We plaster the walls of aerated concrete with our own hands. Plaster of walls from gas silicate blocks: choice of mixture and features of finishing

Often, developers have a question about how to plaster aerated concrete outside. Before starting work, it is recommended to determine the important characteristics and, based on this, choose the best finishing option.

Aerated concrete plaster must meet the basic requirements - the mixture adheres tightly to the surface and has good adhesion. The finishing layer is durable, frost-resistant while having the required level of vapor permeability and water repellency.

When to plaster

It is recommended to carry out external plastering after finishing the finishing works in the building. It is generally accepted that if the surface of the gas blocks is not protected from the street, it will absorb moisture. This is not so, the primed walls can stand the whole winter without a protective layer; when the climate changes in spring, moisture from the surface will evaporate. In the opposite case, when the house is processed from the facade, the evaporation vapors will be directed into the room, which will lead to the appearance of dampness.

Note! An exception is the option of building a house on the seashore or a reservoir. When it is required to protect external walls from the influence of a humid climate and winds.

Before plastering, the walls of the gas blocks must dry well. If during the construction process, cement mortar was used, which has the ability to absorb moisture. For this reason, outdoor decoration will be ineffective during the rainy season. But especially dangerous for the walls is cold water, which then turns into ice. In the process of melting, the structure of aerated concrete begins to collapse.

Insulation of the facade

If the building is properly insulated, then you can quickly heat the room and save money on heating costs. It is recommended to insulate the outside with mineral wool, polystyrene foam, expanded polystyrene or other options. For example, insulation and plastering of the facade of a house can be replaced by building an additional brick wall or treated with liquid polyurethane foam.

Types of plasters

There are several types of plaster that are suitable for the treatment of aerated concrete walls. There are certain requirements for the composition of the mixture for outdoor work.

The material must be permeable and at the same time its coefficient must be higher than that of the treated surface - aerated concrete or a sealant.
The plaster must be frost and temperature resistant.
To prevent cracking, the applied layer must be elastic.
The plaster must have strong adhesion properties with aerated concrete.

Mineral

How to plaster aerated concrete walls? Professionals and private builders recommend using mineral-based plasters. They are among the thin-layer compounds specially designed for finishing aerated concrete. Such solutions are made by hand, they have an affordable cost, good vapor permeability and low weight.

The ready-made formulations include the following components:

lime;
white cement;
marble chips and other fillers.

The color palette of such plaster mixes is limited. They can be easily painted, the only caveat is the use of vapor-permeable coloring compositions. Painting is able to protect the coating from moisture, because a humid environment can destroy mineral plasters.

Silicate

This type of building plaster is based on potassium water glass, which is a binder.

Advantages of a silicate mixture:

Ease of application;
Resistance to moisture influences;
Water vapor permeability;
If necessary, it can be painted in any color;
Acceptable price;
Long service life (up to 25 years);
Decorative qualities.

Silicone

Plastering aerated concrete blocks is better with front silicone plaster. It possesses high technical and operational characteristics, surpasses other plaster mixtures.

The advantages of silicone plasters include:

water repellent properties;
building material is easily applied with your own hands, without the involvement of specialists;
plaster has a high degree of resistance to weathering and vapor permeability;
Long service life;
Fillers have a different texture;
The material is elastic.

Acrylic

The material has high decorative qualities and durability. A big disadvantage of acrylic plaster for processing aerated concrete and other cellular textures is the low level of vapor permeability. For this reason, condensation forms in the inner layer of the plastered surface. As a result, with such an impact, surface deformation occurs - delamination and cracking.

Cement-sand

Cement plaster is not suitable for external aerated concrete surfaces. For what reasons, this popular building material is not suitable:

The mortar does not adhere to the smooth surface of aerated concrete due to insufficient adhesion properties. The mixture has a high density and high weight;
When a cement mortar is applied to the surface, aerated concrete absorbs moisture, and the adhesion of materials is weakened. As a result of such rapid drying, the integrity of the layer is destroyed;
Low vapor permeability of cement mixtures - non-compliance with building codes, and violation of optimal microclimatic indicators in residential premises.

If cement plaster is used for interior work, it will protect the aerated concrete walls from steam penetration into them.

Important! Expanded polystyrene and polystyrene are not recommended for processing aerated concrete surfaces.

Gypsum

The plaster in the base, which includes gypsum, has the following positive qualities:

dries quickly;
the solution does not shrink;
the mixture lays down smoothly;
no finishing coat required.

Cons of plastering walls with gypsum:

average level of vapor permeability;
more water is required compared to special mixtures, about 10-15 liters per 1 bag of 25 kg;
the surface will get wet quickly after rain and snow;
spots appear on the surface that need to be painted over.

Facade

The mixture is most effective for processing, both external walls and indoors, the material is easily applied with your own hands. The plaster has a number of positive qualities - good adhesion to the base, attractive appearance. Including the material has indicators of vapor permeability identical to that of gas blocks. When choosing plaster for building aerated concrete, it is better to choose a high-quality special mixture, this will simplify the process of finishing the house.

If there is a choice of plaster or drywall, which is better for aerated concrete inside the house. The following facts should be taken into account: the walls made of gas blocks are even, and they do not require alignment. Accordingly, the plaster will be cheaper, the solution will lie in an even and beautiful layer.

Self-finishing

We plaster aerated concrete outside with plaster intended for outdoor use. There are two options for applying the mixture - in a thick layer or in several thin layers, which are applied no more than 3 layers and no more than 1 cm each.

Work order:

the surface is prepared for plastering - dirt is removed;
then you should do the hanging of the surface with your own hands along the lighthouses;
spray is applied - the first layer of plaster coating;
a primer is applied and leveled;
cutting corners;
finishing of slopes;
a covering layer is applied;
the surface is rubbed.

Work technology outside

If necessary, a heater is mounted for blocks under the plaster.
Wall preparation - leveling the surface to reduce material consumption and application thickness.
Before you start plastering the walls, aerated concrete must be treated with a primer. For this, compositions are used intended for the fine-mesh structure of materials.
Application of a thin layer of plaster mixture for aerated concrete surfaces - up to 5 mm. This base will be used for attaching the net.

It should be noted right away that it is unacceptable to plaster aerated concrete blocks from the outside with adhesive solutions. Because the glue won't do the job. In order to protect and level the surfaces, it is recommended to use specially designed mixtures that meet all performance requirements.

When plastering aerated concrete facade is carried out, it is recommended to follow some rules, which are described below.

after the building is erected, it is necessary to withstand a certain period of time so that the internal moisture evaporates naturally;
the brand of plaster must be suitable for outdoor use;
the sequence of repair work - first inside the house, then outside;
the temperature regime must correspond to from +8 to +30 С0 - for external finishing;
Building rules that should be observed in relation to the increase in thermal conductivity coefficients. Each mounted or applied material to the gas block should be considered.

Reinforcement

When asked whether it is necessary to reinforce the plaster, and whether a mesh is needed. The answer is simple, since the layer of aerated concrete coating plaster can vary from 5 to 15 mm. If the layer exceeds 10 mm, a metal mesh with a fine mesh texture is used as a reinforcing layer. For example, a mesh with a wire diameter of 0.1 mm and a mesh size of 0.16 x 0.16 mm is suitable, or fiberglass mesh with cells of 5x5 cm.

You need to mount the mesh with an overlap of 5 cm; perforated corners with a mesh are used for the corners of the house. This method will help prevent the formation of cracks in the plaster after the building has shrunk. It is better to install the mesh into the applied solution with a spatula. An especially important point is the installation of the mesh in places with an increased level of stress - the area of windows and doors.

Advice! If you attach the mesh to a dry surface, the result will be zero. Because the mesh must be fixed to the wall with self-tapping screws, and then a layer of mortar must be applied. Otherwise, the non-fixed mesh will move along with the putty.

Work order:

Align the plaster layer with the mesh using vapor-permeable plaster.
It is necessary to wait until the first layer is completely dry. Otherwise, it will fall off under the weight of the next layer. This technique provides for a thin-layer application of the mixture. It will take three to four days to completely dry. Accordingly, the thicker the layer, the longer to wait for it to dry. Checking whether the surface is dry is carried out with water. Having sprinkled the liquid on the surface, it quickly absorbed - this means that it is time to start further work.
A second layer of plaster is applied, which is considered leveling. Therefore, the layer must be even and smooth;
A third finishing layer of plaster is applied and, if necessary, will require subsequent trowelling.
Surface painting, materials for outdoor use or applying putty.
Treatment with a water repellent. Experts recommend applying this solution 12 months after painting and completing all work on the facade cladding. A water repellent agent gives any coating additional water-repellent properties.

Note! When the plaster layer dries, it must be protected from the influence of such undesirable environmental factors as moisture, snow, rain.

Putty

When deciding whether to putty aerated concrete, it is recommended to learn about the types of building mixtures. There are 3 types of product varieties on the market that are designed for finishing. By and large, this is a facade plaster intended for thin-layer finishing of an already plastered surface, differing only in composition. Ready mixes are sold in buckets and are silicate, silicone and acrylic.

Important! When plastering outside the house, it is recommended to use only steam-permeable building materials. This will provide not only a reliable finish, but also serve as a decoration for the building.

Aerated concrete blocks are incredibly in demand today - and not only in private construction, but also in the construction of frame-block multi-storey buildings. The products are compact, lightweight, easy to assemble, which allows a person to build a warm and inexpensive home with their own hands.

However, raising the walls and bringing them under the roof is not all. You need to know exactly how to plaster aerated concrete inside the house, and understand by what principle the internal plaster is generally selected. These questions have become the topic of this article.

The principle of selection of plaster to the base

Both aerated concrete and aerated concrete belong to the category of cellular concrete. There is an opinion that they are one and the same, but there is still some difference between them.

In both materials, there is a combination of two cement-lime binders. However, their percentage is different, resulting in a material with completely different strength characteristics.

Leveling coatings for aerated concrete

Aerated concrete contains up to 60% of cement, and the rest is lime and sand. In gas silicate products, there is only 14% of cement, almost twice as much lime, and many times more sand. It is clear that if there is so little cement, then the strength of the products is no longer the same. In general, aerated concrete is no longer a structural material, but a heat-insulating material.

Perhaps now you have a question: "What does the internal plaster of the walls have to do with it?" And despite the fact that it is selected depending on the type of base, and in order not to have problems with the coating later, you need to know exactly what can be combined with what. The characteristics of the binder are decisive here.

Note! Cement, or rather products and solutions based on it, always has greater strength than lime and gypsum. When creating multi-layer screeds, the following principle must be observed: the base must always be more durable than the coating - otherwise, it will inevitably peel off.

From the above, it is not difficult to conclude: if there is no or almost no cement in the blocks, then the internal plaster of the walls, and even more so the external one, cannot be produced, for example, with a cement-sand mortar (see Optimal ratio of cement and sand for plaster ). Applicable to gas blocks, it can be used, since they have a high percentage of cement, and the wall surface has sufficient strength.

You can even use non-special commercial mixtures, one of which we see in the photo, but knead the solution yourself. You just need to keep in mind that the plaster should not be done as for heavy concrete or clay brick - in proportions of 1: 3, when a solution of the M150 brand is obtained.

Plastering of internal walls from aerated concrete, performed with a solution of half the strength: M75. For its manufacture, take cement M400, and mix with sand 1: 5.

With an increase in the grade of cement, its amount in the solution should decrease to 1: 6, or even to 1: 6.7 - this is the arithmetic. Everything is done quite simply, and the lower price of self-mixed plaster will significantly save on finishing work.

How to plaster gas silicate

Now, as for the gas silicate wall, in which there is very little cement. Accordingly, such a plaster as for aerated concrete is not suitable for it. However, it is impossible to infinitely reduce the amount of the binder in the solution - you can only replace part of it with another, less weak binder in strength.

There is a large percentage of lime in gas silicate blocks, and it is most logical if it is also present in the plaster. That is, the most ideal option for plastering such walls would be lime-cement plaster. It is more difficult to make it yourself, since lime dough must be present in the solution.

It is much easier if the plaster of the house is inside, it will be produced with a purchased mixture. And by the way, if it is suitable for gas silicate, then it is also suitable for aerated concrete (and not vice versa). Manufacturers often orient plaster mixes to both materials, which means that in addition to cement, lime is also present in them.
Sometimes the instruction on the packaging says that the mixture can be used for all aerated concrete. This means that they can also be applied to walls made of foam concrete, which contain only cement from binders. Just keep in mind that there are also cementless types of foam blocks made on the basis of lime.
Like gas silicate, this material is also more of a heater than a structural material. Foam blocks, in which there is no cement at all, are used for the construction of interior partitions. They can also be plastered, but only there should be no cement in the solution.

It should be noted that the best option for leveling walls made of gas and gas silicate blocks, lime foam blocks, as well as silicate bricks, are silicate plasters. But since they contain liquid glass, and they are very caustic, they are not used for living quarters - only in production workshops and on the facades of buildings.

Feasibility of using gypsum mixtures

Plastering inside a house with limestone surfaces can be done with gypsum or lime-gypsum mixture. In principle, they are suitable for all types of foundations, but there is one but, and it concerns walls erected from aerated concrete.

Given their high vapor permeability, and a similar property of gypsum, it is not always advisable to use plaster based on it indoors:

Here it is already necessary to consider the structure of the wall decoration as a whole, and oddly enough, you need to focus on the option of external decoration. For example, outside the aerated concrete walls will be monolithically lined with brick, clinker tiles, or stone, or plastered on expanded polystyrene.
Due to their poor vapor permeability, these materials will trap moisture in the thickness of the walls, preventing it from escaping. In this case, inside you need to use only cement plaster, or provide for such a decorative coating that will become a barrier to steam.
For example: if it is paint, then alkyd; if wallpaper, then vinyl or cork. Yes, the same tile or stone, any cladding with insulation - all this will not allow the porous walls to be saturated with moisture.
In what case can internal plastering of walls made of aerated concrete, or other cellular material, be done with a gypsum mixture? There are only two options. The first is when the outer walls are aligned with the base base with plasters with a high degree of vapor permeability: silicate, silicone, special for cellular concrete.
The second option is a ventilated facade. When there is an unobstructed outlet for steam and condensate on the outside of the wall, the internal plastering of the walls, like their finishing, can be done as you like. But note that if the facade is insulated, then the thermal insulation boards should be loose: soft mineral wool or the cheapest loose foam.

Let us also clarify this situation. Decorative plaster for interior decoration, most often made on the basis of gypsum. How to properly prepare a porous base when the use of gypsum mixtures is undesirable. With cement-based blocks, there is no problem.

In any case, the base before decorative plastering should be leveled as for gluing wallpaper. Therefore, the walls should first be leveled with a cement compound, and when it dries, decorative gypsum plaster can be applied for interior decoration. You will learn more about this in the next chapter.

Internal plastering of aerated concrete

So, in our story, we came directly to the implementation of internal plastering work on aerated concrete walls. We will try to highlight the most important nuances of this process, and for clarity, we suggest watching the video in this article.

The nuances of preparation

Porous surfaces are characterized by the strongest moisture absorption, which must be reduced by priming. It is produced more abundantly on aerated concrete walls than, for example, on brickwork. To do this, you need to take not just an adhesive primer, but a deep penetration composition.

Important! Primers are ready-made, but they are concentrated - that is, they are diluted with water in a proportion determined by the manufacturer, which must be observed. Do not think that if you apply undiluted primer, you can, for example, reduce the number of passes. The composition should be of normal concentration.

The first layer is applied generously, preferably with a spray gun. You can also take an ordinary garden sprayer for this purpose, with which trees are sprayed. After the aerated concrete wall dries slightly after processing, another layer is applied, after which the surface should already completely dry.

Double impregnation significantly reduces the absorbency of the wall, but does not completely eliminate it. Yes, this is not necessary - otherwise how will the solution stick to the surface? The surface of the gas blocks is very smooth, and for the plaster, it is necessary to ensure good adhesion. It is not allowed to make notches like on heavy concrete. How to get out of the situation?

How to make your plaster as durable as possible

After priming, task number two is surface reinforcement. This is necessary not only for the best adhesion of the layers, but also for the prevention of cracking.

This is especially important when the walls are built of gas silicate, which has five times less cement than gas blocks. The strength of such a base is rather weak, and plaster, even gypsum, will be more durable and will work to tear.

Your task is to create a strong interlayer between the subfloor and the plasterboard, which will give them the best adhesion. Therefore, no matter what type of plaster you use, the starting layer must be made with an adhesive mixture, which is intended for the installation of cellular blocks.

To create a reinforcing layer, ordinary tile glue is also suitable. Many craftsmen, due to the lower cost than the masonry mixture, prefer to use it. Why is an adhesive composition needed, and not just a plaster?

Note! The fact is that adhesives are always modified with polymer additives, which do not just adhere, but firmly glue the surfaces. The layer of glue is thin and durable; the fiberglass mesh is also embedded in it. It is not only an excellent base for plaster, but also reliably fixes blocks, preventing microcracks from appearing and expanding.

This approach to preparatory work is especially important when self-made mortars are used for plastering. In them, unlike the factory ones, specially designed for gas blocks, there are no improving modifying additives, as well as fiber reinforcing the plaster in the mass.

There are no words, factory mixes solve all problems, but due to their high cost, they are more often used for facades. On the internal plaster, which is not exposed to such influences as on the street, you can save money - only you need to do it wisely. If you do not want to have problems in the near future, the adhesive layer must be done in any case.
Installation of the mesh, in principle, is not necessary, and is carried out by craftsmen at the request of the owner of the house. But the customer should know that the creation of a reinforcing layer only improves the quality of both the plaster and the base - after all, no one knows what shrinkage processes will occur in the soil.
It is better to play it safe, and spend a little money on the mesh, than to incur the costs of a full renovation in the future. We especially advise you not to neglect the mesh when the walls are being prepared for painting - after all, any crack on them will be immediately visible. Cracks are invisible under dense wallpaper or tiled cladding, but the task is not to hide them, but to prevent them from appearing.

There is nothing complicated in the installation of the grid, and in the video presented in our article, you will see it. The canvases are applied with an overlap on freshly applied adhesive solution, and then pressed, combing with a notched trowel. The use of such a tool is very important, since thanks to it, scallops from the squeezed out solution remain on the surface of the mesh.
When they dry, you get a beautiful embossed surface on which you can apply any plaster. First, the mesh is pressed into the glue layer with chaotic movements, trying to press it as tightly as possible to the base. If you are going to carry out the usual leveling plastering on the walls, in the end, you need to do a horizontal comb.
This is necessary only so that the plaster, which in the next stage will be applied to this surface, does not slide off the wall. Well, for decorative plaster - if it will be used for interior wall decoration, the base should be smooth. In this case, the relief is not left, and the solution on the mesh, squeezed out with a notched trowel, is smoothed out.

When can I start plastering directly? Let's say right away that it is undesirable to do this right the next day.

Even if the surface appears dry, the cementitious adhesive has not yet gained sufficient strength. It is not scary if plaster is applied to it with gypsum. If it is a cement mortar, then the glue layer must be given at least five days - or better a week, to gain strength.

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 matters of finishing, and in what ways can these problems be solved - 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 precision 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 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 either case, 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 to immediately give a thick outline - it is best to limit yourself to a 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 drying such a substrate, you can 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 mixture 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 topcoat, 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 using 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, whose long-term practice allows him to "by eye" determine the condition of the wall, and the need for moistening or priming it, and the exact 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, you 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?

For 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 it will be possible to plaster 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, with the dilution of the primer with water during the initial application, and the creation of a preparatory reinforced adhesive layer 5 mm thick. Calculations will show the result with a 15% margin "just in case" adopted by builders-finishers.

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

Internal and external aerated concrete plaster should 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 mixes that will improve and maintain the quality of the base. The correct application technology will ensure a long service life and decorative effect of the coating.

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

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

Aerated concrete blocks

Basic requirements for plaster

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

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

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

Aerated concrete plaster should be:

resistant to external atmospheric influences;
have good adhesion (adhesion to aerated concrete);
resistant to sudden changes in temperature;
high degree of compressive strength (crack protection);
vapor permeable;
moderately dense;
improving the thermal insulation of the walls;
have a decorative look.

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

Plastering a house from aerated concrete blocks

The lack of facade finishing of aerated concrete structures will lead to darkening, deformation, flaking of the surfaces of the blocks.

Types of plasters suitable for aerated concrete blocks

The choice of a plaster mix for aerated concrete primarily depends on whether you are going to wall the outside or from the inside. Plasters by type of application are divided into external and internal.

As you can imagine, external plaster is intended for facades. Since here it performs protective functions, its strength, moisture resistance and thermal insulation indicators should be higher.

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

Application of a finishing layer of plaster on aerated concrete

Popular plasters for aerated concrete

Mixtures for finishing facades from gas 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. To eliminate the low level of water resistance, elasticity and the limited choice of the color palette of the material, you can use 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 as a decorative finish, it is durable and reliable.

Silicate plaster for aerated concrete is made on the basis of liquid potassium glass. The coating has good moisture resistance, vapor permeability and strength. The silicate-type solution is easy to apply. The finishing layer is resistant to dirt and abrasion, providing a decorative finish 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, organosilicon polymers. The quality characteristics of the material are optimal for creating a durable coating. Silicone-type plaster retains its elasticity after application, which ensures that there are no cracks on the surface even when the blocks are shrinking. It is important to note the special decorativeness of the finish, thanks to special fillers and color variations, you can give an original look to the facade.

Silicone plaster can undoubtedly be called the leader among others, it has all the advantages of silicate compositions, 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 from 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 amount of plaster mixes of various brands for finishing aerated concrete surfaces. Popular formulations have optimal characteristics for work.

Applying plaster to the internal walls of a house from aerated blocks

Ceresit CT 24. The mineral composition of the mixture endows the solution with plasticity. The material is easy to apply. The coating can withstand up to 100 cycles of low temperature effects. Coloring is recommended after complete drying (after seven days).

CERESIT ST 77. The acrylic type of the mixture is used for facade decoration, providing the strength of the coating with a sufficiently thin application layer. The material is frost-resistant, resistant to external influences. It is used if there is water protection and ventilation inside the house.

Founding Startwell T-21. Cement-lime plaster is characterized by frost resistance, 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 SilikonTop. A high level of adhesion and plasticity is achieved thanks to the mixture based on silicone resins. The coating retains its decorative effect for a long time due to its dirt-repellent properties. A wide selection of material paint palette (up to two hundred shades).

Weber.pas silikon. A mixture based on a silicone emulsion. There is a choice of suitable grain size. Optimum material resistance to moisture, temperature, dirt.

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

Surface priming before plastering

Internal plaster of aerated concrete walls

Internal work on plastering walls from aerated blocks is carried out with gypsum solutions with various additives. Composites in the form of perlite and marble chips will enhance the decorative effect of the finish. There is a possibility of coloring the composition with various colors.

Gypsum mixtures without additives differ in the required level of vapor permeability, which allows the use of plaster as a base for wallpapering. Standard work sequence:

elimination of irregularities, chips on the surface of the walls;
dust removal and application of the first layer of solution;
installation of reinforcing mesh;
application of the second layer.

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

Internal work is carried out only on condition of preliminary application of a waterproofing compound, priming.

Internal wall plaster

Exterior wall plaster made of aerated concrete

Facade type aerated concrete plaster can be applied using various technologies: thick-layer or thin-layer finishing. The sequence of work includes:

mandatory preparation of wall surfaces, alignment;
priming (formulations based on acrylatesiloxane);
applying a thin layer of mortar - the basis for attaching the mesh;
reinforcement (crack protection);
leveling the finishing layer;
second layer of coating (formation of a smooth, even surface);
finishing layer of plaster, grout.

One year after the completion of the facing work, it is recommended to apply a water repellent solution. Due to the processing of the facade with this composition, the moisture-proof and water-repellent properties of the coating increase.

Features of plastering walls from aerated blocks

Correct performance of work must take into account the characteristics of the material of construction. Aerated concrete blocks may have differences in structure. Sawed versions 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 to increase 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 cladding should be twice as thin as interior cladding.

It is strongly not recommended to carry out work on plastering surfaces from gas blocks earlier than 6 months after the walls were erected. The structure must completely dry out, getting rid of excess moisture accumulated during the laying of the material

Plastering on a reinforcing mesh

Optimal conditions for plastering

Exterior plastering of aerated concrete must be done under certain conditions. It is important to first complete the internal work of a high humidity level. The load-bearing structures of the walls made of gas blocks must be completely dry, not exceeding 27%. Otherwise, high humidity will provoke a violation of adhesion and lead to flaking of the finishing layer of the facade.

The optimal time for finishing inside the house is spring, the facade of the building is at the end of summer.

External temperature conditions for work must correspond to + 5- + 30 ° C, with an air humidity of no more than 80%. If it is necessary to perform finishing at low temperature indicators, it is recommended to use a special soil composition of deep penetration before the onset of acceptable weather conditions.

Correct work will help to avoid flaking, cracks and defects. Do not apply the coating in hot, direct sunlight or windy conditions.

Plastered facade of aerated concrete house

Conclusion

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

Recently, with the help of aerated concrete blocks, they not only carry out thermal insulation, but also erect houses. This material is somewhat "capricious", so the plastering of aerated concrete walls indoors and outdoors should be carried out taking into account some nuances.

Many craftsmen believe that finishing work on the walls of aerated concrete must be carried out immediately after the construction of the building, but this is a rather risky undertaking. This procedure is best done after a year. The fact is that aerated concrete must have time to dry out before the onset of cold weather, which can be hindered by the plaster layer. If moisture remains inside in winter, it will freeze, causing the material to crack.

The first step is to carry out the internal plaster for aerated concrete, after which you can start finishing the external surfaces. You can even stall for a little time by doing internal work in the fall, and external work in late spring. The only exception can be buildings on the sea coast. In this case, the first step is to protect the external walls from the weather.

First of all, internal plastering is carried out, and then external

Important! It is strictly forbidden to plaster a house from aerated concrete from November to March.

Is it necessary to plaster the gas blocks outside

External plaster for aerated concrete is completely optional. On the contrary, many craftsmen recommend immediately ordering walls of such a thickness, which would be enough to ensure a comfortable temperature inside the house without using plaster outside. An incorrectly selected composition or a violation of the application technology can lead to the destruction of the entire structure.

Many masters oppose external plastering of aerated concrete walls

Some advise using expanded polystyrene for insulation, but this material is practically impervious to water vapor. This leads to the fact that condensate accumulates at the junction of the insulation and the gas blocks. In the cold season, it freezes and leads to cracking of aerated concrete. If, nevertheless, it was decided to use expanded polystyrene, then it is necessary to lay a layer of 80 mm, while the thermal resistance of the heat-insulating material should not be lower than this indicator of aerated concrete.

On a note! To get rid of the need for additional procedures, it is enough to order a wall 10 cm thick in warm regions, 30 cm in cold regions, and 20 cm is suitable for baths.

How to plaster gas blocks

The question of how to plaster aerated concrete outside and inside the room is not at all idle. It should be noted right away that plastering on aerated concrete cannot be carried out using cement-sand mortars.

To properly plaster aerated concrete walls outside or inside the house, you must use the following compounds:

Interior plastering of aerated concrete walls

Before plastering aerated concrete, you should pay attention to thorough preparation of the base. To do this, remove all irregularities with a planer or a special tool for processing aerated concrete blocks. This process is recommended to be performed even at the stage of wall construction, but some builders simply forget about it in order to save time. The processing with a plane does not affect the operational properties of the future coating, but with its help it can be significantly reduced during finishing.

After that, you need to apply a primer. Some craftsmen dilute the primer with water, but this is fundamentally wrong. So you can save a little on the solution, but at the same time the adhesion of the treated blocks will drop significantly, which can affect the duration of the coating. To save a primer, it is better to pre-moisten the roller with water and walk it along the wall, then repeat the procedure, but with a primer. For damp rooms it is better to use a deep penetration impregnation, for dry rooms - a simple one.

For better adhesion of the plaster to the blocks, it is necessary to pre-treat the walls with a primer.

Then proceed to the installation of plaster beacons. This is one of the simplest operations as the planed blocks do not have large drops. Using the building level, you need to find the maximum protruding point, add the profile height to the value, and, according to the obtained value, install beacons over the entire treated area with an interval of 130-160 cm.

Installation of plaster beacons will allow you to apply the plaster perfectly evenly

When the preparatory work is over, they begin to plaster the walls from the aerated block. It is carried out using the following technology:

The first step is applied by the sketching method. It is called spatter and is no more than 3 mm thick.
After the spray has set, you can grab the base layer. It is called a primer, it is on the quality of the application of this layer that all indicators of the finished coating depend. The material is collected on a spatula and transferred to the wall, so the entire area between the two beacons is treated.
Then you need to take the rule, press it against the beacons at the bottom of the wall and lift it up, while making zigzag movements from side to side. The solution will remain on the blade of the rule, it should be thrown up the wall. The procedure must be repeated until the blade remains clean after lifting.
After the material has set, beacons are removed from it, and the resulting grooves are filled with a solution. Further, corners and hard-to-reach places are processed, after which the entire wall is left to dry.
After the main layer has dried, the last one is applied - a cover. It is considered decorative, therefore its thickness is 1-3 mm. It is carefully leveled, and when it dries, it is rubbed with sandpaper.
It is necessary to wait for the material to gain strength (the time is indicated by the manufacturer on the packaging), and you can proceed to the finishing.

The plastered coating is pasted over with wallpaper or painted. It is better to use materials based on acrylic, latex, cement or organic solvents as paint.

Plastering external walls made of aerated concrete

Plastering of aerated concrete outside can be carried out in two ways: by applying in one layer or in several. The single-layer version loses somewhat, so it is recommended to opt for the second method. Before plastering a concrete wall, you need to carry out the same manipulations with it as with the inner wall. After that, you need to install a reinforcing mesh.

External plastering of aerated concrete walls is made using a reinforcing mesh

For these purposes, metal products with a wire with a diameter of 1 mm and a side of 16 mm or a fiberglass mesh with a cell of 5 cm are used. This product is cut into fragments of such an area that it is convenient to work with them. After that, a plaster mortar is applied on the surface with a layer of no more than 5 mm, while it is fresh, the mesh is pressed against it and sunk into it.

Then you need to pause and wait for the solution to dry. It's easy to check: you need to spray a little water on the coating, if the liquid is quickly absorbed, you can continue working.

In turn, with an interval of 3-4 days, two more layers of material, 10 mm each, are applied. After drying, the plastered surface is rubbed in the same way as the internal ones.

The last stage of wall decoration is plastering

On a note! Before plastering concrete walls, it is important to immediately decide on the type of finish. Different types of paint require different types of plaster.

Aerated concrete blocks rarely require any finishing other than decorative, but if such a need arises, then, first of all, you need to choose the right material for plastering aerated concrete, and also follow the above rules and technologies.