Plaster mix for aerated concrete. Plastering aerated concrete walls indoors

Aerated concrete, as a material, appeared about a hundred years ago. However, in our construction market, in mass access, aerated concrete was introduced much later.

It is a lighter and more convenient material to process, from which you can assemble load-bearing structures and engage in the construction of low-rise buildings.

However, aerated concrete has several features that should be taken into account during its processing. In particular, this concerns the choice of material that will be used for plastering aerated concrete walls. Below we will understand in more detail how to plaster aerated concrete and all the nuances of such work.

Features and purpose

First, let's figure out what aerated concrete really is. In its structure, aerated concrete is very similar to standard concrete. It is poured in the same way using a binder, filler and water.

However, the pouring technology is slightly different due to the fact that aluminum powder or powder is also added to the mixture. When reacted with water, aluminum begins to release an excess amount of carbon dioxide, which fills the entire mold cavity and makes the solution bubble.

As a result, the concrete solidifies, having inside many small cells ranging in size from 1 to 3 mm. When the technology for creating a gas block for the house was invented, everyone thought that in all respects it would defeat ordinary concrete and become more popular for work, taking over the entire building materials market.

However, such thoughts were premature. Of course, if you compare what type of material better in terms of ease or convenience in processing, then aerated concrete will win. It is better finished and processed, as it has a specific structure. It is also worth understanding that correctly created aerated concrete will better withstand temperature drawdowns.

And it is also well characterized by a vapor-permeable structure. That is, concrete essentially forms breathable walls. Unlike ordinary cement mortar, which is no different in these parameters.

But aerated concrete also has its drawbacks. In particular, it is an indicator of strength. If we make a comparison solely on this indicator, then already standard concrete will win here.

The construction technology makes it possible to erect buildings of any height from it, while in most cases it is allowed to build buildings up to 10 meters high from aerated concrete. Of course, he will probably withstand 4 or 5-storey buildings, but it's better not to risk it.

Also, aerated concrete absorbs moisture more strongly. Moreover, when holding it, negative processes begin inside the block. This affects the composition of the mixture that the aerated concrete plaster should have.

The surface of the gas block, from which houses are assembled, also has an effect. The fact is that initially it has rather weak adhesion to individual solutions. Thin-layer gypsum plaster of aerated concrete walls, if you do not select special-purpose mixtures, can generally collapse in a matter of months. Well, or it can crack well, which is also unacceptable.

From this it follows that mixtures for performing plastering work on aerated concrete must be special and meet several requirements at once.

1.1 Requirements for plaster

So, aerated concrete plaster should be slightly different from the standard one. Moreover, we immediately notice that it is completely forbidden to use ordinary plaster when decorating a house from aerated concrete.

This is explained by the fact that standard sand solutions are too dense. They do not fit well on such surfaces and quickly crack. Their even more unacceptable property is low vapor permeability or its absence. This leads to rather negative consequences.

If you plaster standard concrete or brick houses, then no problems arise. But home from gas block Ytong - this is a completely different conversation.

Here, in the race of popularity, plaster with a vapor-permeable base will definitely win. Otherwise, steam that escapes from the house will be blocked by a layer of decoration from the outside, and get stuck inside the walls. The dew point in the house will move towards their center, which will lead to the accumulation of moisture.

Nothing terrible will happen in one year. It won't happen in a couple of years. But 5 years of such operation can already lead to the beginning of the process of destruction of the supporting structures of the house.

Now let's note the specific requirements that the plaster on the gas block must satisfy. She must be:

1. Vapor permeable.
2. Moderately dense.
3. Protect the wall from external influences.
4. Moisture resistant.
5. Improve wall insulation.
6. It is good to lie down on aerated concrete.
7. Be easy to handle.

As you can see, there is nothing extraordinary in such a list, but it is better not to ignore any of these indicators.

2 Types and differences

Now let's turn to the main types of plasters for aerated concrete blocks. If you are going to make your choice correctly, then you will have to figure out which mixtures are best for which jobs. Fortunately, there are no major differences in most cases.

Plaster can be used by type of application:

• outdoor;
• internal.

External plaster, as you yourself understand, is intended for facades. Outside the house, it must perform protective functions, therefore, the mixture is characterized by higher strength, water resistance and improved thermal insulation. The cost of compositions for finishing gas blocks from the outside will also be higher.

Indoor samples are intended for indoor work. They no longer need water-repellent properties, unless we mean the mixtures that are intended for finishing the bathroom.

This naturally lowers their cost. However, if we compare the plaster by the main parameters, then, of course, the first option will win.

2.1 Popular plasters

By the type of composition, they are divided into:

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

In the first version, lime is the main element. It replaces the sandy mortar, making the final composition of the mixture quite durable, but at the same time with the possibility of vapor permeability.

Acrylic plaster will win if you need to choose a composition for decorative finishes. It is the most durable and reliable, capable of forming an extremely tenacious finished surface.

The problem with acrylic is its poor vapor permeability. Outside the house, such mixtures can be used only after thorough work on the insulation of the walls from the inside of the building. Inside, the plaster is not so dangerous, but it will prevent the passage of vapors through the walls, and hence the self-regulation of the microclimate in the room.

Silicate formulations are much better than the first two. If you apply them correctly, then you will not have any problems in your work. They are vapor permeable, have a high density and are easy to process. The problem with silicates is quite small selection of color rates and dust settling on the plaster layer, which does not in the best way affect its appearance.

As for silicone samples, they are the undisputed leaders when it comes to the specific qualities of plaster mixes. They have all the advantages of silicate compounds, but at the same time they are very durable and look great. The only drawback, as you probably guessed yourself, is the high price.

The choice of plaster must be approached with great responsibility. It is the choice that influences what results you get in the end. Remember to always find a trade-off between cost and performance. But at the same time, it is better not to go too far by buying the cheapest option.

If you are going to finish the walls inside the house, then in a pinch, ordinary lime-cement compositions are also suitable. Of course, in terms of their characteristics, they will be inferior to all others, but the interior decoration does not require anything extraordinary from the plaster mixture. And you will save a decent amount.

Acrylic renders are best used only for decorative interior or exterior decoration. Moreover, if you are going to use it outside, then here you already need to take care of high-quality vapor barrier inside the house, as well as the arrangement of normally functioning ventilation.

Silicate compounds are perfect for any type of work, but after plastering, they must be finished with another layer of putty in order to neutralize the problem with flowers and dust emission.

It's even easier with silicones. It is difficult to name a method of their application that would be considered unacceptable. In any situation, such mixtures will perfectly fulfill their purpose. The only barrier is price. It's up to you to decide.

As for specific manufacturers, the most popular at the moment are Profit, Ceresit Atlas, etc. Their products are particularly well known in the market:

• Ceresit CT 24;
• ATLAS KB-TYNK;
• Profit Contact MN;
• Sh-36 Decor.

2.3 Technology of wall decoration from aerated block

As an acceptable and simplest technology for plastering walls, we choose work with the help of lighthouses.

Lighthouses were still used by our grandfathers, although they adapted wooden planks for these purposes, and not small aluminum profiles. However, this technology has proven itself from the best side, and for a reason.

Before starting work, it is necessary to prime the walls from the gas block. For this, special primers are used, which can already by themselves slightly reduce the water absorption of the material, improve its thermal insulation properties and adhesion.

Then you can apply beacons. The lighthouses are mounted on small bubbles of solution. They are laid in increments of 1-1.5 meters. Each lighthouse is exposed to its own level, and the next lighthouse.

Aerated concrete is a modern building material that resembles foam concrete in structure, but differs in air bubbles located inside. The hollow structure of aerated concrete absorbs moisture well, which requires external finishing of the material. The better to plaster the walls of aerated concrete is discussed in the proposed article.

For the manufacture of material are used:

• quartz sand - the basis of the mixture;
• lime;
• cement;
• water;
• aluminum powder is added during the manufacturing process of the material. It acts as the main blowing agent and gives the material a specific structure.

Advice: When purchasing aerated concrete, it must be borne in mind that the pores of the blocks, unlike foam concrete, are open. This determines the features of its application and decoration.

Comparative characteristics of foam concrete and aerated concrete are presented in the table:

Foam concrete	Aerated concrete
In its structure, air bubbles do not connect to each other, which increases the resistance of the material to wetting.	Air bubbles are interconnected, which allows moisture to move freely through them.
Good qualities of frost resistance and thermal conductivity.	Gives off warmth and freezes from frost.
The inner layer of the plaster layer should be twice as thick as the outer	The walls should be plastered indoors and then on the facade of the building.
To improve adhesion, the walls must be sanded, then thoroughly sanded to remove the upper hydrophobized layer. Due to poor moisture absorption, to increase adhesion, a spray of solution is done, and then a base coat is applied.	Higher adhesion rates

When plastering the outer surfaces of aerated concrete, its high hygroscopicity must be taken into account.

This requires the use of non-standard plasters, which over time will not lead to:

• Cracking of the internal and external surfaces of the building, as in the photo.

• Manifestation of traces from masonry after fog or rain, which impairs the visual parameters of the walls.
• Changes in technical characteristics.

• An increase in indoor humidity.
• The appearance of mold in the corners of rooms.

For finishing external surfaces, special facade plasters are used. A special danger for aerated concrete slabs is temperature drops and high frosts.

During operation, a certain amount of liquid begins to accumulate inside the structures, which will expand when freezing and can greatly harm the structures of the structure. Plastering aerated concrete bases is possible only with mixtures that have good water-repellent properties that do not prevent moisture from evaporating from the walls.

For exterior finishing of aerated concrete, the plaster must have:

• Good adhesion parameters.
• High compressive strength.
• Frost resistance.

Tip: Owners of buildings made of aerated concrete blocks need to take into account that external wall decoration is carried out only after all internal facing work. Otherwise, when carrying out "wet" interior finishing work, the walls will absorb a significant amount of moisture, which will subsequently evaporate.

If the external facade is finished before applying the internal plaster, with its intensive evaporation, the external plaster layer will peel off from the surface of the aerated concrete. After the interior decoration of the room, you can revet the walls of the house from the outside with special compounds with the highest vapor permeability.

Advice: Facades cannot be plastered using standard cement-sand mixtures due to their insufficiently high vapor permeability properties.

Plaster for aerated concrete

For wall decoration, a vapor-permeable plaster for aerated concrete is used, which is well permeable to water vapor, does not get wet, with good adhesion to the surface of the blocks and high frost resistance.

Plaster type	Material features
	Acrylic aerated concrete plasters are used to reinforce structures with increased stress, such as a plinth. They are used for interior and exterior decoration of the house. Used for decorative coating. They keep their color and invariable texture for a long time. They have good adhesion. Disadvantages of the material: Not too high vapor permeability. Burning. Tip: When choosing such a material, you must first waterproof the walls.
	The basis of the composition is liquid glass. It is a breathable aerated concrete plaster. Has a low water absorption. Acceptable price. There are many textures that can be: scratches, roughness, pits. They are used for plastering facades and internal walls made of aerated concrete, on the material itself and insulating elements for it. Disadvantages: a small choice of colors, loss of appearance, due to the deposition of dust and dirt on the surfaces of the walls.
	Silicone plaster for aerated concrete is made on the basis of organic silicon polymers. Possesses great resistance to harmful atmospheric influences. Practically does not get wet, the mixture is hydrophobic. Has a high vapor permeability. Easy to apply. Such plaster mixes for aerated concrete do not lose their pleasant appearance for a long time. Disadvantage: high cost, but over time, it is likely to pay off. In this case, it is appropriate to remember that the miser pays twice.
	Composition advantages: Dries quickly. Does not shrink. You can make a smooth surface. No need to apply a top coat. Disadvantages of gypsum plaster: Not very good vapor permeability. It gets wet quickly in rain or snow. Spots appear on the surface that need to be painted over.

Lime-cement plaster

All the necessary properties are inherent in lightweight thin-layer plasters, specially created for finishing aerated concrete surfaces. An example of such a plaster can be - Baumit HandPutz for wall decoration with your own hands, produced in bags weighing 25 kilograms.

Its main physical properties are shown in the table:

Indicator name	Its meaning
Granularity, mm	1
Material bending strength, tensile, N / mm2	≥0,5
Compressive strength of the composition, N / mm²	≥3,5
Vapor permeation resistance coefficient μ,	15
Thermal conductivity coefficient λ, W / mK	0,8
Density of the mixture in dry form, kg / m³	1600
Liquid consumption, liter / bag	6-7
Consumption of the mixture (with a thickness of the applied layer of 1 cm), kg / m2	15
Minimum plaster layer, mm	5
Maximum plaster layer, mm	20

Advice: Before plastering aerated concrete with this plaster, it is necessary to spray the previously cleaned wall surface with Baumit Vorspritze mortar.

Material selection

To choose which plaster is better to plaster the walls of aerated concrete, you need to purchase a plaster composition that meets the characteristics:

• good vapor permeability;
• the optimal volume of liquid for mixing the mixture: for one kilogram of the mixture - no more than 0.2 liters of water;
• certain values ​​of the minimum and maximum thickness of plastering;
• good adhesion to the base of at least 0.5 MPa;
• resistance to negative temperatures;
• high resistance to cracking;
• long pot life of the mixture, the greater it is, the easier it is to work with the solution, especially for beginners.

The procedure for plastering walls from aerated concrete

Before starting work, it is better to get acquainted with the video in this article.

Tip: Aerated concrete building blocks are fairly flat with almost invisible seams. It is not necessary to use plaster mortars for leveling surfaces. It is enough to apply only a thin layer of the mixture.

The instruction for plastering walls suggests the following procedure for carrying out work:

• Surface priming. A compound specially designed for aerated concrete, the surface of which actively absorbs moisture, is applied with a brush or roller.

• A reinforcing mesh is mounted, which is attached to the surface with self-tapping screws (see How to attach a plaster mesh to a wall).

• The walls are finished with a thin layer of plaster.

Correctly selected plaster mixes for aerated concrete blocks allow you to make your home not only beautiful, but also warm, retaining all its positive characteristics for a long time.

But it differs from them in the composition of the air bubbles inside.

Aerated concrete blocks are made of cement with a mass fraction of at least 50%.

Aerated concrete walls need external and internal finishing due to their porosity and high level of moisture absorption.

Features of aerated concrete

This building material has a cellular structure, which gives it special properties:

• good thermal insulation - in terms of characteristics, aerated concrete is comparable to wood;
• low mechanical stability, which leads to the appearance of cracks and chips over time;
• the porous material is blown through by air currents, which is why houses made of it without finishing are considered rather cold;
• unaesthetic appearance;
• high absorbency leads to corrosion of the material in winter, during frost.

The special structure of aerated concrete blocks requires careful processing with finishing materials to improve its quality characteristics. External plastering is carried out using special solutions that are selected for specific environmental conditions. Correct plastering of aerated concrete walls provides reliable protection of the base and its durability, and also allows you to give a more aesthetic appearance to the room.

How and with what to plaster aerated concrete indoors?

Regardless of the choice of the type of plaster, you need to start finishing work indoors. Changing the order and plastering the facade of the building will lead to excess moisture in the room. The fact is that when steam leaves the room, especially in winter, condensation accumulates between the blocks and the finish, creating places with excess moisture. This is the main cause of surface cracks and plaster shedding. To avoid such troubles, you should first tackle the plastering of the walls from aerated blocks inside the room. Experienced craftsmen distinguish two types of technology for plastering aerated concrete walls in a house:

• providing complete vapor barrier;
• preservation and increase of vapor permeability of the material.

The main element of aerated concrete plastering using the first technology is polyethylene film. It is fixed between the layers of mortar, and the vapor permeability of the walls decreases several times. Also, oil paints are used for vapor barrier, which are applied as a finish, and the base is primed with special compounds.

Dependence of inside plastering technology on external finishing

To accurately determine the approach to internal work, you need to decide on the external plastering. Plastering of aerated concrete walls outside the room affects the method and sequence of actions for finishing the room:

1. When the outer wall already has some kind of coating or is insulated with dense and vapor-proof materials, then moisture will accumulate in the walls. In this situation, interior decoration is carried out using materials with low vapor permeability. You also need to take care of a reliable ventilation system so that moisture does not accumulate in the corners of the room and on the windows.
2. When the aerated concrete facade is not covered with anything, or is treated with porous insulation, for example, mineral wool, then its vapor permeability is not disturbed. In this case, you must first carry out work on the interior decoration of the room, and then move on to the outside.

Preparation of the base

The technology of plastering walls made of aerated concrete practically does not differ from work with any other surface. First of all, you need to make sure that the walls are even, and if this is not the case, grind them with a plane or a grater for aerated concrete. Many craftsmen skip this stage, but as a result, the costs of plaster increase, which is also used to level defects. Before applying the primer, aerated concrete walls are moistened with water. For drier rooms, it is recommended to choose a universal composition, and for the kitchen and bathroom - a deep penetration soil. \

Construction beacons are mounted on the dried surface, which will serve as a guide for the successful plastering of the room. After installing the lighthouses, the internal plaster of the walls made of aerated concrete will lie flat, and the work will move faster.

The technology of finishing the facade of the building is somewhat different in standards. First, the walls are cleaned of dust and leveled. Crevices and cracks are filled with special aerated concrete glue. After drying, it is necessary to apply a layer of primer for cellular materials. An important stage in the preparatory work for plastering the facades of buildings made of aerated concrete is to reinforce the surface with a mesh. When choosing the type of reinforcing mesh, it is necessary to pay attention to the fact that under the influence of an alkaline environment, the material from which it is made can dissolve. Experts recommend choosing fiberglass types.

Aerated concrete plaster (video)

How to plaster aerated concrete surfaces

In order for the repair of an aerated concrete house to serve for many years, it is necessary to correctly approach the choice of material for decorating the walls inside and outside. Masters distinguish as many as four options for processing walls made of cellular material:

1. Gypsum plaster.
2. Cement-sand mortar.
3. Facade mixtures.
4. Drywall.

The last option is the so-called dry plaster. What is better drywall or plaster on aerated concrete walls is a controversial issue. Plastering a surface is a costly and time-consuming process. Working with gypsum board takes less time and, as a result, smooth walls are obtained. Procedure:

• vapor barrier of surfaces using polyethylene film, membrane or glassine;
• installation of the lathing for fastening the gypsum board;
• fastening drywall to the frame;
• putty of joints between sheets using serpyanka tape.

Any kind of decorative finish can be applied to the aerated concrete wall leveled in this way. What plaster is better to plaster aerated concrete walls? To answer this question, it is necessary to know the specifics of the solutions and their interaction with the base material.

Disadvantages of different types of plasters

Name	Flaws
Cement	Low level of adhesion in relation to the gas block
	High moisture content
	The vapor permeability index is lower than that of the aerated block, therefore, the cement mortar can only be used when used for interior decoration of vapor-impermeable materials (plastic film, etc.)
Gypsum	Gains moisture during snow and rain
	Stains on the plaster
	Low vapor permeability
Facade	The only drawback of this type of plasters is their high cost.

Gypsum plaster

The main advantages of a gypsum solution for treating aerated concrete walls include:

• fast drying;
• high rate of adhesion level;
• there is no need to apply an additional smooth layer;
• the possibility of leveling the plaster for finishing.

Knauf Rotband, Bonolit and Pobedit Velvet are popular among the masters.

Cement-sand plaster

If this option was nevertheless chosen for finishing aerated concrete walls, then there are several ways to improve the composition for better interaction with the base. Adhesion can be increased by adding more cement mortar to the standard mixture recipe (for 100 kg of concrete, 8-10 kg of lime will be needed). The second option, which is acceptable, but still not recommended by the masters, is to add a mixture for processing aerated concrete to the cement-sand plaster (ratio 1: 1). Among the leaders in sales of mixtures of this type are solutions of the Baumit brand and the domestic Craps Extra-light.

Facade solutions

This type of mixture, in the case of aerated concrete, is suitable for both indoor and outdoor use. The main positive points in working with special plasters for aerated concrete:

• high adhesion rate;
• resistance to deformation and cracking;
• vapor permeability is equal to that of aerated concrete;
• nice view;
• does not require additional finishing work.

Plastering walls on aerated concrete with your own hands is demonstrated in the video below. With a competent approach to work and the study of materials, even a novice master will cope with plastering a house from aerated concrete blocks.

The construction of houses from gas silicate blocks is one of the most promising areas in the field of private construction. In particular, aerated concrete blocks have become very popular, during the production of which special additives are introduced into the composition of the solution, causing abundant gas formation. As a result, aerated concrete has a pronounced open porous structure, which determines its significant advantages over other materials for masonry walls.

However, such a structure of aerated concrete also brings a number of difficulties in finishing the erected walls. This requires a special approach, both in terms of the sequence of work and the materials used. In addition, the plastering of aerated concrete walls inside the premises will also depend on their planned exterior finish.

What is the "capriciousness" of aerated concrete in terms of finishing, and what methods can be used to solve these problems - this publication is devoted to these issues.

Features of aerated concrete

But on the materials for the work, you should go through in more detail.

• The open porous structure of aerated concrete will not allow you to limit yourself only to filling the walls - a thin layer simply will not stay on such a surface. Therefore, even if the wall is laid out with the highest accuracy and does not require special adjustments to its plane, you still cannot do without plaster. And on the aerated concrete wall you will have to "throw" a layer of at least 5 mm.
• Such a layer will be susceptible to cracking and shedding (the adhesive features of a highly porous structure are affected) if it is not reinforced with a reinforcing mesh. If on other wall materials the use of a reinforcing mesh is desirable, then in the case of aerated concrete this condition should be considered as mandatory. The mesh is best of all - fiberglass, resistant to an alkaline environment, so that over time it simply does not dissolve in the thickness of the frozen plaster mass.

The use of reinforcing fiberglass stacks is a prerequisite for high-quality plaster

• Aerated concrete walls are distinguished by high moisture absorption. As experienced painters say, this material literally "drinks" water. It would seem that this is not bad for good adhesion, but it turns out just the opposite. Aerated concrete "sucks" moisture from the applied material, which causes its rapid drying, cracking and shedding - in the case of gypsum compositions, and disruption of the normal hydration of cement, if plasters based on it are used. In both cases, the quality of the coating will be low, and the finish itself will be extremely short-lived.

It is important to find the right "moisture balance", otherwise the work will be of poor quality

On the other hand, excessive oversaturation of aerated concrete with water is also fraught with negative consequences. Yes, and such a wall is very difficult - the thrown solution begins to "creep", the layer becomes loose or heterogeneous, etc.

Which exit?

- you can use special plaster mixes specifically for aerated concrete, intended for interior finishing work. Their component composition, when properly mixed with water, in accordance with the instructions, is fully optimized for the characteristics of such a surface and sometimes does not even require preliminary priming of the surface. All this is necessarily indicated by the manufacturer in the instructions for use of the composition.

- the use of special deep penetration primers. Here, however, the balance is also important - the oversaturation of aerated concrete with impregnating compounds can lead to the opposite effect, since the absorbency of the surface for applying plaster on it is still important.

In both cases, professional masters do not advise you to immediately give a thick outline - it is best to limit yourself to the minimum layer in which the reinforcing fiberglass mesh is embedded. Such an interlayer does not require a large amount of moisture, it is much easier to “rub” it into aerated concrete with effort, and the reinforcement will create a solid foundation, without cracks. But after such a substrate has dried, it will be possible to safely proceed to the main plastering on the lighthouses.

Video: the work of a master for plastering an aerated concrete wall

As already mentioned, the composition of the plaster mix directly depends on whether it is necessary to leave its high vapor-permeable properties to the wall, or, conversely, to make it as difficult as possible for moisture to penetrate into the material.

• In the first case, preference is often given to special gypsum-based plaster compositions, which often include light perlite sand. Usually, the instructions for the use of the composition indicate that it is combined with aerated concrete (gas silicate) walls. A classic example of such mixtures is Plaster or Osnovit - Gipswell plasters.

Manufacturers claim that for the application of such compositions, a reinforcing mesh is not even required. But in the case of aerated concrete, it is better not to ignore this moment.

• Silicate based plasters are very well suited for aerated concrete, especially in terms of vapor permeability. However, such a wall decoration will significantly limit the owners in choosing a finishing coating, since silicate mixtures are incompatible with many other organic-based decorative compositions - acrylic, silicone, latex, etc.
• Cement-lime-based plasters have been developed especially for aerated concrete or similar surfaces. Their composition is optimized precisely for such surfaces that do not even require preliminary priming before plastering. An example is "Baumit HandPutz" plaster or a mixture from a set of a whole "ensemble" of mortars specially developed for aerated concrete "AeroStone".

The composition of such plasters includes cement, construction lime, special lightweight aggregates and plasticizing additives, fine-graded refined sand. Such a coating has good vapor permeability, and can be used for both external and internal work on aerated concrete.

• If, in the plans of the owners of the house, to achieve the minimum vapor permeability of the walls from the inside, then they usually resort to the use of cement-sand plasters without the inclusions of lime or dolomite chips (flour). Naturally, the composition usually includes special plasticizing additives that stifle the adhesion of the created coating with a porous base.

All specialized mixtures for gas silicate surfaces have one common drawback - they are quite expensive, and with large volumes of work, such internal plastering of walls will result in a hefty amount. But this is only a preliminary alignment, excluding finishing! Is it not possible to do something simpler, use more affordable mixtures or generally ordinary home-made plaster solutions, for example, based on cement and sand?

It is possible, but only an experienced craftsman can perform such a finish with high quality, for whom his many years of practice allows him to "by eye" determine the condition of the wall, and the need for its moistening or priming, and the exact component composition of the plaster. And without the experience of such work, making a mistake on an aerated concrete surface is as easy as shelling pears, and all the work will be done down the drain.

However, we can recommend one very interesting way of preliminary preparation of the gas silicate wall for further. If everything is done in accordance with the recommendations, it will be possible to apply almost any plaster composition without fear of cracks, mortar creeping, its rapid drying, or, conversely, excessive waterlogging of the wall.

How can you properly prepare an internal aerated concrete wall for plastering

To work, you will need the usual, the most inexpensive of all those presented in the store, glue for ceramic tiles, fiberglass mesh, deep penetration soil (ordinary, such as Ceresit CT 17). And then plastering will be possible with any composition on a gypsum, cement, cement-lime and other basis. In particular, the usual cement-sand mixture is also quite suitable, even in a ratio of 1: 5.

It is quite difficult to determine in advance the amount of plaster mixture to put the wall in order, since it depends on the condition of the surface, its evenness, the presence and depth of level differences both vertically and horizontally. But our calculator will help to determine the amount of materials for the preparatory cycle.

It takes into account the conditions for priming the surface in two layers, and with the dilution of the primer with water during the initial application, and the creation of a preparatory reinforced adhesive layer with a thickness of 5 mm. Calculations will show the result with a 15% margin "just in case" accepted by builders-finishers.

The calculation is carried out for rectangular surfaces, minus window and door openings.

But if such wetting occurs in winter, then this can lead to the development of a destructive process. The fact is that freezing water tends to expand, and therefore small cracks will appear in the blocks, which will not only spoil the appearance of the facade, but also significantly weaken the supporting structure.

The process of preparing walls, made of gas silicate or aerated concrete blocks, for applying cement-based plaster

Facade plaster is the best choice for aerated concrete

Of all the options available on the modern construction market, it is the facade plaster that is exactly the material that most closely matches the technical characteristics of aerated concrete. It has optimal vapor permeability, excellent adhesion and attractive appearance. Therefore, such aerated concrete plaster will be the best choice for decorating walls lined with aerated blocks.

Let's consider its main advantages over analogues:

• High vapor permeability, which allows gas blocks " breathe».
• The minimum amount of water required to mix the mixture. This indicator should not exceed 0.2 liters per 1 kilogram.
• Resistant to low temperatures.
• Excellent adhesion.

• Resistant to cracking.
• Long pot life of the solution.

What plaster is not suitable for aerated concrete and why

One of the most popular types of plaster is a cement-sand mixture. However, it is completely unsuitable for working with gas blocks. Regardless of what material the blocks themselves were laid on (glue or cement), the use of this finishing material is unacceptable for the following reasons:

• Vapor permeability of cement is lower than that of aerated block... This is the main reason why you should refrain from using this type of plaster.

• Moisture content is also an important indicator for gas blocks... In a cement-sand mortar, it is increased, since it requires the addition of a fairly large amount of water to mix it. Since aerated concrete is characterized by high moisture absorption, it will absorb water from the solution, which can not only destroy the structure of the blocks themselves, but also reduce the quality of the plaster solution.
• Cement slurry is characterized by low adhesion rates... This is due to the large weight of the solution and the presence of large impurities in its composition.

Gypsum plaster is a good option for plastering aerated concrete walls. But at the same time it has a number of disadvantages in front of the facade:

• The vapor permeability of such compositions leaves much to be desired.

The manifestation of white bloom - efflorescence

• In case of snow or rain, such compositions are characterized by rather quick wetting.
• On such a surface, spots may appear that need to be painted over.
• Contains more water than specialized plaster mixes for aerated concrete.

The best time to apply plaster

Considering that aerated concrete has a high water absorption, it needs to provide good protection against wetting. As mentioned above, the wetting of this building material is not critical, if frost is not predicted at the same time. In any case, after laying the walls, you need to give time to dry. It is enough to wait about a month and you can apply the plaster mixture.

Ideally, aerated concrete house facade plastering is done during the warm season. If it is impossible to carry out these heat works, then the walls should be covered with a deep penetration primer. It will reduce water absorption rates. It is also advisable to protect the walls using polyethylene left over from the packaging of aerated concrete pallets.

Masters advise to carry out work during a period when the air temperature at night does not drop below zero degrees. Thus, walls can be plastered from the end of March to the beginning of November.

How to properly plaster the walls of a house from aerated blocks

One of the main misconceptions is that the main task of plaster is to protect the walls from the outside. The only problem is that if such walls are not primed, then with the arrival of spring they will "give back" the accumulated moisture. And since there will be a layer of plaster outside, then all the moisture will go inside the house. As a result, cracks in the interior walls are possible.

Advice! The priority of protecting external walls exists only if the construction of a house takes place in close proximity to the sea, lake or any body of water.

Simultaneous finishing of interior and exterior walls is also unacceptable. The fact is that in this case, the moisture that the gas block will somehow pick up in itself, in this case, simply will not have any way out. And its subsidence inside the block will only accelerate the processes of its destruction.

Yes, aerated concrete plaster has good vapor permeability. But still they will not be enough for quick moisture removal.... And this becomes especially critical when the average air temperature at night drops below zero. As a result, the gas block will begin to deteriorate quickly.

Considering all of the above, it should be noted that the most profitable and correct option is as follows: first, internal plaster is applied, and after this layer has dried - external... In this case, the moisture accumulated inside the aerated concrete blocks will have an outlet to the outside, which will not bring negative consequences for the building itself.

How to carry out interior decoration

Consider the sequence of work on the interior decoration of aerated concrete walls:

• Preparatory stage... First of all, the walls must be properly prepared: leveled, for which a special aerated concrete plane is used.

• Apply a primer... Some masters suggest diluting the primer with water in a 1 to 1 ratio, which is incorrect, since it negatively affects the adhesion of the material. The primer composition is selected depending on the purpose of the room. For example, if deep penetration soil is required for the kitchen or bathroom, then any universal material can be taken for the hallway.
• Installing beacons... They allow you to adjust the thickness of the applied solution. They are arranged according to the width of the rule, and the accuracy is controlled by means of a level.
• Throw in a starting layer or "fur coat"... Work should be carried out from the bottom up. Next, we describe the rule for beacons, leveling the resulting layer. When voids are formed, they immediately close.

• We carry out the processing of the first layer... After the applied plaster dries, it is necessary to moisten it with a spray gun, and then level it. In this case, it is advisable to dismantle the lighthouses, since they are cold bridges. The recesses formed after them are immediately sealed with a solution.
• Form corners... To create even and strong outer corners, a perforated corner should be used, which is installed on a small section of the mesh and covered with a compound.

• Apply the finishing layer... Grouting is done if necessary, then paint can be applied to the walls. Finishing of the walls is not carried out if they are subsequently covered with wallpaper.

Since the paint is also characterized by certain indicators of porosity, it is necessary to approach its choice with all care. Good options are compositions based on latex, PVA, acrylic emulsions, cement and paints based on organic solvents.

How to plaster walls outside

How to plaster aerated concrete outside? The best material for such a finish is decorative facade plaster. There can be two application options:

• A high build finish where the material is applied in one thick coat.
• Several coats require thin-layer plaster. This option for wall decoration will be discussed below. It involves the application of a finishing material, no more than 10 mm thick.

External plaster is applied as follows:

• The wall is being prepared. It is about leveling the surface, which is done in order to reduce material consumption.
• Before plastering, the wall must be properly primed.
• After that, a starting layer of the mixture is applied. In thickness, it should not exceed 5 mm.

• The finishing layer is reinforced with a metal mesh with small cells. It is overlapped by 50 mm. At this stage, the corners of the house are also formed, for which a perforated corner is used. The main task of the mesh is to prevent the formation of cracks in the plaster layer, which can occur during the shrinkage of the building.
• A spatula is used to "sink" the mesh in the solution.