Characteristics of buildings constructed from aerated concrete blocks.

What is it?

The main regulatory document describing the features of production and application of cellular concrete is GOST 31359-2007. According to the established rules, autoclaved or non-autoclaved aerated concrete can be called a combination of two binders (cement and lime), supplemented with a solution of highly silica crushed sand.

Classic dihydrate gypsum is added to this solution as a hardening regulator, as well as a block of aluminum paste or powder, which starts the process of pore formation. The result is an excellent building material – a set of wall stones suitable for the construction of various buildings.

Almost all the key advantages of an aerated concrete block are ensured by a fairly complex technological production regulation. Molecules of the binder blowing agent enter into a chemical reaction with atoms of Portland cement, due to which the effect of “swelling” is formed.

On the surfaces and seams of ready-to-use aerated concrete blocks, small, evenly distributed pores appear – openings that allow achieving excellent properties in terms of thermal insulation, vapor permeability, heat resistance, etc.

Stages of production

The production of aerated concrete blocks is a difficult and responsible job, which can only be handled by people working in equipped and equipped factory enterprises. Any mistake made at any stage of production will result in the entire batch of wall material being sent for rework. The process itself looks like this:

1. Assembly of stamping forms – small rectangular structures consisting of four sides and a solid bottom.
2. Preparation of the solution – a mixture of cement, lime, sand and warm water. A foaming agent in the form of aluminum paste is also added there.
3. Direct molding pouring – the substance is sent to the matrices preheated to 45-50 ° C.
4. Functional drying – sending almost finished wall stones to thermal chambers.

To produce this type of building material, craftsmen have to use all kinds of modern and quite expensive equipment. However, the result is worth all the effort spent on the operation.

What are the types?

Aerated concrete blocks can have different characteristics – their properties directly depend on what additives were introduced into the filling mixture before stamping. In accordance with the standards prescribed in GOST 31359-2007, all aerated concrete blocks produced by different enterprises must be divided into three categories:

1. Structural – used for the construction of load-bearing walls. Density varies between 900 and 1,200 kg/m³.
2. Structural and heat-insulating – a popular type used in low-rise construction sectors. Density is 400-900 kg/m³.
3. Thermal insulation – low density (around 300 kg/m³) supplied complete with a low thermal conductivity coefficient – 0.112 W/m °C.

Of course, you can’t build a durable house from thermal insulation autoclaved cellular gas block. However, it should be used to solve other problems – for example, for the purpose of insulation and soundproofing in existing premises.

Advantages and disadvantages of building material

The pros and cons of aerated concrete blocks should be discussed using specific buildings as examples – private houses and cottages erected using the presented building material. The obvious advantages of wall bricks of this format are the following factors:

• cheapness of masonry – if you build a building from aerated concrete, the work will cost less, compared to any other material of a similar format;
• ideal environmental safety – minimal radiation background, no mold and fungal deposits;
• no need for additional insulation – the air trapped in the pores of the aerated concrete block creates an excellent heat-insulating gasket;
• the ability to save on heating – you will not have to make significant investments in the installation of secondary convectors, batteries and radiators;
• extreme “lightness” of the material – to carry out construction operations you will not have to involve powerful equipment in terms of bearing capacity and lifting capacity;
• erection of structures with any configurations – the building material can be easily and quickly processed.

However, autoclaved and non-autoclaved cellular gas blocks also have quite a few disadvantages. These include:

• the need to perform a huge number of complex calculations – aerated concrete belongs to the class of rather whimsical materials, creating an impressive number of problems for design engineers;
• characteristically low thermal inertia – structures and their fastenings, as well as the fastening points themselves, quickly warm up, sharply dropping the temperature into the environment (a destructive process that harms, for example, fundamental foundations);
• minimal deformation during shrinkage – the inevitable appearance of cracks that do not cause much damage to the building, but affect the quality of its appearance and image;
• requirements in terms of finishing – a newly erected cottage needs competent plastering and priming along the entire geometry, at least due to the ability of the building material to absorb excess moisture;
• poor smoothness of internal and external walls, which have to be reinforced with mesh – porous floors create additional problems for specialists decorating rooms, for example, using various mixtures.

According to manufacturers, a building constructed from aerated concrete can easily withstand about 20-25 freeze-thaw cycles. Simply put, a house or bathhouse with utilities will last no more than a quarter of a century, and then the owner of the land will have to think about constructing a new building for living.

Choosing a high-quality aerated concrete block

Aerated concrete is an excellent masonry material for building a house, with unique technical and operational properties. Many companies are engaged in the production of such products. There are really a lot of offers for the supply of aerated concrete blocks for building houses, but in fact, there is nothing good in such a variety of advertising, which appears at a tremendous speed.

An impressive range of products plays into the hands of only experienced craftsmen, and beginners simply get confused in multi-sheet catalogs. When choosing a building material of the appropriate type, a person should rely on a set of its key characteristics:

1. Density – to solve the problem of constructing a low-rise private house from aerated concrete, you need to pay attention to the D400, D500 and D600 brands. Thermal insulation categories of the component (D100, D200 and D300) will not help when organizing full-scale construction work.
2. Vapor permeability — it is possible to create a comfortable microclimate in the future house made of aerated concrete with the help of aerated concrete walls at 0.1 mg/(m*h*Pa). You can find products with the specified characteristics almost everywhere.
3. Durability — direct structural reliability is determined as needed, depending on the number of floors of the future building. For example, a two-story house will require a product with the B2.5 marker. Using less durable classes is a serious risk.
4. Active thermal insulation — in terms of thermal insulation properties, we again draw attention to the D400, D500 and D600 brands. They produce 0.083, 0.098 and 0.112 W/m °C, respectively. True, the cost of such brands is, of course, higher compared to analogues that retain heat a little weaker.

When choosing aerated concrete blocks and foam concrete for building a house, you can use various third-party ratings – tables, the authors of which compared the performance characteristics of certain specialized products. Such calculations even contain quite unusual points, for example, about the possibility of protecting the building from fungus, mold, rodents and insects with separate plaster.

Where is it better not to use aerated concrete blocks?

How to properly use autoclaved aerated concrete is described in a whole list of various standards and building regulations. The relevant calculations are presented in SP 15.13330, SP 31-105-2002, GOST 13579 and GOST 6133. There you can also find a list of restrictions regarding the building material in question.

The fact is that aerated concrete is an element that is not capable of providing the structure with the necessary margin of safety and physical stability. Moreover, it seriously reduces the operational reliability of a house made of aerated concrete already at the design stage. The voids and cavities present inside the masonry stones affect the weight that the load-bearing part of the building can withstand. That is why such elements should not be used for the purpose of:

1. Arrangement of fundamental foundations. If the owner of the house really wants, he can put a frame of FBS modules with a filler in the form of crushed stone and slag. However, classic aerated concrete will not cope with the corresponding tasks.
2. Construction of buildings of four floors or more. The strongest brand of cellular autoclaved concrete (D600 / B3.5) is suitable for the installation of a three-story private house with monolithic floors and small attics, display windows or balconies. It is impossible to build a house from aerated concrete in height, since it will not have the necessary margin of safety.

In general, construction technologies, regulations and standards prohibit the use of gas blocks for the arrangement of foundations and high-rise buildings. In all other cases, this material can be used without any additional conditions, because its pros and cons equalize each other with ease. The construction of a house from aerated concrete is carried out step by step according to easy instructions, without the need to use large-sized equipment.

Reviews of owners about the process of building a house from aerated concrete and the material itself

Due to the prevalence of the building material, you can find a huge number of reviews on the Internet, both from home owners and from specialists responsible for the construction of buildings. Visitors to various forums are happy to talk about the pros and cons of blocks of this type.

People have practically no complaints about this building material, so there are very few complaints on the Internet. Its only critical drawback is the service life, varying between 20 and 25 winters. However, even such a rather impressive drawback can be removed and leveled by using high-quality protective dry mixes.

Qualified builders and ordinary property owners talk about their experience of interacting with such buildings, sharing personal observations and giving useful advice.

Examples of structures

Despite their shortcomings, which any building material has, houses made of aerated concrete are deservedly popular. Below we will look at examples of houses and show what can be built from gas blocks..

A small one-story cottage with a total area of about 130 m². The building is equipped with a foundation made of a monolithic slab, and is capable of not collapsing for many years. The owner Dmitry Man spent 40 days creating the box and roof.

A small country house made of aerated concrete with a total area of about 57.5 m². The walls are made of aerated concrete blocks, the foundation is made using FBS and monolithic tape, and simple wooden beams are used as floors.