How to plaster the sibit inside the house. Plastering of aerated concrete walls indoors: finishing features

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

For the manufacture of material are used:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Plaster for aerated concrete

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

Lime-cement plaster

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

Its main physical properties are shown in the table:

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

Material selection

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

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

The procedure for plastering walls from aerated concrete

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

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

The instructions for plastering walls offer the following procedure for carrying out work:

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

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

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

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

Indoor repairs are carried out in several stages. When carrying out repair work, it is important not to forget about plastering the concrete walls from the inside. Plaster for aerated concrete plays an important role, even when it comes to work in modern panel buildings. As a rule, concrete slabs have an uneven surface, and this defect cannot be corrected with putty alone. Block coverage is necessary for a number of reasons. These include the smoothness and cleanliness of the wall surface.

The ways

For plastering the internal surfaces of a building, during the construction of which aerated concrete was used, two methods are used. The first method consists in the fact that aerated concrete plaster is carried out in such a way as to achieve vapor permeability in concrete walls due to the unique qualities of the material. Builders advise against using mortar and cement and sand for finishing blocks indoors. Aerated concrete blocks instantly absorb liquid, after which they become covered with cracks. It will not be easy to disguise the irregularities that have appeared, even after priming the vapor-permeable wall.

Some specialists are engaged in plastering gas blocks using a different method - vapor barrier. In this case, the microclimate in the room will be the same as in reinforced concrete buildings. The only difference is that such plastering will be more reliable.

Promotes vapor permeability of the walls

The components contained in aerated concrete contribute to the vapor permeability of the building material. However, this factor requires the choice of a certain composition of mixtures for carrying out repair and finishing work on the walls of the building. To do this, it is necessary to do the plastering in such a way that the inner wall is vapor-permeable or, on the contrary, vapor-proof. In a house with such a wall, the microclimate will self-regulate. Also, there won't be any in the wall.

Vapor barrier

In order to treat the inner wall and increase the vapor barrier at least tenfold, specialists apply a solution, the thickness of which should reach two and a half centimeters. The plaster contains cement and other ingredients. Sometimes, for this purpose, workers put a polyethylene film under the layer of plaster. But experienced builders are not advised to carry out such work, since the film can peel off from the plasters and walls due to the appearance of condensation.

What materials and tools are used?

It all depends, first of all, on the task set by the customers and specialists. For its implementation, building materials are selected that can correctly interact with aerated concrete and have the property of vapor permeability. Professionals recommend processing the inner surfaces of the walls from blocks of a mixture with gypsum, sand and lime. Also, builders use tools that include chalk or marble.

For finishing work, specialists use plastering tools. The mixture is prepared in an appropriately sized container. The solution is mixed using a mixer or. Thin-layer aerated concrete plaster is applied to the blocks with a trowel or trowel. Surfaces are rubbed with a float. The poluter is used to remove excess mixture. The surface of the blocks inside the walls is leveled with beacons. Aerated concrete plaster is pulled together by the rule between the guides. The builders determine the quality of the work performed by the rail.

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 carry out 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, first of all, to protect the walls of aerated concrete from the moist wind.

Another option for finishing can be the simultaneous execution of finishing outside and 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 on 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 performance 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:

Before plastering aerated concrete walls with this plaster, it is recommended to spray Baumit Vorspritzer on the cleaned surface of aerated concrete, which is part of the plaster, 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 renders 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.

Pour a bag of the mixture (25 kg) into a container with 6-7 liters of clean water and mix thoroughly 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 not uncommon 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.

Renovation inside or outside the premises will not do without plastering walls and other surfaces. At the design stage of work you need to familiarize yourself with the features of the plaster, which are divided into types, they differ in characteristics and price. The correctly chosen type of finishing material is half the battle, because characteristics of mixtures can differ significantly among themselves, and what is ideal for one type of room may be completely unacceptable for another.

Some features of plaster

Plaster is a mixture that is used for surface treatment as a rough finish. What are the functions of the material? Plaster can be used to level walls, repair cracks and other defects. Itself the structure of this solution is a coarse mixture, therefore, after drying, the surface will have rough surface... These effects can be easily eliminated in the future.

Walls can be plastered of almost any type, concrete and wooden structures will be protected from the harmful effects of environmental factors. Various techniques and materials are used for plastering aerated concrete walls. Trends in the field of construction are developing in such a way that such building material as aerated concrete is gaining more and more popularity. It has many advantages over concrete and brick construction.

The building, erected from aerated concrete, has increased energy-saving properties. This material is much lighter than traditional counterparts, due to this fact, you can reduce the cost of arranging the foundation and the construction time is significantly reduced. What kind of plaster is better to plaster the walls of aerated concrete blocks?

How to plaster aerated concrete walls?

One of the ways to decorate aerated concrete walls is plastering... For plastering walls made of cement-sand type blocks, this is the best option. As for the process of applying the finishing layer itself, if you wish, you can apply it directly to the wall. The same can be done with brick walls. However, this may pose some difficulties.

The brick is small, therefore seams between bricks serve as a connecting element when applying plaster. In the case of aerated concrete, the situation is somewhat different, because aerated concrete itself is large. This problem can be solved in several ways. Let's consider the main ones that are often used in practice.

Walls can be plastered both inside and outside the premises. Both types of finishes have some peculiarities. When choosing a plaster, it is best to select the one with the maximum adhesion coefficient. This is to ensure the quality of adhesion of materials.

Preparatory work

Before applying a layer of plaster, the walls are prepared from aerated concrete, this is necessary in order to ensure adhesion of materials. How is this done and what does this stage of surface finishing include?

First, you need pay attention to the seams between aerated concrete, they need to be well sealed, approximately by 4 - 5 mm... The wall is leveled, and all defects that may occur, dust and other microelements that reduce the quality of adhesion of materials are cleaned out. Sandpaper can be used to clean the surface to help sand the blocks more thoroughly.

How to apply mesh correctly when plastering walls?

If you decide to use the third method of surface finishing, then you need to know what is used in this galvanized mesh... It is more durable, reliable and does not rust. As for the size of the grid cells, you should pay attention to the one in which the cells are small. After carrying out the preparatory work, it will be necessary to attach the mesh directly to the wall. This must be done using ordinary nails. They are hammered into the wall first by one third, after which the nail is bent, fixes the mesh.

Particular attention should be paid to the edges of such a cross, they usually stick out, before applying the plaster, all the edges should be folded, then they will not stick out from under the plaster.

When the mesh is secured it is necessary to start applying the first layer of plaster. This is done in what is known as "Splash", it is mainly used to fill mesh cells with a solution. After it, several more layers of plaster will follow. This will necessarily be a primer layer, which must be kneaded by adding slag sand to the solution. The final layer will be the final layer; fine sand must be used to prepare the solution for it.

All layers of plaster can be apply with incomplete drying of the previous layer... This will shorten the time without compromising the strength and quality of the finishing layer.

Mortar for plastering walls can be purchased ready-made, it is sold in a dry state. To prepare the mixture, you just need to add water. But, you can also prepare a cement-sand mortar yourself. In this case do not skimp on the quality of the cement itself, since the water-repellency of the plaster will suffer as a result. When plastering walls, a lot of tasks and requirements are solved, such as thermal insulation characteristics of the surface, water resistance, noise insulation, and so on.

Plastering of aerated concrete walls requires special materials and a correct application process. If unsuitable materials are used or if the plastering process is not followed, it will not last long and will quickly deteriorate and flake off.

Briefly about aerated concrete

Aerated concrete is a building material that is used to erect the walls of a building. Preferably produced in blocks of 400x200x600 mm (dimensions may vary depending on the manufacturer).

Aerated concrete is produced from components such as:

• Cement.
• Quartz sand.
• Lime.
• Water.

By mixing the above components with aluminum powder, hydrogen is released, which increases the crude solution several times. When concrete hardens, a large number of hydrogen bubbles create its porous structure.

Advantages and disadvantages of aerated concrete

Advantages:

• Good thermal and sound insulation.
• The blocks are lightweight and easy to handle.
• Environmental friendliness of the material.
• High fire resistance.

disadvantages:

• Exterior finishing is imperative.
• The fragility of the material.
• High price.

The use of aerated concrete in construction can significantly reduce time and financial costs, since its laying does not require special skills, and the thermal insulation properties allow you to save on insulation.

Preparing the walls

Since aerated concrete walls have a smooth surface, plaster does not adhere well to them. Regardless of whether external or internal plastering of aerated concrete walls needs preparation before finishing. It is also worth knowing that aerated concrete has a high vapor transmission capacity, this fact must be taken into account when plastering walls from this material.

Preparation of aerated concrete walls for plastering is carried out as follows:

After the walls are prepared and reinforced, you can start plastering work. It should be borne in mind that after reinforcing the walls with glue, you need to wait a few days, since the glue has poor water absorption when it dries and the plaster may lag behind.

Technology

Aerated concrete wall plastering technology consists of the following stages:

1. Preparing the walls.
2. Priming the walls. It is recommended to use a primer based on acrylatesiloxane.
3. Reinforcement of walls. For wall reinforcement, I use a fiberglass mesh that is resistant to stretching and has a high tensile strength.
4. Installing beacons... Beacons are installed at a distance of no more than 120 cm from each other. The use of beacons allows you to perfectly even plaster the walls. If the walls are even, beacons can be omitted.
5. Application of the first layer of plaster. The first layer of plaster is poured with a methodical bucket or trowel, after which it is leveled with a wide spatula or a wooden lath of at least 1 meter.
6. Application of the second layer of plaster... For the second layer, it is necessary to use the finishing plaster, it has fine sand, which allows you to hide the flaws of the first layer. The second layer is applied in the same way as the first, only it is smoothed more carefully.
7. Grouting. A few days after the application of the plaster, the joints can be trowelled. Grouting is done with a wooden float, after slightly moistening the wall with water. Rub the seams, lightly pressing the grater against the wall in a circular motion.

After grouting, the walls are ready and you can apply decorative plaster or wallpaper. Finishing work on plastered walls must be carried out only after they are completely dry.

The choice of facing for aerated concrete

Plaster mixes for aerated concrete walls must necessarily have the following properties:

• Good durability.
• Resistance to atmospheric influences.
• Good waterproofing properties.
• High vapor permeability.
• Elasticity.
• Good adhesion to walls.

These are one of the main criteria for aerated concrete wall plaster for interior and exterior decoration.

Aerated concrete wall cladding can be made with the following materials:

It is important to use plaster designed for aerated concrete walls. The use of other types of plasters in the future may lead to their flaking.

Working conditions with facing material

For high-quality and durable wall plaster, you must adhere to the following conditions:

1. Consistency plaster first external then internal.
2. Plaster walls can be carried out after the end of all wet screed, puttying, etc. Walls must be thoroughly dry after previous work.
3. Plastering walls can be produced at a temperature of +5 +30 degrees. In no case should work be carried out at sub-zero temperatures, as the plaster will fall off.

You should also be aware that for buildings made of foam concrete for exterior decoration, foam plastic cannot be used, since it does not have vapor permeability properties, and the accumulated moisture between the wall and the insulation will contribute to its delamination.

Interior and exterior decoration

The process of plastering external and internal walls consists of the following stages.

Internal plaster:

• Initially, the walls of the building must be carefully prepared. Clean them from mortar residues, paint, bitumen stains, dust and dirt. If necessary, the walls can be washed with water and soapy water. It is also necessary to seal all the seams and joints of the blocks with a special putty.
• After the putty is dry, the walls can be primed. The primer must be compatible with the applied plaster. The primer is applied evenly with a roller or brush, in two layers, without missing a single section of the wall. After about three hours, the primer is dry and the process of plastering the walls can be started.
• Initially, it is necessary to apply a starting layer of the solution., made according to the manufacturer's instructions, which are indicated on the packaging. The mortar is evenly applied to the wall surface with a metal trowel or spatula.
• After the first layer is dry you can apply the finish in the same way. After a day, the dried plaster is rubbed with a wooden float, pre-wetting the wall with water.
• At the final stage the plastered wall can be painted with vapor-permeable emulsion paint.

External plaster:

• Exterior wall decoration must be made strictly with materials that have vapor permeable properties. Just as for internal plaster, it is necessary to clean the walls and remove all cracks, chips, etc. This can be done with tile adhesive. The ambient temperature at the time of plastering work should be from +10 to +25 degrees.
• After the walls have been prepared, the fiberglass reinforcement mesh must be reinforced. You can strengthen the mesh with glue or wood screws. The mesh prevents the mortar from dripping and holds it well on the wall, and also avoids cracks when the plaster shrinks.
• The next step is the application of plaster. Plaster is applied in the same way as for interior decoration. You should know that it is necessary that the vapor transmission capacity of the plaster is higher than that of aerated concrete. If necessary, you can install beacons to level the walls.

  You should also know that the thickness of the outer layer of the plaster should be two times less than the inner one.

  Plaster leveling is done with a wooden lath.

• When the plaster dries up, it is necessary to grout the joints and flaws. After 48 hours, the plaster will dry and you can carry out the final stage of finishing work.

Therefore, it can be summed up that finishing a building made of aerated concrete is an expensive pleasure, but saving on materials will lead to much disastrous consequences and high financial costs.

Plastering of aerated concrete walls with cement-sand mortar

In order to save aerated concrete walls, you can plaster with a cement-sand mortar, this is done as follows:

• Initially, you need to prepare the walls: for this, it is necessary to remove dust, dirt and glue residues from them, and then prime.
• The next step will be to reinforce the walls with fiberglass mesh and the usual cheapest tile glue. With a spatula or metal trowel, glue is applied to the primed surface of the wall, after which a mesh is applied. After that, the attached mesh must be smoothed horizontally with a notched trowel. When the glue dries, you will get a grooved surface that will promote good adhesion of the cement-sand plaster.

  Thus, in addition to reinforcing the wall, the seams of the blocks are smoothed out and small irregularities in the wall are removed, and the glue grooves will prevent the plaster from sliding during its application. And the fiberglass mesh will prevent cracking when the plaster shrinks.

• After the glue has completely dried, you can start plastering the wall. To do this, it is necessary to mix a cement-sand mortar with a ratio of 1: 3 and throw it on the wall with a ladle. After that, with a long rail with light movements from left to right, distribute the solution evenly along the wall, this procedure must be repeated until the wall becomes even.
• When the walls are completely plastered and dry, you can start grouting, after which the walls will be ready for further finishing, wallpapering or decorative plastering.

Plastering bare walls made of aerated concrete with a cement-sand mortar is unacceptable, since it does not have good enough adhesion and will slip, and cracks will appear when dry.