How to plaster aerated concrete inside a house. How to plaster aerated concrete: technology for applying plaster to aerated concrete walls. Is it necessary to plaster aerated concrete blocks inside?
Plastering walls made of aerated concrete indoors is one of current issues during construction from aerated blocks. The fact is that the material needs to be plastered for a number of reasons, the main ones being the cleanliness and smoothness of the surface, since without additional measures the finishing layer will not hold well. To make it clearer, all these nuances should be understood in detail.
Aerated concrete blocks are characterized by ease of use: the material is warm and light. This facilitates their trouble-free cutting to obtain the required sizes. However, a completely logical question may arise: why is aerated concrete plaster needed? The fact is that the blocks have a smooth surface, which will not allow the finishing layer to be properly fixed. In this case, the choice of plaster mixtures for aerated concrete blocks should be approached with particular care. Plastering walls from the inside allows you to solve the following problems:
- protects the surface from sudden temperature changes;
- provides a good level of adhesion to other materials;
- improves thermal insulation characteristics;
- provides vapor permeability;
- protects against dampness.
It is worth considering that aerated concrete, like foam concrete, has a cellular structure. Therefore, plastering must be carried out in compliance with technology. Otherwise, air circulation is disrupted, which leads to deterioration of the properties of the material. Plastering aerated concrete walls outside the room is also necessary. External finishing protects against the effects of precipitation and the accumulation of harmful gases and dust.
When to plaster?
Due to its porous structure, aerated concrete blocks easily absorb moisture, so it must be immediately protected from such negative effects. If the building material gets wet, there is nothing critical about it. However, you should not allow the water in the block to freeze. As a result, cracks may simply appear, the strength will decrease, and there is no need to rush with the cladding. After completion of the masonry, the walls must dry. That's why aerated concrete walls It is necessary to plaster only in warm conditions. If the blocks are not laid on a special adhesive mixture, which ensures a thin joint, the drying time increases.
There are situations when warm time year is not possible to fulfill Finishing work. In this case, the walls are covered with soil deep penetration which will reduce moisture absorption. In addition, it is recommended to cover the walls plastic film. If you follow the advice of the experts, then it is best to finish walls made of aerated concrete during a period when the temperature at night does not fall below 0˚C. Depending on the region, these temperature indicators correspond to the time from late March to early October. From what has been described, we can conclude whether it is necessary to plaster aerated concrete walls.
Types of plaster mixtures
Before you figure out how to plaster walls made of aerated concrete, you need to decide on the materials that are suitable for these purposes. Construction mixtures can be purchased ready-made or mixed yourself immediately before application. To prepare quality solution, it is necessary to use a filler, which is sand, gravel, sawdust or stone chips and a binder (slaked lime, clay, gypsum, cement). Water is added to these components. Cement-sand plaster and mixtures containing slaked lime, cement and sand are prepared using construction site. Today, clay is used quite rarely.
As for ready-made mixtures for plastering, they are supplied in bags in dry form. They include:
- cement;
- gypsum;
- sand;
- fillers.
Such mixtures are divided into cement and gypsum, which have their own properties and application features. Cement-based compositions have a longer drying period and are subject to cracking and settling. Plaster on aerated concrete is applied in a layer 5-10 mm thick.
Which mixture should you choose?
All the mixtures that were listed above have different properties and, when applied to a building material, have different effects. But the question of which plaster is best for plastering aerated concrete walls remains open. First, let's look at what is used to protect external walls, which are constantly exposed to precipitation, wind and temperature. As a rule, these are solutions based on cement and sand. They have proven themselves to be excellent constant contact with moisture. But the question is: can they be used for plastering aerated concrete? Due to the porous structure, the gas block quickly absorbs moisture, as a result of which the cement simply does not have time to gain the necessary strength.
To plaster aerated concrete walls with cement mortar, you need to do it correctly, i.e. in compliance with technology. To prevent moisture from the building mixture from being absorbed into the block, the surface must be prepared. For these purposes, it is coated with several layers of deep penetration primer, and each layer must dry completely before applying the next one. Before applying the plaster, the surface of the wall is wetted. To avoid cracking, it is recommended to use mesh.
How to plaster aerated concrete inside a house? Gypsum mortars, unlike cement mortars, dry faster and the surface is less susceptible to cracking. Mixtures based on gypsum are used for partitions and interior walls, since such compositions are unsuitable for external use due to the constant influence of moisture. Ready-made plaster mixtures contain various additives and fillers, due to which the surface is endowed with resistance to cracking and negative influences.
If there is a choice between ready-made mixture and prepared before use, it is worth taking into account that the properties of dry plaster are more predictable. During the production of such compositions, the moisture content of the sand, the quality of the cement, and the accuracy of all components are controlled. As for mixtures that are prepared on site, checking the quality of cement is quite problematic, if not completely impossible. The main disadvantage of dry plasters is their high cost.
Preparatory activities
To fully answer the question of how to properly plaster an aerated concrete surface, you should start with the tools that you will need for the job. In fact, the tools used are the same as for applying traditional plaster mixture. To prepare the solution, you will need a container, which can be a plastic bucket or tank. They should be sufficient in volume to mix all the components.
After pouring the dry mixture into the container, add water. To mix the solution use construction mixer or a drill with an attachment. To achieve the required consistency, determine the proportions of water and material according to the inscriptions on bags of dry plaster. To work you will need the following tools:
- Master OK;
- plaster ladle;
- trowel.
Plastered aerated concrete is floated, and the excess solution is removed with a float. Beacons are used to level the surface, and the solution is tightened using a rule. A mandatory tool used to check defects on the surface of walls is a long strip from floor to ceiling. The maximum deviation should be no more than 7 mm.
Plastering the surface from the inside
After deciding how to plaster aerated concrete, they proceed directly to the work process. As with any other type of finish, you first need to prepare the surface. The aerated blocks must be cleaned of any remaining masonry mixture and the seams sealed. As already noted, a primer is applied before plastering. Internal plastering of aerated concrete walls consists of the following stages:
- Fastening the reinforcing mesh. To increase the strength of the rough finish, you can use a chain-link mesh with a small mesh size. In addition, reinforcing material with alkali-resistant fiber is added to the mixture. The mesh is attached using nails 120 mm long, which are driven well into the aerated concrete wall.
- If the reinforcement process is not intended, special grooves need to be made for better adhesion of the block surface to finishing materials. For these purposes, use any suitable tool, for example a hacksaw.
- Applying plaster mixture to a reinforced base. In this case, they resort to applying the mixture by spraying, when the voids of aerated concrete are completely filled. The first layer of plaster is not leveled, which will provide better adhesion.
A primer must be applied over the rough layer of plaster. It is recommended to add slag sand to the priming solution. It is advisable to apply the finishing layer of plaster using building mixtures with fine sand in a composition that allows you to obtain a smoother surface. At the end of the process, the already dried solution is smoothed to make the surface as smooth as possible. As a rule, smoothing begins 24 hours after application. To make the surface smoother, the blocks are sprayed with water.
The final stage is painting work, which involves the use of paints. In this case, materials are selected with a high degree of vapor permeability. After the surface is painted, it is recommended to apply a water repellent, which will increase the durability and strength of the finishing layer. The service life of interior decoration depends on many factors. One of the main ones is the quality of the materials used, i.e. You should be guided by cost. The characteristics of an aerated block are no less important, because even a good finishing mixture will not adhere well to a low-quality surface.
Plastering walls outside
The most inexpensive and common plaster for exterior work is cement-sand. However, the mixture is not suitable for aerated concrete due to low vapor permeability. For these purposes, mineral, silicate or silicone facade plasters are used. They have a number required characteristics: vapor permeability identical to aerated concrete, good adhesion, have a beautiful appearance. They begin plastering the facade only after all processes that result in the release of moisture inside the room have been completed and the surfaces have completely dried. Aerated blocks must be dry, and as much as possible permissible humidity is 27%. If this indicator is too high, water vapor that will escape will cause peeling of the finishing layer. Facade plaster for aerated concrete must have the following qualities:
- frost resistance;
- high adhesion to the base;
- increased compressive strength;
- weather resistance;
- decorativeness.
Plaster for exterior finishing can be applied to the walls of the house in a thick layer (thick layer) or thin layer (thin layer). Thin-layer plaster is characterized by the fact that the material is applied in several layers no more than 10 mm thick. After preparing the surface and covering with primer, a thin layer of plaster (up to 5 mm) is applied and reinforced with mesh.
For reinforcement, use metal (wire diameter - 0.1 mm, cell size - 0.16 * 0.16 mm) or fiberglass mesh (cell size - 50 * 50 mm). Its installation is carried out with an overlap of 50 mm. In addition, the corners of the building are formed, for which a perforated corner with a mesh is used, which prevents the appearance of cracks due to shrinkage of the building. Using a spatula, the mesh is embedded in the applied mixture. Reinforcing material must be installed at the locations of doors and windows. Then plaster layer level and wait for it to dry. The second layer is considered leveling, so you should strive to create as smooth a surface as possible. Afterwards the finishing layer is applied and the surface is rubbed with subsequent grout. All that remains is to coat the outside of the building with paint, apply textured plaster and water repellent.
Aerated concrete is a modern building material that resembles foam concrete in structure, but is distinguished by air bubbles located inside. The hollow structure of aerated concrete absorbs moisture well, which requires external finishing of the material. The best way to plaster walls made of aerated concrete is discussed in this article.
For the manufacture of the material the following are used:
- quartz sand is the basis of the mixture;
- lime;
- cement;
- water;
- aluminum powder is added during the manufacturing process of the material. Acts as the main gas generator and gives the material a specific structure.
Advice: When purchasing aerated concrete, you must take into account that the pores of the blocks, unlike foam concrete, are open. This determines the features of its application and finishing.
Comparative characteristics of foam concrete and aerated concrete are presented in the table:
| Foam concrete | Aerated concrete |
| In its structure, air bubbles are not connected to each other, which increases the material’s resistance to getting wet. | The air bubbles are interconnected, allowing moisture to move freely through them. |
| Good qualities of frost resistance and thermal conductivity. | Gives off heat and freezes from frost. |
| The inner layer of the plaster layer should be twice as thick as the outer one | The walls should be plastered indoors and then on the façade of the building. |
| To improve adhesion, the walls need to be cleaned, then thoroughly sanded to remove the top hydrophobic layer. Due to poor moisture absorption, to increase adhesion, the solution is sprayed, and then the base layer is applied. | Higher adhesion rates |
When plastering external 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.
- The appearance of traces of masonry after fog or rain, which worsens the visual parameters of the walls.
- Changes in technical specifications.
- Increased indoor humidity.
- Mold appears in the corners of rooms.
For finishing external surfaces, special facade plasters are used. Particular danger for aerated concrete slabs– temperature changes and severe frosts.
During operation, a certain amount of liquid begins to accumulate inside the structures, which will expand when freezing and can greatly damage the structures of the structure. Plastering aerated concrete bases can only be done 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.
Advice: Owners of buildings made of aerated concrete blocks should take into account that exterior decoration walls is carried out only after all internal cladding 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 begin to evaporate.
If the external façade will be finished before application interior plaster, with its intense evaporation, peeling of the outer plaster layer from the surface of aerated concrete will occur. After finishing the interior of the room, you can clad the outside walls of the house with special compounds that have the highest vapor permeability.
Advice: You cannot plaster facades using standard cement-sand mixtures because they are not enough high properties vapor permeability.
Plaster for gas concrete
To decorate the walls, vapor-permeable plaster for aerated concrete is used, which is highly permeable to water vapor, does not get wet, has good adhesion to the surface of the blocks and high frost resistance.
| Type of plaster | Features of the material |
|
Disadvantages of the material:
|
|
Flaws: small selection color range, loss of appearance due to the settling of dust and dirt on the surfaces of the walls. |
|
Disadvantage: high cost, but over time, it will most likely pay for itself. In this case, it is appropriate to remember that the miser pays twice. |
| Advantages of the composition:
Disadvantages of gypsum plaster:
|
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 plaster would be Baumit HandPutz for DIY wall finishing, produced in bags weighing 25 kilograms.
Basics of it physical properties are given in the table:
| Indicator name | Its meaning |
| Grit size, mm | 1 |
| Strength of material in bending, tensile, N/mm2 | ≥0,5 |
| Compressive strength of the composition, N/mm² | ≥3,5 |
| Vapor permeation resistance coefficient μ, | 15 |
| Thermal conductivity coefficient λ, W/mK | 0,8 |
| Density of the mixture in dry form, kg/m³ | 1600 |
| Liquid consumption, liter/bag | 6-7 |
| Mixture consumption (with applied layer thickness 1 cm), kg/m² | 15 |
| Minimum plaster layer, mm | 5 |
| Maximum layer of plaster, mm | 20 |
Tip: Before plastering aerated concrete with this plaster, you need to spray the previously cleaned wall surface with Baumit Vorspritze solution.
Material selection
To choose which plaster is best for plastering aerated concrete walls, you need to purchase a plaster composition that satisfies the following characteristics:
- good vapor permeability;
- the optimal volume of liquid for mixing the mixture: per kilogram of mixture - no more than 0.2 liters of water;
- certain values of the minimum and maximum thickness of plaster application;
- good adhesion with a base of at least 0.5 MPa;
- resistance to negative temperatures;
- high resistance to cracking;
- long viability of the mixture, the larger it is, the easier it is to work with the solution, especially for beginners.
Procedure for plastering aerated concrete walls
Before starting work, it is better to familiarize yourself with the video in this article.
Advice: Building blocks made of cellular concrete are quite smooth with almost invisible seams. There is no need to use plaster mortars to level surfaces. It is enough to apply only a thin layer of the mixture.
The instructions for plastering walls suggest the following procedure:
- Surface primer. A composition 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 mixtures 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.
External and internal plastering of walls made of gas silicate blocks has 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
The task of properly 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.
The brand of plaster used should reduce the intensity of the process to an optimal value that does not pose such a risk, and 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 this 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:
- 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.
- 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.
- 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.
- You should not use moisture-proof extruded polystyrene foam as external insulation. It will retain condensation at the border of contact with the masonry.
- Problems high humidity separate rooms in a residential building, you should not decide 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. It is the main 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 a large amount of water, it 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 cement or gypsum base has a pronounced alkaline environment, so fiberglass 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 plastering work on blocks begins only after complete finishing of the wall finishing work 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 done external protection in the cold season it will collect at the border of 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:
- 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). Application for exterior finishing 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.
- 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. Take a container for stirring of sufficient size, maintaining the recommended proportions and water temperature with precision. The amount of water added 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, but too liquid solution will drain. It is better to stir evenly until smooth electric drill with a special nozzle.
- 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.
Aerated concrete is a popular building material that produces strong, durable, warm and resistant to various negative impacts buildings. He has reasonable cost, and construction with its help can be done with your own hands, even by beginners. After building the house, you need to decide what materials will be used for finishing work. Initially, the walls are covered with high-quality plaster, so it is important to understand how to plaster aerated concrete outside and inside the house, as well as how to do this work correctly.
Important! It is not allowed to use the same material for exterior and interior work, since it is important that the resulting coatings are resistant to the existing operating conditions, and they differ significantly on the street and inside the house.
Types of plaster for aerated concrete
There are numerous types of plasters on the market. Not all varieties are suitable for aerated concrete, so the parameters of each material must first be studied, after which the desired option for external use or for internal work is selected.
Important! Plaster for external use must have high thermal insulation parameters, resistance to moisture and temperature changes, and at the same time it must provide good sound insulation and have an attractive appearance.
There are several most popular plasters used for aerated concrete. Each option has its own characteristics, so it is important to study the parameters of any type before making a specific choice.
Cement plaster
This material is considered in demand for various types of work, but it is considered unsuitable for aerated concrete. This is due to the fact that it produces smooth walls, on which cement mortar does not adhere well. Also, aerated concrete has a specific feature of absorbing moisture from the solution. Cement plaster has vapor permeability, which is lower than that of walls, so if it is used for finishing work, the microclimate established in residential premises can significantly deteriorate.
Also cement mortar It has a low adhesion rate to aerated concrete surfaces. Lime is often added to the composition to increase this parameter. If, nevertheless, this particular material is chosen for external work, then a special finishing layer must be applied after the plaster has dried, which allows you to obtain a perfectly smooth surface. 
Important! If the vapor permeability of aerated concrete is impaired, this can cause various cracks, mold or traces of seams.
Adhesive intended for aerated concrete
There is a special product on the market glue mixture, intended for application to walls made of aerated concrete. It has an optimal composition for working with this material, but its main purpose is to connect individual blocks, so it is used at joints.
The material is applied in a thin layer, therefore it is not considered suitable for forming the outer layer on aerated concrete walls. It won't be possible to make the best out of it. protective covering, and its cost is considered quite high, so it is not advisable to use it for these purposes.
Gypsum plaster for aerated concrete
This material has many advantages for use on aerated concrete walls. Its advantages include:
- quick drying, so after the layer has hardened you can quickly begin subsequent finishing work;
- the coating does not shrink;
- with proper application of plaster on aerated concrete, the formation of a perfectly smooth surface is guaranteed;
- due to High Quality of the material there is no need to apply a finishing coat after the layer has dried.
But this material is not without certain significant shortcomings. These include:
- not very good vapor permeability ();
- to obtain a high-quality mixture, a sufficiently large amount of water is required;
- if moisture or snow gets on a coating that is not protected by any additional layer, it quickly gets wet;
- Often unsightly and clearly visible stains appear on surfaces, therefore, for an attractive appearance of aerated concrete walls, it is necessary to use special coloring compounds to eliminate them.
Important! Even with many disadvantages gypsum mortar It is considered relevant for use on aerated concrete walls, but is usually used for interior decoration in rooms with low humidity.
Special facade plaster designed for aerated concrete
There is a special material on the market for walls made of aerated concrete, used for both external and internal use. The advantages of using it for a house built from aerated concrete include:
- good vapor permeability, equal to the vapor permeability of the building material itself;
- excellent appearance of the resulting coating;
- good adhesion to aerated concrete.
It is this material that is most often chosen for finishing aerated concrete buildings. It provides a high-quality, uniform and durable layer with interesting view. But this material has a fairly high cost, so a lot of money is spent on finishing the entire house. For interior walls, the use of gypsum mortar is considered optimal.
Competent choice of plaster for aerated concrete walls
When choosing a material intended for plastering aerated concrete walls, the basic requirements and criteria that it must meet are taken into account. To obtain a truly high-quality and optimal coating, the plaster must have:
- good indicator of vapor permeability;
- resistance to low and high temperatures;
- resistance to exposure to significant humidity;
- resistance to the appearance of cracks, mold or other negative factors on the created surface;
- the duration of the solution’s viability, and this factor is most important for people who independently carry out the process of applying plaster, and who do not have experience working with such solutions.
Important! For each buyer, an additional important parameter is the cost of the solution, and it must correspond to its quality and properties, but it is not recommended to pay attention to the most affordable material, since it will not have optimal properties for use on aerated concrete walls.
When is plaster applied to aerated concrete walls?
Aerated concrete is considered a specific material characterized by good moisture absorption, so immediately after construction of the structure it is recommended to take care of protecting the walls from exposure to water. Getting the material wet is not considered critical, but the moisture in the aerated concrete must not freeze, as this can cause cracks or weakening of the walls.
Important! However, you should not rush, since after building a house from aerated concrete, it is recommended to give the material time to dry thoroughly.
Plaster is applied to aerated concrete only in the warm season. If a cement mixture is used in the process, then its drying time is considered significant, and this is due not only to its parameters, but also to the fact that a layer of sufficient thickness is certainly created.
If it is not possible to apply plaster in the warm season, then the walls are certainly covered with a special primer, and it is important to choose a deep penetration agent. The resulting layer reduces the water absorption of aerated concrete. It is permissible to cover the entire structure with polyethylene or other similar material.
From what part of the house does the finishing of the aerated concrete structure begin?
There are several options that determine the sequence of actions necessary to repair a house built of aerated concrete. These include:
- Exterior finishing is carried out initially, and then internal. Experts assure that first of all it is necessary to protect the building from various negative atmospheric factors that can adversely affect the condition of a house made of aerated concrete. It is not permissible for the walls to collect a large amount of moisture. However, on the other hand, in a house closed from the outside, water vapor will accumulate, which will negatively affect the duration of its drying, and difficulties may also arise with interior finishing work. This option is considered preferable for houses built on the banks of various rivers or lakes.
- First, interior finishing work is carried out. This option involves partially closing the pores in the walls of aerated concrete buildings. After interior finishing, it is not allowed to immediately carry out exterior work. The fact is that this can lead to a large amount of water vapor accumulating in the aerated concrete blocks, so moisture will settle in the walls of the house, which can cause their destruction. Therefore, external finishing of aerated concrete walls is carried out only after the plaster inside the house has completely dried.
- Simultaneous execution of work. This method assumes that both internal and external finishing processes are immediately implemented. This method is considered the least popular, and this is due to the fact that moisture will not have time to leave the aerated concrete blocks.
Important! Although modern quality plasters They have good vapor permeability, they dry for quite a long time, and this is especially important if the finishing of walls made of aerated concrete is planned for the cold season, so it is advisable to leave the process until the warm season.
Technology of interior finishing of aerated concrete walls
Using plaster for the interior decoration of a house built from aerated concrete is a simple and straightforward process. It is divided into successive stages:
- Preparing the base. It is important to eliminate significant irregularities in aerated concrete walls. To do this, they are polished with a plane or a special grater. It is possible to skip this stage, however, during the work you will need a large amount of plaster, which will significantly increase the cost of finishing.
- A high-quality primer is applied. It is not recommended to mix this product with water, as this action will lead to a deterioration in the quality of the material. Before applying the primer, it is necessary to clean the base from dust, for which the walls are washed with plain water. The primer is applied after the aerated concrete walls have completely dried. A specific type of primer is selected in accordance with the specific room in which you have to work. For standard rooms, which include a bedroom or living room, you can choose an inexpensive and universal material, but for the bathroom or kitchen a blue penetration agent is purchased.
- Installation of beacons. The next stage involves installing beacons on aerated concrete walls. They are presented with special metal structures, ensuring perfect smooth surface from plaster. They are usually installed using a small amount of plaster solution. The distance between them is left in accordance with the width of the rule that will be used to level the solution. Must be used during work building level, guaranteeing evenness of fixation of beacons.
- Preparation of plaster. In the process of creating the solution, you must strictly follow the instructions that are included with the material by the manufacturer. In this case, obtaining an optimal mixture with the desired consistency and homogeneity is guaranteed.
- Applying plaster using the throwing method. It is this method that is used to form the first layer of plaster. The procedure is performed from the bottom up, and the mixture is poured over the entire surface of the base. Next, the resulting layer is stretched using a rule. When voids form, they must be filled with solution. It is important that the material does not peel off, because if this happens, the plaster is removed and then reapplied.
- Processing the resulting layer. This is done only after the mixture has dried. Next, the coating is slightly moistened, for which it is recommended to use a spray bottle. Then it is carefully leveled and the beacons are removed. The resulting empty spaces are filled with plaster.
- High-quality and even corners are created. To obtain an ideal result, special perforated metal corners are used, equipped with a mesh on the sides.
- Finishing of aerated concrete walls. After the final drying of the plaster layer, finishing. To do this, the walls are covered with paints or other finishing materials.
Thus, the process of plastering walls made of aerated concrete is a fairly simple process that can be easily performed by every home owner.
Important! You can get an ideal work result only by strictly following the basic rules and observing correct sequence actions.
How to plaster aerated concrete walls outside?
Exterior finishing work for a house made of aerated concrete involves creating a fairly thick layer. Therefore, several layers are usually applied at once, and reinforcement is also performed. The whole process is divided into stages:
- walls are prepared from aerated concrete, and this process involves the elimination of large transitions and irregularities, which will have a positive effect on the cost of purchasing finishing materials;
- coating the surface with a primer;
- applying plaster, and the thickness of the first layer should not exceed 5 mm;
- reinforcement of pre-purchased metal mesh, equipped with small cells;
- the layer of plaster is leveled along the fixed mesh;
- a second layer of material is applied after the first has dried, and it is important to pay a lot of attention to proper leveling and obtaining a flat and smooth surface of the aerated concrete walls;
- a third layer is applied, which, if necessary, is rubbed over after drying;
- the resulting coating is painted or covered with textured plaster;
- it is treated with a water repellent, and it is usually applied a year after finishing, and the main purpose of this product is to protect aerated concrete walls from moisture.
Video: plastering aerated concrete
Thus, applying plaster to walls made of aerated concrete is a simple process. It can be easily done both inside and outside the house. To obtain a high-quality result, it is important to carefully study the instructions and strictly follow the sequential steps. Another important point in creating an ideal coating for aerated concrete walls is right choice the plaster itself, which must correspond to the operating conditions existing outside or inside the house. The article “” may also be useful.
Plastering aerated concrete surfaces is a necessary measure due to the fact that the porous structure of the material allows moisture to pass through well, and this is unacceptable for the durability of any residential building. Aerated concrete bricks are highly hygroscopic. Therefore, facade plaster for aerated concrete must be applied, preferably in two layers, and with preliminary protection of the walls with a primer and antiseptics.
Any precipitation is a risk of dampening the walls made of aerated blocks, which, after drying, can begin to collapse, becoming covered with microcracks inside and outside the house. And this risk increases noticeably in winter, because water in aerated concrete, when frozen, will expand and burst the building material, breaking its monolithic structure.
Before plastering the facade and side walls of the house, especially in winter, outside surface must be protected from moisture with a polyethylene film. After mandatory plastering, any surface can be attached to the surface finished with mortar. decorative material For external cladding facade.
Purpose of exterior finishing:
- Increasing the heat and noise insulation of buildings and premises;
- Minimizing the likelihood of walls being wetted by precipitation;
- Protection of external surfaces from contrasting street temperatures;
- Decorative function.
Applying plaster is the most common method of finishing facades and walls made of aerated concrete due to its relative cheapness and ease of execution. But even such a simple process requires study, so short review characteristics used in construction plaster compositions for external work and methods of plastering aerated concrete surfaces will be useful.
Three types of practical and cheap building materials for wall finishing are common, therefore, how to plaster aerated concrete should be decided after studying all the options:
Cement-sand mortar
- This is the most common internal plaster mixture among builders, but it is not recommended to use it for plastering aerated bricks on the outside, since aerated bricks do not hold cement well. And, if on the walls inside the house you can use a primer or fiberglass mesh to hold the plaster cement-sand mortar, then these methods are not suitable for working outside due to the constant exposure to temperatures and precipitation. It is not advisable to protect aerated blocks with a cement-sand mortar, since aerated blocks immediately absorb moisture from the mixture. The reasons for the ban are as follows:
- The cement-sand mixture has a lower vapor permeability coefficient than aerated concrete. And the most important rule for a plasterer is to use a material whose vapor permeability coefficient is the same as this indicator or greater than that of aerated concrete;
- It is not recommended to insulate a house with expanded polystyrene or foam for the same reason.
- Cement plaster applied over aerated concrete contains a lot of water, since it is mixed with it. Aerated concrete is initially produced with a high coefficient of moisture absorption, so moisture from the solution will quickly get inside the wall, leveling the adhesion, layer quality and strength of aerated concrete blocks, because the main condition for the strength of concrete is slow setting and hardening;
- Cement-sand mortar has low adhesion, that is, adhesion. Therefore, to plaster internal walls, lime can be added to the solution in a ratio of 1:10 (lime - cement);
- The cement mortar must be covered with a finishing layer of plaster, since the starting layer will be rough.
Construction adhesive mixture
- Construction adhesive is a very expensive solution, and applying it in a large layer instead of plaster is impractical and uneconomical;
- When plastering aerated concrete blocks with construction adhesive solution The vapor permeability of aerated concrete will decrease, since the glue does not allow air to pass through well. As a result of clogging of the pores in the blocks, the material may begin to crack, mold may appear in poorly dried areas, and local peeling of the adhesive plaster may occur.
Gypsum for aerated concrete
Positive aspects of plastering with gypsum mortar:
- The gypsum plaster mixture quickly sets and dries;
- Gypsum mortar does not shrink;
- Even a thin plaster surface will be smooth;
- This type of plaster does not require a finishing decorative layer.
Flaws:
- The vapor permeability coefficient leaves much to be desired;
- High water consumption;
- Any precipitation moisturizes gypsum plaster to the entire depth of the layer;
- Due to too good adhesion, colored spots may appear on the surface from the penetration of mineral dyes in the composition of aerated concrete into the gypsum layer.
Plaster or alabaster is considered the most effective composition when plastering aerated concrete surfaces outside and inside the house. This mixture is for finishing facade works has a vapor permeability coefficient identical to that of aerated concrete, excellent adhesion, and attractive appearance.
What plaster is best for plastering aerated concrete walls?
There are special mixtures for working on aerated concrete. It is preferable to use mixtures with the following properties:
- High or medium vapor permeability;
- No more than 200 ml of water per 1 kg of mixture for mixing;
- Minimum and maximum thickness of the plaster layer (than more difference, all the better);
- Adhesion index to the main surface – ≥ 0.5 MPa;
- Low temperature resistance;
- Resistance to cracking;
- Long lifetime of the working solution.
Conditions for plastering aerated concrete surfaces
Carrying out plastering works in the warm season there is a rainy season, but getting wet aerated concrete blocks is not as critical as freezing the moisture inside them. Therefore, it is better to protect a home made of aerated concrete with moisture-proof films at any time of the year, since the walls may simply not have time to dry in the fall before frosts.
The newly erected walls of the house must dry before they are plastered, therefore both construction and plastering of aerated concrete should be carried out in the summer. Due to the fact that the first row of gas bricks is usually laid on a cement-sand mortar, the drying time of the walls increases, and this circumstance must be taken into account when calculating technological processes.
Applying two or three layers of primer to aerated concrete will significantly reduce its water absorption. The practice of constructing private housing has shown that the best time to erect aerated concrete walls of a building is the season when the temperature at night does not drop below 0 °C.
There are three options for finishing aerated concrete surfaces, taking into account the order of finishing work:
- The exterior finishing is carried out first. Private developers mistakenly think that first of all it is necessary to protect the outside of the house so that the walls do not get wet from rain and snow. But even when wet in the fall, but primed, aerated concrete will dry quickly in the spring at positive temperatures. If the walls are covered with plaster, moisture in winter will evaporate only inside the home, which will not only extend the drying time of the walls, but will also affect the occurrence of cracks on the walls. internal walls Houses;
- The first is the interior finishing. With this organization of the process, the moisture accumulated in the aerated concrete has an outlet only to the outside, and the possibility of cracks appearing will be minimal. Therefore, this finishing option is considered the most correct;
- External and internal finishing is carried out simultaneously. This option is the worst of all three. Moisture in aerated blocks becomes clogged, and its slow evaporation will lead to the appearance of cracks, mold, and peeling of the plaster layer.
Internal plastering technology
Before plastering the walls, they must be leveled with a special plane, grinder or aerated concrete float. Leveling will help save on the thickness of the plaster layer - if you apply too thick a layer, the plaster may begin to crack or even peel off.
Sanded walls should be primed, but it is not recommended to dilute the primer with water. Then metal beacons are attached to the walls - 2-3 meter perforated ribbed corners, which determine the thickness of the plaster layer. The corners are attached to plaster or alabaster, the distance between them is determined by the width of the rule or the widest spatula. The verticality of the fastening is checked by level.
On walls for aerated concrete, plaster is applied from bottom to top and leveled according to the rule. Voids and irregularities are filled with mortar using a smaller spatula. After an hour and a half, when the first layer of the solution has set a little, it is moistened with a spray bottle and leveled with a wide spatula (rubbed). It is advisable to remove the beacons before this operation, since they can serve as a point of occurrence of “cold bridges”. Internal corners are leveled and reinforced by the same beacons, external corners are reinforced with metal perforated corner without fins, and fiberglass mesh. After the last layer has completely dried, the wall needs to be rubbed down.
If indoor walls are to be painted, it is recommended to use paint with good vapor permeability, for example, acrylic, water-based or PVA-based paints, as well as those based on organic solvents.
How to plaster aerated concrete inside a house updated: January 23, 2017 by: Artyom
