Foam concrete is a material that does not tolerate moisture, and the most affordable way to protect it from wet shrinkage and cracking is plaster on the foam block.
Foam blocks are special building blocks made of cellular concrete.
This material is well known even to non-professional builders, it has long enjoyed great popularity and is used in modern construction.
Such high popularity is characterized by such indicators as:
- small weight;
- good thermal insulation properties;
- inexpensive;
- is easy to install.
To ensure that the material has served you for a long time, it is necessary to know how to plaster the walls of a foam block, after all, a competent outer covering is the main factor of strength.
The surface of the foam blocks must be trimmed outside the facade and from inside the house.
The importance of plastering the blocks can not be overemphasized, if you work incorrectly, as shown in the video, you can ruin all the positive characteristics of this building material.
Video:
Plaster on the foam block is a very complex process, as this material has very poor adhesive properties, conventional 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 mixtures for plastering.
To prevent moisture from entering your room, the foam blocks do not crack, and mold pockets 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 main indicator is vapor permeability, for this it is necessary to observe the ratio of the thickness of the plaster layer from inside and outside the room.
If you are plastering with your own hands and are unfamiliar with technical aspects, then in order for your walls to remain permeable, the thickness of the inner layer should be 2 times that of the outer one.
The layer should not be thick - 1 centimeter inside and 2 centimeters outside is completely enough.
Despite all the seemingly complex process, plastering the foam wall of the house with your own hands will be able not only by a professional builder, but also by anyone, you just have to read the instructions and see the videos that we will provide.
Content:
- Types of foam concrete blocks
- Solutions used for plastering foam blocks
- Finishing tools
- Preparing for plastering
- Plastering of a wall of foam blocks
Types of foam concrete blocks
Foam blocks are produced by mixing cement, sand, water and a foaming agent, which can be natural or synthetic.
The foam blocks are produced by two different technologies:
- Injection technology - the ready solution is poured into the special. Form, where it goes through the process of molding and drying. Simple production technology does not give a perfectly flat surface of the block, to improve the adhesive properties it is desirable to make surface treatment with coarse emery paper;
- Sawing method - from foamed concrete cast a single large structure, which is then divided into blocks of the desired size by the sawing method. Blocks produced by this technology have better adhesion properties, and plastering them is easier.
Plastering of walls from foam concrete is made not earlier, than in 28 days from the moment of their manufacturing. These days, the possibility of crack formation remains.
If plastering blocks that do not pass the shutter speed, then this can negatively affect the whole process and quality of the plaster.
Solutions used for plastering of foam blocks
Before finishing the foam block wall, it is necessary to select the plaster correctly, having a wide range of characteristics:
- vapor permeability;
- elasticity;
- high adhesive properties;
- moisture resistance;
- resistance to minus temperatures.
Plaster raw materials for foam blocks are produced by a number of construction companies that produce dry mixes.
Wall plastering in houses with high humidity level is better to be carried out with mixtures that are resistant to moisture produced on a cement basis.
Video:
Exterior façade finish uses the same mix. Preliminarily, such walls should be properly treated with moisture-repellent coatings.
Packages with dry mortar compounds intended for foam concrete are marked with a special notation that this material is suitable for use on surfaces with porous cellular structure.
The price category of such mixtures is usually higher than that of classic finishing compounds. But in case your premise is made of foam concrete, you will not have to skimp on the building mix, because only with its help you can perform a quality coating.
Tools for finishing
The set of tools used for plastering works is small:
- construction level;
- cushion;
- profile;
- spatula or malk;
- rule;
- construction mixer;
- brushes.
Preparing for plastering
Before starting the plaster application, the surface must be leveled first, and chipped and cracked.
Then, on the facade of the foam concrete wall, it is necessary to apply a layer of primer solution with a roller in places where this is not possible, or apply it with a paintbrush.
For the priming of the facade, a deep penetration solution with a high level of adhesion is necessary. Typically, the primer is applied in two layers, so the plaster will be applied much more easily.
One of the main rules before application of a primer coat is application to a clean and non-greasy surface, if oily stains are visible on foam blocks, they must be removed with the help of special tools.
Otherwise, the coating will fall off immediately after drying.
Primer of the facade should be made only with high-quality materials, so that the material applied over it will last a long time.
Allow the primer to dry well and then proceed directly to plastering.
Plastering of a wall of foam blocks
After buying all the necessary tools and materials, you can safely proceed to the workflow.
For better adhesion to the foam concrete wall surface, a reinforcing mesh with alkali resistance is laid, in case of mesh failure, cracks appear on the plaster and its service life will be significantly reduced.
After this, you need to dilute the mixture for plaster in a convenient container for water, this is done with a construction mixer, if not, then you can use a conventional drill with a nozzle that can be purchased in almost any construction shop.
Now you can start applying plaster to the wall of the facade. To do this, we take the plaster mack or spatula and start applying the finished solution from the bottom to the top.
The application technology itself does not differ from the plaster of any other surfaces.
But do not overdo it, the thickness of the finishing layer should not exceed 2 centimeters outside and accordingly 4 centimeters in.
The wall, consisting of cast foam concrete blocks, must first be laid with a layer of fiberglass mesh, which is fastened with dowels or nails.
It is important to properly fix the grid - as tightly as possible to the wall, as shown in the video, this directly depends on how thick the layer of plaster you will overlay.
Video:
If you have laid a layer of fiberglass mesh, then reinforce the reinforced mesh is not necessary.
Since the foam concrete does not absorb moisture, the plaster will dry considerably longer, this will allow the grouting to take place slowly and smooth the finishing coat.
After the grouting of the facade, the primer is again applied in one coat. After completion of all the finishing works, it is possible to treat the plaster with water-repellent solution for additional protection against cracking.
To give an attractive appearance to the facade of the house, it is possible to paint the wall after full hardening of the plaster. The paint for the facade is also chosen specifically for working with foam concrete.
It is best that the paint is produced by silicone-based agents that have an appropriate level of vapor permeation. You can also trim the wall with any material to your taste.
To top it off, a few practical tips. When buying a foam block, pay attention to its color, it should be gray, yellow color indicates an excess of sand, such material will be fragile.
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If you are forced to store foam blocks for a long time, then do it under a canopy and plastic wrap.
After completing all the above works, you will get a smooth, durable surface of your house.
