How to choose fasteners for aerated concrete, types of fasteners

Attaching the Mauerlat to the walls is considered a purely technical issue, uninteresting and boring for most private developers. Not many of them know the purpose of the Mauerlat and the requirements for its design. Therefore, the owners of the future home rely entirely on the opinion of hired builders. And the majority of “experienced builders,” even if they just arrived from their villages and villages yesterday, insist on erecting an armored belt in order to attach the Mauerlat to it.

To understand the goal of the builders, as well as find out how fastening the Mauerlat affects the quality of the house and the developer’s wallet, you should start with a description of the basic concepts: Mauerlat, reinforced belt, characteristics of gas blocks and other porous wall block materials, calculation of loads on block walls.

Fastening building structures to aerated concrete

On such fragile walls it is necessary to fix not only wires and pipes, but also heavy structures: floors, roofing elements, etc.
In such cases, fixing self-tapping screws into aerated concrete is not a solution; a serious decision is needed. As a rule, it is carried out during the process of laying walls, when a monolithic reinforced concrete armored belt is made at the installation level of such structures. During pouring, studs and other embedded parts are installed into it, onto which the fastening is subsequently carried out.

If for some reason you did not make an armored belt, or did not provide mortgages in it, fastening is carried out only with chemical anchors.

What is a Mauerlat

The word Mauerlat arose as a derivative of the German “wall” and “crossbar”. This perfectly describes the essence of the design. Mauerlat (mother log, matitsa, uterus) is a power frame made of beams, which are located along the perimeter of the load-bearing walls, taking on the load of the roof and distributing it evenly. If we consider the crossbar in the overall design of the roofing system, we can see that it has rather modest dimensions (shown in brown in the photo).

The support is made entirely of wood. For this, a beam with a cross-section (thickness) of 150x150 mm is used. You can replace it with three boards 150x50 mm thick, nailing them together in such a way as to form a beam of the required thickness. Other parameters are also acceptable, but the ones indicated are optimal and are more common. For example, a roof with a thickness of 100 mm will not support it, and a beam of 250 mm will not be able to support a wall.

When choosing fastenings for aerated concrete walls, take into account such features

When choosing hardware, take into account the strength of the working surface, the dimensions of the parts and their resistance to corrosion.

The higher the density of the material, the stronger the aerated concrete. This indicator sets the load limits on the fastener. Technical characteristics in digital terms are indicated on the packaging of building blocks after the letter D.

The strength of the connection is affected by the size of the dowels. Thus, when fixing massive structures, products of large diameters and lengths are used.

The resistance of fasteners to corrosion ensures the possibility of their use when installing external structures and arranging unheated premises.

Material selection

Since the Mauerlat is an important element that ensures the durability and reliability of the roof structure, it is necessary to carefully select the material for its manufacture. It should be well-dried wood with a moisture content of no more than 8%. There are no unevenness, knots, cracks, defects of biological origin, or curvature on the surface of the timber. It is best to choose timber from selected hardwood or pine products. At the same time, you should not skimp on the quality of the material.

The cross-section of the beam depends on the number of floors, the dimensions of the building, the configuration of the roof, the roofing material, and the climatic characteristics of the construction region.

The weight of the Mauerlat should take into account the recommended loads so as not to overload the foundation of the building. The length of the timber is chosen so that when it is laid along one wall, a minimum number of joints are formed. When choosing the height of the Mauerlat, take into account the fact that the rafters are attached to it using the cutting method, which uses at least half the height of the element.

Scope of application

Chemical anchors in aerated concrete are used less frequently. It is used in cases where it is necessary to provide reliable fastening for massive objects. Mechanical anchors are not capable of supporting, for example, the weight of massive equipment.

Epoxy compounds are used mainly on solid bases. They are used for fastening:

• wall structures;
• beams;
• fences along roads;
• creating noise-insulating screens;
• when installing reinforcement outlets;
• when installing attachments.

This composition can be used:

• in a humid environment;
• under the water;
• both outside the building and for interior work.

Its composition:

• does not create stress in the structure of the porous wall;
• does not contain styrene;
• creates fastenings with smooth reinforcement.

The hardening of the mass depends on the air temperature. The time can last from 7-180 minutes. or 7-48 hours.

Polyester anchors are used to create:

• enclosing structures;
• when installing façade elements;
• for installation of translucent elements;
• during installation of utilities.

Typically, threaded rods are installed along with polyester compounds. The polyester anchor does not contain styrene. Therefore, it can be used on interior and exterior fasteners. The polyester anchor takes from 2 to 30 minutes to set and hardens from 25 to 180 minutes.

The anchor bolt for aerated concrete can be smooth or threaded if a vinylester anchor is used. It is used to create fasteners in wet substrates. It does not create unnecessary stress in the structure of aerated concrete. This adhesive solution is safe because it does not contain harmful substances. It is used for making internal and external fasteners. Does not create stress after installing fasteners in the structure of the aerated concrete block. Hardening is observed after 15 minutes or a day.

Epoxy acrylate anchor composition has become more widely used due to its properties. The period of setting and hardening of the composition is 2-24 and 15-180 minutes, respectively. Epoxy acrylate retains its properties when the temperature drops to -5°C, and also resists fire in case of fire for up to 2 hours. Epoxy acrylate anchor composition is suitable for anchoring floor slabs in aerated concrete houses.

How to choose the best type of fastening

The choice of optimal fasteners for aerated concrete must be made after a thorough analysis of the upcoming loads, as well as an examination of the load-bearing surfaces. In addition, it is necessary to take into account the weight of the kitchen set and related equipment, its configuration and operating features.

When choosing the type of fastener, you must first consider the load vector. There is hanging furniture that creates a shear load. If it is static, i.e. There are no jerks or vibrations, then you can limit yourself to elements designed for small or medium loads. However, for mounted or suspended devices with variable loads, as well as with efforts aimed at tearing, powerful anchor elements are needed - chemical, or acting on expansion. It is important to follow the installation technology and use drills of the correct diameter. When installing chemical anchors, you should first carefully study the instructions and strictly follow them during the installation process.

As a rule, threaded fasteners (anchors) are used for hanging appliances, gas boilers, ventilation and other items that require strong and immovable fixation on the walls. These devices are usually installed once and for all, therefore, fasteners of this type are the most effective. For wall cabinets, shelves and other furniture, dowel fasteners with self-tapping screws as supporting elements are more suitable. They allow you to periodically remove cabinets to clean walls, perform cosmetic repairs or other work.

Why you shouldn’t attach excessively heavy structures to gas block and foam block

About the gas block

Autoclaved aerated concrete has thermal conductivity characteristics close to foam plastic because, like insulation, it contains air bubbles in its structure. At the same time, foam plastic has almost zero load-bearing capacity.

Why should a gas block be so much more durable? It should be noted that it copes well with a load evenly distributed over an area, for example, in wall masonry. But it does not tolerate local loads from ordinary dowels and anchors, that is, it simply does not hold

And no matter what the manufacturers of such blocks say, you need to load the material locally with great care - use special fasteners, spread them over a large area, do not hang very heavy structures without a metal frame

Excessive load on aerated concrete can lead to similar consequences

The weakest point of an aerated block in terms of load-bearing capacity is variable pressure. Periodically attaching and removing any heavy structure from an anchor will contribute to the crumbling of the material around the fastener and failure of the attachment point.

About the foam block

Foam concrete is used less frequently in modern construction, and on average it is heavier and stronger than aerated concrete. Of course, strength depends on the class of the material - the higher the class, the more durable it is, but at the same time it loses somewhat in its heat-insulating properties.

Perhaps we can say that the foam block is somewhere between concrete and aerated concrete in terms of strength. However, when choosing an anchor for foam concrete, it is better to be guided by the same principles that apply when using aerated concrete.

Load-bearing wall masonry

The next row of walls is laid after the cement mortar of the first row has set. The laying of the second and subsequent rows is done with dressing in half a block. In some places, block overlap is allowed less than half a block, but not less than 10 cm.

The position of the blocks, as when laying the first row, is controlled by a stretched mooring cord and level.

The mortar is applied to the surface of the blocks using a trowel or carriage made to fit the width of the masonry or a trowel used in tiling work. The solution must be applied evenly over the surface of the masonry.

Using a trowel, the solution is also applied to the vertical surface of the blocks.

The project may indicate that the adhesive solution is not applied to the vertical surfaces of the blocks of the tongue-and-groove system; such a decision is justified if subsequent double-sided plastering of the walls is provided, and the load on the block is significantly lower than the load-bearing capacity.

The ends are cleaned using a sanding board or plane. The length of the outermost block must be at least 10cm.

The mortar protruding from the seams is removed using a trowel. Rubbing the solution is not allowed.

The alignment of the masonry is repeated after laying each row of blocks.

After laying each row, the deviation from the horizon will be checked using a level.

If it exceeds the established tolerance, the deviation is eliminated when laying subsequent rows. After 2-3 rows in height, the evenness of the masonry is checked with a level.

Characteristic

Aerated concrete is rightfully recognized as one of the most practical and affordable materials. It makes durable and strong houses, as well as reliable outbuildings. However, you need to take into account that this material has a cellular structure, when faced with which you need to take into account many nuances. The main characteristic feature of this material is its fragility and pliability. Porous blocks can be trimmed or cut off the excess part without any extra effort. And we must also not forget that special fasteners are used for such a structure. Traditional fasteners, as a rule, do not adhere well to such foundations, which is why the whole point of their use is lost.

For aerated concrete, special dowels should be used. The design of such parts is a sleeve in the form of a spiral, on the surface of which there are ribs. When screwing in a self-tapping screw, the last elements become wider, so they fit firmly into the loose aerated concrete surface. This simple but effective device can easily withstand impressive loads. With the use of special dowels, home owners have the opportunity to hang heavy decorative objects of any size on the walls.

Modern manufacturers produce these types of dowels in two variations. They differ in design features.

• According to the shape of the fixation ribs. Such fasteners can be equipped with a classic helical spiral or have cone-shaped ribs. The edges of the latter may resemble spiral-like blades.
• By installation method. The dowels are either screwed into the base or driven into it. Screw-in types are considered to be the most reliable. It is recommended to use driven-in fasteners if the aerated concrete floor is planned to be equipped with a collet.

Fastening building structures to aerated concrete

In general, the process of installing fasteners is similar for all options. First of all, a hole is made, and then the cartridge is inserted. The only difference can be with a chemical anchor, since it uses glue.

Chemical anchors are secured as follows:

1. Preparatory work. You need to drill a hole using a drill.
2. Next, the hole needs to be cleaned of dust. To do this, use a brush or a medical bulb.
3. A cartridge with a chemical composition is installed. To do this, you need to insert a capsule with glue into the recess. The last one is squeezed out.
4. An anchor is screwed into the hole.
5. You need to wait until the glue dries. There are times when you need to wait 2 days for complete drying. It all depends on the composition, but temperature, humidity and other environmental features are also considered important factors.
6. Once the compound has hardened, you can install the washer and nut.

The installation process using a mechanical anchor, dowel nail or self-tapping screw is the same, but without the use of glue.

This is what the fastening looks like inside aerated concrete.

Video on the topic:

Each fastening method has its own advantages and disadvantages. When choosing, you should take into account the material, density, and characteristics of the room.

Previous entry How to attach a window sill to a plastic window Next entry Features of attaching gates to brick pillars

How to lay a gas block: a step-by-step guide

The first row of blocks requires increased laying accuracy, since the accuracy and ease of laying subsequent rows and the wall as a whole depends on it.

The installation of waterproofing units between the foundation (basement, plinth) and aerated concrete masonry must be carried out in accordance with the decisions made in the project or in accordance with the album of technical solutions.

A mooring cord is stretched between the lighthouse (outer) blocks.

The blocks are laid on opposite sides of the wall, further laying is carried out from the outer blocks to the center using a cord.

The height of the beacon blocks is selected based on the block located at the highest point.

If it is necessary to obtain a cut block, the cut is made with a hacksaw for aerated concrete using a square. In multi-story construction, the use of a band saw is recommended. After cutting, be sure to clean the surface with a sanding board.

The first row of blocks is laid on a leveling layer of cement-sand mortar.

The height of the first row of blocks is adjusted using a mooring cord stretched between the outer blocks of the wall. The position of the blocks is controlled by a level and adjusted using a rubber mallet.

Existing unevenness in the masonry is eliminated using a sanding board or plane. Small dirt and dust are removed with a brush.

Subsequent rows are laid on a special adhesive solution.

Dowel

The part is a spiral-shaped bushing with ribs on the surface. At the moment the screw is screwed in, they expand, due to which they firmly fit into the soft surface of the base. Such fasteners can be made of galvanized steel or plastic.

The first option is the most common and is considered the most expensive. It is used when installing profiles, installing attachments and furniture, and fixing various pipelines. Such fasteners have become widespread in fire-hazardous spaces.

Metal dowels for aerated concrete are produced in 2 modifications, which differ in design features and installation methods. The parts can either be screwed into the base or driven into it. The latter option is used if the aerated concrete floor is planned to be equipped with a collet.

Based on the shape of the fixation ribs, fasteners with a classic helical spiral and dowels in the form of a cone, equipped with spiral blades, are distinguished. The design of metal elements also provides for the presence of a locking flange or cuff, thanks to which the part will not rotate.

Corrosion resistance is the main advantage of plastic products. The materials used for them are polypropylene and polyethylene. The positive characteristics of the parts include their efficiency, environmental friendliness, and immunity to aggressive environments. Such dowels are not intended for outdoor work, since with the onset of cold weather the plastic may burst.

A separate group consists of fasteners for aerated concrete made of nylon. They are more wear-resistant, so they can be used for cladding facades. Together with them, galvanized screw elements with 2 types of heads are used - countersunk or hexagonal. The disadvantage of this type of fastening is the high price.

Depending on the scope of application, there are several types of dowels:

1. Universal. It can be mounted in any concrete surface. In a solid base, fixation occurs in a standard way. In a cellular coating, the product is rolled into a persistent knot. However, the load-bearing capacity of universal dowels is lower than that of spacer elements.
2. A dowel-nail that has a wide range of applications. At the moment of fixation, a nail is inserted into the fastener, rather than a screw being screwed in. In order to avoid turning the part, use a sleeve.
3. The “pancake-like” structure of the frame dowels allows you to reduce the load on the porous surface of the block.

Functional purpose of the Mauerlat

Heavy rain, gusts of wind, a layer of snow - all this creates additional loads on the building frame.

The presence of a Mauerlat in the roof structure makes it possible to simplify the installation work on arranging the roof and protect the load-bearing elements of the structure from additional loads.

The beams, laid along the entire perimeter of the building in conjunction with the rafters, provide a stable and durable structure that serves as the basis for any roofing.

The Mauerlat keeps the rafter system from moving.

Mauerlat is made of coniferous wood, except in cases where the roof sheathing is made of metal structures. Then steel profiles (angle, channel, etc.) are used to frame the external walls.

In addition to its main purpose - fastening the roof and distributing the load on the building frame - the strapping can serve as a monolithic belt. When building a one-story house, it is allowed to install timber along the inner edge of the wall directly on aerated concrete blocks, without installing an armored belt. In this situation, the Mauerlat also serves as the main connecting element for external enclosing structures.

Tool and surface features

Installation tools:

• electric hand drill;
• drill bit with pobedite tip;
• hammer;
• a wrench or screwdriver for screwing in a screw;
• adhesive mixture for chemical anchor;
• special gun for glue mixture.

The main condition when installing objects and accessories is the correct choice of hardware.

Aerated concrete, having a porous structure, is a relatively fragile material, so the question arises - what kind of hardware is needed to ensure that the fastening is reliable and meets all the operating requirements of the structure.

There is a wide range of products that make it possible to fasten structures reliably and quickly.

From the video below you will learn about fasteners for aerated concrete.

Why does foam concrete need special fasteners?

Foam blocks are made from water, sand, cement and a special foaming agent. The blocks are cellular, the material is fragile enough for installation of various fasteners.

The main distinctive features of foam blocks: low weight, low density, high level of hygroscopicity, porous structure. For the most part, properties act as advantages during the construction and operation of buildings, but not at the moment of attaching some objects to the walls.

The structure of foam concrete is porous, the adhesion to materials is not very good, so the blocks cannot always cope with the loads, and therefore special dowels are provided for them.

Properly selected fasteners for foam blocks will not only secure equipment or furniture with high quality, but will also strengthen the working structure and significantly increase the percentage of permissible loads.

Fasteners for foam blocks require a certain design of fixing parts - they usually consist of the following elements: a screw, a ring, a half-ring, a side, an empty sleeve with a spacer. Many anchors are made with teeth, which become a reliable obstacle to the part turning.

There are also chemical anchors for foam blocks, which are created specifically for use and provide maximum quality of fastening. In this case, the main task of the dowel is to create internal support in the block during the expansion process inside the aerated concrete and preserve the fragile material from destruction.

Dowels can be of different diameters and lengths, made of metal or plastic, and are supplied in packs of 50-1000 pieces. According to the scope of application, they are intended for external/internal work, according to the installation method - driven, screwed and others (chemical anchors are distinguished separately).

Chemical anchor

This type of fastening, such as a chemical anchor, is a fairly new and already in demand method. The builders appreciated it. Chemical anchoring has its advantages and disadvantages. The advantages of a chemical anchor include:

• high load capacity factor on fasteners;
• compliance with GOST, the chemical composition is safe and environmentally friendly;
• versatility, it is used for any building material;
• high resistance to weather fluctuations and low temperatures;
• low price when compared with steel anchors.

The disadvantages include:

• strict adherence to technology;
• purchase of special equipment, namely brushes, pumps, guns and drills;
• additional time for the chemical solution to harden.

Chemical fasteners for foam concrete include a threaded steel pin, maybe a special rod, a chemical mixture, and additional bushings.

Chemical anchor fastening sequence

1. Use a drill to make a cylindrical hole. Then it needs to be shaped into a cone with an expansion in depth.
2. The finished hole is thoroughly cleaned. You can use a pump for this.
3. A centering sleeve is inserted into the base.
4. A chemical solution is poured into the hole through the sleeve; a construction gun is used for this.
5. The threaded rod (stud) is screwed in.
6. Leave time until the chemical solution hardens completely.

The chemical anchor kit includes an easy-to-use package with a dispenser. Installation is easy, while achieving high structural strength.

Fastening chemical anchors

And so, for fastening light structures and decorative elements, ordinary self-tapping screws are quite suitable. They can be designed for working on wood or on cellular concrete. Nails for aerated concrete should have a wedge shape or a curved tip inside the concrete cavity.

For heavy structures, such as plumbing fixtures, kitchen cabinets, boilers, it is worth using foam concrete fasteners with wedging dowels. Reliable fixation is achieved precisely thanks to the internal stop. All hardware must be resistant to corrosion. This especially applies to mountings on an external wall.

Tips and tricks

When installing dowels into a gas block, you cannot use a screwdriver, since this device runs on electricity, which makes it more difficult to control. Such a device can strip the thread by twisting the screw

When making a hole for dowels in a gas block, it is important to note that they should not be larger than their diameter. Otherwise, the fasteners simply will not hold securely in the base

The depth of the holes should be slightly greater than the length of the dowel. The tip of the screw must leave the dowel for the fastening to be as reliable as possible.

Many people, having become acquainted with dowels, begin to use them at any opportunity. However, experts do not advise using too powerful fastenings if you plan to hang hooks, pictures and other small items. For such purposes, simple plastic fasteners, the size of which is about 8 mm, are more suitable.

About fastening for aerated concrete - a nylon dowel and a metal dowel (crocodile), see the following video.

Types of fasteners and performance of work

The type of product is selected depending on the expected load:

• for fastening hanging mirrors or lamps, nylon dowels with a cross-section of up to 12 mm are suitable;
• when installing pipelines and bulky objects, choose metal parts;
• frame types of fastenings are used to fix window and door frames;
• universal facade dowels are used when installing external profiles for facing slabs;
• Only light objects are attached to wood screws - photo frames or decorative elements.

Installation is carried out in several stages.

In order for the products to fit tightly into the base, it is necessary to drill the holes correctly. To do this, it is best to use a hammerless drill or a hammer drill with the impact turned off. The drill should have a cross-section 1 mm smaller than the fastener itself. The only exception is steel hardware. For them, the hole will be reduced by 2 mm.

After cleaning the recess from concrete dust, install a dowel. The plastic fastener is screwed in using a screwdriver. Metal parts are driven into the mounting hole with a hammer. During the work, it is necessary to ensure that the product does not warp.

At the final stage, screw in a self-tapping screw or a standard mounting bolt. In this case, it is not advisable to use an electric tool, since when connecting to an aerated concrete block, the screw element may be damaged.

Fixing the Mauerlat using wire

Before attaching the Mauerlat to aerated concrete using steel wire, it must first be fixed in the thickness of the wall. This should be done while laying the last rows of gas blocks - the wire is placed under them.

The installation technique in this way looks like this:

1. A couple of rows before the end of the masonry, a twisted wire of several thinner wires with a cross-section of 6 mm is placed between the blocks.
2. In this case, the central piece of wire will be placed in the thickness of the masonry, and the ends will hang down on both sides of the masonry. The length of the ends is made such that they are enough to wrap freely around the beam.
3. There should be so many pieces of wire that it is enough to tie all the rafter legs.

Fasteners for cellular concrete

Using ordinary wood screws, only very light objects such as photo frames can be attached to aerated concrete. In all other cases, special fasteners will be required.

Fastening requirements

When choosing which fasteners to use for aerated concrete, you need to consider the following points:

The density of wall blocks, indicated in product labeling by numbers after the letter D. The higher it is, the fewer pores in the material, and the stronger it is. The load limit when pulling out fasteners depends on this indicator, and the manufacturer’s instructions on the packaging contain this information.

The numbers show how many kilograms are in a cubic meter of material

The fastener parameters are its length and diameter. The larger they are, the greater the load it can withstand. The load-bearing capacity must also be indicated on the packaging or certificate.

Chemical anchors have the highest load-bearing capacity

Corrosion resistance. This parameter is especially important when fastening into aerated concrete is carried out from external walls or in unheated rooms. Steel hardware must be coated with a protective layer.

Punch for aerated concrete

Mounting options

Let's take a closer look at which aerated concrete fasteners are used most often.

Let's start with the traditional types:

All these elements may have other varieties that differ from the images shown in the table. For example, turbo dowels with self-tapping threads are made from nylon.

Turbo dowel FTP K

And made of galvanized steel - four-leaf toothed expansion dowels. Their segments move apart when the screw is screwed in, reliably biting into cellular materials.

Steel expansion dowel

As already mentioned, one or another hardware and fastening method are chosen depending on the expected load.

If you need to fasten aerated concrete shelves, you need to carefully drill at a right angle, insert a dowel into the hole and screw a screw into it.

Shelves with covered mounting on aerated concrete wall

• And to hang a light picture or install an electrical switch, a simple self-tapping screw screwed at an angle of 45 degrees to the wall is enough.
• If you need to securely fasten heavy equipment or install a metal entrance door, it is best to use chemical anchors.

When installed, they are capsules made of synthetic resins and organic polymers that seal holes in a wall made of aerated concrete, firmly holding a metal rod or threaded rod in it.

The advantages of such fastening include exceptional reliability and durability, the adhesive base is not susceptible to thermal expansion and resistance to aggressive environments.

No special qualifications are required for fastening with chemical anchors; everything can be done with your own hands.

For this:

• A hole of the required depth is drilled in the wall, its bottom is slightly expanded by oscillating movements of the drill;
• Construction dust is blown out of the hole, and a sleeve is inserted into its neck;
• The cavity is filled with adhesive solution using a mounting gun;
• An anchor rod is immediately installed into it;
• After the solution has hardened, fastening can be done.

The price of such fasteners is higher than that of other types, but the reliability does not raise the slightest doubt.

Construction of houses

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Aerated concrete is a synthetic building material, which is a type of cellular concrete, its weight does not exceed 0.5-1.2 t/m3 (against the weight of brickwork of 2-2.5 t/m3), that is, it is a light, porous substance, produced on a mineral basis. Small round pores up to 3 mm in diameter are evenly distributed throughout the entire volume of aerated concrete products, due to which the weight of the material is reduced. The article will discuss the installation of walls made of aerated concrete blocks.

Aerated concrete blocks are widely used in construction around the world; they are manufactured in 50 countries at 250 factories and have high quality and strength indicators. The products are used in the construction of walls of any type. Buildings built using this material are distinguished by high thermal insulation qualities, which are achieved thanks to the precise geometry of the blocks, the composition and technology by which they are produced, as well as by laying them on a 3 mm adhesive layer that prevents freezing of the seams.

Aerated concrete production technology

The composition of the mass for the production of aerated concrete includes several mandatory components and some additional ones, which may not be added, depending on the production technology.

Required elements:

• quartz sand;
• highly alkaline cement;
• water;
• gas formers (paste or suspension of fine metallic aluminum).

Additional Additives:

• gypsum;
• lime;
• metallurgical slag;
• ash.

The dry components are thoroughly mixed together and then kneaded with the addition of water. The resulting mass is poured into metal-plastic molds without filling them to the top. The foaming process occurs as a result of the interaction of a gas-forming agent and cement in an aqueous environment. After a short time, the mixture increases in volume and hardens, after which the monolithic slab is removed from the mold and cut into rectangular bricks of the required size.

• At the last stage of production, the workpieces are dried in an autoclave (a device that allows the material to be processed under pressure and at high temperatures) or in electrically heated drying chambers. It is according to the technology of final processing that aerated concrete is divided into autoclave and non-autoclave. For most types of construction work, it is recommended to use autoclaved aerated concrete, which has improved technical characteristics. Due to steam treatment, the structure of the products becomes more uniform and durable.

• Non-autoclaved aerated concrete blocks, as a rule, are produced in small factories with manual production, since this technology does not require special equipment; the mixture hardens in forms naturally. The finished material has less strength, and when constructing buildings it is recommended to lay it in two rows, or use such products as an additional layer in multi-layer masonry.

Advantages of aerated concrete blocks

Aerated concrete blocks have many positive qualities:

• This is a material with increased sound insulation and heat protection;
• produced on the basis of only mineral components;
• has high frost resistance;
• has a low specific gravity - the mass of a standard block measuring 62.5x10x25 cm does not exceed 10 kg;
• has good fire resistance, withstands open flames for 3-4 hours;
• does not rot in a humid environment;

• it is characterized by quick and easy installation, it is easily processed, sawed and cut without the use of special tools, due to which the price for installation of aerated concrete blocks is lower than for brickwork;
• economical material, due to the low cost of the blocks themselves and lower cement consumption during production, as well as due to reduced costs for transportation and foundation installation, in addition, the installation of blocks can be carried out by one person, without the involvement of assistants;
• over time, the finished aerated concrete masonry gains even greater strength;
• has low natural radioactivity;
• environmentally friendly material;
• for low-rise construction (up to 3 floors), it is allowed to use blocks for the construction of load-bearing structures;
• reinforced aerated concrete products can be used as floor slabs.

Of course, like any other material, aerated concrete has its drawbacks. The main negative qualities include the presence of through pores, due to which the blocks require additional waterproofing, and such pores also reduce mechanical strength.

Technical characteristics of aerated concrete blocks

Aerated concrete products are divided into two main types.

• Partition aerated concrete blocks - thickness varies from 7.5 cm to 20 cm, main purpose: construction of interior partitions and internal walls (non-load-bearing structures), can also be used as an insulating layer for brickwork.
• Aerated concrete wall blocks - thickness from 25 cm, main purpose: construction of load-bearing walls. For the construction of buildings in cold climatic zones, it is recommended to use aerated concrete products with a thickness of 37 cm or more; in this case, plastering work on the outside of the structure is sufficient for insulation.

Aerated concrete products have the following parameters :

• density: 350-1700 kg/m3 (marking “D”, the lower the grade, the warmer the material);
• compressive density: 1-7.5 mPa;
• length: 60 cm, 62.5 cm;
• width: 7.5 – 50 cm;
• height: 20 cm, 25 cm;
• frost resistance: up to 75 cycles (marked “F”);
• environmental coefficient: 2.0;
• water absorption: less than 20%;
• thermal conductivity: 0.16-0.81 W/m3;
• drying shrinkage: 0.5 mm/m.

Construction of a house from aerated concrete blocks

Calculation of aerated concrete blocks

• Before starting construction, you should calculate the required material. As an example, we can take a house whose dimensions are 15x13 m, with a height of 3 m. To calculate the area of ​​the perimeter walls, you need to add the width of all four walls and multiply by the height: (15+15+13+13)x3 = 168 m2.
• If several walls have the same dimensions (as in our example), then you can proceed as follows: 15x2x3 + 13x2x3 = 168 m2.
• To find out how many cubic meters of aerated concrete blocks are needed, the result should be multiplied by the thickness of one block (for example, 0.3 m): 168x0.3 = 50.4 m3. This number of blocks is necessary for the construction of the external walls of the building (blocks are sold in pallets and measured in m3). Internal walls and partitions are calculated using the same scheme.
• If you need to calculate the piece quantity of products in 1 m3, then you should calculate the volume of one block used; for this, the lengths of all its sides are multiplied. For example, you can take a product with a standard size: length 60 cm, height 20 cm and thickness 30 cm. First of all, you need to convert centimeters or millimeters into meters. As a result, you will get the following formula and result: 0.2x0.3x0.6 = 0.036 m3. Next, it remains to divide 1 cubic meter by the resulting volume of blocks: 1/0.036 = 27.7. It turns out that to build one cubic meter of masonry you need to purchase 28 blocks of the established size, and for a house of 168 m2 you will need approximately 1400 blocks.

Based on the calculations, you can calculate the approximate cost of the entire construction.

Foundation for a house made of aerated concrete blocks

Having calculated the required amount of material, you can begin building the foundation. Several types of foundations are used for aerated concrete construction:

• columnar;
• tape monolithic;
• tiled monolithic.

A specific type is selected based on a number of parameters, such as house design, soil characteristics, groundwater depth, etc.

Advice: experts recommend pouring a monolithic strip foundation. If substances for accelerated hardening were not added to the foundation solution, then the foundation will need to be left for a month to completely harden and gain strength.

Whatever foundation is chosen for the house, it should be carefully insulated and waterproofed. This can be done using 1-2 layers of rolled material, for example, roofing felt. The base for laying walls must be leveled in a horizontal plane.

Tools for installing aerated concrete blocks

Before laying aerated concrete blocks, you need to prepare the necessary tools and materials for the work:

• aerated concrete blocks;
• adhesive solution;
• spatula, serrated and straight;
• building level;
• plane or sanding board;
• hand saw or electric band saw;
• brush.

To prevent cold bridges that form in the cement-sand mortar, when laying the blocks, a special adhesive composition based on Portland cement, quartz sand and additives (mineral, polymer) is used. Mix the mixture in clean water, the temperature of which is no more than 30 degrees.

The specified norms for adding water to the composition should not be violated, since glue that is too liquid will have reduced strength characteristics. It is recommended to apply glue in a layer not exceeding 3 mm using a notched trowel. The prepared solution cannot be stored for a long time, and the location of the blocks can be adjusted within 3-4 minutes.

For several years now it has been producing various tools, the main purpose of which is to increase the quality and speed of work on installing aerated concrete. A professional tool is developed taking into account the technical characteristics of individual blocks, taking into account their dimensions and geometry.

Basic set of specialized auxiliary tools:

• trowel - the width is equal to the width of the blocks, provides a thickness of the applied layer from 1 to 3 mm, the advantage is that when applied, the solution does not flow down the sides, but is accurately distributed over the surface of the block, as a result of which the masonry remains clean;
• carriage with dispenser – also in size corresponds to the width of the blocks and is used for the fastest possible application of the adhesive mixture, has a maximum width of 500 mm;
• mallet - a rubber hammer that prevents damage to aerated concrete (this product should not be replaced with a simple metal or wooden hammer, since their use leads to damage to aerated concrete blocks);
• wall chaser - helps to manually cut grooves in aerated concrete;
• hand saw or cutter - used for neat cutting of blocks, have carbide tips;
• plane - helps to change the shape of the block and level out large unevenness in the masonry;
• sanding board – eliminates minor irregularities and defects in erected aerated concrete structures;
• corner – fixes the block and helps to make even cuts on it.

In addition to specialized tools, the German company also produces Ytong aerated concrete blocks themselves, as well as adhesive compositions and winter mixtures.

Laying aerated concrete blocks

• The strength of the entire structure depends on how well the first row is laid. Masonry made from aerated concrete blocks differs from brickwork, since aerated concrete is a relatively lightweight material that does not squeeze out excess mortar from the joints during installation. In addition, walls can be erected from it without technological pauses.
• For the construction of external walls, building codes recommend using blocks with a thickness of at least 37-40 cm; for external walls, blocks with a thickness of 25 cm or more are sufficient, and decorative walls and partitions can be built from aerated concrete with a thickness of 10 cm or more.
• So, before you begin building the first row of masonry, you should carefully prepare the foundation. This primarily concerns the installation of waterproofing materials. Any rolled bitumen or polymer material (for example, roofing felt) or a special waterproofing solution based on polymer-cement components can be used as waterproofing.

• A 2-3 cm layer of cement mortar is applied on top of the waterproofing material (approximate composition: 1 part cement, 3 parts sand), which will help compensate for uneven foundations. Horizontalness must be checked using a building level. The first row is laid along a stretched thread starting from the corner.

• The adhesive mass is applied in a thin layer to the blocks and the first row is laid out. Each laid block is checked for level in the horizontal and vertical planes; if necessary, the blocks are tapped with a special rubber mallet.

• If, when laying blocks in a row, there is a space between them that is less than the standard length, then an additional element should be made. To do this, use a hand or electric saw to cut the required length from the aerated concrete block and trim the cut with a sanding board or plane.

Advice: when installing such an element, it is important to coat its ends adjacent to the main row with adhesive. This should be remembered at any stage of wall construction; if the block has cuts, then it is necessary to treat it with glue on all sides to add strength to the structure being built.

• The second and subsequent rows are laid from the corner with an offset of half a block to the right or left (at least 8-10 cm). To install a more reliable masonry, before installing the second row, you should wait 2-3 hours for the cement mortar of the first row to harden. Use a brush to sweep away all small particles and dust. In cases where excess solution appears, such smudges are cleaned off, but not rubbed over.

• In order to achieve optimal evenness of the rows, it is recommended to install wooden structures along the entire row or in the corners. Alignment of the horizon and vertical is done after each row. If even small differences remain, this can lead to the appearance of stress in certain areas, and subsequently to the formation of cracks.
• You should refrain from unpacking all aerated concrete products at once, since the material may reduce its technical parameters due to exposure to precipitation and various atmospheric phenomena. If it starts to rain during construction, then the unfinished masonry must be covered with film, and when work is stopped for the winter, be sure to carefully insulate the structure from moisture. On hot days, it is recommended to moisten the installed aerated concrete blocks with water.
• Upon completion of the construction of aerated concrete building, it is best to leave the structure for some time to shrink. As a rule, buildings made of cellular concrete do not shrink much and after 1-2 months you can begin interior decoration.
• The finishing of the inside of the building is carried out earlier than the finishing of the facade, since the moisture generated from pouring the floors and painting work must come out. When installing windows, doors or other elements, you should use special dowels and do not use an impact drill for drilling.

Adhesive solution for laying aerated concrete blocks

• It is worth mentioning separately about the adhesive composition used in the process of erecting aerated concrete structures. Until now, many people use cement-sand mortar for these purposes in an attempt to save money. In fact, this is only an appearance of savings, since the cost of special glue, although it exceeds the cost of sand and cement by about 2-3 times, but the consumption of the adhesive composition is much less, approximately 6 times.
• In addition, by making the interblock seam of a minimum size, you can achieve a significant reduction in heat consumption, and this is only possible using special glue.

• By laying blocks on a cement-sand mortar, it is impossible to obtain their maximum density in relation to each other, so it will not be possible to avoid the appearance of cold bridges. As a result, the interior decoration will also suffer, since condensation will accumulate on the outer part of the wall and over time this will lead to the formation of bacteria, mold and fungi. Also, cement-based mortar significantly reduces the compressive strength of the structure and it is quite difficult to achieve acceptable evenness of the entire masonry.
• Preparing the adhesive solution is not difficult. The mixture is sold in the form of a dry powder, which is added to water according to the instructions before use. The resulting mass is kneaded until smooth with a construction mixer or using a special attachment on a drill. The resulting solution has a medium consistency, reminiscent of thick sour cream. It can be applied either with a trowel or using a special carriage or bucket with a curved edge. Then, the applied layer is leveled with a spatula with a notched comb.
• The load-bearing joints should be filled completely with the composition, regardless of the shape of the aerated concrete products. Interblock joints with tongue-and-groove joints are partially filled with the mixture. In winter, it is recommended to use adhesive solutions with special frost-resistant additives.

Internal and external finishing of aerated concrete structures

Thermal insulation

• Aerated concrete products retain heat well. Most often, a significant part of the heat loss occurs due to the presence of cold bridges in the interblock seams, as well as through other structural elements - windows, roofing, foundation, and so on. Therefore, when building a house from cellular concrete, care should be taken to ensure increased thermal insulation of these elements. If there is a need for an additional insulating layer for the walls, then you can use mineral wool-based products, and then use plastering or ventilated facades.

Finishing

• When choosing materials for finishing a house, you need to take into account the fact that aerated concrete is a porous material that can absorb water. You should not be afraid of this process, since moisture does not penetrate deeply into the material, but only slightly wets its surface. At the same time, dark spots or smudges may form, which greatly spoil the appearance.
• Interior finishing can be done using vapor-proof materials, in which case the building will lose natural ventilation, but the external finishing of the facade, especially with plaster, will last much longer. It is also possible to perform cladding with vapor-permeable material; such finishing will require a little more effort, but at the same time the house will maintain comfortable living conditions.

• When starting interior decoration, you should smooth out all the unevenness on the walls, filling them with adhesive or a mixture of cement and sand. First of all, the masonry must be treated with a special primer (for hygroscopic materials). To do this, the surface is dust-free and generously coated with a primer. Then wait for 3-4 hours and begin plastering.
• For living rooms, it is best to use non-moisture-resistant compounds; the same rooms where there is high humidity (corridor, bathroom, kitchen) should be additionally treated with waterproofing mixtures and then covered with moisture-resistant plaster. After the initial processing, you can begin the decorating process. It is recommended to use paints for aerated concrete for these purposes.
• For finishing facades, it is best not to use products based on foam glass or foam plastic; you should also refrain from painting with vapor- and air-tight compounds or use polymer plasters. It is optimal to arrange various ventilated structures from siding, lath or decorative slabs for external wall cladding. If you want a plastered facade, then you can only use special compounds developed for aerated concrete, since ordinary plaster will begin to lag and peel over time.

Masonry made from aerated concrete blocks does not collapse under the influence of the environment, even without the use of additional exterior finishing. In general, cladding is carried out only to improve the aesthetic qualities of the exterior. A properly installed roof, a reliable drainage system, as well as elements such as canopies and window sills will help preserve the erected structure in its original form for many years.

Classification of self-tapping screws for aerated concrete and foam concrete blocks

Dowels for self-tapping screws

Without dowels, self-tapping screws for aerated concrete are not often used due to the porous structure of the blocks. They are used for fastening lightweight structures. Thus, they can easily secure a reinforced mesh to an aerated concrete surface before applying plaster. For such fastening, self-tapping screws with a wide pitch and a length of at least 10 cm are selected.

In this case, it will not be possible to use a hammer drill, since the aerated concrete will crumble greatly. A drill with a thin drill bit is used. There is a way to screw self-tapping screws into a porous surface using machine oil. A few drops of oil are added to the prepared hole, so the hardware can be easily screwed in. The hardware will fit tightly, and it will be difficult to unscrew it in the future.

Self-tapping screws with a herringbone profile can be hammered into foam concrete blocks. The consumables along with the dowels are driven in “forever”; it is almost impossible to dismantle them. The work must be done quickly so that the prepared hole does not begin to crumble.

How to use?

The principle of installation of dowels is the same as for other types of fasteners. You need to act in the following order:

• first you need to prepare holes for the dowel, which should be smaller than the diameter of the fastening; for example, for 8 mm fasteners you will need to use a 7 mm drill;
• if you take a tool such as a hammer drill, then you need to turn off the impact mode; of course, it is advisable to use a drill, since it is more effective;
• the plastic fastener must be carefully screwed in using a screwdriver; if metal parts are used, then they should be driven into the mounting hole with a hammer;
• When performing work, you must ensure that the products do not touch or are positioned crookedly;
• when the cuff is installed all the way, you can proceed to screwing a self-tapping screw or a universal-type bolt;
• It is necessary to screw in the self-tapping screw using a screwdriver, adhering to the required depth.

How to hang a TV on a wall made of aerated concrete?

Mounting even a light TV on the wall must be reliable. The equipment is not cheap, so that if it falls, it can be immediately replaced. In addition, damage to the TV can cause a fire. Therefore, it is better not to take risks, but to secure such items correctly.

Mounting a TV on a wall made of aerated concrete

You need to proceed as follows:

1. Make a hole in the wall using a hammerless hand drill or a hammer.
2. Drive a wooden bushing with a diameter of 2–3 cm into it.
3. Install metal fasteners into it.

To increase adhesion, the dowel can be placed on a special glue or any sealant. The fastening will be reliable and durable. It can also be used when you need to hang a cabinet on a wall made of aerated concrete. The main thing is to choose fasteners that are proportional to the weight and dimensions of the furniture. And, of course, you should think twice before hanging something heavy not on a load-bearing wall, but on a partition made of aerated concrete.

Selection and features of fastening anchors for foam and aerated concrete

Which anchors are best to choose?

Anchors should be selected based on the weight that will fall on each individual fastener:

1. Anchors that can support up to 10 kg per fastener. Such products work mainly due to expansion and are a thickened plastic element that in working condition acquires a conical shape or expands inside the material. With their help you can hang small shelves, pictures, hangers, etc.

Anchors for fastening lightweight structures into aerated concrete

1. Anchors for a mass of 20-25 kg. These are fasteners of a special shape that allow the load inside the material to be distributed over the maximum possible area inside the base. They usually have a helical shape, significant length and diameter. They can be used to hang, for example, heating system radiators, kitchen cabinets, and façade cladding systems.

Anchors for fastening medium and heavy structures into aerated concrete

1. Chemical anchors for 30kg and more. They are special solutions supplied in tubes. Under them, a long hole of large diameter is drilled in the aerated concrete base, cleaned, filled with the compound and a metal pin is inserted. After hardening, the solution essentially turns into a solid capsule, comparable in strength to concrete. At the same time, it takes on the local load from the suspended structures and, due to its large surface area, more evenly transfers this load to the aerated concrete. This solution allows you to attach boilers and other heavy interior and exterior elements to walls made of foam block and gas block.

Chemical anchors for fastening heavy structures to aerated concrete

When choosing an anchor for aerated concrete, give preference to dimensional products with a large surface area. The longer and thicker the anchor, the better.

Practical recommendations for fastening into aerated concrete

Before fastening it into aerated concrete with your own hands, remember that:

• Installation of fasteners must be carried out with a minimum distance from each other of 10 cm. Otherwise, the overlap of stress areas in the gas block can lead to its collapse and the fall of the structure being fixed. The greater the spacing of the anchors relative to each other, the better and more reliable the fastening.
• The anchor should not be attached close to the edge of the block; the minimum offset here is also 10 cm.
• As already noted, the class of aerated concrete largely determines its ability to withstand the fastening of massive structures. For example, a B2.5 class block will withstand approximately 2 times less weight compared to B5.0, although the latter is used extremely rarely in low-rise construction.
• Despite everything described above, it cannot be said that this or that fastening to aerated concrete can be considered 100% reliable. The material is fragile, and it will be better if heavy objects are secured through a specially mounted metal frame, rigidly fixed to the concrete floor and/or ceiling. At the same time, to save space, the frame can be “drowned” into easily chipped aerated concrete.
• It is necessary to drill holes in the gas block for anchors in the drilling mode without impact. The drill should be selected 1-2 mm smaller than the diameter of the dowel, so that after driving, the fastener “sits” tightly in the hole.

Video on the use of Fisher chemical anchors in walls made of various materials.

So, we figured out how and with what help you can attach to aerated concrete and foam concrete blocks. You can find out how to attach to other building materials in our next articles.

Alternative ways to install kitchen furniture and equipment

There are other ways to hang kitchen cabinets or appliances. Most often, structures similar to plumbing frames for installations are used. These are support systems that represent a supporting frame with an emphasis on the floor and technological holes for installing fasteners. These frames do not have to be attached to the walls, but it is difficult (if not impossible) to ensure their stability using other methods. The advantage of this type of hinge is reliability, the ability to adjust the height of the frame to a given height, and high load-bearing capacity. In addition, you can use frames (or supporting slats) of different sizes to suit the existing set. The frame can be attached to the walls at randomly selected points where it is more convenient to install anchors. In a similar way, you can hang not only kitchen cabinets on aerated concrete, but also equipment or heating devices.

Feasibility of application

Chemical injection compositions and ampoules are expensive, their purchase is advisable when working with hollow and porous types of concrete; in dense structures they are justified when installed near the edge or in the case of increased expected loads: tensile, vibration, weight. Anchors of this type can withstand the weight of steel elements, consoles, columns, facade systems, equipment, fences, and, if necessary, they are used for additional fastening of reinforcing bars. When choosing this option, the quality of the base material has virtually no effect on the reliability of the fixation; the products of Hilti, Fischer and their analogues are designed for use in concrete with cracks.

They are also advised to buy:

• In the absence of an accurate calculation of the hole size.
• At high seismic and vibration loads on the object.
• If necessary, violation of the recommended intervals: placement along the edge of the structure or next to an adjacent anchor. Unlike standard dowels for concrete, they do not have a thrust force.
• For use in conditions of high humidity (the chemical composition reliably protects metal fasteners for concrete from corrosion).
• For installation in fire protection systems, the fire resistance of specialized types reaches 2 hours.

The importance of waterproofing during installation

Wood and aerated concrete blocks absorb moisture well, so when preparing wooden products it is necessary to treat them with hydrophobic compounds and then dry them under natural conditions.

Before laying the Mauerlat, you need to lay 2 layers of roofing material or insulation along the monolithic belt and only after that install the elements. The durability of installed structures, including the rafter system and roof covering, depends on the correct implementation of waterproofing work.