Aerated concrete is a stumbling block to a considerable number of construction controversies. Despite the battles, many professional builders believe that it is a good, though not perfect, building material. As, however, and all the rest. To decide to build a house of aerated concrete blocks, we must remember that the material has many useful qualities, has already received fairly widespread.
For centuries, people used to build houses natural building stone - tuff. He was appreciated for the ease, simplicity of processing and the ability to retain heat well. Since the 19th century, scientists have tried to reproduce these qualities by experimenting with concrete mixtures. Important milestones on the way to the creation of modern aerated concrete is considered to be the consistent work of several researchers:
Engineer Hoffmann (Czech Republic). In 1889, he conducted a series of experiments with cement mortar, adding acid and salt to it. In the process of solidification, the evolved gases formed a characteristic porous structure.
Americans Aulsworth and Dyer . In 1914, they were the first to use aluminum and zinc salts. The reaction was with the release of hydrogen, which formed a homogeneous porous structure. The method laid the foundation for future technology.
Architect Erickson . In 1922, the Swede patented a method for the production of cellular concrete using aluminum powder, becoming the godfather of modern autoclaved aerated concrete. The first aerated concrete for the construction of industrial and residential buildings began to be produced in 1929.
In the USSR, the industrial production of cellular concrete was also set up in 30 years The first autoclaved block aerated concrete was produced in Riga in 1937; in the city there are still buildings erected from these blocks. In the post-war 50s gas-concrete helped restore the destroyed infrastructure, both in the USSR and in Europe. In modern Russia, more than 80 modern manufacturers meet the material requirements.
Aerated concrete is a representative of the category of cellular concrete, building materials of various properties and operating features. The unifying characteristic is the porous structure, low weight and low density. By production of a gas concrete such components are used:
Binding . Portland cement.
Filling . Quartz sand.
Gas generator . Aluminum powder or paste.
Industrial treatment water .
Improving additives . Lime, gypsum, industrial waste (slag, ash).
The production of aerated concrete begins with mixing the ingredients and pouring the mixture into molds. Chemical reaction leads to the formation of hydrogen. The gas increases the volume of the mixture (swells it up) and forms pores. After the end of the reaction, the mixture sets, it is removed from the molds and cut according to the standard. Further processing goes in two ways. Depending on what method of drying is used, one of two types of aerated concrete is obtained:
Autoclave (synthetic) hardening. Blocks gain hardness (are steamed) in autoclaves (devices that generate high pressure in a water-saturated environment).
Non-autoclave (hydration, air) curing. Blocks harden at atmospheric pressure in drying chambers.
According to the standard, cellular concrete (including aerated concrete) are functionally divided into three types:
Constructional . Density ranges from 1000-1200 kg / m³.
Constructional and heat insulating . From 500 to 900 kg / m³. The D500 mark says that in 1 m³ part of the volume is filled with 500 kg of solid material, the remaining volume is air filling the voids (cells).
Heat insulating . From 200 to 500 kg / m³.
Aerated concrete serves as an example of optimal Ratios between the main performance characteristics:
Durability . Despite the low density (specific weight), the strength is sufficient for the use of aerated concrete in the construction of load-bearing walls.
Lightness . The ease of aerated concrete is due to porosity, which can reach 85-90% of the volume of the material.
Low thermal conductivity . Good thermal efficiency is also a result of the porosity of the material. Aerated concrete boasts the lowest coefficient of thermal conductivity, 0.12 W / m ° C (in the dry state).
Having discovered on the Internet a lot of tips for producing aerated concrete with their own hands, and making sure that they are quite realizable, many decide to start their own production. At the same time, domestic craftsmen do not consider it necessary to strictly follow technological standards, but they always find those who want to purchase the product at dumping prices.
On our site you can familiarize yourself with the most popular projects of aerated concrete block houses from construction companies, presented at the exhibition houses "Low-rise Country".
The use in factory production of high-quality raw materials and technological equipment allows to obtain aerated concrete products with stable physico-chemical characteristics:
Accurate dimensions and correct with minimal marriage, form.
Given physical and mechanical parameters .
The uniform density of the material is , which is confirmed visually (by the uniform distribution of air cavities).
Chemical inertness of the material , which is confirmed by laboratory control throughout the production cycle.
The conditions of handicraft production cannot ensure manufacturability and control at the level of a modern workshop. Hand-made gas-concrete blocks are distinguishable with the naked eye: the cells (cavities) are unevenly distributed, and the geometry leaves much to be desired. Sometimes these products smell significantly chemistry (often - lime). The use of blocks made in artisanal conditions is likely to reduce the cost of construction, but is guaranteed to be a source of serious problems:
Blocks with arbitrary density and composition have increased fragility and with most likely begin to crack in the first year of operation of the house.
Blocks with imperfect geometry will not be able to put on a special glue; have to use mortar. Seams from 1 to 2 cm thick will become cold bridges that reduce the thermal efficiency of housing and contribute to the freezing of walls.
Blocks with residual undecomposed lime will have a persistent chemical smell (and affect the health of people living in the house). Excessive lime can trigger metal corrosion in the wall.
The country gas silicate house has the same strengths and weaknesses as the source material. Based on the structure of aerated concrete, there are many advantages:
Cheapness . Due to the low consumption of cement in the manufacture of products.
Construction speed . The blocks are of considerable size, and weigh 3-5 times smaller than a brick of a similar volume. This allows you to build 1 m² wall in 20-25 minutes, which is unattainable in the case of masonry.
Construction costs . Savings are obtained through the rational use of working time and building materials.
On our website you can find contacts of construction companies that offer the service construction of houses from aerated concrete blocks. Directly to communicate with representatives, you can visit the exhibition of houses "Low-rise Country".
Low thermal conductivity . According to this indicator, aerated concrete is better than brick by 2-3 times. A wall of 37.5 cm thick blocks retains heat as well as brickwork 60 cm thick.
Ease of processing . Blocks without any problems are cut with any hand tool, sawn, milled and puned. Such compliance allows you to create complex architectural projects.
Fire resistance . Aerated concrete is characterized by a high degree of fire resistance and belongs to the group of flammability NG (non-flammable). When exposed to a flame with a temperature above 100 ° C for two hours, the wall of aerated concrete begins to lose strength and crack to a depth of 3-4 cm (time is enough to leave the house and cause a fire brigade). The wooden house during this time will burn to the ground.
Vapor permeability . High. Due to the presence of interconnected voids, the material successfully regulates the humidity in the room (breathes).
Environmental friendliness . Used in the production of lime and aluminum powder after the gas reaction is converted into inert solids. Therefore, the material made according to all the requirements of technology does not emit any volatile substances into the air.
This is interesting! In various building forums one can often find references to a certain table of factors of environmental friendliness of materials.Some figures are even given - for example, for claydite, this coefficient is 20, for a brick - 10, aerated concrete - 2, and the leader and standard is a tree - it has a value of 1. In practice, the existence of such a table is not confirmed in any official document , although if we consider the materials precisely in terms of the release into the air of any substances, then there is a grain of truth in this separation.
Durability . In the Scandinavian countries, Germany and France there are many houses of aerated concrete, built 40-50 years ago and still not showing signs of destruction. Such resistance is due to the quality of the factory-made material and installation, carried out in compliance with the technology.
Frost resistance . Aerated concrete is well opposed to cyclic freezing.
Features of aerated concrete blocks determine the weak points of the structure:
Flexural strength . Aerated concrete is characterized by a relatively low coefficient of limiting deformation (0.5-2 mm / m). The deformation of the foundation that goes beyond these limits leads to the appearance of cracks in the wall of the house. Means of struggle will be the device of solid foundation with monolithic strapping or mesh reinforcement, trimming of floors and reinforcement of masonry. It is also not recommended to build private houses above 3 floors.
Fasteners . Nails, anchors and screws are perfectly included in the aerated concrete wall, but hold it disgusting. The characteristic lack of all cellular concrete is corrected using special fasteners for porous surfaces (steel, nylon, frame). Attention should also be paid to the installation of windows and doors (if improperly installed, they may loosen over time).
Adhesion (adhesion with finishing materials). Low, so before plastering the wall must be prepared (make reinforcement or put a layer of primer).
On our site you can find contacts of construction companies that offer the service designing houses. Directly to communicate with representatives, you can visit the exhibition of houses "Low-rise Country".
Shrinkage . Shrinkage of non-autoclaved aerated concrete reaches 2 mm / m, autoclaved - up to 1 mm / m.
In order for the erected house to serve for a long time and without problems, it is necessary to take into account the peculiarities of the material:
Hygroscopicity . A porous wall is able to absorb and release moisture (as, for example, wood). To protect the facade from excessive moisture, the walls are veneered, best of all - with ventilation.
Heating . A house of aerated concrete can significantly reduce heating costs, but we must bear in mind that the higher the grade of aerated concrete, the worse its thermal insulation properties. Energy efficiency can be enhanced by simple plastering.
Flushability . Since aerated concrete is a sufficiently large building blocks, it increases the likelihood of poor installation, even taking into account the excellent geometry of the products. For example, if the glue is too thick, it does not completely fill the space between the blocks and the through gaps are formed. If there is such an opportunity, then after construction it is recommended to conduct a thermal imaging survey of the house in order to know whether there are joints and seams that need to be repaired.
Many greeted not the most flattering reviews about aerated concrete and operational characteristics of houses that had the misfortune to be built from it. Such judgments and conclusions often have little to do with reality and are caused by a lack of understanding of the characteristics of the material and technology. Most often you can hear such "expert" opinions:
Aerated concrete walls are prone to cracking . Cracks can appear not only in the aerated concrete wall, but also, for example, in brickwork. After the examination, we have to admit that in most cases the cause of the defect is not the quality of aerated concrete. Most often the culprit - poor-quality foundation, the design of which did not take into account the features of the soil and the location of groundwater. Another reason could be reinforcement errors (both walls and foundation). The quality of aerated concrete will play an unlucky role only if the material used in garage production was used.
Structures made of aerated concrete need an indispensable insulation . If during the development of a house project the thickness of wall structures was laid in accordance with the norms of SNiP 23-02-2003 (on thermal protection of buildings), additional insulation is not required.But since aerated concrete houses necessarily need finishing of the facade, they often install insulation at the same time.
It might be interesting! In the article on the following link read about the kitchen in a wooden house.
Home gas blocks are a very fragile material that cracks when hit by a hammer. The same brick can also be split by applying a certain force. According to SNiP, D500 gas concrete blocks are recommended for low-rise construction (up to three floors), which are quite strong and light and warm at the same time. Material brand D400 more fragile and warm, brand D600 - on the contrary, more strong and cold. The houses, built with regard to technological features, perfectly cope with the arising loads, even in seismically active areas.
Aerated concrete absorbs moisture like a sponge , so a freshly-built facade requires a quick waterproofing. One of the main features of the material is its gas and vapor permeability, which, however, is not very different in terms of performance from the characteristics of wood. Like wood, aerated concrete is able to absorb moisture, and then return it, adjusting the microclimate in the rooms. Both materials have a humidity corresponding to the humidity of the surrounding air, and since the concrete does not dissolve in water, gas blocks are not in danger. Exterior walls will not be excessively wetted in cottages with year-round living and properly equipped facing (not interfering with the circulation of moisture).
About the construction of gas silicate blocks in the following video:
Aerated concrete block gets wet and immersed in water , therefore it is not suitable for the construction of suburban housing. Strange logic, if we recall that the foam remains lying on the surface of the water, and the brick instantly goes to the bottom. The degree of water absorption of the aerated concrete wall during operation is in no way connected with buoyancy, these are two different signs.
It is dangerous to live in a house with aerated concrete walls , since the material contains lime and aluminum, and sometimes it smells of lime in the rooms. These elements are part of the initial mixture; then they enter into a chemical reaction (reaction of transformation, transformation) with other components. The output is an artificial stone, aerated concrete, in which the original elements are missing. Industrial production is characterized by precise dosage of the starting materials and high-quality drying, as a result of which only safe silicates remain in the material. The smell of lime appears in the garage aerated concrete, when the components are measured on "by eye" and lime is added more than necessary.
When developing the project of a country house from gas-concrete details lean on features of material. To make the housing comfortable and durable, the following points are taken into account:
Wall thickness . It is given by constructive necessity. The optimal thickness of the bearing walls in the climatic conditions of central Russia varies in the range of 300-400 mm, interroom partitions - 100-150 mm.
Suitable foundation . For walls of aerated concrete, a reliable and stable foundation is important. A monolithic slab base is generally recommended; It is beneficial to use on different soils.
About a typical house of gas blocks in the following video:
Roof . Pitched or flat, the roof needs competent installation on aerated concrete walls. Light construction with a metal tile, professional sheet or shingles as a roof is preferable.
Need for conservation . Laying autoclaved aerated concrete is not carried out at temperatures below -5 ° C. If the cold comes, the house canned; it is desirable that by this time he already had overlap above the first floor. The walls are covered with waterproofing film, as well as pallets with blocks (it is better if they are packed in factory shrink tape).
It can be interesting! In the article on the following link read about lightweight aggregate blocks.
Aerated concrete - a material offering the widest possibilities for architectural solutions, one has only to recall the famous Dancing House in Prague. The design of a country cottage made of aerated concrete, the following requirements:
Originality . Details of the architectural style are able to convey the taste of the owners and emphasize their individuality. Exclusive appearance is often achieved by a combination of modern and traditional styles.
Practicality (functionality). Currently, houses are made of aerated concrete with a well-thought-out layout and with any additions - a garage, a terrace (including the top floor), an attic, a glazed bay window or a balcony.
Comfort . The concept of comfort is different, and the interior of the house of aerated concrete blocks can be decorated in any style, from the traditional classical, to the ascetic-minimalist. Often the choice of the customer is a cozy country style, a picturesque Provence or an energetic loft.
If you decide to build a house of aerated concrete, its price in any case will be lower than that of a similar brick cottage. Many variables will affect the cost:
Project type . You can buy a popular sample project (with ready-made documentation) or order individual development that takes into account personal preferences.
Building materials brands . Price depends on the manufacturer (domestic or foreign) and the volume of purchases.
The complexity of the architectural solution is . Determined by the area and number of floors of the project, as well as the type of the foundation and roof.
Relief of the site . If the site has a bias, the project will have to be finalized.
About the thermal imaging inspection of a house from gas blocks in the following video:
By choosing to build a house from turnkey aerated concrete blocks, you You will be able to appreciate all the benefits of this service, because from the moment of signing the contract, the concern of the contractor company is all the current issues related to the construction of the house:
Inevitable improvements and changes to the project.
Geological and geodetic surveys of the site.
Selection of workers and quality control of construction.
Construction work specified in the contract (from the zero cycle with laying the foundation to laying utilities and finishing).
Of course, you can get a report at any time or personally control how construction is proceeding and how the agreed estimates are spent.
When choosing a construction company, you should focus on its time existence, quantity and quality of completed projects, reviews of real clients. Companies with extensive experience have their own design bureau, regular suppliers and professional teams of different profiles. Construction companies that care about their reputation, work according to a well-established pattern, prefer to keep the best prices and often have a system of discounts on materials.
Prices for the construction of country houses from gas blocks in the Moscow region are as follows:
An area of to 100 m² : average 2.25 - 3.700 million rubles
From 100 to 200 m² : 4,150 - 5,200 million rubles.
From 200 to 300 m² : 5.560 - 8.670 million rubles.
It can be interesting! In the article on the following link read about the design of the hallway in the house.
When conceiving the construction of a country house from aerated concrete blocks, you need to be sure that housing will delight you with comfort for many decades. Such confidence will be provided by high-quality raw materials and a reliable construction company, whose specialists know and strictly follow construction technologies.