Plastering walls made of aerated concrete is a justified measure. , like foam block, despite all its advantages, the material is hygroscopic. This means that it easily absorbs moisture. Therefore, a house made of aerated concrete must be protected from bad weather. If a gas block gets wet in the rain and then dries, it will not lose its properties. And if it gets wet in winter, then the water accumulated in the pores of the aerated concrete will freeze and expand. This is fraught with the appearance of small cracks that spoil the appearance, as well as the occurrence of more serious damage.

Conclusion: protecting aerated concrete from the outside from freezing, moisture, snow and other precipitation is a necessary measure. During and during winter conservation (if necessary), this function can be performed by a film stretched over the walls. During the operation of the house, it can be any facing material for external finishing of the facade - plaster for cellular concrete. The main thing is to create conditions for vapor permeability so that the aerated concrete “breathes.”

Exterior finishing of a house made of aerated concrete, in addition to protecting the blocks, allows you to:

• enhance the heat and sound insulation of walls;
• eliminate the possibility of walls getting wet;
• protect the house from sudden temperature changes;
• decorate the facade of the house ( decorative plaster for aerated concrete).

One of the most popular methods of exterior finishing of an aerated concrete house is applying plaster. Therefore, questions often arise, for example, how and with what to plaster aerated concrete, which we will try to answer as fully as possible. Let's carry out comparative review characteristics the best mixtures for finishing the facade, and we will also describe the technology of plastering walls in the form of step-by-step instructions, understandable to beginners without construction experience.

Plaster for aerated concrete

Having summarized the experience of builders and owners of aerated concrete houses, we can conclude that three types of finishing materials are used for plastering walls made of aerated concrete:

Cement-sand plaster for aerated concrete

Is it possible to plaster aerated concrete with cement mortar?

No you can not. Regardless of whether the aerated blocks were laid with cement or glue. In general, plastering aerated concrete with cement mortar is extremely undesirable, because aerated concrete is very smooth and the mortar does not stick to it, and also strongly absorbs water from the mortar.

Reasons why you cannot plaster a house made of aerated concrete with cement mortar:

• Cement mortar has a lower vapor permeability rate than aerated block. This is the most important reason why it should not be used. In the case of finishing walls made of aerated concrete, professionals have a rule that you can only use finishing material, which in terms of vapor permeability does not differ from aerated concrete itself or has a higher indicator in comparison with it. Only in this case will the optimal microclimate of the aerated concrete house be maintained.

Note. For the same reason, it is undesirable to use rigid insulation materials (foam plastic and expanded polystyrene) to insulate a house made of aerated concrete.

• Cement-sand mortar has a high moisture content. To mix the components into the sand-cement mixture, you need to add water. It is also obvious that aerated concrete, having a significant moisture absorption rate, will tend to absorb this water from the solution. This, in turn, reduces the quality of the applied solution and its ability to adhere to the wall. After all, concrete gains strength only if it dries evenly and slowly.

Remember, the foundation must be periodically moistened and covered with film to ensure uniform drying. So why should it behave differently on the wall? The primer helps the situation, but not much. The appearance of a web of small cracks on the plastered surface of aerated concrete cannot be avoided.

Note. In order to save money, you can mix a cement-sand mixture and a special mixture for finishing aerated concrete blocks in a ratio of 1 to 1. But is such saving necessary, which will significantly reduce the speed of work, and the finished surface will not be of 100% quality.

• U cement mortar for plaster low adhesion. It cannot provide high-quality adhesion to aerated concrete. One of the reasons may be the weight of the solution and the presence of large impurities in its composition.

You can increase the adhesion rate (adhesion, adhesion of surfaces) by adding lime to classic recipe cement mortar (proportion: 8-10 kg of lime per 100 kg of concrete).

Cement-lime plaster can be purchased in the form of a ready-made dry mixture. For example, dry construction cement-lime mixture KREPS Extra-light (240 rubles/25 kg), Osnovit Startwell T-21 (208 rubles/25 kg), Baumit HandPutz 0.6 (300 rubles/25 kg).

• mandatory application of the finishing layer. Because It is difficult to make a smooth surface using a sand-cement mixture.

Is it possible to plaster aerated concrete with aerated concrete adhesive?

Also undesirable. Despite the fact that it was developed taking into account the specifics of aerated concrete, it is intended for application in a thin layer and the formation of seams, and not for exterior finishing walls

Violation of the vapor permeability of aerated concrete will lead to problems such as cracking of the finishing layer, the appearance of traces of seams (disappear after drying), and the appearance of mold.

Gypsum plaster for aerated concrete

Advantages of gypsum-based plaster:

• high drying speed;

• non-shrinkability of the solution;

• the ability to make a smooth surface;

• no need to apply a finishing layer.

Disadvantages of gypsum plaster:

• mediocre vapor permeability;

• higher water content required for mixing the mixture compared to a special mixture (10-15 liters per bag);

• getting wet quickly during rain or snow;

• the likelihood of stains appearing on the surface that have to be painted over.

Despite the disadvantages, plastering walls with gypsum is an acceptable option for finishing aerated concrete. Well proven: gypsum vapor permeable highly plastic plaster mixture Pobedit Velvet G-567 (previously Pobedit-Egida TM-35 for 320 rubles/25 kg), Knauf Rotband (360 rubles/30 kg) and Bonolit (290 rubles/30 kg).

Facade plaster for aerated concrete

Most efficient material for plastering external and internal walls made of aerated concrete. Plaster for facade works has a number of characteristics, including a vapor permeability indicator identical to that of aerated concrete (for most types of plasters), good adhesion to the base, beautiful appearance.

When choosing what to plaster aerated concrete with, it is best to choose a high-quality special mixture. In addition, the use of facade plaster simplifies the finishing of an aerated concrete house with your own hands.

What plaster is best for plastering aerated concrete walls?

The market offers a variety of ready-made mixtures for plastering aerated concrete walls. To do right choice, you should pay attention to the characteristics of the plaster:

• vapor permeability;

• the required amount of water for mixing the mixture (no more than 0.2 liters per 1 kg of mixture);

• boundary values ​​for the thickness of plaster application (minimum and maximum);

• adhesion to the base (minimum 0.5 MPa);

• resistance to low temperatures;

• crack resistance;

• pot life of the solution. The more, the easier it is for beginners to work with it.

And only when choosing between two equivalent mixtures should you be guided by the price; it plays not the last role in this matter, but not the key one either.

According to reviews, plastering walls made of aerated concrete outside the room is popular among users - a dry mixture with plasticizers Ceresit CT 24 (380 rubles/25 kg), the leader in terms of price/quality.

Material prepared for the website www.site

When can you plaster aerated concrete walls?

Since aerated concrete easily absorbs moisture, it is better to immediately protect it from getting wet. Let us repeat, it is not critical if the material gets wet, but you should not allow the moisture in the aerated block to freeze. This can cause it to weaken and cause unwanted cracks to appear.

There is also no need to rush into cladding. After laying aerated concrete, the walls should dry thoroughly. That is why plastering of aerated concrete walls is carried out only in the warm season. If a concrete-sand mortar is used as a binding element when laying aerated concrete blocks, the drying time increases, since such a seam is several times thicker than a seam made with a special adhesive mixture.

If finishing the house during the warm season is not possible, you need to cover the walls with any primer deep penetration. For example, Ceresit ST-17 (549 rubles/10 l).

The primer will reduce water absorption. It is also advisable to cover the walls with polyethylene left over from packaging pallets of aerated concrete.

According to the craftsmen, the most preferable time for finishing work is the period when the night temperature exceeds 0 °C. For central Russia, this time is from the end of March to the beginning of October.

Which side should you start finishing a house made of aerated concrete from?

Let's carry out comparative analysis several popular options for the order of wall finishing.

Option 1
First, the exterior finishing of the house is made of aerated concrete.

There is an opinion that the most important thing is to protect the gas block from the street, because... it picks up moisture. However, this is not so, even after standing without protection (but primed) for the whole winter, the aerated block will “give up” the accumulated moisture in the spring. And if it is closed from the outside, where will the vapors be directed? That's right, indoors. This will not only increase the drying process and delay the interior finishing, but also risk the appearance of cracks inside the room.

Option 2
First, the interior decoration of the house is made from aerated concrete.

With this approach, the pores of the aerated concrete block are partially closed during the finishing work. And if they are plastered on the outside first, the accumulated water vapor will simply have nowhere to go. Moisture settling inside the block will contribute to its destruction. Plastering aerated concrete walls indoors will avoid this situation.

After the plaster has touched the internal walls and has dried well, you can begin finishing the external walls.

Option 3
Simultaneous finishing of the inside and outside of the house

The method is the least preferred. The moisture that the gas block will “pull” simultaneously from the outside and from the inside will not have the opportunity to quickly escape.

Despite the fact that plaster for aerated concrete has good performance vapor permeability, the speed of this process is not so high. Which is especially critical in the cold season (at night temperatures below zero). In this case, water vapor will settle in the form of condensation and may ultimately lead to peeling of the plaster layer from the aerated concrete. In practice, this option will lead to the destruction of the gas block as quickly as possible.

Theoretically, each of the options has the right to be implemented. But the second one is correct.

How to plaster aerated concrete walls with your own hands

The question of whether it is possible to plaster aerated concrete has been sorted out. Now it is important to understand how to do this correctly, without damaging the aerated concrete to allow moisture to pass through.

Plastering aerated concrete blocks is not fundamentally different from performing work of a similar type on other materials. The putty application technology differs only in a few details that will be emphasized.

Internal plaster of aerated concrete walls

Technology for finishing aerated concrete with plaster indoors - sequence of work:

1. Preparing the base

It starts with leveling the walls - removing unevenness is done using a plane or aerated concrete grater. It is recommended to carry out this work at the stage of building a house, but many people neglect it, saving time. In principle, this stage can be omitted, which will lead to a significant increase in mixture consumption and an increase in the thickness of the application layer. In turn, this is fraught with peeling of the plaster and cracks.

2. Applying primer

There are often recommendations that the primer should be diluted with water 1 to 1. This is fundamentally wrong, because reduces its ability to increase surface adhesion. There are better ways to save money. For example, remove dust from the surface by applying clean water to it. Water is applied with a brush or roller as if it were a primer. And then, after drying, a primer is applied.

The choice of primer depends on the purpose of the room to be finished. For a corridor or hallway, any universal primer is suitable, for example, Unis (250 rubles/5l). For the bathroom and kitchen, it is advisable to use deep penetration soil, for example, Prospectors (450 rubles/10 l).

3. Installation of beacons

Beacons, as the name suggests, determine the thickness of the solution. They are set to the width of the rule. The accuracy of installation is determined by the building level.

4. Throwing on a “fur coat”

This is the name of the method of applying the first layer of plaster. The work is carried out from the bottom up. Next, you need to rest the rule on the beacons and align (stretch) the sketched layer along them. If voids appear, they must be filled immediately. The main thing is that the plaster does not peel off from the base. If this happens, you need to remove the plaster, treat the surface with a primer and apply the solution again.

5. Processing the first layer

After the first layer of plaster has dried, it needs to be slightly moistened (with a spray bottle) and leveled. Since the beacons serve as cold bridges, it is advisable to remove them at this stage, and seal the places (recesses after dismantling) with mortar.

6. Formation of corners

To arrange and strengthen the outer corners, a perforated corner with a mesh is used.

7. Finishing

Grouting (if necessary) and painting of aerated concrete walls is carried out. In case of wallpapering, finishing is not required.

Paint for aerated concrete also has requirements regarding vapor permeability. Interior paints based on PVA, latex, acrylic emulsions, organic solvents and cement paints have these properties.

An example is ESKARO AKZENT (antibacterial paint, 325 rubles/0.9 kg). At the same time, for rooms with high humidity, special paints should be used, for example, AquaNova Premium (282 RUR/2.8 kg)

How to properly plaster aerated concrete walls - video

External plastering of aerated concrete walls

Decorative plaster of the facade of a house may involve applying plaster for external use in a thick layer (thick-layer finishing) or several layers (thin-layer plaster).

Let's consider a multilayer option for applying thin-layer facade plaster for aerated concrete. Its peculiarity is the creation of three thin (no more than 10 mm) layers.

External plaster application technology:

• wall preparation. Includes leveling the surface to reduce the consumption of the mixture and the thickness of its application;

• surface priming;

• applying a thin layer of plaster mixture (up to 5 mm). Its purpose is to serve as a basis for attaching the mesh;

• reinforcement of plaster with mesh;

How to properly reinforce plaster

A metal mesh with small cells can be used as a reinforcing layer, for example, steel mesh with a wire diameter of 0.1 mm and a cell pitch of 0.16x0.16 mm (average price 950 rubles/m2 = 2,850 rubles/roll) or fiberglass mesh (for example, reinforcing fiberglass mesh with a cell pitch of 50x50 mm ( approximate price 17.60 rubles/sq.m = 880 rubles/roll).

The mesh is attached with an overlap of 50 mm. At the same stage, the corners of the building are formed using perforated corner with mesh. The mesh helps prevent cracks in the plaster due to shrinkage of the building. Thus, the plaster of the aerated concrete facade will not be covered with a web of small cracks. The mesh is embedded in the applied solution using a spatula. It is especially important to install the mesh in high-tension areas, near windows and doors.

Advice. Attaching the mesh to a dry wall will not give any result, because the mesh will be fixed to the base with self-tapping screws. If it is installed on a solution, it will form a monolith with the solution and will move with it.

• leveling the plaster layer along the grid;

Next, you need to wait until the first layer dries completely. Otherwise, it may fall off under the weight of the second layer. Since this method involves thin-layer application of the solution, you will need to wait 3-4 days. The thicker the layer, the more. You can check whether the layer is dry using water. If you spray it on the wall and the water soaks in, it’s time to get to work.

Note. When the plaster dries, it must be protected from the influence of environmental factors (moisture, snow, rain).

• applying a second layer of plaster. This layer is considered leveling, so increased attention is paid to the evenness of application and the formation of a smooth surface;

• applying the third (finishing) layer of plaster mixture followed by grouting if necessary;

• painting a plastered wall made of aerated concrete or applying a textured plaster mixture, for example, Pobedit-Bark Beetle (340 rubles/25 kg).

  For painting aerated concrete, only paints for exterior use are used. For example, Nova Facade (590 rubles/7 kg), Gasbetonbeschichtung from Dufa (2674 rubles/25 kg), ROLPLAST Gordianus (3700 rubles/10 kg), Dyotex (concentrate, 5500 rubles/15 kg).

• application of water repellent. This is a special solution that professionals recommend applying a year after painting, after all facing works. A water repellent will give any surface additional water repellent properties. The special water repellent for aerated concrete “Neogard” (350 rubles/1 l) has proven itself well.

Aerated concrete putty

When deciding how to putty aerated concrete, you need to know that there are three types of finishing materials on the market, similar in purpose, but differing in their composition. All this is facade plaster for aerated concrete, sold in the form of a ready-made mixture. Designed for thin-layer finishing of plastered surfaces.

Ready-made silicate plaster, for example, Baumit SilikatTop Kratz Repro 3.0 mm (3,700 RUR/25 kg)

Silicone plaster, for example, Baumit SilikonTop (RUB 3,300/25 kg) Acrylic plaster, for example, Ceresit CT 77 (RUB 3,800/25 kg) Front "fur coat" Weber.pas akrylat or Weber.pas akrylat Fur coat 615С 1.5mm (1800 RUR/25 kg)

Conclusion

By consistently plastering aerated concrete walls and using only vapor-permeable materials, you can ensure a reliable finish that will decorate the facade of the house for many years. And planned repair work will be reduced to periodic painting to restore the color of the paint and eliminate small cracks.

Private construction from lightweight expanded clay concrete compositions, various porous gas and foam blocks, large-format gas silicate elements is becoming increasingly popular for a number of reasons. However, the technology for plastering aerated concrete walls is somewhat different from the methods for processing brick and wooden bases.

This article will discuss the basic requirements for finishing compounds for plastering concrete. different types, criteria for their selection, application technology and proportions for self-production.

Requirements for internal and external plastering of concrete

Presenters European manufacturers cellular concrete Masa-Henke, Ytong and Hebel, based on in-depth research, have developed the requirements for decorative and protective plaster of aerated concrete walls indoors and outdoors:

• The adhesion of the material to the hydrophobic layer of cellular concrete must be at least 0.2 MPa (the indicator is usually indicated on the packaging of the dry building mixture);
• High level protection against penetration of atmospheric moisture to the base - water absorption of the finishing layer (W) should be less than 0.5 kg/(m 2 h 0.5);
• Vapor-permeable plaster for aerated concrete must have a low vapor transmission resistance (S) of less than 2.0 m.

Structure of foam concrete block

Each subsequent layer must have a higher vapor permeability and lower water absorption than the previous one. The coefficient is calculated using the formula:

W×S = 0.2 Kg/(mh 0.5) – for internal walls and intermediate coverings;

W×S = 0.1 Kg/(mh 0.5) – for building facades.

The sequence of applying layers of plaster on walls made of foam blocks with your own hands, video presentation:

Internal plasters on cellular concrete

Complete leveling of internal walls made of foam concrete and aerated concrete is carried out using cement-lime mortars or polymer-cement mixtures with a large number of plasticizers in the composition. The plaster for indoor foam blocks contains organic plasticizers, which increase the mobility and life span of the solutions. For rooms with humidity not exceeding 60%, use finishing mixtures of the following composition:

• For inner surface external walls made of foam concrete, aerated concrete and for concrete floors– mixtures of lime and Portland cement;
• Plaster on aerated concrete for interior work on load-bearing walls, partitions or partitions - uses lime as a binder.

Technology for plastering walls made of aerated concrete indoors, video sequence of processes:

Important! At self-production plaster mortars, compositions for spraying and soil must be sifted through a mesh of no more than 3x3 mm (provided there are no reinforcing additives); for covering, sifting through a mesh of 1.6x1.6 mm is used.

External plaster on aerated concrete blocks

Plaster on aerated concrete for external use must meet the following requirements:

• Bulk weight of the mixture is about 0.8 kg/dm 3 ;
• The size of filler fractions is 2–4 mm;
• Mobility class of the plaster mixture P1 – low-moving, thick solution;
• Compression resistance class CS-1 – has significant strength;
• Fire resistance class A1 – non-combustible material;
• Water absorption properties - less than 0.5 kg/m 2 h 0.5;
• Vapor permeability resistance properties – from 10 to 12.

Before purchasing external plaster for walls made of aerated concrete, you must check the presented indicators with the information indicated on the packaging of the dry mixture.

Self-production

Ready-made specialized dry building mixtures for foam concrete and aerated concrete are quite expensive building materials. You can make an analogue of such mixtures yourself, but in this case the base must be reinforced metal mesh from rolled wire on dowels or notches are made - strokes 3-5 mm deep with a frequency of 50-70 mm. There should be at least 30 of them per 1 m2 of wall.

The cement-sand mixture is made in a ratio of 1:3 for external use and 1:5 for internal use. Screened quartz sand with fractions of 1-2 mm is used as a filler, and Portland cement of at least M400 grade without slag impurities is used as a binder. To increase elasticity, liquid soap is added to the mixture in a proportion of 25-30 g. onto a bucket of the finished composition.

Most popular manufacturers

A number of special dry construction mixtures and universal plasters are produced that are suitable for finishing foam concrete and aerated concrete surfaces in their own way technical parameters. The most popular claddings on this moment are:

• Ш-36 Decor – based on cement binder with reinforcing additives made of polymer fibers;
• PROFIT CONTACT MN – cement-sand mixture with special additives for machine application;
• Dali - plaster for foam concrete, aerated concrete and polystyrene concrete walls;
• Ceresit CN 24 – leveling mixture with a combined binder, used for leveling the surfaces of foam concrete walls;
• Mska mix – contains polymer modifiers and quartzite;
• ATLAS RD-TYNK is the lightest plaster for the facade of a house made of aerated concrete and foam concrete.

It must be remembered that foam concrete and aerated concrete have significantly less adhesion than brick walls, That's why key parameter The main advantage of choosing a plaster mixture is its light weight. In addition, you should pay attention to the type of binder. The basic technical and operational characteristics of aerated concrete wall plasters inside and outside the house depend on this.

Properties	Type of binder for plaster mixture
	Mineral	Acrylic	Silicate	Silicone
Main binder	Cement	Acrylic resin	Liquid glass	Silicone resin
Vapor permeability	High	Low	High	High
Water absorption	High	Low	Average	Low
Sensitivity to pollution	Average	High	Low	Very low
Pigmentation	Inorganic	Inorganic organic	Inorganic	Inorganic organic
Elasticity	Low	High	Srednaa	High
UV resistance	High	Low	High	High
Resistance to biological damage	Average	Low	High	High
Abrasion resistance	Low	High	High	High
Ionization resistance	High	low	High	High

Features of applying plaster to aerated concrete and foam concrete

There are several key nuances that distinguish the use of plaster walls made from gas silicate blocks. Blocks made of foam concrete and aerated concrete can be sawn - with an open structure and formed - with a closed cell structure and a hydrophobic layer. The latter, before applying the solution, must be treated wire brush for extra adhesion. In addition, it is necessary to remember the main rule of moving the dew point beyond the inner perimeter of the walls - the outer plaster layer should be twice as thin as the layer inside the room.

Grouting seams and depressions on foam concrete

Surface preparation processes for internal aerated concrete plastering; the video reveals many of the nuances of finishing work:

Applying plaster to the facade

The result of wintering foam concrete without protective finishing

Facade plaster for foam blocks is carried out in the following sequence:

1. Preparation and pre-treatment of the surface of a foam concrete or aerated concrete block. As a primer for aerated concrete under plaster, it is recommended to choose combination compositions based on acrylate siloxane. This composition not only strengthens upper layer, but also hydrophobizes it. The use of such a primer is mandatory; it will prevent capillary diffusion of porous surfaces of foam concrete and aerated concrete and dampening of the walls. The primer should be applied to a completely dry surface at a positive temperature of 10-25°C. Before application, the surface must be dust free.

Foam concrete primer

1. Placement of reinforcing mesh. Although buildings made of porous concrete have insignificant weight of load-bearing structures. The processes of building shrinkage are very active, especially in the first year of operation. To prevent the plaster from cracking, a mounting plaster mesh is attached to the foam concrete and aerated concrete bases. The reinforcement is made with special glass fiber that is resistant to alkalis, this is due to the fact that special solutions have a pH value of about 12.5. An ordinary mesh will completely dissolve in such plaster after 3-5 years, which will lead to its peeling.

Attaching reinforcing mesh to foam concrete blocks

1. Applying plaster. The total thickness of all layers is, if possible, 7-9 mm. On a primed surface it is allowed to apply without preliminary stage spray When using plaster using markers, it is possible to apply up to 1.5 cm in one layer. If the plaster mixture is a multi-finish coating, then the use of finishing can be omitted. Instead, façade plaster for aerated concrete can be painted.

Applying plaster to foam concrete blocks hopper bucket

1. Fastening the outer decorative layer. Protection of external plaster for gas silicate blocks is carried out using the same water repellent or paints that have maximum high elasticity and vapor permeability.

Rules for plastering walls made of aerated concrete with your own hands, video of the process of applying mesh - reinforcement of facade finishing:

Plastering internal partitions and walls

• Surface preparation. Removing beads of adhesive from seams. All chips and cavities are filled with the same glue on which they were laid. gas silicate blocks. The surface is removed from dust - wiped with a slightly damp cloth. Treated with a primer. Sylitool 111 Konzentrat is suitable for this, which must be diluted with water in a ratio of 2:1. The composition must be applied to poorly absorbent surfaces such as foamed gas silicates and other foam concretes with a closed structure.
• Capatect Leichtunterputz 170 can be used as a leveling layer to be applied over beacons. The advantages of this composition are that internal aerated concrete plaster can be applied in a layer of up to 20 mm in one go. With repeated application, the thickness can reach 40 mm. The density of this solution is 1.5 lower than that of standard plasters. Consumption is only 1.25 kg/mm ​​per 1 m 2 of plastered surface.
• Mineralputz, Mineral-Leichtputz and Capatect are suitable for finishing. Finishing internal plaster of aerated concrete walls is carried out in a layer of no more than 0.3-0.5 mm

Rules for plastering walls made of aerated concrete indoors, video sequence of the process using mechanization:

And in conclusion, what happens if you do not adhere to the developed technologies and do not use recommended and proven materials. How not to plaster concrete walls with your own hands, video of an unsuccessful attempt to replace specialized mixtures with cheaper structural paint:

External and internal plastering of walls made of gas silicate blocks has become a widespread type of finishing work thanks to wide application this material in the construction of individual and multi-apartment residential buildings. Gas silicate products provide good thermal protection of premises and significantly reduce the load on the foundation, but the technology of plastering requires knowledge of the purpose and behavior of each component involved in this process. Otherwise, the strength of the coating on the plastered wall will be less than expected.

Subtleties and tasks of gas silicate plaster

Task correct plastering walls is important specifically for gas silicate blocks, because due to their specific structure they have a very high degree of vapor permeability. Saturation of the entire mass of material with water vapor during the season of severe frosts will lead to the destruction of its structure by the expansion of ice crystals.

Reduce the intensity of the process to optimal value, which does not pose such a risk, and the brand of plaster used should establish a comfortable balance of humidity and temperature in the house.

As an example, we can give the characteristics of a typical plaster mixture, summarized in the following table:

On the packaging of its products, the manufacturer indicates recommendations for the possibility of application to certain surfaces. Usually on the front side it is indicated in large print whether the composition is intended for plastering.

Fundamental points

In order to perform its function fully, certain requirements must be met. They are associated with the characteristics of the material, which appear even after it is laid in the wall structure.

Depending on the planned completion dates of all construction work The following points are taken into account:

1. The permissible humidity, which is inherent in gas silicate products at the exit from the production line, is up to 30%. The drying procedure for the entire block takes at least 1 cycle of operation, so after the first winter the blocks tend to develop large or small cracks. Before finishing work begins, the laid out frame of the building is kept, if possible, for about 1.5 years. If such a period is unacceptable, then it is better to first plaster these walls inside the house so that the moisture has the opportunity to evaporate through the outer area accessible to air movement.
2. The appearance of cracks can also be caused by shrinkage of the foundation. Before plastering the walls, you need to let the house sit for 1 - 2 cycles of freezing and thawing of the soil. Otherwise, the cracks in the plaster will go deep into the base material of the walls and cosmetic rubbing will no longer be enough.
3. Air circulation from the outside is ensured by using the operational capabilities of the ventilated façade of the house. Facing with various types of panels (stone, wood, siding) or using well brickwork creates conditions for the constant removal of moisture vapor through a specially left air gap.
4. You should not use moisture-proof extruded polystyrene foam as external insulation. It will retain condensation at the border of contact with the masonry.
5. Problems of high humidity in individual rooms in a residential building should not be solved only by plastering blocks and selecting a composition with exceptional characteristics. In the future, the walls in this room can be additionally protected with moisture resistant tile adhesive or finishing coatings (tiles, waterproof paint or vinyl wallpaper).

One of the options for the appearance of defects on gas silicate blocks 1-2 years after installation is visible in this photo:

The reason for the destruction is that a material such as aerated concrete needs reliable protection from aggressive environmental influences and destructive forces:

• mechanical damage;
• precipitation;
• ultraviolet;
• direct contact with water;
• weathering.

The porous material intensively absorbs water, which, expanding when heated or freezing into ice, breaks the cellular structure.

The means of protection will be waterproofing the base, covering with a layer of plaster (outside and inside the building), and installing external thermal insulation.

Effective operation of gas blocks is largely determined by consistent and quality creation internal vapor barrier made of plaster.

Stages of plastering aerated concrete

Plastering walls made of gas silicate blocks should begin by thoroughly impregnating the entire area of ​​the wall with a special primer. Unlike, which has a closed porous structure, during production the material develops open pores, since fine aluminum chips are added to the base solution as an additive. She is in charge gas generator when reacting with lime present in the liquid mixture.

The purpose of the primer in this case is to close surface pores, prevent active absorption of moisture from plaster mortar(give it sufficient time to harden evenly), ensure high adhesion for strong adhesion to the surface.

Primer impregnation can be applied generously without gaps over the entire wall using a sprayer or roller, as in this photo:

Attempts to replace special compounds by simply spraying with water, as a rule, give poor results in terms of the strength of the resulting plaster - the material absorbs moisture very quickly, and if it is soaked in large quantities water, then he will not give it back.

Reinforcement

To prevent subsequent cracking of the plastered surface, to maintain the integrity of the monolithic seamless solid mass - this is the task facing. IN construction mixtures cement or gypsum base has a pronounced alkaline environment, so fiberglass must be resistant to this category of substances.

When laid, gas silicate blocks form a fairly flat plane, which, if necessary, can be easily further leveled with a float with an abrasive attachment, so the sufficient thickness of the plaster mortar layer is from 2 to 7 mm. A flat mesh is placed in it.

On walls of a large area (height), it may be necessary to level the surface with plaster vertically or horizontally. Then it is advisable to choose a more durable coarse mesh, as in this photo:

A flat mesh is pressed onto a thin (1 mm) layer of plaster or glue, which is covered with another layer of plaster mixture. The total thickness of the resulting coating should not exceed 1 cm.

Advice on how to determine the need to reinforce internal plaster walls made of gas silicate blocks is discussed in this video:

Requirements for plaster application technology

External plastering work on blocks begins only after complete finishing of the wall finishing work from the inside of the house, completion of wet mortar processes for installing floor screeds, plastering, and puttying work.

All moisture evaporating during these operations comes out not so much through ventilation and other openings (drafts are harmful here), but is actively absorbed by the surrounding materials and then tends out through the pores of the gas silicate walls.

If the walls on the facade of the building are plastered prematurely, then the external protection made in the cold season will accumulate at the border of the plaster and aerated concrete, freeze and tear off the plaster layer (shooting, peeling).

The decision on how to plaster gas silicate is made taking into account the following factors:

1. Cement-sand mortar is poorly suited for this purpose for the following reasons: poor adhesion due to rapid loss of water (a primer will not always help); a significant reduction in the vapor permeability of aerated concrete (disturbance of the microclimate inside the house). For exterior finishing, the use of cement-sand mixture prepared according to the usual recipe is simply unacceptable. This leads to a violation of the basic rule - the vapor permeability of a multilayer wall should increase from the inner layer to the outer one or be a comparable value.
2. A solution of dry plaster mixture (for gas silicate blocks) must be prepared strictly according to the manufacturer’s instructions indicated on the product packaging. The mixing container is of sufficient size, maintaining the recommended proportions and water temperature with precision. The amount of added water is strictly metered, since subsequently it is undesirable to dilute a swollen plaster mixture with an overly thick consistency that has been kept for the required time, and a solution that is too thin will drain. It is better to stir evenly until smooth electric drill with a special nozzle.
3. In addition to strength, for external plasters you should pay attention to frost resistance and elasticity. Changes in external temperatures create the preconditions for the appearance of cracks in monoliths that are too rigid. We should not forget about the flammability class of the material - fire resistance is an important indicator of home safety.

Approximate consumption necessary materials and approximate prices for determining the budget structure are given in the table:

The approach to plastering gas silicate blocks inside is simpler - for this purpose there is a wide range of gypsum compositions for interior work, which do not need to resist weather conditions.

You should not abandon the procedure of plastering the room from the inside, limiting yourself to making a thin coating of one putty. The effort expended should form a complete wall covering.

Saving through cheap materials or their quantity often leads to bad consequences. We can confidently say that it’s usually not a matter of bad building materials, but in their incorrect use. If there is a need to plaster gas silicate blocks of external walls, then this must be done using only materials specially designed for such types of work.

Internal and external aerated concrete plaster must have optimal parameters, protecting the walls of the structure from destruction and cracks under the influence of external influences. There are several basic options for finishing mixtures that will improve and maintain the quality of the base. The correct application technology will ensure a long service life and decorative appearance of the coating.

Aerated concrete has good thermal insulation properties and a high degree of vapor permeability due to the porous structure. Proper finishing of aerated concrete will help preserve the quality of the material, preventing the accumulation of condensation and the occurrence of mold.

In this article we will answer the main question, how to plaster aerated concrete outside and inside the house.

Aerated concrete blocks

Basic requirements for plaster

It is worth noting right away that it is not recommended to apply ordinary plaster to a house made of aerated concrete blocks. First of all, because standard sand solutions are characterized by high density, this leads to poor adhesion when applied to a gas block and the rapid appearance of cracks.

Adhesion(from Latin adhaesio - adhesion) in physics - adhesion of the surfaces of dissimilar solid and/or liquid bodies.

The plaster should maintain an optimal microclimate inside the building, protecting the walls from moisture. Therefore, you should choose mixtures with a vapor-permeable base. Otherwise, the steam coming out of the house will get stuck inside the walls, since the plaster will simply block its exit to the outside. Thus, moisture will begin to accumulate in the walls, which will ultimately lead to their destruction. Of course, nothing will happen to the house in a few years, but in six to eight years, an almost irreversible process of destruction will begin.

Plaster for aerated concrete should be:

• resistant to external weather influences;
• have good adhesion (adhesion to aerated concrete);
• resistant to sudden temperature changes;
• high degree of compressive strength (protection against cracking);
• vapor permeable;
• moderately dense;
• improving the thermal insulation of walls;
• have a decorative appearance.

When choosing plaster for aerated concrete, you should not ignore any of the points listed above.

Applying plaster to a house made of aerated concrete blocks

The absence of facade finishing of aerated concrete structures will lead to darkening, deformation, and peeling of the surfaces of the blocks.

Types of plasters suitable for aerated concrete blocks

The choice of plaster mixture for aerated concrete primarily depends on whether you are going to cladding the walls from the outside or from the inside. Based on the type of application, plasters are divided into external and internal.

As you understand, external plaster is intended for finishing facades. Because here she performs protective functions, its strength, moisture resistance and thermal insulation indicators should be higher.

Internal mixtures are intended for finishing indoor walls, so the presence of moisture resistance in the characteristics of these plasters can be ignored, with the exception of cases of wall cladding in the bathroom. Due to the lack of resistance to moisture, internal mixtures are much cheaper than external ones.

Applying a finishing layer of plaster to aerated concrete

Popular plasters for aerated concrete

Mixtures for finishing facades made of aerated blocks are divided according to the type of composition into:

• lime-cement;
• acrylic;
• silicate;
• silicone.

Lime-cement mortars quite durable and at the same time vapor-permeable, because their main component is lime, which replaces sand. Eliminate low level water resistance, elasticity and limited selection color palette material can be made using various additives. Modern ready-made mixtures contain special fillers that improve the properties of the coating.

Acrylic It is advisable to finish a building made of aerated concrete only if there is high-quality internal insulation of the walls. Such plaster cannot boast of good vapor permeability, but in quality decorative finishing, it is durable and reliable.

Silicate plaster for aerated concrete is produced on the basis of liquid potassium glass. The coating has good moisture resistance, vapor permeability and durability. The silicate solution is easy to apply. The finishing layer is resistant to dirt and abrasion, providing decorative effect finishing coating for a long period (more than 25 years). The problem with silicates is the limited choice of colors.

Leveling walls with silicate plaster

Silicone mixtures contain resins and organosilicon polymers. Qualitative characteristics materials are optimal for creating a durable coating. Silicone-type plaster retains elasticity after application, which ensures the absence of cracks on the surface even when the blocks shrink. It is important to note the special decorativeness of the finishing; thanks to special fillers and color variations, you can give the facade an original look.

Silicone plaster can undoubtedly be called a leader among others; it has all the advantages of silicate compounds, moreover, it is durable and looks great. But the price of silicone mixtures is much higher than others.

On our website you can find contacts of construction companies that offer the service of designing houses made of aerated concrete. You can communicate directly with representatives by visiting the “Low-Rise Country” exhibition of houses.

Most popular manufacturers

The building materials market is saturated with a huge number of plaster mixtures various brands for finishing aerated concrete surfaces. Popular formulations have optimal characteristics for carrying out work.

Applying plaster to interior walls houses made of aerated blocks

Ceresit CT 24. The mineral composition of the mixture gives the solution plasticity. The material is easy to apply. The coating can withstand up to 100 cycles of low temperature influences. It is recommended to paint after completely dry(after seven days).

CERESIT ST 77. The acrylic type of the mixture is used for facade finishing, ensuring the strength of the coating with a fairly thin layer of application. The material is frost-resistant and resistant to external influences. Used when there is waterproofing and ventilation inside the house.

Founded by Startwell T-21. Cement-lime plaster is frost-resistant and has a sufficient level of adhesion. The resulting coating is resistant to shrinkage and moisture.

Video description

Watch the video comparison of facade plasters for aerated concrete:

Baumit Silicone Top. A high level of adhesion and ductility is achieved thanks to the base of the mixture - silicone resins. The coating remains decorative for a long time due to its dirt-repellent properties. Wide choose palette of paints of the material (up to two hundred shades).

Weber.pas silicone. Mixture based on silicone emulsion. It is possible to select the appropriate grain size. Optimal resistance of the material to moisture, temperature, and dirt.

Baumit Silikat Top. Silicate type of plaster. The coating is durable and has good vapor permeability. The composition has different grain sizes and up to two hundred tinting variations.

Priming the surface before plastering

Internal plaster of aerated concrete walls

Internal work on plastering walls made of aerated blocks is carried out with gypsum solutions with various additives. Composites in the form of perlite, marble chips will increase the decorative effect of the finish. There is the possibility of painting the composition in various colors.

Gypsum mixtures without additives have the required level of vapor permeability, which allows the plaster to be used as a base for wallpapering. Standard sequence of work:

• elimination of irregularities and chips on the surface of the walls;
• removing dust and applying the first layer of solution;
• installation of reinforcing mesh;
• applying the second layer.

After complete drying, you can glue wallpaper, paint the walls, or apply a third, decorative layer of plaster.

Interior work is carried out only subject to the preliminary application of a waterproofing compound and priming.

Interior plaster walls

External plastering of aerated concrete walls

Plaster for aerated concrete facade view can be applied when using various technologies: thick-layer or thin-layer finishing. The sequence of work includes:

• mandatory preparation of wall surfaces, leveling;
• priming (compositions based on acrylate siloxane);
• applying a thin layer of solution - the basis for attaching the mesh;
• reinforcement (protection against cracks);
• leveling the finishing layer;
• second layer of coating (formation of a smooth, even surface);
• finishing layer of plaster, grout.

A year after completion of the facing work, it is recommended to apply a water-repellent solution. Thanks to the treatment of the facade with this composition, the moisture-proof and water-repellent properties of the coating are increased.

Features of plastering walls made of aerated blocks

Proper execution of the work must take into account the characteristics of the material of construction. Aerated concrete blocks may have differences in structure. Sawn options have an open, pronounced cellular structure and do not require special preparation for finishing.

The formed blocks are covered with a hydrophobic layer with a buried pore structure and require additional processing. Grinding the surfaces with a wire brush will help improve the adhesive properties of the material.

Video description

Watch the video of the process of applying plaster to a house made of aerated concrete:

It is also important to remember the rule of increasing the degree of vapor permeability from the inner layer to the outer surface. Facade finishing should be twice as thin as the inner coating.

It is strictly not recommended to carry out plastering work on aerated block surfaces earlier than 6 months after the construction of the walls. The structure must dry completely, getting rid of excess moisture accumulated during laying of the material.

Plastering on reinforcing mesh

Optimal conditions for applying plaster

External plastering of aerated concrete must be carried out under certain conditions. It is important to complete first interior work increased humidity levels. The load-bearing structures of walls made of aerated blocks must be completely dry, not exceeding 27%. Otherwise high humidity will provoke adhesion failure and lead to peeling of the finishing layer of the facade.

The optimal time for finishing the interior of the house is spring, the façade of the building is the end of summer.

External temperature conditions for work must correspond to +5-+30°C, with air humidity not exceeding 80%. If it is necessary to perform finishing at low temperatures temperature indicators, it is recommended to use a special deep penetration primer before the onset of acceptable weather conditions.

Carrying out the work correctly will help avoid peeling, cracks and defects. It is forbidden to apply the coating in hot weather, under direct sunlight and in windy weather.

Plastered facade of aerated concrete house

Conclusion

Choosing a high-quality solution for plastering aerated concrete structures will help improve the performance characteristics of the material and create strong and durable surface protection.

The article popularly talks about widely used building materials, lightweight concrete, main characteristics and finishing methods using traditional technologies, plastering house elements.

Plastering aerated concrete walls

Plastering interior and exterior structures made of lightweight concrete is the most commonly used method of protecting against the effects of external climatic conditions and giving the house an original, respectable appearance, as well as internal comfort.

The prevalence of the technology is due to the ability to inexpensively and independently carry out a set of works on the preparation and finishing of structures and achieve the desired results.

Special characteristics of aerated concrete blocks

Aerated concrete belongs to cellular concrete, consists of quicklime, cement, sand and gas-forming aluminum powder. When mixing components and water, a reaction occurs with the release of gas, forming voids, the number of which determines the weight, density, thermal conductivity of concrete and areas of use:

• Concrete with a density of 300-400 (kg/m3) is used for thermal insulation.
• Density 500-900 (kg/m3) allows it to be used for constructing partitions and walls.
• With a density of 1000-1200 kg/m3, concrete is used to make load-bearing walls.

Concrete has gained popularity in housing construction due to its properties:

1. Low thermal conductivity allows it to be used as a heat-insulating substance.
2. Frost resistance can reach 150 cycles; among lightweight concrete, only expanded clay concrete has greater durability.
3. High fire resistance.

One of the negative qualities for construction is hygroscopicity, which means that aerated concrete needs a coating.

The hygroscopicity of aerated concrete requires isolation from moisture.

Preparing gas silicate blocks indoors for plastering

In aerated concrete the amount of cement is up to 60 percent, in gas silicate concrete no more than 14, lime is twice as much, the rest is sand. The percentage matters because the more cement, the higher the strength, and the base must be stronger than the coating, otherwise it will peel off. That is, the finishing of the house must be done with a lime-cement composition.

When finishing, you need to remember that the base must be stronger than the coating.

The main function of plastering surfaces made of gas silicate blocks is to form a vapor-impermeable barrier and limit moisture absorption. To improve the adhesion of the coating to the base, the structural elements are coated with a deep penetration primer, the first layer is applied generously, preferably with a spray gun, after drying it must be painted over again.

After priming, given that the gas silicate composition of the base is weak, it is necessary to carry out reinforcement to prevent the appearance of cracks.

The rough layer of reinforcement is made from glue on which the blocks were laid, experienced craftsmen They use tile adhesive for this as a cheaper composition.

Using glue instead of regular mortar is associated with polymer additives in a composition that ensures strong adhesion with a thin layer of the mixture.

After applying a thin layer of glue, 2-7 millimeters thick, a fiberglass mesh is embedded into it, which fixes the blocks and serves as a reliable base for the coating. The mesh is overlapped over the applied glue and pressed in with a notched spatula.

It is advisable to start applying the solution after 5-7 days, when the reinforced layer gains strength.

Plastering gas silicate blocks inside a building: technologies used

Protection of gas silicate structures occurs in three stages:

1.Plastering with lime-cement mortar.

2.Priming.

3. Putty.

A lime-cement or lime-gypsum mortar no more than one centimeter thick is applied to the reinforced surface.

Technology hand plastering ordinary, if the wall is large and uneven, install beacons and level the applied layer using a broad rule.

The solution is mixed in a bucket, small tank or trough, water is poured into the poured mixture and stirred to the required consistency, you need to cook a little, gypsum sets in 20 minutes, cement needs a little more time, so the amount should be sufficient to be processed during this time. You can level it immediately after throwing it on, the last stage is grout.

After finishing, use a long strip to check the evenness of the surface; unevenness within 5-7 millimeters will not be noticeable.

Is it necessary to plaster the aerated concrete block from the outside?

The need to protect the façade made of aerated concrete is due to its properties:

1. Hygroscopicity will lead to the saturation of gas blocks with water, which in frost will cause destruction of the structure.
2. Mechanical impact will cause chips, dents, and cracks.
3. The material has a porous structure with open pores through which circulating air carries away heat.
4. Rough aerated concrete house looks unpresentable.

For aerated concrete structures, the danger is the accumulation of moisture inside the blocks, which freezes and destroys the block from the inside due to temperature changes. Therefore protection external surfaces mandatory, the method of protection by plastering is widely used for various reasons, one of which is the low cost of this technology.

Materials used for exterior work

For application protective equipment externally, substances with the following qualities are needed:

• permeable to water vapor;
• not getting wet;
• with good grip;
• resistant to frost.

The main types of mixtures for finishing aerated concrete outside:

• Acrylic for aerated concrete, strengthens loaded structures, base.
• Silicate, include liquid glass;
• Silicone, based on silicon-organic polymers, is well suited for facades, but high in price;
• Gypsum mixture;
• Lime-cement composition.

Do-it-yourself internal plaster of aerated concrete block: features of the work

Due to the high hygroscopicity of the material, plastering inside the house has its own characteristics.

Plastering surfaces must necessarily include a reinforcement process. It is recommended to use fiberglass mesh, which does not break down in an alkaline environment.

The surface should be painted with a deep penetration primer twice.

Apply thin layer plaster about 5 millimeters thick and drown the mesh in it. After drying, apply the base coat using beacons.

Which is better plaster

If vapor permeability is required for the kitchen, bathroom or sauna, mixtures of gypsum with perlite sand are used. Silicate is also suitable, but it must be taken into account that such mixtures are incompatible with acrylic, silicone, and latex materials.

For use on aerated concrete, you can use cement-lime mixtures, which do not require priming the walls.

Set of tools

Finishing aerated concrete surfaces requires the following tools:

1. Spatulas.
2. Scraper to remove dirt and debris.
3. Metal brushes.
4. Hammer for knocking down irregularities and protruding mortar.
5. Sandpaper.
6. Brushes, rollers for priming.
7. Master OK.
8. Tank for mixing the solution.
9. Mixer for preparing the solution.
10. Falcon, shield where the mixture is applied.
11. Grout grater.
12. Poluterok.
13. The rule is to align the corners.

How to plaster: progress of work

Ready-made mixtures are excellent for finishing, but have a high cost, so for do-it-yourself wall preparation technology is proposed, after which you can safely use any composition.

For preparation you will need tile adhesive, fiberglass mesh, and deep penetration primer. It is necessary to smooth out all chips and cracks with a compound for laying aerated concrete blocks, then remove dust and debris from the wall with a cheek and paint it with a deep penetration primer twice.

Tile adhesive is diluted and applied to the surface with a thickness of 5 millimeters, the mesh is pressed on top with a notched trowel. When the layer is completely dry, apply plaster in the usual way, any solution can be used.

The costs of this technology will be an order of magnitude less than when using ready-made plasters.

How long before you can move on to the next stages of wall finishing?

After completion, the beacons are removed, and the resulting dents are subsequently sealed with putty.

To move on to the next types of finishing, you must wait until the walls are completely dry at a constant temperature. Drying will require about a month in the warm season to ensure that temperature changes do not lead to cracking or peeling. It is not advisable to speed up the process; if necessary, a heater is used.

Internal and external finishing home is an important stage of construction work, the quality of which determines the durability, comfort of living and aesthetic appearance of the house. There are many modern materials and technologies available for finishing work, but traditional methods do not lose popularity and are still relevant today. These methods allow you to achieve the necessary results at low cost and labor intensity.

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