How to choose fasteners for aerated concrete, types of fasteners

1. Fasteners for aerated concrete and requirements for them
2. Steel dowels
3. NEMA nails
4. Frame dowels
5. Spiral nails
6. Nylon anchors
7. Chemical anchors

Aerated concrete is a lightweight building material with a cellular structure that is very popular. Porosity improves its thermal insulation properties. It also leads to rapid loosening of blocks when trying to hammer a nail into them or drill a hole. For this reason, hanging a shelf, TV, sink or other object on a wall made of aerated concrete using conventional methods is quite problematic: under mechanical stress, the material begins to crumble, and the fastenings become unreliable. How to fix the situation? This will be discussed further.

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.

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.

Types of masonry

There are several ways to lay cinder blocks. They can be laid:

• in one stone;
• one and a half stones;
• spoon method (using half the stone);
• two stones.

Masonry thickness

To determine the thickness of the masonry, it is necessary to analyze how many degrees the air temperature drops in a given area. If the winter is warm, then a thickness of 45 cm is sufficient to build a house; in northern latitudes, the thickness of the walls should be at least 60 cm.

It is advisable to plaster the outer walls so that moisture cannot enter them. The internal walls are covered with plasterboard.

Fasteners for cinder blocks

To attach cinder blocks, it is better to use Fischer nylon dowels. They are perfectly fixed in hollow materials. The built-in impact stop helps prevent expansion of the dowel during installation.

Also suitable for cinder blocks is UPER DOUBLE, which has an increased wedging zone. Its design guarantees self-centering of the screw. Thanks to the durable wings and the 8-gonal ring neck, the dowel does not rotate in the drilled hole.

Glue for cinder blocks

The choice of laying with mortar or glue depends not only on personal preferences, but also on geometric deviations. If there are deviations of up to 10 mm on the blocks, they can only be laid on a solution that helps level them out.

All types of adhesives are available in bags of different capacities.

The adhesive solution is prepared before starting work. If the masonry is done in winter, you need to buy special glue with anti-frost chemical additives. Sometimes glue is added to masonry mortar to create a more durable composition.

Plasticizer for cinder block

For strength and increased frost resistance, a plasticizer can be added to the solution. It helps increase the density of the mixture and reduces porosity. After adding a plasticizer, the masonry mortar acquires the following properties:

• uniformity;
• plastic;
• increased strength;
• moisture resistance;
• self-sealing;
• frost resistance;
• stickiness.

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.

Strong arguments against the armored belt

Most craftsmen involved in the construction of buildings made of aerated concrete are confident that installing an armored belt can solve all problems with installing the mauerlat and roof. In fact, this is not entirely true, for one simple reason - the future house is being built from extremely weak aerated concrete. Therefore, it is impossible to transfer the techniques and technologies of the armored belt, which successfully work on brick, block and concrete buildings, to aerated concrete walls.

There are only two fundamental objections to the armored belt:

• First of all, with any manufacturing scheme, the reinforced belt can be secured only to the top row of aerated concrete, so the roof has to be made with the same restrictions, as in the case when this belt is not present. The concrete frame redistributes the thrust load well, but all the forces from the reinforced belt fall only on the top row of aerated concrete, hence the appearance of cracks along the upper edge of the walls;
• Attaching the Mauerlat to an armored belt means creating huge problems with a cold bridge in that part of the roof where aerated concrete is least ventilated. Even laying a layer of EPS insulation helps little; you have to look for ways to install vents to remove condensation from the reinforced belt.

The third argument against concreting is related to costs. The installation of reinforcing tape will cost an amount approximately equal to a third of the estimate for the construction of the foundation. For a house 4x8 m this is approximately 60-100 thousand rubles. It is clear that it is much easier to fasten the Mauerlat and roof frame to a Mauerlat rigidly connected to a concrete reinforced belt. Sometimes master roofers even refuse to install a roof on aerated concrete without an armored belt, but technologically this is quite possible.

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.

Mounting the Mauerlat

Mauerlat is a wooden support beam to which roof rafters are attached.

During any construction of a residential building, great attention must be paid to how reliably all elements of the roof structure are strengthened. The load from the roof, its correct and uniform distribution on the load-bearing walls of the building, is assumed by the mauerlat - a special wooden beam that must be accurately and correctly fixed on the top of the walls. It is relatively easy to attach such a beam to the surface of aerated concrete blocks, but all the features of this technology must be fully observed.

A wooden beam must be taken with a cross-section of 100*100 mm. These are the minimum permissible figures; according to technology, it is permissible to take timber only with large dimensions. All logs are fixed on one side only; they must fit very tightly to the aerated concrete surface.

There are several options for attaching the Mauerlat; for this, the wooden beam must run along the entire perimeter of the upper part of the aerated concrete walls. Before you start laying it, you should definitely waterproof the surface.

The studs are installed immediately when the armored belt is poured. They should be 3 cm higher than the Mauerlat itself and installed in increments of 1-1.5 m.

Most often, the timber for the Mauerlat is secured using metal pins. The walls are completed by laying special U-shaped blocks, which help create a monolithic reinforced concrete belt. Metal pins must be installed in these blocks while they are filled with concrete mortar, this is done strictly under the fishing line. All studs must be placed at the same level, which will make future installation of the timber quick and easy. Before you begin to install the wooden beam itself, you need to make holes in it for the studs installed on the walls.

There are the following types of mechanical anchors: expansion, universal, driven, spring and specialized.

The Mauerlat is placed on metal studs, after which it is secured with ordinary nuts and washers. The height of such studs above the foam blocks after pouring should be equal to the cross-section of the wooden beam plus 4 cm, so that the stud can be secured with a washer.

But there is another way to attach the Mauerlat. For this, special anchors are used, which can be:

• mechanical;
• chemical.

Mechanical anchors, designed for fastening to a foam block, are wedge-shaped dowels in the form of a cylinder, which has harpoon-shaped teeth along the entire outer side. There is a cut along the central part for insertion. The dowels are secured, after which the fasteners are screwed in, expansion is carried out, as a result of which the teeth are pressed into the thickness of the foam blocks.

A chemical anchor consists of a metal rod and synthetic resin. The resin penetrates into the base material and, when hardened, holds the anchor and base together.

This method is considered one of the most reliable, but there is also a minus - attaching the Mauerlat to the foam block using mechanical anchors is quite expensive, one piece costs about 3,500 rubles.

The chemical method is cheaper. It lies in the fact that the chemical binder quickly penetrates the pores of aerated concrete, after which excellent fastening occurs. In this case, the fixation is reliable and the connection is sealed.

The Mauerlat itself, which will be attached to aerated concrete, must be of very high quality, without knots or signs of damage. It is also important to perform waterproofing.

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

Fastening with metal studs

A metal stud is a steel rod with a metric thread, having a diameter of 10-16 mm.

Installation of embedded parts can be carried out in two ways:

• in the process of assembling the frame by welding;
• connection to reinforcing bars using tie wire.

Fastening with metal pins.

If you plan to lay the Mauerlat without a monolithic belt, then a metal plate with a thickness of 1.8-3.0 mm and a size of 100 x 100 mm is welded to the bottom of the part. The devices are embedded into the masonry to a depth of 40-60 mm. Upon completion of installation, the upper part of the rod should rise 3-5 cm above the surface of the beam.

Installation of studs into a finished monolithic base or solid masonry of solid gas blocks occurs as follows: every 1.2-1.5 m, holes are drilled with a depth of at least 20-30 cm and fastening parts are installed.

The Mauerlat is lowered onto the prepared structure and pressed in order to make marks for the holes with pins. They drill the beam, and when all the samples are ready, they string the profile onto the rods, throw on washers and nuts. Check the level of the bearing and tighten the connections.

The number of studs under the Mauerlat must correspond to the number of rafter legs in the roof structure.

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.

Aerated concrete

Structure

• The building material, called aerated concrete, is a stone made of cellular concrete with evenly distributed pores with a diameter of 1 to 3 mm, which communicate with each other (stone foam). To manufacture this product, cement and quartz sand are used, to which specialized foaming agents are added (in some cases, the composition may also include gypsum, lime, ash, slag). The interaction of finely dispersed metallic aluminum with cement or lime mortar forms a substance that foams the cement mortar.
• The resulting material can be easily drilled, sawed, planed with various tools such as a plane, and you can also easily hammer a nail, staple, or screw a self-tapping screw into the block. Since the product consists of mineral components, it increases its own density over time, just like cement-sand mortar (concrete). Compared to foam concrete, this block has better strength and thermal insulation, and less cement is used in its production.

Note. GOST 31359-2007 allows the construction of buildings from aerated concrete blocks of no more than 5 floors, but the same instructions allow the construction of nine-story buildings with self-supporting walls made of similar stone.

Fasteners

Table - fasteners for aerated concrete

Cellular concrete, despite all its advantages, can be called a soft material and, for example, attaching a Mauerlat to aerated concrete can be a serious problem when building a house. However, construction practice suggests that if you use the right accessories for fixation, then everything is possible, and the installation process is quite easy, quick and simple. In the laboratories of AS Teede, Tehnokeskuse, tests were carried out on the AEROC screw 65 mm long, and in comparison with other self-tapping screws it showed excellent results - the pull-out strength was 3.765 kN ().

The best self-tapping screw for cellular concrete was ESSVE Heavy Load 10×185 - with this device you can attach siding to aerated concrete or attach a roof to walls made of aerated concrete. All tests carried out were recorded in protocols under No. 001/12 and No. 359/13 - you can see the results by these names.

Various objects with a small mass can be attached to the wall with your own hands quickly and easily, just like to wood - simply by screwing a screw into the body or driving a nail, and for this you do not need any special tools. But it should be taken into account that the nail that works for tearing out must have the shape of a wedge or at least its end must be of a modified shape. But for self-tapping screws, a thread with a large pitch along its entire length with a dowel of the required diameter () is most suitable.

To increase the fixation strength, you need to select a dowel that is smaller than usual - this allows the plastic to expand in the hole, making it almost impossible to pull it out.

For example, for a screw with a diameter of 10 mm, take a dowel of the same cross-section - this way the plastic or nylon is smeared along the walls of the hole. But here you should avoid choosing short dowels - this reduces the contact area and, therefore, reduces the strength of the fixing element.

In the top photo you see how to attach the Mauerlat to aerated concrete - here the fixation is carried out not to the blocks themselves, but to a reinforced belt that is poured with concrete - the strength of such a pour is quite high and can withstand not only the weight of the roof, but also strong gusts of wind. But for hanging furniture, you will not fill the wall with mortar, so it is best to screw in the screw at a slight angle - this will significantly increase the fixation strength.

From a technical point of view, fastening windows in aerated concrete is not much different from installing the same doors - both are inserted into the opening, only here it is better to use a little trick. It is best to make something like a groove in the blocks under the door or window frame so that it is supported not only by screws and dowels, but also by the wall itself, as shown in the top image.

Fasteners in aerated concrete - AEROC screw

Since you have to attach various elements to aerated concrete not only indoors, but also outdoors, you should make sure that all nails and screws have an anti-corrosion coating - this can be hot-dip galvanized or they can be made of stainless materials. But this applies not only to open surfaces - even in a room, such material must at least be galvanized. This, of course, increases the price of the product, but along with the cost, the quality of the repair also increases ().

Note. It should be noted that cutting reinforced concrete with diamond wheels and diamond drilling holes in concrete have nothing in common with cellular aerated concrete. In this case, cutting and drilling is very easy - this can be done even with a hand drill or a regular wood hacksaw.

Conclusion

Different products made of lightweight cellular concrete, depending on their purpose, can have different densities - there are only two classes - this directly affects the ultimate tensile strength. When purchasing any elements for fixation, you need to pay attention to the permissible load - it is usually indicated by the manufacturer on branded products. If the dry density changes between 400 and 500 kg/m 3, the tensile strength also changes accordingly (can change 2-3 times).

Due to the unique properties of the materials, construction from foam and gas silicate blocks has gained great popularity. These cellular building materials have a low specific gravity, as a result, they are easy to transport and easy to handle. So, due to their structure, the blocks lend themselves perfectly to cutting with a regular hacksaw. Houses made from these materials are built in a short time.

A variety of fasteners for aerated concrete structures

But the porous structure of the blocks, in addition to positive qualities (lightness), also has negative ones. It is precisely because of their porosity that aerated concrete blocks crumble easily. This, in turn, creates the problem of selecting fasteners when installing electrical equipment, plumbing, furniture, water and gas pipelines to aerated concrete.

There are special self-tapping screws and dowels for foam blocks that will help ensure high-quality fastening of any structures to walls made of gas silicate blocks and foam blocks.

Characteristics of fastening material for foam blocks

Manufacturers of fastening materials produce specially designed fasteners for aerated concrete blocks:

• self-tapping screws;
• screws;
• anchor;
• screws;
• dowels;
• dowel-nails;
• chemical anchors;
• M4 screws.

Screws, self-tapping screws, screws, and anchors are made from high-tech varieties of steel. This is stainless steel, carbon steel.

Their diameter can be 4-10 mm. The dowels are made of plastic, the dimensions of which are 10 by 50 mm. The dowels have a special thread. When screwed in, this thread creates additional internal stops in the aerated concrete blocks, preventing spontaneous unscrewing. In this case, the dowel is easily screwed into cellular concrete. Each fastener designed for foam blocks performs its own fastening task.

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).

Final stages

After all the preparatory work has been completed, you can begin installing the gypsum board sheets. Drywall must be screwed using special self-tapping screws. It is best to attach the sheets in large pieces, without cutting them unless absolutely necessary. The installation itself depends on the surface on which the plasterboard is attached, whether there is a need to create a multi-level surface (this is usually used for ceilings, but often plasterboard is used to create various wall niches).

After the gypsum board sheets are completely strengthened, all joints and fastening points should be puttied, and finishing work should begin.

An increasing part of a wide variety of buildings today are being built using lightweight aerated concrete, which has numerous advantages. Its special cellular structure makes the material not only very durable and light, but also allows for relatively simple processing. This also includes the ease of attaching a wide variety of elements to the blocks, from the installation of roof parts to interior finishing work.

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.

Selection of material and calculation of parameters

When choosing a material, you need to pay attention to the structure of the wood, the absence of curvature and the integrity of the surface. Products must be free from knots, cracks and traces of biological influence. The moisture content of purchased wood should not exceed 8%.

The Mauerlat is made from a wooden rectangular profile with dimensions:

• 80 x 180 mm;
• 100 x 150 mm;
• 100 x 100 mm;
• 150 x 150 mm;
• 200 x 200 mm.

The choice of beam section is influenced by the following factors:

• number of floors and external dimensions of the building;
• design features (number of slopes, presence of an attic, etc.);
• roofing material;
• climatic conditions of the region.

Dimensions of wooden beams.

The weight of the timber used is calculated as follows:

• Determine the cross-sectional area - multiply the width by the height.
• We multiply the resulting value by the perimeter to obtain the volume of the material.
• We multiply the result by the specific density of wood - in this way we calculate the weight, or the amount of load that the Mauerlat will exert on the external walls.

The length of the profile should be such that the number of connections on one side of the building is minimal. The standard size of the produced material is 3-6 m, so for a distance of 8 m you need to purchase 2 segments of 6 m each.

When choosing the height of the profile, it is necessary to take into account that the connection of the rafters to the Mauerlat is made by cutting, and 50% of its actual size is used.

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.

Threaded elements

The complete set of chemical anchors for aerated concrete uses threaded rods, the diameter of which can range from 5 to 30 mm, the length of such threaded elements reaches 380 mm.

Galvanized Anchor Stud for Chemical Anchor

In order to improve the quality characteristics of the formed connection and the ease of use of threaded rods, their surface can be covered with a special protective layer, a mark of the recommended laying depth is applied to their side, and the special design of their tip facilitates better mixing of the glue.

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.

Rules for installing drywall

First of all, you need to calculate the plasterboard for the ceiling. When performing finishing work, quite often plasterboard is attached to the surface of an aerated concrete wall, which allows you to perfectly level the surface before finishing individual works, for example, before gluing wallpaper, painting walls, applying decorative plaster and much more. To properly attach drywall, in addition to sheets of material of the selected type, you need to prepare the following elements:

Tools: electric drill with hammer drill function, screwdriver, hacksaw, construction knife, metal scissors, plumb line, level, tape measure, tapping thread, pencil.

• self-tapping screws for drywall;
• insulation (mineral wool is best suited for this, as it has the necessary properties; it is easy to install);
• a special metal profile for fastening drywall (with its help, a reliable, durable frame is created);
• building level;
• ruler and simple pencil;
• breaker cord;
• screwdriver

Drywall is attached to the surface of aerated concrete as follows:

After the frame is mounted, the insulation - mineral wool - is tightly laid.

1. GKL sheets are attached to aerated concrete only with self-tapping screws (the adhesive method is not used here). In this case, the space between the wall itself and the gypsum board sheet should be no less than 3-5 cm. Experts recommend filling this space with mineral wool. Such insulation will not only help retain heat, but also create an excellent soundproofing layer. The metal profile is attached directly to the surface of the foam concrete, for which a series of preparatory work must first be carried out. The surface of the wall must be marked using a building level, marking the places where the profile will pass. After this, it is recommended to cut the drywall according to the existing contours.
2. For the frame under the gypsum plasterboard sheets, a guide profile is first attached, after which, using a building level, you can begin fastening the guide profile. Thus, a metal rectangular frame is obtained on the surface of aerated concrete. It is to the surface of such a profile that the sheathing sheets will be attached. The profile is mounted to the surface using self-tapping screws, which are screwed into the wall or ceiling blocks.
3. After the frame is mounted, it is necessary to consider whether any communications will pass under the surface of the sheets. Electrical cables must run in a special corrugated pipe. The places where elements such as switches, sockets, and other electrical accessories will be located are immediately determined.
4. The insulation is chosen in the form of mineral wool; it is best to take slabs that are more convenient to install. The insulation must be installed tightly, without leaving gaps or cavities; the quality of heat and sound insulation will depend on this.
5. When attaching the profile to the wall, it is necessary to take into account that in addition to self-tapping screws, it is necessary to use additional metal strips - perforated strips, one edge of which rests on the aerated concrete, the other on the profile.

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.

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.

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.

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.

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.

Selection of building materials

In the manufacture of wooden mauerlat, beams are used. At the same time, experts advise making fastenings from deciduous trees treated with special antiseptic agents. The beams should be laid around the perimeter of the wall. To connect them together, specialists install a lock, which must be secured with nails. This will help make a strong, solid wood structure. It is important that its size be smaller than the width of the aerated concrete walls. The timber must be secured to the inner surface in such a way that there is a gap of five centimeters between the outer cut and the fastening. Sometimes builders use brick for a protective belt on the outside of the wall. Before starting installation work, waterproofing should be provided between the walls and beams.

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.

Design features of the armored belt

Mounting the Mauerlat on studs without an armored belt

Armopoyas is a kind of reinforced concrete foundation for the roofing system. This structure is heavy and experiences strong wind, snow and tensile loads. Based on this, the roof needs a strong, powerful and stable support that can withstand the influence of external factors for decades.

The armored belt has the following device:

• Formwork. It can be made removable or non-removable. The first option involves arranging a cold attic, while the second option uses insulation (foam plastic, basalt wool) as formwork.
• Steel frame. Provides contour integrity and flexibility. Consists of fittings, square frames and corner parts. The parts are fastened using binding wire.
• Concrete. Gives the structure strength and shape constancy. It is made from crushed stone, sand and cement in a ratio of 3:3:1.
• Embedded parts. Serve for fastening the Mauerlat. Pins or studs are used.

The width of the armored belt corresponds to the parameters of the wall or is taken 5 cm narrower. The minimum height is 15 cm.

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.