Plastering of 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, the facade plaster for aerated concrete is applied without fail, preferably in two layers, and with preliminary protection of the walls with a primer and antiseptics.
Any precipitation is a risk of wetting the walls of gas blocks, which, after drying, can begin to collapse, becoming covered with microcracks inside and outside the house. And this risk increases markedly in winter time, because the water in aerated concrete when freezing will expand and expand the building material, breaking its monolithic structure.
Before plastering the facade and side walls of the house, especially in winter, the outer surface must be protected from moisture with a polyethylene film. After the obligatory plastering, any decorative material can be attached to the surface finished with mortar for exterior cladding facade.
Purpose of finishing outside:
Plastering is the most common way 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 a small overview of the characteristics of plastering compounds used in construction for outdoor work and methods of plastering aerated concrete surfaces will be useful.
Three types of practical and cheap building materials for wall decoration are common, therefore, than plastering aerated concrete, you should decide after studying all the options:
Positive sides when plastering with gypsum mortar:
Flaws:
Gypsum or alabaster is considered the most effective composition for plastering aerated concrete surfaces outside and inside the house. This mixture for finishing facade works has a vapor permeability coefficient, the same as that of aerated concrete, excellent adhesion, attractive appearance.
There are special mixtures for working on aerated concrete. It is preferable to use mixtures with the following properties:
Carrying out plastering work in the warm season assumes the rainy season, but getting wet aerated concrete blocks is not as critical as freezing moisture inside them. Therefore, it is better to protect the aerated concrete dwelling with moisture-proof films at any time of the year, since the walls may simply not have time to dry out in the fall before frosts.
The newly erected walls of the house must dry out before plastering them, therefore, both construction and plastering on 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 building private housing has shown that the best time for the construction of aerated concrete walls of a building - 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 priority finishing works:
Before plastering the walls, they must be leveled with a special plane, grinder or float on aerated concrete. Leveling will help to save on the thickness of the plaster layer - if applied too thick, the plaster may begin to crack or even flake 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 determining 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 attachment is checked by level.
On the walls for aerated concrete, plaster is applied from bottom to top, and leveled with a rule. Gaps 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 over). It is advisable to remove the lighthouses before this operation, since they can serve as a point of occurrence of "cold bridges". Internal corners are leveled and reinforced with the same beacons, the outer corners are reinforced with a metal perforated corner without ribbing, and a fiberglass mesh. After the last layer has completely dried, the wall must be wiped off.
If the walls inside the premises will be painted, then it is recommended to use paint with good vapor permeability, for example, acrylic, water-based or PVA-based paints, as well as based on organic solvents.
How to plaster aerated concrete inside the house updated: January 23, 2017 by the author: Artyom
Plastering walls made of aerated concrete indoors is one of the topical issues in the construction of aerated concrete blocks. The fact is that the material needs to be plastered for a number of reasons, the main of which are the cleanliness and smoothness of the surface, since without additional measures the finishing layer will be poorly adhered to. 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 lightweight. This contributes to their trouble-free cutting to obtain the required dimensions. However, a completely logical question may arise, why do we need aerated concrete plaster? 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 mixes for the gas block should be approached especially carefully. Plastering walls from the inside allows you to solve the following tasks:
It should be borne in mind that aerated concrete, like foam concrete, has a cellular structure. Therefore, plastering must be carried out in compliance with the technology. Otherwise, air circulation is impaired, which leads to a deterioration in the properties of the material. Plastering of aerated concrete walls outside the room is also necessary. The exterior finish protects the effects of atmospheric precipitation and the accumulation of harmful gases and dust.
The gas block, due to its porous structure, easily absorbs moisture, so it must be immediately protected from such negative impact... 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, while there is no need to rush with the cladding. After completing the masonry, the walls should dry out. Therefore, aerated concrete walls must be plastered only when warm. If the blocks are not laid on a special adhesive mixture, due to which a seam of small thickness is provided, the drying time increases.
There are situations when in the warm season it is not possible to carry out 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 with plastic wrap. If you follow the advice of the masters, then it is best to decorate the walls of aerated concrete during a period when the temperature at night does not drop below 0˚С. Depending on the region, such temperature readings correspond to the time from late March to early October. From the above, we can conclude whether it is necessary to plaster aerated concrete walls.
Before figuring out how to plaster aerated concrete walls, you need to decide on the materials that are suitable for these purposes. Building mixtures can be purchased ready-made or mixed by yourself immediately before application. To prepare a high-quality solution, it is necessary to use a filler, which is used as sand, gravel, sawdust or stone chips and an astringent (slaked lime, clay, gypsum, cement). Water is added to these components. Cement-sand plaster and mixtures, which include slaked lime, cement and sand, are prepared at the construction site. Today, clay is rarely used.
As for the ready-made mixtures for plastering, they are delivered in bags in a dry form. They include:
Such mixtures are divided into cement and gypsum, which have their own properties and features in application. Cement-based formulations have a longer drying time and are prone to cracking and settling. Aerated concrete plaster is applied in a layer 5-10 mm thick.
All mixtures that have been listed above have different properties and, when applied to a building material, act in different ways. But the question of which plaster is better to plaster the walls of aerated concrete remains open. First, consider what is used to protect the outer walls, which are constantly affected by precipitation, wind and temperature. As a rule, these are cement and sand based mortars. They have proven to be excellent in 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, the cement simply does not have time to gain the required strength.
To plaster aerated concrete walls cement mortar, you need to do it correctly, i.e. in compliance with technology. To prevent moisture from the building mixture from absorbing into the block, the surface must be prepared. For these purposes, it is covered with several coats of deep penetration primer, with each coat must be completely dry before applying the next. Before applying the plaster, the surface of the wall is wetted. To avoid cracking, it is recommended to use a mesh.
How to plaster aerated concrete inside the house? Gypsum mortars, in contrast to cement mortars, dry faster, and the surface is less susceptible to cracking. Mixtures based on gypsum are used for partitions and internal walls, since such compositions are of little use for external use due to the constant influence of moisture. Ready-made plaster mixes contain various additives and fillers, thanks to which the surface is endowed with resistance to cracking and negative influences.
If there is a choice between a ready-made mixture and one made before use, then it should be borne in mind 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 the mixtures that are prepared on site, it is rather problematic, if not impossible, to check the quality of the cement. The main disadvantage of dry plasters is their high cost.
In order to fully answer the question of how to properly plaster an aerated concrete surface, it is worth starting with the tools that will be needed for work. In fact, the tools used are the same as for the application of traditional plaster mix. To prepare the solution, you need a container, which can serve as a plastic bucket or tank. In terms of volume, they must be sufficient to stir all the components.
After filling the dry mixture, add water to the container. To mix the solution, use a construction mixer or a drill with a nozzle. To achieve the required consistency, determine the proportions of water and material according to the inscriptions on the bags with dry plaster. To work, you will need the following tools:
Plastered aerated concrete is trowelled, while the excess solution is removed with a half-trowel. Beacons are used to level the surface, the solution is pulled together using a rule. An obligatory tool used to check for defects on the surface of the walls is a long strip from floor to ceiling. The maximum deviation should be no more than 7 mm.
After deciding how to plaster aerated concrete, they proceed directly to the work process. As with any other finish, you first need to prepare the surface. Gas blocks need to be cleaned of residues masonry mix and close up the seams. As already noted, a primer is applied before plastering. Internal plaster aerated concrete walls consists of the following stages:
A primer must be applied over the rough plaster layer. 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-grained sand in a composition that allows you to get a smoother surface. At the end of the process, the already dried solution is smoothed out to make the surface as even as possible. As a rule, smoothing is started 24 hours after application. To make the surface smoother, the blocks are sprayed with water.
The final stage is Painting works that involve 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 agent, which will increase the durability and strength of the finishing layer. The service life of the interior decoration depends on many factors. One of the main ones is the quality of the materials used, i.e. should be guided by cost. The characteristics of the gas block are no less important, because even a good finishing mixture will not hold well on a poor quality surface.
The most budgetary and widespread plaster for outdoor use is cement-sand. However, the mixture is not suitable for aerated concrete due to its low vapor permeability. For these purposes, mineral, silicate or silicone facade plasters are used. They have a number of necessary characteristics: vapor permeability identical to aerated concrete, good adhesion, and have a beautiful appearance. They start plastering the facade only after the completion of all processes, as a result of which moisture is released inside the room, and the surfaces are completely dry. The gas blocks must be dry, and the maximum allowable humidity is 27%. If this figure is too high, water vapor, which will escape to the outside, will cause flaking of the finishing layer. Facade plaster for aerated concrete should be endowed with the following qualities:
Plaster for exterior decoration can be applied to the walls of the house with a thick layer (thick layer) or a thin layer (thin layer). Thin-layer plaster is characterized by the fact that the material is applied in several layers with a thickness of no more than 10 mm. After surface preparation and primer coating, a thin layer of plaster (up to 5 mm) is applied and reinforced with a mesh.
For reinforcement, a metal mesh (wire diameter - 0.1 mm, mesh size - 0.16 * 0.16 mm) or fiberglass mesh (mesh size - 50 * 50 mm) is used. 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 sunk into the applied mixture. Reinforcing material must be installed at the locations of doors and windows. Then the plaster layer is leveled and wait for it to dry. The second layer is considered leveling, so you need to strive to create the smoothest possible surface. After that, a finishing layer is applied and the surface is rubbed with subsequent grouting. It remains to cover the outside of the building with paint, apply textured plaster and water repellent.
Comments:
At the end of construction, the question arises of how to decorate your home from the inside, that is, how to plaster aerated concrete inside. This material is more often used in small buildings that have 2 floors.
This popularity of aerated concrete has several reasons:
But you should know that aerated concrete plaster is selected depending on the density grade.
Due to the porous structure, aerated concrete was assigned the role of insulation. During masonry, ordinary adhesive solutions are used, since the exact geometric shape allows you not to think about the number and size of the joints.
But it is worth noting one negative feature - low bending strength. This, in turn, requires the creation monolithic foundation, reinforced masonry, floors and roof structures.
You should be aware that aerated concrete walls are somewhat different from surfaces created using other materials. Aerated concrete has a porous block structure, as it is included in the category of light aerated concrete... As noted above, at first this material was used as additional insulation, and later it became independent.
The porosity of the structure is achieved by adding aluminum powder to the mixture. It reacts with other components to form gas bubbles. And this improves the properties of the vapor barrier. This feature affects how the internal will be done.
The lowest cost and easy way interior wall decoration - plaster. It is used not only for internal walls, but also for the facade of the house, but you should always start plastering from the inside. This is done so that the water is provided with an outlet, otherwise it accumulates in the walls of the house, which leads to the formation of condensation, fungi and mold.
When conducting construction in winter period the fumes will crystallize, which inevitably leads to cracking of the plaster, followed by its peeling. Therefore, plastering must start from the inner surfaces, moving towards the outer walls.
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An important selection criterion finishing material- do not clog the pores, otherwise the vapor permeability will be impaired. This means that cement-sand mortars are not suitable for such purposes. Otherwise, moisture will be absorbed into the body of the block, and when it begins to dry, cracks will appear. Moreover, neither a primer nor a high-quality putty will save the situation.
It is necessary to select a material that could emphasize the breathing feature of aerated concrete, otherwise home microclimate will be broken. The modern construction market offers a special plaster that is designed for working with aerated concrete.
In some cases, they adhere to a different direction - to create maximum vapor barrier. This option provides a longer service life for the building. This is due to the fact that aerated concrete is saturated with the required level of moisture due to the lack of steam out into the street.
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There are several options for how interior wall decoration is carried out:
It should be remembered that the plaster will last for a long time only if the surface of the aerated concrete is pre-primed.
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For walls made of aerated concrete, it is necessary to use a porous plaster mixture with high vapor permeability.
This point is also important when working with purl surfaces. For this purpose, you can simply apply plastic wrap. But if the technology is not followed, condensation may appear, and the plaster itself will swell.
Therefore, it is necessary to plaster the walls with sand-cement mixtures, which do not contain lime or dolomite. This will help to reduce the transfer of water vapor, but the plaster itself will certainly flake off. Therefore, this moment must be taken into account without fail in order to imagine the consequences of the choice.
To reduce the effect of vapor barrier, you can pre-prime the walls with 3-4 layers, and if you paint them additionally oil paint, then the effect will increase.
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To prepare the mixture and then apply it to the walls, you must have the following materials:
Typically, plaster is prepared by mixing dry mix and water in the proportions indicated on the package. As soon as the composition has reached the desired consistency, it is applied to the surface using a trowel by means of a throw-over method. It is necessary to distribute the solution as well as possible over the aerated concrete, which will help to create a minimum of drops and seams. So that the surface is evenly processed, beacons are installed.
After the solution is completely dry, it is treated with a grater. Next, you need to prime the walls. The number of layers depends on the quality and grade of the plaster used.
To detect possible defects, a rail is required with a length equal to the height of the ceilings. It is tightly applied to the surface and see if there are any differences. If they do not exceed 0.5 cm, then they are left; otherwise, such irregularities must be eliminated.
Renovation inside or outside the premises will not do without plastering walls and other surfaces. At the design stage of work you need to familiarize yourself with the features of the plaster, which are divided into types, they differ in characteristics and price. The correctly chosen type of finishing material is half the battle, because characteristics of mixtures can differ significantly among themselves, and the fact that for one type of room there will be ideal option, for another may be completely unacceptable.
Plaster is a mixture that is used for surface treatment as a rough finish. What are the functions of the material? Plaster can be used to level walls, repair cracks and other defects. Itself the structure of this solution is a coarse mixture, therefore, after drying, the surface will have rough surface... These effects can be easily eliminated in the future.
You can plaster walls of almost any type, concrete and wooden structures will be protected from the harmful effects of environmental factors. For plastering walls made of aerated concrete are used various techniques and materials. Trends in the field of construction are developing in such a way that such building material as aerated concrete is gaining more and more popularity. It has many advantages over concrete and brick construction.
The building, erected from aerated concrete, has increased energy-saving properties. This material is much lighter than traditional counterparts, due to this fact, you can reduce the cost of arranging the foundation and the construction time is significantly reduced. What kind of plaster is better to plaster the walls of aerated concrete blocks?
One of the ways to decorate aerated concrete walls is plastering... For plastering walls made of cement-sand type blocks, this is the best option... As for the process of applying the finishing layer itself, if you wish, you can apply it directly to the wall. The same can be done with brick walls... However, this may pose some difficulties.
The brick is small, therefore seams between bricks serve as a connecting element when applying plaster. In the case of aerated concrete, the situation is somewhat different, because aerated concrete itself is large. This problem can be solved in several ways. Let's consider the main ones that are often used in practice.
Walls can be plastered both inside and outside the premises. Both types of finishes have some peculiarities. When choosing a plaster, it is best to select the one with the maximum adhesion coefficient. This is to ensure the quality of adhesion of materials.
Before applying a layer of plaster, the walls are prepared from aerated concrete, this is necessary in order to ensure adhesion of materials. How is this done and what does this stage of surface finishing include?
First, you need pay attention to the seams between aerated concrete, they need to be well sealed, approximately by 4 - 5 mm... The wall is leveled, and all defects that may occur, dust and other microelements that reduce the quality of adhesion of materials are cleaned out. Sandpaper can be used to clean the surface to help sand the blocks more thoroughly.
If you decide to use the third method of surface finishing, then you need to know what is used in this galvanized mesh... It is more durable, reliable and does not rust. As for the size of the grid cells, you should pay attention to the one in which the cells are small. After the preparatory work you will need to attach the mesh directly to the wall. This must be done using ordinary nails. They are hammered into the wall first by one third, after which the nail is bent, fixes the mesh.
Particular attention should be paid to the edges of such a cross, they usually stick out, before applying the plaster, all the edges should be folded, then they will not stick out from under the plaster.
When the mesh is secured it is necessary to start applying the first layer of plaster. This is done in what is known as "Splash", it is mainly used to fill mesh cells with a solution. After it, several more layers of plaster will follow. This will necessarily be a primer layer, which must be kneaded by adding slag sand to the solution. The final layer will be the final layer; fine sand must be used to prepare the solution for it.
All layers of plaster can be apply with incomplete drying of the previous layer... This will shorten the time without compromising the strength and quality of the finishing layer.
Mortar for plastering walls can be purchased ready-made, it is sold in a dry state. To prepare the mixture, you just need to add water. But, you can also prepare a cement-sand mortar yourself. In this case do not skimp on the quality of the cement itself, since the water-repellency of the plaster will suffer as a result. When plastering walls, a lot of tasks and requirements are solved, such as thermal insulation characteristics of the surface, water resistance, noise insulation, and so on.
External and internal plastering of walls made of gas silicate blocks has become a widespread type of finishing work due to the widespread use of this material in the construction of individual and multi-apartment residential buildings... Products made of gas silicate provide good thermal protection of premises, 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.
The task of correct plastering of walls is important precisely 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 severe frost season will lead to the destruction of its structure by the expansion of ice crystals.
Reduce the intensity of the process to optimal value, which does not pose such a risk, and the brand of plaster used should be used to 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 applying to certain surfaces. Usually on the front part it is indicated in large print whether it is intended this composition to plaster.
To fulfill its function in in full, some requirements must be met. They are associated with the characteristics of the material, which also appear after it has been laid in the wall structure.
Depending on the planned completion date of all construction works take into account the following points:
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 against aggressive environmental influences and destructive forces:
The porous material intensively absorbs water, which, expanding when heated or freezing into ice, breaks the cellular structure.
Means of protection will be waterproofing the basement, covering with a layer of plaster (outside and inside the building), arrangement of external thermal insulation.
The effective operation of gas blocks is largely determined by the consistent and high-quality creation of an internal vapor-tight barrier made of plaster.
Plastering walls made of gas silicate blocks should be started with a thorough impregnation of the entire wall area with a special primer. Unlike, which has a closed porous structure, during production, open pores are formed in the material, since fine aluminum crumbs are added to the base solution as an additive. It is the main gas generator for the reaction with the lime present in the liquid mixture.
The purpose of the primer in this case is to close the surface pores, prevent active absorption of moisture from the plaster solution (give it sufficient time for uniform hardening), and ensure high adhesion for strong adhesion to the surface.
The primer impregnation can be applied generously without gaps along the entire wall using a spray gun or roller, as in this photo:
Attempts to replace special compounds with simple spraying with water, as a rule, give a poor result 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.
To prevent subsequent cracking of the plastering surface, to maintain the integrity of a monolithic seamless solid mass - this is the task ahead. In building mixtures based on cement or gypsum, there is a pronounced alkaline environment, therefore, fiberglass must be resistant to this category of substances.
During laying, gas silicate blocks form a fairly flat plane, which, if necessary, can be additionally leveled with a float with an abrasive nozzle, therefore, a sufficient thickness of the plaster layer is from 2 to 7 mm. A flat mesh is laid in it.
On walls of a large area (height), it may be necessary to level the plane 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 the internal plaster of walls from gas silicate blocks is discussed in this video:
The external plastering work on the blocks begins only after the completion of the finishing work on the wall from the inside of the house, the completion of the wet mortar processes for the installation of floor screeds, plaster, and putty work.
All moisture that evaporates during these operations leaves not so much through ventilation and other openings (drafts are harmful here), but is actively absorbed by the surrounding materials and then seeks out through the pores of the gas silicate walls.
If the walls on the facade of the building are plastered prematurely, then the external protection made in the cold season will be collected at the border of the plaster and aerated concrete, freeze and tear off the plaster layer (shooting, flaking).
The decision of how to plaster the gas silicate is made taking into account the following factors:
Estimated consumption necessary materials and approximate prices for determining the budget structure are shown in the table:
The approach than plastering gas silicate blocks inside is simpler - for this purpose there is a wide range of gypsum compositions for internal works that do not need to resist the weather.
You should not give up the procedure to plaster the room from the inside, limiting yourself to making a thin coating from one putty. The efforts expended should form a full-fledged wall covering.
Saving on cheap materials or on their quantity often leads to bad consequences. It is safe to say that it is usually not bad building materials, but in their misuse. If there is a need to plaster the gas silicate blocks of the outer walls, then this should be done using only specially provided materials for such types of work.
