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

Subtleties and tasks of gas silicate plaster

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

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

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

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

Fundamental points

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

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

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

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

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

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

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

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

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

Stages of plastering aerated concrete

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

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

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

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

Reinforcement

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

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

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

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

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

Requirements for plaster application technology

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Plaster for aerated concrete

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

Cement-sand plaster for aerated concrete

Is it possible to plaster aerated concrete with cement mortar?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Gypsum plaster for aerated concrete

Advantages of gypsum-based plaster:

• high drying speed;

• non-shrinkability of the solution;

• the ability to make a smooth surface;

• no need to apply a finishing layer.

Disadvantages of gypsum plaster:

• mediocre vapor permeability;

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

• getting wet quickly during rain or snow;

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

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

Facade plaster for aerated concrete

The most effective material for plastering exterior and interior walls from aerated concrete. Plaster for facade work has a number of characteristics, including a vapor permeability indicator identical to that of aerated concrete (for most types of plasters), good adhesion to the base, and a beautiful appearance.

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

What plaster is best for plastering aerated concrete walls?

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

• vapor permeability;

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

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

• adhesion to the base (minimum 0.5 MPa);

• resistance to low temperatures;

• crack resistance;

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

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

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

Material prepared for the website www.site

When can you plaster aerated concrete walls?

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

How to plaster aerated concrete walls with your own hands

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

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

Internal plaster of aerated concrete walls

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

1. Preparing the base

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

2. Applying primer

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

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

3. Installation of beacons

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

4. Throwing on a “fur coat”

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

5. Processing the first layer

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

6. Formation of corners

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

7. Finishing

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

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

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

How to properly plaster aerated concrete walls - video

External plastering of aerated concrete walls

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

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

External plaster application technology:

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

• surface priming;

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

• reinforcement of plaster with mesh;

How to properly reinforce plaster

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

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

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

• leveling the plaster layer along the grid;

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

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

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

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

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

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

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

Aerated concrete putty

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

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

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

Conclusion

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

Treating walls with plaster: advantages and disadvantages compared to other types of finishing work
Construction and repair technologies are changing, new materials are appearing, but plaster remains a popular method of wall finishing that has stood the test of time. Reliability, thoroughness and durability of the result obtained are strong arguments in favor of plastering.

Drywall, which gained popularity due to its ease of installation and became an excellent option for perfectly leveling walls, could not completely displace its “fundamental” competitor. Although communications are conveniently hidden under sheets of plasterboard and a thermal insulation layer can be placed - these are undoubted advantages, but they do not withstand loads, reduce the area of ​​the room and require finishing - these are disadvantages.

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

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

Selection of material for plastering aerated concrete walls

Aerated concrete (gas silicate blocks) is relatively new construction material, but received 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 conductivity characteristics place special demands on the technology, quality of finishing and 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, while providing good air exchange, can quickly “dry out” a plastered wall and cause cracks to appear on it.

Therefore, the choice of material for plastering aerated concrete surfaces are approached with special care. It is necessary to use specially formulated plaster mixtures marked “For aerated concrete”. They have added components that bring the properties of the plaster as close as possible to the properties of cellular concrete and improve its adhesion, adhesive and vapor-permeable characteristics.
In addition, the solution prepared from these mixtures acquires elasticity and durability and can be applied to the walls in a thin layer.

Sequence of work

For the same reasons, the sequence of work has its own specifics: first they plaster the internal walls, wait for them completely dry, and only then can you begin exterior finishing work. The moisture must completely escape from the inside to the outside, and not vice versa.

The plastering process consists of three stages:

• preparation of the base;
• applying the base layer;
• applying the finishing coat.

Preparing the base. Gas silicate walls They have a smooth, uniform surface with very thin seams, since glue, rather than concrete, is used for laying. 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.

Applying the base layer. After the primer has dried, the dry mixture is diluted with water in accordance with the manufacturer’s instructions and a base reinforcing layer of plaster is applied to the wall using a notched comb trowel. It is reinforced with alkali-resistant fiberglass mesh: it is simply pressed with a trowel into the upper third of the layer and smoothed. The mesh sheets are embedded in the plaster with a one-on-one overlap of 8-10 mm. They prevent the occurrence of deformations, shrinkage and cracks.

Sufficient thickness of the base layer is about 4 mm - special additives in the mixture for aerated concrete make it possible to obtain a durable coating with minimum thickness. The plaster takes a long time to dry - you have to put up with this. As a rule, 1 mm is given 1 day to dry, i.e. The entire layer will dry for about 4 days.

Applying the finishing coat. 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 waited a little until it “sets”, they “texture” it with a plastic trowel - giving it relief. Some finishing coatings do not require further painting, because already contain color pigments.

It would be useful to know that finishing work in a house made of aerated silicate brick is not recommended to begin immediately after the construction of the frame. The humidity of a “fresh” aerated concrete block from the factory is high - about 30%, it is advisable to wait about six months for it to dry to 15%. Aerated concrete walls do not require special insulation, so the house can be used at first without finishing.

Finishing begins with plastering the aerated concrete inside the house, i.e. from the internal walls, and finish with the external ones, and in no case vice versa. Drying should take place through the outer wall.

Work is carried out in compliance with temperature regime within the range from +8 to +30 C. Optimally – at 15-20 C.

If you follow the recommendations, the right technology works and selection of appropriate materials, plastered aerated concrete walls will last for decades, providing comfortable air exchange, absence of dampness and cracks on the surface.

A house made from a material such as aerated concrete has many differences from houses built using foam concrete or brick. Aerated concrete is light artificial stone, which has a porous structure and high thermal insulation properties, which means that the plaster used for aerated concrete is not ordinary.

So what kind of plaster should be used for the exterior finishing of houses made of aerated concrete blocks? What kind of solution should this be, and why can’t you use regular mixtures?

As you may have guessed, to perform external protection of walls, you cannot use ordinary cement-sand plaster mortar. The reason for this ban is that ordinary plaster has lower vapor protection parameters than the aerated concrete blocks that make up the building.

There is an unspoken principle that any multi-layer breathable wall structure must be built using such a method that each subsequent layer has greater vapor permeability than the previous one. The closer to the street, the greater the permeability.

As an exception, it is possible for all layers to have this indicator of the same level, but this is not encouraged.

To work with aerated concrete blocks, you should use exclusively special facade plaster for aerated concrete, which is called that way.

How to plaster aerated concrete

Plastering walls made of aerated concrete is done as follows: apply to the walls facade plaster for aerated concrete blocks. This material is a special porous plaster mixture that has high vapor-permeable properties.

It is advisable to apply the plaster on the mesh so that it does not crack or fall off when it dries.

Plaster, which is used for finishing buildings made of aerated concrete, must have the following necessary qualities:

• bulk weight – about 0.8 kg/dm³;
• fraction within 2 – 4 mm;
• it should be a light plaster mortar belonging to plasters of group P I;
• resistance to compression pressure – class CS I;
• low water absorption coefficient;
• non-flammability - class A1.

The plaster mixture used to finish the façade of aerated concrete houses must have good ductility, it must be easy to process and should be applied on top of the base. This plaster can be applied in a layer whose thickness does not exceed 1.5 cm at a time.

Once hardened, this plaster should have good water-repellent properties.

However, nevertheless, it must have a good throughput with respect to water vapor, and in addition, it must easily cope with the harmful effects of adverse weather conditions.

How to plaster aerated concrete video

It’s worth saying right away that plastering work on aerated concrete is neither simple nor cheap.

If you have already firmly decided to carry out plastering work in a house made of aerated concrete, then use only suitable materials. Don’t forget, this is the guarantee that the work you perform will be of high quality, and the plaster will delight your eye for many years.

Aerated concrete blocks are increasingly used in the field of low-rise construction. That is why the question of how to do interior plastering of aerated concrete walls is becoming more and more popular.

In this article we will look at the features of using various plaster mixtures when finishing low-rise buildings, mainly for residential purposes.

The need for timely finishing of walls

Before deciding what is the best way to plaster walls made of aerated concrete, let’s figure out what this material is and what its characteristics are that can affect the finishing work.

Aerated concrete has a low specific gravity, which allows minimizing the degree of mechanical load on the foundation. The low weight of the building material is explained by the cellular structure of the blocks. And, if low weight is an advantage, then the cellular structure turns out to be a disadvantage.

The fact is that aerated concrete blocks characterized by low hydrophobicity. They literally absorb moisture, like external environment, and from inside the building. By absorbing moisture, the blocks lose their original heat-saving qualities. In addition, excess moisture leads to the gradual destruction of building materials and structures erected with its use.

It is for this reason that plastering of aerated concrete walls should be carried out in a timely manner.

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Features of wet plastering of walls made of aerated concrete blocks

Plastering of construction projects constructed using cellular concrete, must be carried out both externally and internally inside. The finishing process should begin from the inside and then proceed to cladding the facade.

External plaster is a serious mistake aerated concrete walls carried out in the warm season. In this case, interior decoration begins with the onset of cold weather. Meanwhile, the water used in the manufacture of wet plastering solutions will, for the most part, penetrate to the outside both through ventilation and through the cellular concrete blocks.

As a result, water vapor will condense inside the blocks at their interface with the exterior finish, since the walls will eventually be covered with plaster on both sides. With a significant decrease in ambient temperatures, the external plaster, due to the freezing of moisture in the walls, will crack and peel off.

The technology for plastering walls made of aerated concrete does not involve the use of cement-sand mortars, since such a coating will ultimately become a serious obstacle to vapor permeability. As already mentioned, excess moisture in the walls must find a way out, otherwise the external plaster will deform over time and come into disrepair.

Solve output problem excess humidity without damaging the indoor microclimate, there are two ways:

• Through the use of plaster mixtures specially designed and manufactured for finishing structures made of foamed cellular concrete.

When talking about special mixtures that do not interfere with the release of steam, we mean plaster mixtures with a high gypsum content.

Today in any hardware store You can purchase a wide range of gypsum putties for both exterior and interior use. In addition to gypsum, high-quality modern putties include slaked lime and fine-grained perlite sand. Due to such components, the mixtures are characterized by a high degree of adhesion, and therefore before finishing works, the surface of the walls does not need to be primed.

The finished plaster layer of putty acts as a filter material, due to which water vapor is effectively removed to the outside, while practically no moisture from the outside enters the walls.

• Using a vapor barrier film installed from the inside of the room.

Vapor barrier material - penofol

The film laid on the wall before applying wet plaster prevents moisture from penetrating into the blocks, so the type of exterior finishing is not fundamentally important.

At first, plastering of indoor walls was carried out using conventional polyethylene film. As it turned out, the use of such a vapor barrier is not The best decision, since there is a high probability of condensation accumulation and swelling of the plaster. The solution to the problem is the use of polyethylene non-woven fabrics with microperforation.

When using a moisture barrier, it is allowed to use cement-sand plaster mixtures made without the use of dolomite flour or lime as fillers.

Selection of tools for finishing work

Before plastering aerated concrete walls, you need to decide on the choice of tools.

In principle, the tools required are the same as for conventional plastering:

• a plastic container for stirring the solution with a volume of at least 10 liters;
• perforator with variable speed control and a special nozzle for mixing;
• plaster rule;
• spatulas different widths(wide 50 cm and narrow 10-15 cm);
• medium-sized trowel or plastering ladle;
• water level;
• graters for leveling and polishing.

Technology of applying gypsum putty

Modern technology for plastering aerated concrete walls inside and outside using gypsum putties is as follows:

• We prepare the surface. To do this, thoroughly clean the walls from dirt and dust.

To increase the adhesion of the putty and the surface, we use an acrylic primer, which can be applied with a wide brush or roller. At the same stage we install beacons. Of course, you can work without beacons, but with special guides the finishing will be done faster and with better quality.

If the wall does not have significant irregularities, we choose the thinnest beacons to reduce putty consumption. Beacons are installed using thick gypsum or alabaster mortar.

• Prepare the solution. In accordance with the manufacturer's instructions, pour water into a previously prepared container and add dry gypsum mixture.

Tip: It is advisable to mix no more than 10 liters of solution at a time, since this amount is on average enough for 1 hour of work.
If you mix more solution, there is a high chance that it will set before it is completely used.

Detailed description of mixing technology gypsum putty you can find in the relevant articles on our portal.

• Apply the first layer of putty. When plastering along the beacons, we apply the mortar from bottom to top to approximately the bottom of one third of the wall. You can apply the mortar into the gap between adjacent beacons onto a pre-moistened wall with a trowel, or you can apply it with a spatula. The fill layer should be 1-2 cm above the surface level of the lighthouses.

• Level the applied solution. To do this, we apply a plaster rule to the surface of neighboring beacons and move it upward, periodically moving the tool from one side to the other. During the leveling process, putty accumulates on the rule, which must be promptly removed with a spatula and mixed into the bulk of the solution.
• After the first layer of plaster has dried, you can begin final leveling. A new putty solution is diluted, which is applied and smoothed with a wide spatula.
• The final stage of plastering is sanding the finished surface and applying a layer of primer. After this, the wall covering is completely ready for painting work or to applying decorative plaster.

Features of the use of cement-sand mortar

As already mentioned, before plastering the walls made of aerated concrete cement-sand mortar from inside the room, it is necessary to take care of effective vapor barrier.

Therefore, the instructions for carrying out the work are as follows:

• The surface of the wall is cleaned of contaminants, after which a film vapor barrier is applied to it. We attach the vapor barrier film in layers overlapping each other.

• Stuffing plaster mesh. In this case, it is optimal to use a metal mesh chain-link with a mesh side of no more than 3 cm. Of course, you can use plastic mesh, But metal chain link has a relief, which allows the solution to better adhere to the wall surface.
  We attach the mesh strips vertically with a gap between the previous and subsequent strips the width of the lighthouse.
• We install beacons in the gap between the mesh strips. We select beacons so that they are approximately 5 mm thicker than the mesh.
• Cooking plaster mortar in a ratio of 1 part cement to 3 parts sand. Mix all ingredients dry until a homogeneous mass is formed.
  After this, add water in small portions to the dry mixture and mix until the solution reaches the required consistency.
  We determine the readiness of the solution as follows: put the solution on a trowel, tilt the trowel and watch how the solution slides down. The ready-to-use solution slides slowly and does not run off or clump together.

• Sketching and alignment, in this case, is performed exactly the same as in the previously described method.
• After sketching and leveling the solution is completed, the dried surface is rubbed with a foam float. Grouting is carried out in a circular motion with periodic spraying of the surface with water from a spray bottle.
  After the grouting is completed, you can begin applying decorative plaster.

Dry plaster technology

When finishing walls made of aerated concrete blocks with your own hands, you should not forget about dry plaster. Wall finishing using gypsum fiber board, OSB and other materials in the form of slabs is becoming increasingly popular everywhere.

Of course, this type of finish will be an excellent solution for interior work, while outer side walls can be plastered using the usual wet method.

Let's consider the method of framing walls with plasterboard sheets, especially since the price of such a solution is affordable for most people.

Important: average cost per linear meter frame profile is 30 rubles, while 1 sq.m. drywall will cost from 100 rubles.

Finishing work is carried out as follows:

• We install vapor barrier on the walls. For these purposes we use glassine, membrane or polyethylene nonwovens with microperforation. We fix the vapor barrier vertical stripes with an overlap of 10-215 cm on each other.
• We install the sheathing from metal profile. Until recently, sheathing was made exclusively using wooden beams. But wood is a short-lived and expensive material. Therefore, instead wooden products galvanized metal profiles arrived that are light, inexpensive and stainless.

To decorate the walls indoors, you will need a guide, rack and corner profile.

We fasten the rack profile at a distance of 60 cm from each other, while the guide profile can be installed in increments of 1 meter. We fasten the profile with special dowels for working with foamed concrete.

Important: To prevent the drum effect from occurring, mineral wool slabs should be laid in the gap between the gypsum board and the vapor barrier.

• We fasten the plasterboard slabs with self-tapping screws, but no closer than 15 mm to the edge of the sheet.
• We install the top row of drywall with some offset relative to the bottom row.
• After finishing the walls is completed, you can begin to putty the joints between adjacent plasterboard slabs. We do this using a special mesh tape, which we glue to the joints with a putty mixture.

Conclusion

Now you got general idea about the instructions for finishing walls made of aerated concrete blocks. Despite the fact that there is a common opinion about the fragility and fragility of this material, aerated concrete blocks are not much inferior to other building materials.

However, this is only possible if the walls made of foam blocks are protected in a timely manner high-quality plaster from negative impact environmental factors. Again, despite the fact that plastering such walls is considered problematic, the right approach to the point, in accordance with the above recommendations, will ensure the proper quality of the finished result.

More useful and educational information you can find it by watching the video in this article.