does not have great strength, so it is used only in the construction of low buildings of 2-3 floors. Fragile blocks are completely unable to resist bending loads and need a rigid base that does not allow warping of the walls during movements or seasonal heaving of the soil. If, due to the characteristics of the soil, you still have to use a pile-grillage, tape or monolithic foundation, it makes sense to turn specifically to the lungs wall blocks. They will reduce the load on the base, and it can be made not so powerful.

It will also be possible to save a lot of money when building small auxiliary buildings on the site (garage, hozblok, summer cuisine). Here it is quite possible to get by with a shallow strip foundation.

Price

In recent years, private developers have been using a relatively new material for Russia - gas silicate, to reduce the cost and speed up the process. Is it suitable for capital construction? To make a choice, it is worth asking the opinion of those who built from gas silicate blocks own house or is an expert. Reliable information from practitioners - best source information.

Developer reviews

Victoria, Yaroslavl.

“I bought gas silicate blocks from a reliable manufacturer and laid everything according to technology, so I can’t complain about the material. My two-storey cottage has been standing for 5 years - no cracks, no drawdown. The walls were erected from D400 gas blocks, placed on adhesive mixture. The facade was puttied along the grid, a belt was made of concrete after the first floor.

Ivan Dorofeev, Ufa.

“I will object to those who say that lime in gas silicate corrodes steel reinforcement. After autoclaving, only neutral calcium silicates remain in the material - they do not cause corrosion, there is no need for polymer reinforcement. And the fact that blocks without cladding are destroyed is true.”

Grigory Stepanov, Kursk.

“I read reviews about gas silicate and decided to make an extension out of it. I chose a manufacturer for a long time and settled on Yutong: their density corresponds to the declared one, good geometry, there is a certificate. Just in case, I checked with a dosimeter for radiation. During laying, the gas blocks were measured with a square so that the wall did not turn out to be skewed. With an extension height of 2.5 m, the difference turned out to be only 0.5 cm.

Dmitry, Moscow.

The main types of blocks and cost

The starting material for gas silicate blocks is an aqueous solution of lime and sand, foamed by adding active additives - aluminum powder or dusty magnesium. It is poured into molds, where it gains plastic strength up to 1 kg/cm2. Further, natural drying or autoclaving under a pressure of 12 atm at a temperature of 175-185 ° C is possible.

The length of gas silicate elements is 600-625 mm, width - 250-300, thickness - 100-400. The strength class varies from B 1.5 ( permissible load 15 kg/cm2) up to B 3.5 (35 kg/cm2). By purpose, gas silicate blocks are divided into 3 groups (marking indicates density, kg / m3):

• structural - D1000 - D1200;
• structural and heat-insulating - D500 - D900;
• heat-insulating - D300 - D500.

High-density gas silicate autoclave blocks are more expensive, but, as developers' reviews confirm, their strength is much higher. Of these, you can build not only a bathhouse or a garage, but a house for all-season living. The cost also depends on the brand and the perfection of the technology. The average prices for D500 gas silicate blocks in Moscow are shown in the table.

Advantages and disadvantages

Foamed sand-lime mortar products have both pros and cons. Compared to brick, masonry is produced at a faster pace due to the large dimensions of the elements. With the help of gas silicate blocks, it is convenient to build not only the box of the building, but also to carry out redevelopment. For internal walls, they are simply irreplaceable - they are cost-effective and do not load the foundation too much.

The porous structure makes gas silicate a good sound and heat insulator. Here is an example: when building a house from a gas block D500 in the Moscow region, a minimum thickness of 380 mm is required (according to regulatory documents in the field of building heat engineering). brick construction under the same conditions should be no thinner than 640 mm.

Gas silicate is resistant to fire: it does not sustain combustion for several hours. The walls of gas blocks are vapor-permeable, which ensures stable moisture exchange in the room. A significant contribution to the popularity of building materials is also made by a relatively affordable price.

Experts draw the attention of developers to the numerous disadvantages of gas silicate. The main drawback of the blocks is their instability to moisture, which can penetrate into the pores both from the outside and from the inside. In addition, gas blocks are characterized by low bending strength - this is the reverse side of the low density of the material. Due to hygroscopicity and brittleness, other negative properties of gas silicate also appear.

• High degree of shrinkage. In order to avoid cracking of the blocks, it is necessary to lay a powerful monolithic base - tape or slab. Reviews of builders claim that throughout the year internal plaster you can’t do it: it will crack due to shrinkage. To speed up the finishing process, it is better to choose drywall and wallpaper.

If a house is being built on two floors, an intermediate reinforcing belt of reinforced concrete is made to distribute the load so that it does not collapse lower tiers gas silicate blocks. In addition, the reinforcement must be installed every 3 rows of masonry.

• Deformations. Soaked in moisture, the blocks lose strength and crack even more. According to builders, gas silicate is undesirable to plaster outside: this contributes to an increase in humidity. To extend the life of the walls, the cladding is made of siding or lining, maintaining the ventilation gap. To fix such a finish, special dowels are needed that are not subject to corrosion.
• Low frost resistance. It is only 15-20 cycles - gas silicate is designed for so many cold seasons. Window slopes 0.4 m thick, saturated with moisture, completely freeze through. As evidenced by the reviews, the temperature on them is lower than laid down in the regulations. The use of gas blocks without insulation leads to an increase in heating costs, and the installation of thermal insulation leads to a significant increase in the cost of construction.

According to reviews, gas silicate houses are comfortable, warm and reliable, if we take into account and neutralize the shortcomings of gas blocks:

• do not build a building more than 2 floors;
• insulate the walls and create conditions for their ventilation;
• strengthen the base and masonry;
• use a special glue, not a solution, so as not to create cold bridges;
• choose suitable look interior and exterior finishes.

It can be concluded that the construction of a gas-block residential building requires additional costs and does not lead to the expected savings. Do not forget that gas blocks are very fragile: you need to buy them with a margin of 5-10%.