Aerated concrete wall plastering technology outside. Features of internal plaster of aerated concrete walls

Aerated concrete is a popular building material from which strong, durable, warm and resistant to various negative effects of the structure are obtained. It has an acceptable cost, and construction with its help can be done by hand, even by beginners. After the construction of the house, it is necessary to decide on what materials will be used for finishing work. Initially, the walls are covered with high-quality plaster, so it is important to figure out how to plaster aerated concrete outside and inside the house, as well as how to do this work correctly.

Important! It is not allowed to use the same material for external and internal work, since it is important that the resulting coatings are resistant to the existing operating conditions, and they differ significantly on the street and inside the house.

Types of plaster for aerated concrete

Plasters are presented on the market in numerous forms. Not all varieties are suitable for aerated concrete, therefore, the parameters of each material are necessarily studied in advance, after which the desired option is selected for outdoor use or for internal work.

Important! Plaster for external use must have high thermal insulation parameters, resistance to moisture and temperature changes, and at the same time must provide good sound insulation and have an attractive appearance.

There are several of the most popular plasters used for aerated concrete. Each option has its own characteristics, so it is important to study the parameters of any type before making a specific choice.

Cement plaster

This material is considered to be in demand for various types of work, but it is considered unsuitable for aerated concrete. This is due to the fact that smooth walls are obtained from it, on which cement mortar does not adhere well. Also, aerated concrete has a specific feature to absorb moisture from the solution. Cement plaster has a vapor permeability that is lower than that of the walls, so if you use it for finishing work, the microclimate in residential premises can significantly deteriorate.

Also, the cement slurry has a low adhesion rate to the aerated concrete surface. Often, lime is added to the composition to increase this parameter. If, nevertheless, this material is chosen for outdoor work, then by all means, after the plaster has dried, a special finishing layer is applied, which makes it possible to obtain a perfectly smooth surface.

Important! If the vapor permeability of aerated concrete is broken, this can cause various cracks, mold or traces of seams.

Adhesive for aerated concrete

There is a special adhesive mixture on the market designed for application to walls made of aerated concrete. It has the optimal composition for working with this material, however, its main purpose is the connection of individual blocks, therefore it is used in joints.

The material is applied in a thin layer, therefore it is not considered suitable for the formation of an outer layer on aerated concrete walls. It will not be possible to make an optimal protective coating from it, and its cost is considered quite high, so it is inappropriate to use it for these purposes.

Gypsum plaster for aerated concrete

This material has many advantages for use on aerated concrete walls. Its advantages include:

fast drying, therefore, after the layer has solidified, you can quickly proceed to subsequent finishing work;
the coating does not shrink;
with proper application of plaster on aerated concrete, the formation of a perfectly smooth surface is guaranteed;
due to the high quality of the material, there is no need to apply a topcoat after the layer has dried.

But this material is not devoid of certain significant drawbacks. These include:

not very good vapor permeability ();
a sufficiently large amount of water is required to obtain a high-quality mixture;
if moisture or snow gets on the coating, which is not protected by any additional layer, it quickly gets wet;
often ugly and well-visible spots appear on surfaces, therefore, for an attractive appearance of a wall made of aerated concrete, it is required to use special coloring compositions to eliminate them.

Important! Even with many disadvantages, gypsum mortar is considered relevant for use on aerated concrete walls, but it is usually used for interior decoration in rooms with a low humidity index.

Special facade plaster for aerated concrete

There is a special material for aerated concrete walls on the market, used for both outdoor and indoor use. The advantages of using it for a house built from aerated concrete include:

a good indicator of vapor permeability, equal to the vapor permeability of the building material itself;
excellent appearance of the resulting coating;
good adhesion to aerated concrete.

It is this material that is most often chosen for finishing aerated concrete structure. It provides a high-quality, uniform and durable layer with an interesting look. But this material has a fairly high cost, so a lot of money is spent on finishing the whole house. For internal walls, the use of gypsum mortar is considered optimal.

Competent choice of plaster for aerated concrete walls

When choosing a material intended for plastering walls made of aerated concrete, the basic requirements and criteria that it must meet are taken into account. To get a really high-quality and optimal coating, the plaster must have:

a good indicator of vapor permeability;
resistance to low and high temperatures;
resistance to exposure to significant moisture;
resistance to cracks, mold or other negative factors on the created surface;
the duration of the viability of the solution, and this factor is most important for people who independently carry out the process of applying plaster, and at the same time do not have experience with such solutions.

Important! For each buyer, an additional important parameter is the cost of the solution, and it must correspond to its quality and properties, but it is not recommended to pay attention to the most affordable material, since it will not have optimal properties for use on aerated concrete walls.

When is the application of plaster on aerated concrete walls?

Aerated concrete is considered a specific material characterized by good moisture absorption, therefore, immediately after the construction of the structure, it is recommended to take care of protecting the walls from the effects of water. The wetting of the material is not considered critical, but it is impossible for the moisture in the aerated concrete to freeze, as this can cause cracks or weakening of the walls.

Important! However, one should not rush, since after erecting a house from aerated concrete, it is recommended to give the material time to dry thoroughly.

Plaster is applied to aerated concrete exclusively in the warm season. If a cement mixture is used in the process of work, then its drying time is considered significant, and this is due not only to its parameters, but also to the fact that a sufficiently significant layer in thickness is certainly created.

If it is not possible to apply plaster in the warm season, then the walls are certainly covered with a special primer, and it is important to choose a means of deep penetration. The resulting layer reduces the water absorption of aerated concrete. It is allowed to cover the entire structure with polyethylene or other similar material.

From which part of the house does the finishing of aerated concrete structure begin?

There are several options that determine the sequence of actions required to repair a house built of aerated concrete. These include:

Exterior finishing is initially carried out, and after the internal one. Experts assure that, first of all, it is necessary to protect the building from various negative atmospheric factors that can adversely affect the condition of the aerated concrete house. It is not permissible for the walls to collect a large amount of moisture. However, on the other hand, water vapor will accumulate in a house closed from the outside, which will negatively affect the duration of its drying, and difficulties may arise with internal finishing work. This option is considered preferable for houses built on the banks of different rivers or lakes.
Internal finishing works are carried out first... This option involves the partial closure of the pores in the walls of the aerated concrete structure. After interior finishing, it is not allowed to immediately carry out external work. The fact is that this can lead to the accumulation of a large amount of water vapor in aerated concrete blocks, so moisture will settle in the walls of the house, which can cause their destruction. Therefore, exterior wall decoration made of aerated concrete is carried out only after the plaster inside the house has completely dried.
Simultaneous execution of works... This method assumes that both internal and external finishing processes are immediately implemented. This method is considered the least popular, and this is due to the fact that moisture will not have time to leave the blocks of aerated concrete.

Important! Although modern high-quality plasters have good vapor permeability, they dry out for a long time, and this is especially important if aerated concrete wall decoration is planned for the cold season, so it is advisable to leave the process until the warm time.

Aerated concrete interior wall decoration technology

The use of plaster for interior decoration of a house built from aerated concrete is a simple and straightforward process. It is divided into successive stages:

Preparation of the base. It is important to eliminate significant irregularities on aerated concrete walls. To do this, they are sanded with a plane or a special float. It is allowed to skip this stage, however, in the process of work, you will need a large amount of plaster, which will significantly increase the cost of finishing.
A quality primer is applied. It is not recommended to mix this product with water, as this action will lead to a deterioration in the quality of the material. Before applying the primer, it is necessary to clean the base from dust, for which the walls are washed with plain water. The primer is applied after aerated concrete walls have completely dried. A specific type of primer is selected in accordance with the particular room in which you have to work. For standard rooms, which include a bedroom or a hall, you can choose an inexpensive and versatile material, but for a bathroom or kitchen, a means of blue penetration is purchased.
Installation of beacons. The next stage involves the installation of lighthouses on aerated concrete walls. They are represented by special metal structures that provide a perfectly even plaster coating. They are usually mounted using a small amount of plaster solution. The distance between them is left in accordance with the width of the rule that will be used to level the mortar. In the process of work, a building level must certainly be used, which guarantees the evenness of fixing the beacons.
Preparation of plaster. In the process of creating a solution, you must strictly follow the instructions that are attached to the material by the manufacturer. In this case, it is guaranteed that an optimal mixture is obtained with the desired consistency and uniformity.
Plastering by throwing. It is this method that is used to form the first layer of plaster. The procedure is performed from the bottom up, and the mixture is poured over the entire surface of the base. Next, the resulting layer is stretched using a rule. If voids are formed, it is necessary to fill them with a solution. It is important that the material does not peel off, because if this happens, then the plaster is removed, and then reapplied.
Processing the resulting layer. It is performed only after the mixture has dried. Further, the coating is slightly moistened, for which it is recommended to use a spray bottle. Then it is carefully leveled and the beacons are removed. The resulting empty spaces are filled with plaster.
High-quality and even corners are created. To obtain an ideal result, special perforated metal corners are used, equipped with mesh on the sides.
Finishing of aerated concrete walls. After the final drying of the plaster layer, the finishing begins. For this, the walls are covered with paints or other finishing materials.

Thus, the process of plastering aerated concrete walls is a fairly simple process that is easily performed by every home owner.

Important! You can get the perfect work result only if you follow the basic rules exactly and follow the correct sequence of actions.

How to plaster aerated concrete walls outside?

Exterior finishing work for aerated concrete house involves the creation of a sufficiently thick layer. Therefore, usually several layers are applied at once, and reinforcement is also performed. The whole process is divided into stages:

walls of aerated concrete are being prepared, and this process involves the elimination of large transitions and irregularities, which will positively affect the cost of purchasing finishing materials;
coating the surface with a primer;
application of plaster, and the thickness of the first layer should not exceed 5 mm;
reinforcement of a previously purchased metal mesh equipped with small cells is made;
the layer of plaster is leveled along the fixed mesh;
the second layer of material is applied after the first has dried, and it is important to pay a lot of attention to competent leveling and obtaining an even and smooth surface of the walls of aerated concrete;
a third layer is applied, which, if necessary, is rubbed off after drying;
the resulting coating is painted or covered with textured plaster;
it is treated with a water repellent, and usually it is applied a year after finishing, and the main purpose of this tool is to protect the walls of aerated concrete from moisture.

Video: aerated concrete plaster

Thus, applying plaster to walls made of aerated concrete is a simple process. It is easy to carry out both inside and outside the house. To obtain a high-quality result, it is important to carefully study the instructions, as well as clearly follow the sequential actions. Another important point in creating the ideal coating for aerated concrete walls is the correct choice of the plaster itself, which must correspond to the operating conditions available on the street or inside the house. The article - "" can also be helpful.

Before plastering aerated concrete inside the house, let's figure out the properties of this material for the construction of walls. Aerated concrete blocks have a number of advantages, low specific gravity (2 times lighter than silicate bricks). But their plastering is done according to the rules.

Advantages of aerated concrete blocks

The construction of houses using aerated concrete blocks is carried out quickly, since due to the low weight of the material, the laboriousness of wall installation is reduced. Aerated concrete has a low thermal conductivity, so the coefficient of thermal resistance of the material is 2-3 times less than that of ceramic bricks.

The cellular structure of aerated concrete and wood creates the same microclimate in the house. An increase in the density of aerated concrete blocks during their production causes a deterioration in the heat-saving properties of the material. This requires appropriate wall decoration. The porous structure of this material provides excellent sound insulation in rooms. Walls both "breathe" and let water vapor with carbon dioxide.

Aerated concrete is a good thermal insulation, since it has an open porous structure and great strength, and it is also a fireproof material. Adhesives are used for laying blocks, this helps to maintain the exact geometric dimensions of the building. The very process of building walls does not require professionalism.

Another advantage of the blocks is a reduced sensitivity to the negative effects of the external environment. The disadvantage of aerated concrete is considered to be low bending strength. If we take into account this characteristic of the material, then the construction of a house from it is carried out on the basis of a number of measures.

These include:

arrangement of the foundation of a monolithic type;
reinforcement of floors, masonry, rafter structures.

Rules for finishing a surface of aerated concrete

Before finishing walls made of aerated concrete, take into account that they are very different from brick in their properties. Aerated lightweight concrete has always played the role of insulation. After the insulation of the house from aerated concrete from the outside began to be carried out with the help of special heat insulators, the use of blocks was associated only with the construction of the building structure.

Since aluminum powder is mixed into the raw material for aerated concrete, the structure of the blocks becomes cellular, which increases their vapor permeability. This is taken into account in the process of finishing the walls of a building made of aerated concrete blocks.

Plastering is the most common method used for interior and exterior finishing of vertical surfaces. Before insulating a house from aerated concrete, you will need to plaster the surface of the walls. They begin this work from the inside of the building, after which they move on to finishing and begin to insulate the facade of the house. The mistake will be to first plaster the building on the outside and carry out work on the interior decoration for the cold period of the year.

Most of the water that is used for interior wall finishing works out both through the walls and through the ventilation ducts. Sub-zero temperatures lead to the formation of condensation from water vapor particles inside the walls, as well as on the outside. After the water freezes, the plaster cracks and flakes off. This is proof that it is necessary to plaster aerated concrete walls from the inside of the house, and not on the facade.

Which plaster option to choose

A layer of plaster on the wall should not interfere with its vapor permeability, therefore, a solution of a mixture of cement and sand is not used for plastering the walls. When performing work, one of the methods of interior wall decoration is used. The first of them is based on the fact that the material has a special property that ensures the vapor permeability of the walls.

If, when plastering aerated concrete blocks, a cement-sand mortar is used, then due to their structure they will quickly absorb moisture. As a result, the surface of the walls will dry out and become covered with cracks. It will not be possible to correct the situation even after using a deep primer or putty.

Another reason why a cement-sand mortar is not used for internal plastering of a room is the low vapor permeability of the walls. When a brick house has already been built, then this quality of plaster is no longer important. If aerated concrete was used in the construction process, and not brick, then improper plastering of the walls will cause a deterioration in the microclimate inside the building.

In hardware stores or on the market, special mixtures are sold, with the help of which they perform high-quality plastering of aerated concrete blocks. The finishing is carried out according to the principle of maximum vapor barrier of the blocks. The microclimate conditions inside aerated concrete house will not differ from reinforced concrete buildings.

The outer layer of plaster will be durable. This is due to the fact that after the time that it takes for the moisture balance to be established in the aerated concrete wall, the supply of steam to the external environment decreases. As a result, the plaster will not flake off from the facade surface.

Materials for the vapor-permeable layer of wall cladding

The use of plaster compounds based on gypsum and gypsum putty increases the vapor permeability of aerated concrete walls. This figure should be high as customers and builders choose aerated concrete. Gypsum-based finishing materials are produced with slaked lime and light perlite sand. After plastering with these compounds, it is not required to prime the surface of the walls. The finished plaster is able to easily conduct water vapor.

Plastering the walls inside the house using ready-made mixtures with fillers creates a high-quality cladding layer. It includes the following types of fillers:

limestone;
dolomite;
marble.

It is necessary to choose the right fillers and pay attention to the size of their constituent parts. All fractions must be combined in a single lining solution. Manufacturers producing such mixtures have achieved the convenience of their use. The compositions are easy to rub, they differ in the maximum degree of whiteness.

Polymeric additives with a high vapor permeability coefficient provide a higher quality coating than external plaster. Aerated concrete has a porous structure, so it makes no sense to immediately apply putty, otherwise you will need a lot of primer. It will no longer be possible to save on it, since this will lead to the fact that the putty will begin to crack and fall off.

DIY vapor barrier cladding

Polyethylene is often used for vapor barrier when decorating the interior surface of a room. This is the easiest method. But often after the work is done, there is an accumulation of water particles and swelling of the plaster.

During the construction and decoration of walls made of aerated concrete blocks, a good vapor barrier is required. Here they use plaster made of sand and cement without special additives - dolomite flour or lime. This type of internal plaster can significantly reduce the conductivity of water particles. In this case, the plaster will peel off, but the choice of this technology remains with the developer.

Before performing work on plastering surfaces, the blocks are primed using a special solution. It is applied 3-4 times. Remember that the use of modern block finishing compounds results in a 25-fold reduction in vapor barrier. High-quality adhesives, which are widely used in construction, are capable of eliminating the transmission of water particles. It makes no sense to apply putty.

What tools are required

It is necessary to carry out the finishing work of aerated concrete walls with the same tools that are used for ordinary plastering. To prepare the solution, a suitable plastic container is used, in which it is convenient to dilute the plaster. You will need a construction mixer with a stirring pad.

After adding water, the dry mixture is brought to homogeneity and the required density. The proportions of the components of the composition are indicated in the instructions for the mixtures. The plaster is applied to the aerated concrete using a trowel using a throw-over method. You can use a plaster bucket. In some cases, a trowel is used.

The plastered surface is rubbed with a float. To remove excess mixture from a wall that has a large area, use a trowel. Align the wall using beacons. The plaster is pulled between the guides by the rule.

A vapor-permeable finish is also performed using plasterboard panels. Be sure to comply with the process technology:

the inner layer of the finish should not consist of vapor-permeable compounds;
the outer finishing layer should not be made of vapor-proof materials.

After finishing work, the quality is checked using a lath, the length of which corresponds to the height of the ceilings. It is applied to the wall surface in different places horizontally and vertically. This is how all inaccuracies are revealed. A deviation in the range of 6-7 mm is considered permissible.

Technology for applying plaster to aerated concrete

To carry out the decoration of the inside of the walls made of aerated concrete, they use various methods. The simplest of them is the application of a vapor-permeable finish, that is, plaster. Before using it, a number of preliminary works are carried out. The very technology of decorating walls made of aerated concrete indoors resembles plastering walls.

Before starting work, the blocks are cleaned of dirt and also leveled. After that, proceed to applying a layer of primer. It must be taken into account that then materials that absorb moisture will be used. The drying time of the primer depends on the type of primer. Usually it does not exceed 3 hours. When the applied composition is dry, proceed to the wall cladding.

The choice of gypsum mixture for plaster is carried out taking into account the purpose of the room. If this is a living room, plaster is used for wall cladding, which is intended for aerated concrete. The plaster composition for plastering is fixed to the wall mechanically.

Gypsum plaster is used only for finishing dry rooms. It is not recommended to use it in an environment with high humidity, as well as on highly vibrating surfaces. Gypsum plaster is used to finish finishing the premises, after which the aerated concrete blocks can not be putty.

If the aerated concrete surface of the walls is constantly in contact with moisture (in the bathroom), then it is treated with the help of special preparations that resist the effects of a humid environment. After 1 hour after application, the composition on the wall is leveled and the final drying and smoothing of the surface are waited.

There are several ways to plaster aerated concrete walls. If you understand the properties of this material, then you will decide on the choice of mixtures and you can get a good result yourself.

When building walls.

Aerated concrete and gas silicate are modern building materials, similar in structure to foam concrete, but differing in the structure of air bubbles inside the material.

Due to the hollow structure, aerated concrete and gas silicate absorb moisture well. Therefore, walls made of aerated concrete (gas silicate) cannot be left without external finishing.

Between themselves, aerated concrete and gas silicate differ only in that gas silicate is made from lime and quartz sand, and aerated concrete is based on cement (50-60% by weight). The basic physical characteristics of both materials are very similar.

Let's consider in this article the basic requirements for plaster used to decorate aerated concrete walls.

What is the difference between aerated concrete and foam concrete?

In foam concrete, air bubbles are closed and isolated from each other, due to which its ability to resist getting wet is significantly increased.

Aerated concrete, on the other hand, has an open structure of air bubbles, due to which moisture quickly penetrates into the material.

It is because of this that aerated concrete has lower resistance to heat transfer and frost resistance and needs high-quality external and internal finishing, which allows minimizing the disadvantages of open porosity of the material.

Let's see how to properly plaster aerated concrete walls and what plasters should be used for this.

When is it better to plaster aerated concrete walls?

Many craftsmen start plastering immediately after the walls are erected. In the case of aerated concrete, this can lead to many different problems.

When erecting walls from aerated concrete, it is best to produce plaster for the next season.

If it is necessary to complete the finishing immediately after construction, then you should carefully consider the choice of plaster, which should have high plasticity and allow water vapor to pass outside without hindrance.

A feature of the thermal physics of aerated concrete is rapid wetting, long drying and the inadmissibility of oversaturation with water vapor.

It is recommended that when erecting buildings from aerated concrete, first the interior decoration, and only then the exterior. For example, interior decoration should be done in autumn, and exterior plastering - in the spring of next year.

Rare exceptions can be houses built on the sea coast, when it is necessary at all costs to first of all protect the walls made of aerated concrete from the moist wind.

Another option for finishing can be the simultaneous execution of decoration from the outside and from the inside. But this option is the least preferred.

There is no need to rush. After construction, aerated concrete should dry well, and the process is not quick. As a result of finishing with heavy cement plaster of not dried aerated concrete walls in the cold period, when it becomes warm inside the building, water vapor begins to move to the outer edge of the wall.

But because of the heavy vapor-tight plaster, they have nowhere to go and water vapor falls out in the form of condensation, the freezing of which can lead to the complete separation of the plaster from the wall.

A particularly unfavorable time for plastering walls from aerated concrete blocks is the period from November to March.

Do I need to insulate the walls from aerated concrete outside?

When making walls from aerated concrete blocks, their thickness is calculated based on local climatic conditions. As a rule, a properly selected wall thickness does not require external insulation. Moreover, in some cases this can lead to the destruction of the building.

For wall insulation, many advise using expanded polystyrene, believing that this will improve the thermophysical properties of the structure. However, a material impermeable to water vapor can cause condensation to fall out at the border of the insulation and masonry from water vapor released from aerated concrete blocks. Freezing of condensate can lead to cracks in the walls and further to their destruction.

That is, you should not take the thickness of the walls so that they still need to be insulated. Aerated concrete has high thermal characteristics and does not require the construction of thick walls to save heat inside the building.

So, for country houses in the middle lane, a wall thickness of aerated concrete of 300 mm will be quite sufficient. For the construction of a bath, a wall thickness of 200 mm is enough, and in warmer regions - 100 mm.

In the case of insulating a building with the help of external laying of a layer of expanded polystyrene, its thickness should be chosen so as to prevent condensation from falling out at the border of the masonry and the insulation. The thickness of the insulation layer made of expanded polystyrene or polyurethane should be at least 80 mm, and the thermal resistance of the insulation layer should be at least 50% of the total thermal resistance of the wall.

How to plaster aerated concrete?

It would seem that the easiest way is to prepare an ordinary cement-sand mortar and plaster the walls. But in this case, problems may arise, which were already mentioned above.

As a result of the different physical properties of cement plaster and gas silicate block walls, cracking and peeling of the plaster can occur.

Plaster for aerated concrete must pass water vapor well, not get wet, have good adhesion to the surface of aerated concrete blocks and high frost resistance.

Lime-cement plaster for aerated concrete

All the necessary properties are possessed by lightweight thin-layer plasters, specially created for decorating aerated concrete walls.

An example of such a plaster mixture is Baumit HandPutz sand-lime plaster for hand finishing with a grain size of 1 mm, available in 25 kg bags.

The main physical properties of lime-sand plaster for aerated concrete are shown in the table:

Index	Meaning
Granularity, mm
Compressive strength (28 days), N / mm 2
Flexural tensile strength, N / mm 2
Thermal conductivity coefficient λ, W / mK
Vapor permeation resistance coefficient μ,
Density of dry mix, kg / m 3
Water consumption, l / bag
Material consumption (with a layer thickness of 10 mm), kg / m 2
Minimum plaster layer thickness, mm
Maximum thickness of the plaster layer, mm

Before plastering aerated concrete walls with this plaster, it is recommended to spray Baumit Vorspritzer on the cleaned aerated concrete surface, which is part of the plaster, which is performed as a thin glue joint.

Acrylic plaster for aerated concrete

For a more decorative finish, acrylic plasters are used. It is a very durable material that can be used wherever increased strength is required.

However, in terms of vapor permeability, acrylic plasters are inferior to lime-sand plasters, and as a result of finishing with such plaster, water vapor can accumulate in the thickness of the wall.

To prevent this, you should use a reinforced waterproofing of the wall from the inside, as well as an improved ventilation system.

In addition, acrylic plasters are flammable and therefore are used with restrictions.

An example of acrylic plaster for aerated concrete is Bolix and Bolix Complex plaster.

Silicate plaster for aerated concrete

There are also silicate plasters for aerated concrete. An example of such a plaster is Baumit SilikatTop, a ready-to-use paste mixture based on potassium water glass.

Silicate plasters have excellent vapor permeability and low water absorption, which is very important when decorating walls from aerated concrete blocks.

The disadvantages of such plasters include an extremely meager choice of colors and a loss of appearance due to the deposition of dust on the surface of the plaster.

Silicone plaster for aerated concrete

Another type of plaster mixtures used in the decoration of walls made of aerated concrete blocks is silicone plaster based on organic silicon polymers.

Silicone plaster is resistant to weathering, it practically does not get wet (hydrophobic), has high vapor permeability, is easy to apply and does not lose its attractive appearance over time.

The only drawback of such plaster is the higher price. Such plaster can no longer be classified as "economy class".

Plastering walls with lime-sand plaster

When using a mixture of Baumit HandPutz, the sequence of actions will be as follows.

A bag of the mixture (25 kg) should be poured into a container with 6-7 liters of clean water and thoroughly mixed with a slow-speed mixer. The mixing time is 3-5 minutes.

After that, spray Baumit Vorspritzer on the wall, which promotes better adhesion of the plaster to the surface and reduces the moisture absorption of the aerated concrete.

A layer of plaster is applied with a trowel and pulled out with a rule. After setting, it is rubbed with a float.

The applied plaster should be protected from rapid drying within 2 days.

The hardening time of the layer is 10 days per 10 mm thickness. At this time, the plaster should be protected from mechanical damage.

All work must be carried out at an air temperature of at least zero degrees.

For better protection against getting wet, a thin layer of water repellent can be applied over the plaster. If prolonged rains are frequent in the area of your residence, then such a protective layer will significantly shed the life of the plaster.

In the next publication, we will consider the plastering process in more detail.

Plastering walls: advantages and disadvantages in comparison with other types of finishing works
Construction and renovation technologies are changing, new materials are emerging, but plaster remains a popular way to decorate walls that has stood the test of time. The reliability, solidity and durability of the result obtained are weighty arguments in favor of plastering.

Plasterboard, which gained popularity for its ease of installation and became an excellent option for the ideal leveling of walls, could not completely supplant its "fundamental" competitor. Although communications are conveniently hidden under the sheets of drywall and you can put a heat-insulating layer - these are undoubted advantages, but it does not withstand loads, reduces the area of the room and requires finishing - these are disadvantages.

The process of plastering aerated concrete inside the house, like any other room, is laborious, it takes more money and time, you have to go through a rather "dirty" period, but as a result, the walls acquire a high-quality coating that can last for several decades. Of course, it also requires decorative finishing, but unlike a drywall base, its strength will withstand almost any load - shelves and awnings can be mounted on these walls and any design and repair experiments can be implemented.

The plaster can be applied to any surface, except for very uneven walls, which require a thick layer of concrete to level. In this case, it is easier and more profitable to use plasterboard finishing.

The choice of material for plastering aerated concrete walls

Aerated concrete (gas silicate blocks) is a relatively new building material, but has gained incredible popularity and the title of "revolutionary" in the market. Thanks to its cellular structure, it provides good thermal insulation combined with excellent air and moisture conductivity.
Its excellent air and vapor transmission characteristics place special demands on the technology, the quality of the finish and the materials used.

Firstly, the finishing material should not drown out these valuable qualities, completely blocking the pores and depriving the house of the ability to "breathe".

Secondly, porous aerated concrete, providing good air exchange, can quickly "dry" a wall finished with plaster and cause cracks on it.

Therefore, the choice of material for plastering aerated concrete surfaces is approached with special care. It is necessary to use specially formulated plaster mixtures marked "For aerated concrete". They contain components that maximally approximate the properties of plaster to the properties of aerated concrete and improve its adhesion, adhesive and vapor permeable characteristics.
In addition, the mortar prepared from these mixtures gains elasticity and resistance and can be applied to the walls in a thin layer.

Sequence of work

For the same reasons, the sequence of work execution has its own specifics: first, the internal walls are plastered, they wait until they dry completely, and only then can the external finishing work begin. Moisture should completely come out from the inside out, and not vice versa.

The plastering process consists of three stages:

preparation of the foundation;
applying a base coat;
applying a topcoat.

Preparation of the base... Gas silicate walls have an even, homogeneous surface with very thin seams, since the masonry does not use concrete, but glue. A smooth surface necessarily requires the application of a primer layer, which strengthens the adhesion of the plaster and the wall and reduces the moisture-absorbing properties of aerated concrete so that drying occurs evenly.

Base coat application... After the primer has dried, the dry mixture is diluted with water in accordance with the manufacturer's instructions and a base reinforcing plaster layer is applied to the wall with a notched-comb trowel. It is reinforced with an alkali-resistant fiberglass mesh: it is simply pressed into the upper third of the layer with a trowel and smoothed. Mesh sheets are embedded in the plaster with an 8-10 mm overlap one by one. They prevent deformation, shrinkage and cracking.

Sufficient base layer thickness of about 4 mm - special additives in the mixture for work on aerated concrete make it possible to obtain a durable coating with a minimum thickness. The plaster dries for a long time - you have to put up with it. As a rule, 1 mm is allowed to dry for 1 day, thus. the whole layer will dry for about 4 days.

Topcoat application... It is recommended to prime the base reinforcing layer before applying the topcoat. The decorative layer is applied with a metal float. Its thickness depends on the size of the fractions in the mixture - solid particles that give the plaster a relief pattern. For example, if the size of the fractions is 2 mm, then the thickness of the decorative layer should not be more than 2 mm.

Having leveled the plaster and having waited a little while it “grasps”, it is “textured” with a plastic float - they give relief. Some topcoats do not require further painting as they are already contain colored pigments.

It will be useful to know that it is not recommended to start finishing work in a gas silicate brick house immediately after the construction of the frame. The moisture content of the "fresh" aerated concrete block from the plant is high - about 30%, it is advisable to wait about six months for it to dry up to 15%. Aerated concrete walls do not require special insulation, so the house can be operated at first without finishing.

Finishing begins with plastering aerated concrete inside the house, i.e. from the inner walls, but end with the outer ones, and in no case vice versa. Drying should go through the outer wall.

The work is carried out, observing the temperature regime in the range from +8 to +30 C. Optimally - at 15-20 C.

Subject to the recommendations, the correct technology of work and the choice of appropriate materials, plastered aerated concrete walls will last for more than a decade, providing comfortable air exchange, no dampness and no cracks on the surface.

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 gained great popularity, 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 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 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 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 the wall with its high vapor-permeable properties, 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 suitable for aerated concrete, especially in terms of vapor permeability. However, such a wall decoration will significantly limit the owners in choosing a finishing coat, 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 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 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, and 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.