How to plaster walls made of gas silicate blocks from the inside. Features of plastering walls made of aerated concrete indoors and outdoors Plastering a house made of aerated concrete

Aerated concrete is gaining increasing popularity as a building material. And this is not surprising. The large sizes of the blocks can significantly reduce construction time, and the cellular structure retains heat, allowing you to reduce heating costs. But this material requires serious protection from moisture.

Aluminum powder is added to the basic solution from which aerated concrete is made. At one stage of the technological process, this component releases gas, forming cells filled with air. In this case, the pores remain open and moisture quickly accumulates in them.

Therefore, the material is protected from precipitation both at the stage of wall construction and after the “box” of the house is ready. Moisture accumulated in autumn or spring will also quickly disappear under the influence of sunlight. But in winter this factor will be destructive. And over time, small cracks will appear on the walls, and then peeling.

In addition, aerated concrete has the following characteristics:

Low thermal conductivity.
Strength depends on the foundation. If it shrinks strongly, then cracks will soon appear on the gas block.
Durability if the material is protected from water.
Fire and environmental safety.
Soundproofing properties.
High vapor permeability, which makes homes comfortable, since internal vapors quickly escape outside rather than accumulating indoors.
High levels of moisture absorption, which forces the house to be lined with moisture-repellent materials.

When is the best time to plaster aerated concrete walls?

Most often, plastering is chosen for finishing aerated block walls. But you need to choose the right time to complete the work, as well as the appropriate composition. We’ll look at the type of plaster for the facade a little lower, and now we’ll look at the timing of the finishing work.

You should not plaster immediately after construction. The walls are given time to completely dry and shrink. It's enough to wait a year. If this is not done, cracks will appear on the finish.
Choose a warm season when the night temperature does not drop below 0 degrees. In such a situation, the moisture that the aerated concrete absorbs from the solution will quickly be released and the finish will dry.
To protect the walls from moisture and frost in winter, they are covered with deep penetration soil. Under such protection, the house will withstand the load of one frosty season without changes in the structure.
Polyethylene film is also suitable as a barrier for unlined walls.

Is it necessary to first insulate the outside?

As mentioned above, walls made of this building material retain heat well. Therefore, if you correctly calculate the thickness of the structure, there is no need to insulate the house. It is better to do this by using the services of professionals. They take into account the climatic conditions of the region where the structure is being built.

You should not make the walls too thin so that they need additional insulation, since choosing insulation will be difficult. An aerated concrete structure has high vapor permeability, and if the thermal insulation fails to cope with this task, condensation will appear on the outside of the wall. This will lead to both the destruction of aerated concrete and insulation.

If it is necessary to carry out insulation, then choose a material that can allow steam to pass through from the interior. According to the rules prescribed in State acts, the vapor transmission capacity from the internal walls to the external decoration should increase. Only in this case will it be comfortable to be in the rooms, and mold and mildew will never settle on the walls.

What mixtures are best to use?

When choosing a mixture for plastering aerated block walls, note the presence of the following properties:

Moisture repellent.
Good adhesion to the base.
Low temperature resistance.
Elasticity.
Decorative.

The assortment of construction stores offers several types of plaster mixtures. They all have positive and negative aspects to use. It is especially important to use suitable options for plastering aerated concrete. Therefore, we will consider each type separately.

Lime-cement

This is an example of thin-layer lightweight plaster. It is used only for interior work. It is not worth using ordinary cement mortar. It does not have the necessary characteristics to preserve the properties of our material. But with the addition of lime, everything changes:

The mixture adheres well to the base.
Apply a thin layer.
The vapor permeability of the solution increases.
The finish is durable.
Inert to the appearance of mold fungi.
Affordable low cost.

There are, of course, several disadvantages:

The finished solution hardens quickly, making it difficult to work with, especially for a beginner.
A high consumption per square meter implies an increase in costs, even if the cost of the product is low.
The solution is prepared independently, since only the dry mixture is sold.

Acrylic

This option is used for decorative facade finishing of aerated block houses. It is applied in a thin layer, but has a number of advantages:

durable;
elastic;
resistant to low temperatures;
the color retains its original brightness for a long time;
helps strengthen the foundation in places where the load is increased;
repels moisture.

Despite the large number of advantages, there are some disadvantages that raise serious doubts about the correct use of acrylic compositions for aerated concrete:

Low vapor permeability. Waterproofing is installed on the base or a ventilation system is built in the house.
Acrylic composition is highly flammable, so it is not suitable for wall areas near fire.
High price.

Silicate

Compositions based on liquid glass are excellent for both interior and exterior decoration. This plaster is sold only in finished form. Mix it thoroughly before use. The main advantages are:

vapor permeability;
moisture-repellent properties;
large selection of textures;
affordable price.

But before plastering aerated concrete, it is worth studying the disadvantages that exist here, like any other material:

Dirt and dust accumulate on the finishing surface, which reduces the attractiveness of the coating.
Small selection of colors and shades.

Silicone

This option is made on the basis of silicone emulsions or resins. It is excellent for finishing facade walls. It has the following undeniable advantages:

Hydrophobic (repels moisture, practically does not get wet).
Vapor permeability.
It’s easy to apply, making it suitable for those who decide to do it themselves.
Plastic.
Crack-resistant.
Retains its original color for a long time.
Easy to clean from dust and dirt.

The only drawback is the price, which is an order of magnitude higher than previous options. But is it worth saving your time and day if the material has so many advantages?

Cement-sand

The most famous and affordable option for plaster mixtures, which is perfect for different substrates. But aerated concrete cannot withstand the use of a cement-sand mixture. Everything is due to the lack of certain characteristics.

Is cement mortar suitable for these purposes?

If a beginner gets down to business, then he should learn all the intricacies of plastering aerated concrete. One of these nuances is the impossibility of using a conventional cement-sand mixture. The reasons for this are:

Low steam transmission capacity.
The solution has a large amount of moisture. The gas block quickly absorbs water and then releases it for a long time, which increases the time required to complete the work. In addition, when moisture quickly evaporates, cement plaster loses its strength, resulting in cracks.
Aerated concrete has a smooth surface, and the cement-sand mixture has low adhesion rates. Therefore, the solution does not adhere well to the base and can slide off during work. To avoid this, the walls are coated with aerated concrete primer, but this does not always help.

Add lime to the usual solution.
Mix a special mixture for aerated concrete blocks and cement mortar in a 1x1 ratio.

What about adhesive for porous concrete?

A special adhesive mixture, which is intended for laying aerated concrete, should also not be chosen as a material for plastering walls. Although the glue was developed taking into account all the nuances of using a porous material, it is not suitable for plaster:

Apply only a thin layer.
Designed for grouting joints.
Does not have the ability to pass steam. Which leads to the appearance of condensation on the internal walls, and then mold.

This material is used only for its intended purpose.

Interior decoration

It is customary to carry out internal leveling of walls using plaster first. Thus, the moisture that is absorbed from the solution will leave the thickness of the wall faster. on internal walls made of aerated concrete are not much different from plastering other surfaces. Follow this plan:

Preparing the base. Removal of bumps and other irregularities. It is better to do this while the walls are being erected, since in the future this will lead to increased waste of mortar.
Padding. It is advisable to choose deep penetration soil, especially for rooms with high humidity, such as a bathroom or kitchen. Never dilute the primer with water. This reduces the quality of the soil layer.
– help control the thickness of the applied layer. The distance between elements is slightly less than the length of the rule.
Spray or throw on the first layer. The solution should not reach the top edge of the beacons.
Forming corners using a perforated profile with reinforcing mesh.
Applying the second layer. The thickness will be less. The solution is also poured, but is immediately leveled by the rule. At the same stage, beacons are removed.

If the surface is to be painted or covered with wallpaper, the surface should be made perfectly smooth. To do this, apply a finishing layer and rub it in.

Outdoor

After the interior work is completed, they begin to improve the façade. Be sure to check the dryness of aerated concrete. Plaster applied to wet walls may peel off. It is also important to choose the weather conditions:

The optimal temperature is from +5 to +25 degrees Celsius.
No wind.
Air humidity is no more than 80%.
It is better to hide the walls from direct sunlight.

Preparing the wall

Aerated concrete has a smooth, even surface, and therefore there is no additional need to level the walls. But during the masonry process, sometimes small voids appear in the seams or chips on the blocks. They are sealed with the same glue on which the material was laid.

All flaws are filled with the solution and left until completely dry. Therefore, the treated areas are rubbed with a metal grater in order to remove the protruding solution. Remove dust with a brush or damp cloth, but make sure that the material is not too wet.

Padding

For priming façade walls, deep penetration compounds are chosen. They create a durable film that prevents the absorption of moisture, but at the same time steam passes through quietly. Also, an additional layer will increase the adhesion of the plaster and the base.

The soil is applied in several layers, depending on the climatic conditions of the area. To do this, use a roller or brush. The composition completely covers all walls without bald spots. If there are corners or other inaccessible places, they are treated with a small brush.

Plastering and reinforcement

Reinforcing mesh must be used, even if the layer is small, about 1 cm, and the base is well treated with soil. This will make the plaster layer durable and reliable. Select a fiberglass product that is resistant to alkali.

Reinforcement and plastering are carried out simultaneously, following the following plan:

Cutting the mesh into strips.
Prepare the solution according to the instructions indicated on the package if you purchased a dry mixture. The finished solution is simply mixed so that all components are evenly distributed.
Scoop the solution onto a wide spatula and spread it evenly over the surface, about 0.5 cm thick.
A special perforated profile with reinforcing mesh is applied to the corner. The mesh is smoothed over the applied solution.
Next, separate pieces of mesh are laid. Be sure to make a 5–10 cm overlap. The reinforcement is smoothed by immersing it in the solution. In places where it shows through, add a little mixture and smooth it out again.
The surface is treated in small areas with the expectation of complete use of the finished solution.

After the entire facade has been plastered, it is left to dry completely. There should be no imperfections or protruding reinforcement on the surface.

Finishing layer

A decorative composition is chosen as the finishing coating. The solution is either prepared according to the instructions or mixed in a container. Apply with a wide spatula. The layer does not exceed 0.5–1 cm. At this stage, work especially carefully, since the remaining flaws will be noticeable.

When the layer dries a little, it is rubbed and either a smooth surface or a texture is created, respectively. Then the layer must dry completely and only after that you can start painting, if necessary. , in this case, is selected as carefully as the mixture for plastering.

One of the popular wall materials used for the construction of private houses is aerated concrete. But despite its popularity, very often at the stage of finishing an already built house, fatal mistakes are made, due to which the natural microclimate of the aerated concrete house is disrupted. And before proceeding to a detailed description of the facade treatment process, you need to understand why such misconceptions arise, how to avoid them, and what facade plaster for aerated concrete should be like.

A little about aerated concrete

To understand finishing issues, let's move a little away from this topic to understand how important it is to do everything correctly and what affects the cladding technology. To do this, you need to plunge into block production technology. And to briefly summarize its description, special additives are introduced into the finished cement-sand mortar, the reaction of which results in the formation of a porous structure. If we look at the body of gas silicate concrete in more detail, we will notice not only microvoids, but also many channels dotting them, forming an “open” cellular structure, which has a lot of positive properties, such as:

high heat capacity. It is provided not only by the porous body of the blocks, but also by their precise geometry, which allows the use of a minimal joining seam from a special adhesive composition that prevents the formation of cold “bridges”;
noise insulation;
not susceptible to various fungal formations;
The “open” structure of concrete creates a unique atmosphere inside the room - it will remain cool in the summer and warm in the cold season. But if this natural vapor permeability system is disrupted, for example, by improperly plastering walls made of aerated concrete, then the house will become stuffy, and condensation will begin to accumulate on the walls, which will lead to the appearance of mold.

But the cellular structure of aerated concrete blocks also has certain disadvantages:

a high degree of water absorption leads to rapid destruction of walls without the possibility of restoration. Therefore, special attention is paid to waterproofing;
the structure, consisting of open pores, is very well ventilated, which makes the house quite cold, even despite a good heating system;
The heterogeneity of the body of blocks, even of the highest density, makes them susceptible to mechanical stress, which is imprinted in the form of large chips and potholes.

But is it necessary to plaster aerated concrete blocks or is it necessary to install a more thorough cladding? Of course, the ventilated facade system is an ideal option for decorative protection of walls, but if you choose the best way to plaster aerated concrete on the outside and follow the technology, then this finishing method will be no less effective.

When is the best time to plaster gas silicate walls?

Aerated concrete belongs to the family of cellular concrete, so it has some common properties, namely shrinkage. This phenomenon is inevitable, and if finishing is done earlier than six months later, then cracking is inevitable.

But as we remember, aerated concrete does not like water, so immediately after erecting the walls, they need to be treated with a deep penetration primer, which reduces water absorption. To be on the safe side, you can cover the walls with polyethylene.

The rest of the plastering is best done in the summer, but if the planned finishing occurs during a colder period of the year, then it can be carried out when the temperature at night does not drop below 0 0 C.

The quality of an erected aerated concrete structure directly depends on the sequence of finishing the interior and exterior of the building. Let's consider possible methods, analyzing their advantages and disadvantages.

Method 1 - parallel plastering inside and outside the house

The production of such finishing is very convenient from a technical point of view and significantly saves time. But if we consider this method from the other side, then it is less preferable, since the quality is lost and the characteristics of the newly built house suffer.

Any technology for plastering aerated concrete walls involves significant evaporation of moisture. Of course, most of it will disappear with the help of natural and artificial ventilation, but the bulk of the moisture will fall on the walls. Plastering the outside at the same time will clog it for a certain time, which is undesirable.

Method 2 - when exterior finishing is carried out first

It is more logical to initially finish the walls made of aerated concrete from the outside in order to prevent their destruction under the influence of atmospheric conditions. But this is not entirely true; if you do this, the vapors will be directed inward, which is extremely undesirable.

But even primed walls that have overwintered will easily give up moisture and all the vapors in the spring, without destroying the structure. But if a house is built near a body of water, then priorities change, and under such circumstances, you first need to protect the walls from the street from exposure to abundant moisture.

Method 3 - when interior finishing is done first

Of the proposed options, this is the best, because the volume of moisture formed during finishing will freely come out through the unclogged pores of aerated concrete. After the plaster has completely dried, you can safely begin cladding the facade.

Treating the walls with a deep primer using this finishing method will not interfere with the removal of excess moisture.

Which mixture is preferable as facade plaster?

The building materials market is replete with a huge range of plaster mixtures intended directly for processing aerated concrete. If you believe the manufacturers, then they are all the best in their field. But this is far from true. The characteristics of the main groups of plaster compositions summarized in the table will help you decide.

Type of plaster	Advantages	Flaws
Silicone mixtures based on silicon-organic polymers	resistance to water absorption; does not deteriorate under the influence of precipitation; high level of vapor permeability; easy to apply	high price
Silicate plaster based on liquid adhesive glass	hydrophobicity; low water absorption	not aesthetic appearance after dust settles; limited choice of colors
Acrylic mixture	high strength; good decorative qualities	flammability; low vapor permeability. But this can be corrected by using enhanced protection against moisture and organizing a powerful ventilation system for the room.
Mineral plaster: lime-sand; cement-sand	resistance to temperature changes; good adhesion; resistance to cracking; vapor permeability; low cost	does not have high decorative qualities

All vapor-permeable plaster, except mineral, is produced in the form of a ready-made mixture. In this regard, when studying the characteristics of various types, pay attention to the setting time. The longer it is, the easier it will be for beginners to apply the mixture.

But still, preparing a conventional cement plaster composition is much more profitable from an economic point of view. Therefore, all inexperienced builders are tormented by the question: “is it possible to plaster aerated concrete with cement mortar?” The answer is clear - no, for the following reasons:

low adhesion to gas silicate surface;
high humidity, which is detrimental to such cellular walls;
low coefficient of vapor permeability, which will not allow moisture to escape.

Some craftsmen even manage to mix concrete mortar with plaster mixture in pursuit of profit. But instead they get a bunch of problems and the need for large amounts of money to correct the consequences.

Independent finishing of the facade with plaster

There is nothing tricky about how to plaster aerated concrete as competently as possible. Then it's a matter of technology. Plastering can be carried out using several technologies:

thin layer;
thick-layer.

There is no particular difference between them; the choice is yours, depending on which method will be more convenient for applying the plaster.

Preparation

In both cases, before finishing, you need to prepare the base.

Stage 1. The walls are cleaned of dirt with a stiff brush.

Stage 2. Defects in masonry joints are eliminated with an adhesive composition.

Stage 3. If there are potholes in the blocks, they also need to be “patched” with the same masonry adhesive or polyurethane foam.

Stage 4. Beacons are mounted on the nails - profiles along which the alignment will take place.

Stage 5. The base of the walls is primed with a hydrophobic composition with a surface 2–3 mm thick.

Stage 6. After it has dried, a composition for 5 mm reinforced fabric is applied.

Stage 7. A reinforcing mesh (fiberglass or metal) is attached to the walls with an overlap of 5 cm. It is better to do this with mortar rather than with self-tapping screws. Since in the first case, the mesh will become one with the wall and, accordingly, will “sit” together with the aerated concrete, preventing the appearance of small cracks in the plaster layer. Plastic corners are installed and secured using the same principle. Only after the reinforcing plaster has dried can you continue.

Thick-layer surface plaster

When plastering using this technology, it means applying one layer sufficient to perfectly level the wall - at least 10 mm.

Stage 1. Dilute the plaster mixture in a small amount.

Stage 2. The composition is thrown onto the walls.

Stage 3. The rule is to level the plaster along the beacons.

Stage 4. After plastering the entire surface of the walls, wait until it is completely dry and only then can you paint if desired.

Thin layer surface plaster

Plastering walls using multilayer technology is also not difficult and is more suitable for beginners.

Stage 1. The first layer is applied 3-4 mm over aerated concrete. Only after it has completely dried can you continue.

Stage 2. The applied plaster is considered leveling, so special attention must be paid to evenness. Again we wait for complete drying - about 3-4 days.

Stage 3. The final step is to cover the finishing surface, which can later be rubbed down if necessary.

Stage 4. After the previous application has dried, the walls can be painted.

To increase the service life of the plaster, you need to treat it with a water-repellent solution. It will extend the life of the plastered surface almost twice. The use of such compositions is especially important in areas with high humidity.

As you can see, plastering walls yourself is not that difficult. In the first 10 m2 you will develop your own style of application, after which the process will go much faster.

Requirements for plaster

The range of products for the job is quite large, but not all of them are suitable for gas silicate plastering. The surface of the material is porous, which causes difficulties. Let's consider the requirements for the plaster mixture:

vapor permeability, thanks to which a wall made of gas silicate blocks will breathe;
if work is carried out outside, then the plaster chosen is moisture-resistant and frost-resistant in order to withstand atmospheric influences;
high quality of adhesion (adhesion to the surface);
good strength;
elasticity, so that it can be easily applied, and the plaster does not crack during use;
resistance to elevated temperatures to ensure fire safety.

All this is important to consider before plastering gas silicate blocks. Most of the modern mixtures meet almost all criteria. If we talk about finishing gas silicate blocks from the inside, then it is much simpler, since the composition does not have such an aggressive effect.

Which mixture to choose

The question arises, how to plaster gas silicate blocks inside? Some people prefer to use cement-sand mixtures for plaster. But it's not right. There are two good reasons for this:

The quality of adhesion to the wall is low. Aerated concrete, due to its porous structure, will quickly absorb all the water from the mixture. As a result, the plaster will become covered with cracks when it dries. Even a primer does not always help get rid of this phenomenon.
This plaster will significantly reduce the vapor permeability of a wall made of aerated concrete blocks. The microclimate will be disrupted, and condensation will form on the walls. For walls made of brick or foam concrete, this is not so important. And a house made of gas silicate must breathe.

Instead of a cement-sand mixture, a specially developed plaster for gas silicate blocks is recommended. It has all the necessary properties needed for work. For specifics, we will provide a list of popular compositions: Ceresit ST 24, Atlas Silikat, Glims TS40 Velur, Mask +MSh, Sibit. Average plaster consumption is up to 9 kg/m2.

Note! It’s better to do the plastering yourself, as the price of a professional’s work can be steep. Plastering 1 m2 of wall will cost 300 rubles, priming and putty – another 300 rubles/m2, reinforcing the wall with mesh – 100 rubles/m2, finishing painting – from 120 rubles/m2.

The nuances of working with gas silicate blocks

You cannot compare ordinary brick or concrete with gas silicate. The material has special properties. Plastering walls made of gas silicate blocks has its own difficulties:

Considering all this, you can begin the process of plastering the walls. But first, let's take care of the necessary tools and materials.

Arsenal for plaster

Let's start with the fact that plastering work will be carried out on the beacons. This will make the surface perfectly flat and will simplify the task for beginners. Below is a list of tools that will be required for the job:

Rule for stretching and leveling plaster between beacons.
The lighthouses themselves are made of wood or metal. These are slats or profiles that serve as a guide.
Tape measure, plumb line, marker, level, dowels and screws.
The primer for gas silicate blocks under plaster is done using a roller and a paint brush.
Throwing the plaster is done with a ladle or trowel.
To prepare the mixture, use a bucket and a construction mixer.
Grater and grater.

As for materials, everything is simple: primer, selected plaster, fiberglass mesh, topcoat.

Preparatory stage

It all starts with preparation. It is very important, since the final result directly depends on it. The instructions are:

To begin with, the surface is cleaned of all unnecessary things: dust, dirt, stains, old coating.
After which a primer is applied. It’s easier to do this with a roller, and treat hard-to-reach places with a brush.
Alternatively, you can make notches on the wall instead of primer. They are made by a grinder.
In the end, all that remains is to install the beacons. This is one of the difficult stages, without which gas silicate plaster will be problematic.

Installation of beacons begins with markings on the wall. To begin with, you need to retreat 30 cm from the corner of the wall, 15 cm from the floor and ceiling and draw a straight line. Do the same on the other side. At the points where the lines end, drill a hole, drive in dowels and tighten the screws. Align the resulting fasteners so that they have the same depth. Mark the rest of the wall too, maintaining a distance of 130-150 cm from the lines.

Note! The distance from the beacons should not exceed the length of the working rule.

Then they are connected horizontally with a thread, forming a rectangle on the wall. Markers mark the places where the thread intersects with the line drawn inside. A hole is drilled there, a dowel is inserted and a self-tapping screw is screwed in. It remains to pull the diagonal threads to check the evenness. All elements must be in the same plane.

All that remains is to install the beacons along the drawn lines. Installation is carried out using mortar or fasteners. If the walls are relatively smooth, you can get by with fixing it to a mortar, which is applied in small portions along the line at intervals of up to 20 cm. The profile is sunk into the mortar and aligned using screwed-in screws. Now you can apply the plaster.

Plastering walls

The work begins with preparing the solution. Usually the instructions are indicated on the product packaging. You will need a construction mixer and a mixing container. The consistency of the plaster should resemble a paste. If there is no primer layer, the wall is slightly moistened. Step-by-step instructions for plastering gas silicate blocks:

Using a trowel or ladle, the composition is applied to the wall in a thick layer. The work is done from below, moving upward. You should not fill the entire wall, but only one section of the two beacons.
Then, using the rule, the gas silicate plaster is stretched and the surface is leveled. In this case, the movements should be zigzag, starting from the bottom, moving up.
Excess composition is thrown on top. Work continues until the entire section is filled and perfectly level. Advice! The thickness of the layer depends on the location of the beacons. If the thickness exceeds 3 mm, then a reinforcing mesh is needed. It is sunk into the solution. The surface should be smooth and without wrinkles.
According to this principle, the entire surface of the wall made of gas silicate blocks is processed. Particular attention should be paid to the corners. They must be smooth and well reinforced.
When the wall is processed and has dried a little, the beacons can be removed from the walls. After them, the grooves will remain without solution. They are also filled with the mixture and leveled.
The evenness of the resulting wall is checked using a level.
When the surface has dried, you can begin sanding the walls. It is done with a grater and a grater.

At this stage, the wall plastering stage is completed. Further manipulations depend on the finishing decorative layer. If you plan to decorate with wallpaper, paint or decorative plaster, then the surface is treated with starting and finishing putty. After this, you can paint it or wallpaper it. That's all, the work on plastering the gas silicate blocks is completed.

Let's sum it up

By doing all the work yourself, you can save tens of thousands of rubles. The money saved can be spent on furniture, high-quality finishing materials or something else. If this is your first time doing this work, it is better to study the entire process in detail and only then start plastering gas silicate blocks. Doing everything yourself is quite possible. All that remains is to put all this into practice.

The article popularly talks about widely used building materials, lightweight concrete, the main characteristics and methods of finishing using traditional technologies, and plastering of house elements.

Plastering aerated concrete walls

Plastering interior and exterior structures made of lightweight concrete is the most commonly used method of protecting against the effects of external climatic conditions and giving the house an original, respectable appearance, as well as internal comfort.

The prevalence of the technology is due to the ability to inexpensively and independently carry out a set of works on the preparation and finishing of structures and achieve the desired results.

Special characteristics of aerated concrete blocks

Aerated concrete refers to cellular concrete and consists of quicklime, cement, sand and gas-forming aluminum powder. When mixing components and water, a reaction occurs with the release of gas, forming voids, the number of which determines the weight, density, thermal conductivity of concrete and areas of use:

Concrete with a density of 300-400 (kg/m3) is used for thermal insulation.
Density 500-900 (kg/m3) allows it to be used for constructing partitions and walls.
With a density of 1000-1200 kg/m3, concrete is used to make load-bearing walls.

Concrete has gained popularity in housing construction due to its properties:

Low thermal conductivity allows it to be used as a heat-insulating substance.
Frost resistance can reach 150 cycles; among lightweight concrete, only expanded clay concrete has greater durability.
High fire resistance.

One of the negative qualities for construction is hygroscopicity, which means that aerated concrete needs a coating.

The hygroscopicity of aerated concrete requires isolation from moisture.

Preparing gas silicate blocks indoors for plastering

In aerated concrete the amount of cement is up to 60 percent, in gas silicate concrete no more than 14, lime is twice as much, the rest is sand. The percentage matters because the more cement, the higher the strength, and the base must be stronger than the coating, otherwise it will peel off. That is, the finishing of the house must be done with a lime-cement composition.

When finishing, you need to remember that the base must be stronger than the coating.

The main function of plastering surfaces made of gas silicate blocks is to form a vapor-impermeable barrier and limit moisture absorption. To improve the adhesion of the coating to the base, the structural elements are coated with a deep penetration primer, the first layer is applied generously, preferably with a spray gun, after drying it must be painted over again.

After priming, given that the gas silicate composition of the base is weak, it is necessary to carry out reinforcement to prevent the appearance of cracks.

The rough layer of reinforcement is made from the glue on which the blocks were laid; experienced craftsmen use tile adhesive for this as a cheaper composition.

The use of glue instead of a conventional solution is associated with polymer additives in the composition, which ensure strong adhesion with a thin layer of the mixture.

After applying a thin layer of glue, 2-7 millimeters thick, a fiberglass mesh is embedded into it, which fixes the blocks and serves as a reliable base for the coating. The mesh is overlapped over the applied glue and pressed in with a notched spatula.

It is advisable to start applying the solution after 5-7 days, when the reinforced layer gains strength.

Plastering gas silicate blocks inside a building: technologies used

Protection of gas silicate structures occurs in three stages:

1.Plastering with lime-cement mortar.

2.Priming.

3. Putty.

A lime-cement or lime-gypsum mortar no more than one centimeter thick is applied to the reinforced surface.

The technology of manual plastering is common; if the wall is large and uneven, beacons are installed and the applied layer is leveled using a broad rule.

The solution is mixed in a bucket, small tank or trough, water is poured into the poured mixture and stirred to the required consistency, you need to cook a little, gypsum sets in 20 minutes, cement needs a little more time, so the amount should be sufficient to be processed during this time. You can level it immediately after laying it on; the last step is grouting.

After finishing, use a long strip to check the evenness of the surface; unevenness within 5-7 millimeters will not be noticeable.

Is it necessary to plaster the aerated concrete block from the outside?

The need to protect the façade made of aerated concrete is due to its properties:

Hygroscopicity will lead to the saturation of gas blocks with water, which in frost will cause destruction of the structure.
Mechanical impact will cause chips, dents, and cracks.
The material has a porous structure with open pores through which circulating air carries away heat.
An unfinished aerated concrete house looks unpresentable.

For aerated concrete structures, the danger is the accumulation of moisture inside the blocks, which freezes and destroys the block from the inside due to temperature changes. Therefore, the protection of external surfaces is mandatory; the plastering method of protection is widely used for various reasons, one of which is the low cost of this technology.

Materials used for exterior work

To apply protective agents externally, substances with the following qualities are required:

permeable to water vapor;
not getting wet;
with good grip;
resistant to frost.

The main types of mixtures for finishing aerated concrete outside:

Acrylic for aerated concrete, strengthens loaded structures, base.
Silicate, include liquid glass;
Silicone, based on silicon-organic polymers, is well suited for facades, but high in price;
Gypsum mixture;
Lime-cement composition.

Do-it-yourself internal plaster of aerated concrete block: features of the work

Due to the high hygroscopicity of the material, plastering inside the house has its own characteristics.

Plastering surfaces must necessarily include a reinforcement process. It is recommended to use fiberglass mesh, which does not break down in an alkaline environment.

The surface should be painted with a deep penetration primer twice.

Apply a thin layer of plaster about 5 millimeters thick and embed the mesh in it. After drying, apply the base coat using beacons.

Which is better plaster

If vapor permeability is required for the kitchen, bathroom or sauna, mixtures of gypsum with perlite sand are used. Silicate is also suitable, but it must be taken into account that such mixtures are incompatible with acrylic, silicone, and latex materials.

For use on aerated concrete, you can use cement-lime mixtures, which do not require priming the walls.

Set of tools

Finishing aerated concrete surfaces requires the following tools:

Spatulas.
Scraper to remove dirt and debris.
Metal brushes.
Hammer for knocking down irregularities and protruding mortar.
Sandpaper.
Brushes, rollers for priming.
Master OK.
Tank for mixing the solution.
Mixer for preparing the solution.
Falcon, shield where the mixture is applied.
Grout grater.
Poluterok.
The rule is to align the corners.

How to plaster: progress of work

Ready-made mixtures are excellent for finishing, but have a high cost, so for do-it-yourself wall preparation technology is proposed, after which you can safely use any composition.

For preparation you will need tile adhesive, fiberglass mesh, and deep penetration primer. It is necessary to smooth out all chips and cracks with a compound for laying aerated concrete blocks, then remove dust and debris from the wall with a cheek and paint it with a deep penetration primer twice.

Tile adhesive is diluted and applied to the surface with a thickness of 5 millimeters, the mesh is pressed on top with a notched trowel. When the layer is completely dry, apply the plaster in the usual way; any solution can be used.

The costs of this technology will be an order of magnitude less than when using ready-made plasters.

How long before you can move on to the next stages of wall finishing?

After completion, the beacons are removed, and the resulting dents are subsequently sealed with putty.

To move on to the next types of finishing, you must wait until the walls are completely dry at a constant temperature. Drying will require about a month in the warm season to ensure that temperature changes do not lead to cracking or peeling. It is not advisable to speed up the process; if necessary, a heater is used.

Interior and exterior finishing of a house is an important stage of construction work, the quality of which determines the durability, comfort of living and aesthetic appearance of the house. There are many modern materials and technologies available for finishing work, but traditional methods do not lose popularity and are still relevant today. These methods allow you to achieve the necessary results at low cost and labor intensity.