The foam block has a number of positive properties, among which are strength, thermal insulation, fire resistance, sound insulation. In order to improve the technical characteristics of the material and keep it from aggressive environmental influences, plastering of foam blocks is carried out both inside and outside the task.
First of all, external plaster of foam blocks will have a beneficial effect on such technical characteristics as:
- Thermal conductivity of the walls of the house;
- Protection against frost and temperature extremes;
- Resistant to moisture and dampness;
- Noise isolation of the room.
And secondly, it will allow you to create an interesting coating, which can later be turned into a unique design idea.
Let's take a closer look at the questions of how to plaster the walls of foam concrete outside and inside the room, what materials to choose and how to prime the foam blocks before plastering. We will also present the key nuances that you should pay close attention to during the preparatory and main work.
Why do you need to pre-plaster foam blocks
If the walls of aerated concrete are not previously plastered, then over time the material will be saturated with moisture and lose its technical properties.
Possible consequences:
- An increase in weight, due to which the load on the foundation increases;
- Cracking in walls and foundations;
- Gradual complete destruction of the material;
- The service life of the building is reduced.
Facade plaster for foam concrete performs mainly a protective role:
- Protection against temperature fluctuations;
- Protection against weather influences - rain, snow, wind, dampness, etc.
Internal plaster for foam blocks affects the following properties:
- Thermal insulation;
- Soundproofing;
- Durability;
In addition, the use of plaster mortar will level the surface, hide various defects and create a decorative coating.
Problems when performing work on plastering walls and their solution
The surface of the foam blocks has a smooth, even structure, but this is not very good for further construction work - not every mixture or solution will adhere well, therefore it is required to use plaster and a primer with a special composition.
There are several ways to solve the problem with foam block adhesion:
- Apply primer compounds or concrete contact solution at the preparatory stage - the applied solution penetrates into the inner layers of the material and forms a roughness on the surface.
- Use a reinforcing mesh - it is important to fix it to the wall with nails or self-tapping screws (you can fix it before applying plaster or on top of the first layer of mortar);
- Two methods can be applied simultaneously - this will significantly increase the strength and reliability of the structure.
Aerated concrete is a capricious material, therefore, the Primer for foam blocks under plaster must necessarily have deep penetration. The use of other formulations will not bring an effective result.
The second problem that arises when working with foam concrete is the occurrence of condensation, which appears when an error is made in the ratio of the thickness of the outer and outer layers of the coating.
Thinner plaster of foam blocks outside than inside leads to:
- Damp finish;
- The occurrence of mold and mildew;
- Violation of the microclimate of the room;
- Peeling off the plaster layer;
- Destruction of the material.
It is not difficult to avoid this problem, you just need to monitor the thickness of the overlay layer. The ratio is 1 to 2, for example, outside 5 mm, inside 10 mm.
The choice of material for plastering walls
Before plastering foam concrete, you need to decide what exactly the material will be used for - whether the plaster of the foam block will be carried out from the inside or the external plaster for the foam block is planned.
When finishing the building, you can plaster the foam blocks with cement mortar. It copes well with protecting the surface from external influences, temperature extremes, frost and humidity.
Indoor plastering can be done with a gypsum mixture and other lime-based solutions. They are easier and faster to apply, better retain heat in the house.
Internal and external plaster on foam block should have such qualities as:
- Elasticity;
- Steam permeability;
- Good grip on the substrate;
- Moisture resistance;
- Resistance to temperature extremes.
Before plastering indoors and starting the exterior decoration of the house, it is imperative to prime the surface, this will increase the quality indicators of the finishing.
Tools and materials for work
Before starting work on plastering walls from foam blocks, it is important to carefully approach the choice of high-quality building material and purchase the necessary tools.
Tools that will come in handy in your work:
- Construction mixer;
- Roller;
- The brush is wide and narrow;
- Saw on concrete;
- Capacity for mixing the solution;
- Chisel;
- Putty knife;
- Level;
- Plumb line;
- Rule;
- Reinforcing mesh;
- Self-tapping screws or nails;
- Drill or hammer;
- Forests (for outdoor use).
Materials used at all stages of work:
- Deep penetration primer;
- Dry putty;
- Water for mixing the solution.
You can prepare a solution for plastering walls from foam blocks yourself, based on sand, cement and water, but there is a possibility of various problems. For example, the appearance of stains when the solution dries or peeling of the mixture from the surface. So, it is better to give preference to dry mix purchased in a specialized store.
Stages of work
Let's take a closer look at the algorithm of work, explaining how to plaster a wall and the sequence of actions for interior decoration with our own hands.
All work can be done independently, the main thing is to carefully follow the sequence of actions.
The main key points that answer the question of how to properly plaster walls from a foam block:
- The thickness of the applied layer of putty is from 5 mm to 15 mm. Exceeding this indicator can lead to shedding of the coating;
- To increase the strength of the coating, it is worth using a reinforced mesh;
- Before starting plastering, it is better to apply a waterproofing layer;
- It is worth starting exterior decoration only after interior work;
- It is worth giving preference to mixtures of plaster, in the composition of which there are additional reinforcing fibers and other additives;
- It is imperative to control the ratio of the thickness of the inner and outer layer of the solution;
- Before work, cover the walls with a primer in several layers.
Plastering work on the outside on foam concrete does not differ much from internal work - the outer layer should be two times less than the inner one.
Conventionally, the work can be divided into two processes - preparatory and basic, each of them has its own characteristics.
Stages of preparatory work:
- Before puttingty foam blocks outside the house or indoors, you must carefully inspect the surface for protrusions and irregularities. If there are protrusions, remove them.
- To clean the walls from dirt and dust, use a metal brush for this. Pay special attention to the joints between the blocks. In the event that there are stains of oil origin, you can get rid of them with the help of clay or a grinder for concrete (clean up). A solution of clay is applied to the stain, and after it has completely dried, the mass is removed with a spatula and the place is cleaned.
- After cleaning the surface, it must be primed. For this, only a deep penetration primer is used. It is applied to the wall with a roller; when processing corners, it is better to use a narrow brush. To increase the adhesive properties, the primer is applied in three layers, each drying time from 8 to 24 hours.
A day after applying the third layer of primer, you can start the main finishing work.
Stages of the main workflow:
- Knead the mortar according to the instructions on the packaging of the dry putty mixture. The mass should be homogeneous without lumps, uniform color. For kneading, you will need a large container and a construction mixer;
- Moisten the surface and apply the first layer of putty, its thickness should not exceed 1 cm. It is important to start application from the bottom up, and then carefully level the mass;
- Fix the reinforcing mesh onto the finished surface by slightly pressing it into the first layer of plaster and fix it with self-tapping screws. You can install the mesh before applying the plaster;
- After drying, a second layer of plaster is formed;
- After application, level the plaster using the rule, immediately removing the excess mortar;
- After the plaster is completely dry, clean it with the rule, remove the lumps of solution, if any, and apply a finishing coat with a primer.
The wall is now fully protected and ready for further decorative coatings - wallpapering, spackling, painting, etc.
Paint for foam blocks without plasternot applied.
You can find out how to properly plaster indoors and on its facade, what to look for when working, from the advice of experts in the construction field.
- For ease of work, when leveling the walls, it is worth using beacons. Guided by them, you can control the thickness of the layer on each section of the wall.
- It is necessary to carry out work on puttingtying the surface at temperatures from +5 to +30 degrees. Failure to comply with the temperature regime will lead to poor-quality coating.
- In work, it is important to use only high-quality materials and tools;
- When choosing a dry mixture for puttying, it is better to give preference to compositions with reinforcing fibers;
- The primer should only be of deep penetration, the other type is not suitable for aerated concrete;
- When mixing the mixture, strictly follow the instructions and observe the proportions;
- The ratio of the thickness of the inner and outer layers is two to one.
Plaster is one of the most important stages in the rough finishing of a room; it guarantees the durability and durability of the finish coat and the entire building as a whole. But it is worth remembering that you should never skip this stage. Answering the questions whether it is possible to putty foam blocks without plaster or whether it is possible to paint foam blocks without plaster, experts say a categorical "No".
Surface plastering works are not difficult, they can be done independently, the main thing is to strictly follow the instructions.
Foam block is one of the most popular building materials today. In addition to high performance characteristics, it is distinguished by its relatively low cost and ease of processing. The only "but" is the need to finish it, both internal and external. Therefore, you will need to plaster the walls from the foam block. Let's take a closer look at how to carry it out correctly.
Finishing work is primarily carried out to protect the walls from various influences and improve their properties, and after that they are decorative. Plastering of foam blocks is necessary to improve thermal insulation, protect it from temperature extremes, precipitation and dampness. In addition, with its help, the joints between the blocks are closed up and the surface is prepared for painting, wallpapering and other finishing works. Also, aerated concrete is necessary for houses that are located in humid climatic zones. The fact is that foam concrete absorbs moisture well, as a result of which it loses its operational properties.
How to improve adhesion
Aerated concrete blocks have a smooth structure. On the one hand, this is good, since you will not need to spend a lot of material and effort to level them, but because of this, practically no mixture adheres to the surface of the foam blocks. Moreover, plaster for foam blocks, the minimum layer of which should be 5 millimeters.
There are two simple ways to increase the adhesion of the material, which helps it adhere to the finishes:
- Use of primers and concrete contacts. These substances are applied to the surface and left for a period of 8 to 24 hours. Part of the product penetrates into the structure of the material, and the rest solidifies on its surface, forming a roughness.
- Arrangement of a layer of reinforcing mesh. To properly plaster the walls or ceiling, you need to reinforce the structure with a special product. For these purposes, a metal or ordinary nylon net is suitable. It must be secured with dowels or nails. As a result, the plaster will adhere not only to the surface of aerated concrete, but also to the mesh.
Important! Ignoring the preparatory work is wrong, this will lead to rapid delamination or cracking of the plaster.
Before plastering the foam blocks, you need to take care of the wall insulation. This building material itself is a heater, but cold air will still penetrate through the joints. Due to the temperature difference in the room and outside the dwelling, condensation will form, which will settle on the walls under the layer of plaster. The dew point is located between the grout and the inner surface of the blocks. To exclude the possibility of moisture formation, which will lead to delamination of the plaster, it is necessary to observe the proportions of the layers. The inner one should be about half the size of the outer one.
Required tools and materials
To carry out this operation, you need to acquire the following tools and materials:
- primer - improves the adhesion of the plaster to the base of foam blocks;
- plaster mesh - helps to strengthen the structure and prevents cracks;
- dry plaster mix;
- the container in which the plaster will be diluted;
- nails, dowels, washers;
- drill with mixer attachment;
- spatulas, brushes;
- rule for leveling plaster;
- level;
- plumb line;
- chisel;
- metal brush.
Now a completely fair question arises, how to plaster foam blocks. The main finishing materials for this operation are:
- Primer. To achieve a sufficient level of adhesion, it is necessary to select formulations with deep penetration. According to numerous customer reviews, mixtures produced by Knauf, BOLARS, IVSIL, Prime-Grunt and UNIS cope best with this task.
- Plaster. Most people try to save money on this point and prepare the mixture themselves, mixing chalk, lime, cement, sand and water. The resulting material can be used for plastering foam blocks, but it does not have sufficient resistance to temperature changes and moisture. Construction industry experts recommend using the products of the following manufacturers: EuroMix, PROFIT CONTACT MN, Mask mix and Ceresit. These mixtures can be used as materials for outdoor and indoor work. It is only important to observe the above proportions. In addition, it is recommended to choose mixtures with an increased level of adhesion to ensure tight contact between the plaster and the cellular material - this is exactly what the foam concrete plaster should be.
Plastering technology
Foam block plaster includes the following steps:
- Preparatory. First, you need to clean the work surface so that the solution adheres as tightly as possible to it. For these purposes, you will need a metal brush. To speed up the process, you can attach it to an electric drill. It is important to treat the entire surface, paying particular attention to the joints.
- Primer application. After cleaning, it is better to prime the walls. To do this, first apply the first layer and let it dry (the drying time is indicated by the manufacturer). After that, the second and third. Such a number of layers is necessary so that the primer soaks the foam blocks well, and the plaster eventually lay down tightly and adhered well. This stage is considered one of the most important, so you need to strictly follow the instructions and recommendations of the manufacturer.
- Preparation of the mixture. If you nevertheless decide to prepare plaster for the foam block, then observe the following proportions: lime - 1 part, cement - 1 part, sand - 6 parts. You can do without sand, then you need to mix 1 part of cement and 4 parts of lime. If the solution was purchased in a store, then you need to dilute it in a bucket of water in the proportions indicated by the manufacturer. After that, you need to install a special nozzle on the drill and stir the solution for 5-7 minutes. After that, you need to wait a minute and repeat the procedure again.
- Application of the first layer. To do this, you need to take a spatula, apply plaster to it, and then process the wall. The technology for applying plaster to foam blocks is somewhat different from the standard one. You need to work from the bottom up. At this stage, it is important not to overdo it, since aerated concrete does not require a large layer of mortar. It should be about 1 centimeter.
- Reinforcement. After the first layer has set, it is necessary to reinforce the structure with a reinforcing mesh. The product must be stretched as much as possible so that it fits snugly against the first layer of plaster. If you plan to apply a thick layer, then it is recommended to use a metal net. In other cases, you can do with glass cloth or nylon. The product should be fixed on nails or dowels (the second option is preferable).
- The final stage. Apply the second layer following the same rules as the first. Then we leave the wall to dry completely (the time is indicated by the manufacturer on the package). Then a layer of finishing primer is applied to the hardened plaster.
Important! Only after all the above steps can you start painting or wallpapering.
Nuances of technology
In addition to the above rules, there are some more points worth paying attention to. Before plastering walls from foam blocks, it is better to install beacons that will help level the walls. It is also important to observe the temperature regime. Work cannot be carried out on a cold surface, the minimum operating temperature is +5, and the maximum is +30 degrees.
Advice! If plastering is carried out in hot weather, it is recommended to slightly moisten the aerated concrete before work by sprinkling it with water from a spray bottle.
To properly plaster the walls of the foam block, you must follow the above instructions and the recommendations of the mix manufacturers. It is also recommended to buy materials and tools from large chain stores, since there are a lot of low-quality fakes on the markets.
Among the many materials used for the construction of buildings, foam blocks stand out. They compete successfully with traditionally used bricks and concrete, with many positive qualities. Walls made of foam blocks provide high thermal insulation of the room, do not create obstacles for the release of excess moisture, and provide a comfortable microclimate.
These advantages are due to the cellular structure of the foamed concrete. However, the presence of pores makes the concrete susceptible to moisture penetration, which degrades the performance of the material. You can reliably protect the surfaces of foam blocks indoors if you plaster the foam blocks.
This is a simple process that allows you to independently carry out the interior decoration of walls from foam blocks. It is important to use suitable formulations and adhere to technological recommendations. We will dwell on these points in detail in the article material.
Internal plastering of walls from a foam block, the process is quite simple
Main accents
When thinking about what to plaster and how to carry out finishing activities, pay attention to the following points:
- walls made of foam blocks are characterized by low adhesion associated with the peculiarities of the structure of foam concrete. The cement-based solutions used do not stick to them and flake off. Plaster for cellular products should be performed with compositions characterized by a high degree of penetration;
- the composition for finishing the porous surface must provide vapor permeability. In the opposite situation, by sealing the cells inside the wall, it is possible to disrupt the ability of the foamed composite to freely pass moisture;
- features of the cellular structure provide increased heat-saving characteristics of products, for which it is important to observe the thickness of the foam block plaster from the inside of the building. The thickness of the inner finishing layer of the plaster should be twice the outer one, creating a favorable microclimate of the room;
- products obtained by cutting solid wood have a roughness. This provides improved grip and ease of use without special training;
- cellular composites produced by casting in group forms do not absorb moisture well enough, breaking the adhesion of the plaster mixture with foam concrete. In order for the mixture for foam blocks to hold well, use a reinforcing mesh and soil;
- when purchasing a composition for finishing cellular composite in a retail network, consult the seller. Pay attention to the packaging, which should contain recommendations on the possibility of using the product for porous material.
The structure of foam concrete requires compliance with some rules for its plastering
Why Finish Foam Blocks?
Foam blocks, in comparison with other building materials, have many advantages. The main advantage is increased thermal insulation characteristics. However, inside the wall, moisture is concentrated in the cells of the array, reducing the thermal resistance of the composite.
The increased concentration of moisture in the air cells causes a violation of the integrity of the block, contributes to the appearance of stains that worsen the presentation. Aggressive components contained in a humid environment contribute to the development of corrosion processes and weakening of reinforcement.
Finishing of foam blocks inside the building does not allow the development of fungi, mold, as well as colonies of bacteria that violate the comfortable microclimate of the room and destroy the cellular composite. If you plaster foam blocks with special compositions, you can significantly increase the resource of cellular materials, create a favorable indoor climate, and optimize humidity.
When finishing foam block walls, it is possible to counteract the building shrinkage processes occurring due to saturation of cellular blocks with moisture and gases. Correctly selected plaster for cellular surfaces promotes the escape of household vapors outside the building.
Varieties of foam concrete products
The scope of use of foamed composites has expanded significantly. If earlier blocks were used only as a heater, today light and durable cellular composites are used for the construction of capital walls and the construction of internal partitions.
An important condition for how to properly plaster foam blocks is to ensure the vapor permeability of the plaster.
Naturally, the surfaces of the foam blocks inside the building must be plastered. The choice of mixture for finishing activities depends on the technology for the manufacture of foam blocks. Before completing the finishing work, study the features of the manufacture of blocks that affect the adhesion of the plaster mixture with foam concrete.
Aerated concrete blocks have a number of differences:
- Foam blocks produced by sawing a whole layer of aerated concrete are distinguished by the accuracy of geometric dimensions and the absence of chips. The technology makes it possible to obtain products of the required dimensions. The peculiarities of the sawing method of manufacturing provide increased roughness of products, which makes it possible to obtain increased adhesion of the plaster mixture with foam concrete.
- Blocks made by casting into special group molds have irregularities, chips and are distinguished by the presence of oil stains from traces of the lubricant used to open the molding containers. Products are distinguished by a dark shade, require special surface cleaning to obtain a roughness and remove grease residues.
To summarize, you can plaster any kind of cellular composites from which the wall is made. However, cast products require finishes with increased adhesion. Products also need additional processing associated with providing roughness.
Blocks made by sawing are in good contact with plaster mixes, which are easy and simple to apply to the surface to be treated.
In any case, for the finishing of foamed concrete, special plaster compositions with a high degree of adhesion are required. They are offered in specialized hardware stores. When purchasing a dry mix, pay attention to the manufacturer's recommendations on the package.
The mixtures used for plastering walls made of foam blocks differ from the mixtures used for walls made of bricks and other materials.
Types of compositions
Foam concrete is a material that does not tolerate moisture, and the most affordable way to protect it from wet shrinkage and cracking is to use plaster on the foam block.
Foam blocks are special building blocks made of aerated concrete.
This material is well known even to non-professional builders; it has long been very popular and is used in modern construction.
Such high popularity is characterized by such indicators as:
- light weight;
- good thermal insulation properties;
- inexpensive;
- easy to install.
In order for the material to serve you for a long time, you need to know how to plaster walls from a foam block, because a competent outer coating is the main factor in strength.
The surface of the foam blocks must be finished from the outside of the facade and from the inside of the house.
The importance of plastering blocks cannot be overemphasized; if not properly operated, as shown in the video, you can spoil all the positive characteristics of this building material.
Plastering on a foam block is a very difficult process, since this material has very poor adhesive properties, ordinary plasters based on cement-sand and lime do not stick to it. It is for this reason that it is better to exclude all universal plastering mixes.
So that moisture does not get into your room, foam blocks do not crack, and molds do not appear inside, it is necessary to properly protect the inner and outer sides of the walls.
For a building built of foam blocks, the most important indicator is vapor permeability, for this it is necessary to observe the ratio of the thickness of the plaster layer from the inside to the outside of the room.
If you are doing plastering with your own hands and are unfamiliar with the technical aspects, then in order for your walls to remain permeable, the thickness of the inner layer must be 2 times greater than the outer one.
The layer should not be thick - 1 centimeter inside and 2 centimeters outside will be enough.
Despite all the seemingly complexity of the process, not only a professional builder, but also any person can plaster a foam block wall of a house with their own hands, you just need to read the instructions and watch the videos that we will provide.
Foam blocks are produced by mixing cement, sand, water and a foaming agent, which can be natural or synthetic.
Foam blocks are produced by two different technologies:
- Injection technology - the ready-made solution is poured into a special. molds where it goes through the molding and drying process. Simple production technology does not give a perfectly flat block surface; to improve the adhesive properties, it is advisable to process the surface with coarse sandpaper;
- Sawing method - a one-piece large structure is cast from foamed concrete, which is then divided into blocks of the required size by sawing. Blocks produced using this technology have better adhesion properties and are easier to plaster.
Plastering of walls made of foam concrete is carried out no earlier than 28 days from the date of their manufacture. Cracking remains possible these days.
If you plaster blocks that have not passed exposure, then this can negatively affect the entire process and the quality of the plaster.
Solutions used for plastering foam blocks
Before finishing the foam block wall, you need to choose the right plaster that has a wide range of characteristics:
- vapor permeability;
- elasticity;
- high adhesive properties;
- moisture resistance;
- resistance to subzero temperatures.
Plaster raw materials for foam blocks are produced by many construction companies that produce dry mixes.
Plastering of walls in houses with a high level of humidity is best done with mixtures that are resistant to moisture, produced on a cement basis.
Exterior facade decoration involves the use of the same mixture. Previously, such walls should be properly treated with moisture-repellent coatings.
Packages with dry building mixes intended for foam concrete are marked with a special mark that this material is suitable for use on surfaces with a porous cellular structure.
The price category of such mixtures is usually higher than that of classic finishing compounds. But if your room is made of foam concrete, you will not have to skimp on the building mixture, because only with its help you will be able to perform a high-quality coating.
Finishing tools
The set of tools used for plastering is small:
- building level;
- roller;
- profile;
- spatula or bevel;
- rule;
- construction mixer;
- brushes.
Preparation for plastering
Before starting work on applying plaster, you need to make an initial leveling of the surface, repair chips and cracks.
Then, on the facade of the foam concrete wall, it is necessary to apply a layer of primer mortar with a roller in places where this is impossible, or apply it with a paint brush.
For priming the facade, a deep penetration mortar with a high level of adhesion must be used. Usually the primer is applied in two layers, so the plaster will be much easier to apply.
One of the main rules before applying the priming layer is to apply it to a clean and degreased surface, if oily stains are visible on the foam blocks, they must be removed using special means.
Otherwise, the coating will fall off immediately after drying.
The facade should be primed only with high-quality materials so that the material applied on top of it will serve for a long time.
Let the primer dry well and after that you can proceed directly to the plastering.
Plastering a wall from foam blocks
After purchasing all the necessary tools and materials, you can safely start the work process.
For better adhesion, a reinforcing mesh with resistance to alkaline influences is laid on the surface of the foam concrete wall, if the mesh breaks, cracks will appear on the plaster, and its service life will be significantly reduced.
After that, it is necessary to dilute the mixture for plaster in a container convenient for you with water, this is done using a construction mixer, if there is none, then you can use a conventional drill with a nozzle, which can be purchased at almost any hardware store.
Now you can start applying the plaster to the façade wall. To do this, we take a plasterboard or a spatula and begin to apply the finished solution from the bottom up.
The application technology itself does not differ from plaster of any other surfaces.
But do not overdo it, the thickness of the finishing layer should not exceed 2 centimeters on the outside and, accordingly, 4 centimeters on the inside.
A wall consisting of cast foam concrete blocks must first be laid with a layer of fiberglass mesh, which is fixed with dowels or nails.
It is important to fix the mesh correctly - as tightly as possible to the wall, as shown in the video, how thick the layer of plaster you will apply directly depends on this.
If you have installed a layer of fiberglass mesh, then there is no need to attach the reinforced mesh.
Since foam concrete does not absorb moisture, the plaster will dry much longer, this will allow you to grout slowly and level the finishing layer.
After grouting the facade, the primer is again applied in one layer. Upon completion of all finishing work, you can treat the plaster with a water-repellent solution for additional protection against cracking.
To give the facade of the house an attractive look, you can paint the wall after the plaster has completely hardened. The paint for the facade is also selected specifically for working with foam concrete.
It is best to paint with silicone-based products that have an appropriate level of vapor permeability. You can also finish the wall with any material you like.
To top it off, a few practical tips. When buying a foam block, pay attention to its color, it should be gray, yellow indicates an excess of sand, such material will be fragile.
If you have to store foam blocks for a long time, then do it under a canopy and plastic wrap.
After completing all of the above work, you will have a smooth, durable surface for your home.
Foam block is a material that requires protection from moisture, this can be achieved by plastering. Plastering of foam blocks should be carried out according to a certain technology, which will preserve all the distinctive characteristics of the material: frost resistance, low thermal conductivity and vapor permeability.
Plastering foam blocks
Features of work with foam blocks
Foam block plaster
The foam block is an irreplaceable material in construction, which is so popular due to its lightness and excellent thermal insulation qualities. But the plaster of foam blocks is not easy enough to implement, because the material has a low level of adhesion.
In simple terms, it is almost impossible to plaster walls from foam blocks, because few solutions adhere well to it. Therefore, for such a covering of such a wall, it is better not to buy universal plaster masses and not to rack your brains over the independent invention of all kinds of mixtures.
But, whatever one may say, you need to protect the walls, otherwise, over time, moisture from the environment will penetrate into the porous structure of the blocks, and then into the room itself. In addition to changes in the microclimate, this will lead to the development of mold and mildew.
Fighting bad adhesion
Pay special attention that the plaster for foam blocks should not be applied in a thick layer. The most suitable will be a density of about 1 cm, and for interior decoration - no more than 2 cm.
Due to the fact that this material does not absorb moisture well, it also dries for a long time, so it is better to choose a type of finishing material that will have a high level of vapor permeability.
The characteristics of the features of the foam block are given in the table.
| Characteristic | Units | Indicators |
| Average dry matter density | kg / m3 | 800 |
| Coefficient of thermal conductivity | W / m | 0,22 |
| Acoustic characteristics of dry material | dB | 42-49 |
| Moisture absorption | % | 8,5 |
| Elastic modulus | GPa | 2 |
| Compressive strength within 25 days | kg / cm2 | 30-35 |
| Shrinkage after 90 days | % | 0,03 |
| Frost resistance of material | cycle | does not freeze |
| Creep coefficient | % | 2,6 |
| Vapor permeability coefficient | Mg / m hour Pa | 2 |
| Refractoriness | min. | 120 |
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Block production technology
Plastering the wall in the house
The production of foam blocks can be carried out in two ways:
- cast;
- sawing.
The first option for manufacturing technology is similar to the creation of concrete blocks. In this case, the solution is poured into a metal container and dried to absolute strength. This technique uses a cassette shape, which looks like a metal case with removable stops, and bulkheads divide the container into different sections. Thus, blocks are obtained, the height of which is 60 cm.
This technology is imperfect and has certain drawbacks:
- imperfect geometry of the produced blocks (sometimes blocks from the same batch have different heights, lengths or widths);
- the corners of the blocks are often damaged (and this drawback is very bad for the plastering process).
Wall plaster from foam blocks
The sawing method consists of 3 stages:
- casting foam blocks in large containers;
- demoulding of material;
- cut into blocks of the required size.
This technology has more advantages:
- strict adherence to geometric parameters in accordance with GOST;
- blocks have an increased level of adhesion;
- blocks can be made according to a pre-ordered template;
- the surface has no chips or damage, which significantly reduces the time and money spent during plastering.
From the above, we can conclude that the plaster of foam blocks should be in the search for building material that was obtained by sawing.
Plastering rules
Plastering the wall
A solution of plaster on blocks that were obtained by sawing adheres well, but the material obtained by the casting method is best pre-cleaned or sanded to remove the top coating.
For facing work on injection blocks, it is necessary to use compounds with a high level of adhesion. For a more durable fixation of the mortar and the wall, it is better to use a mesh with reinforcing properties. Such grids allow you to regulate the stress level of problem areas: in the corners, under windows, above doorways, etc.
In order not to violate the distinctive features of the foam blocks, the outer finish should be applied no thicker than 10 mm, and for interior decoration - less than 20 mm.
Plastering a wall from foam blocks