The walls of a house built of aerated concrete blocks differ significantly from walls built of bricks or, for example, foam concrete. Therefore, plaster for the facades of such houses also needs a special one.
What should be the plaster for aerated concrete
Features of aerated concrete
To figure out what the exterior plaster for aerated concrete should be, first of all, you should consider the main features of this material. So, aerated concrete is a light stone of artificial origin. Aluminum powder is used as a gas-forming substance in its manufacture.
Thanks to this component, the resulting material acquires a specific structure. Unlike foam concrete, the pores of the blocks are open. Therefore, they have a high coefficient of vapor permeability.
As a result of high hygroscopicity, the material is prone to cracking. Excessive fluctuations in ambient temperature are especially dangerous for him. This is due to the fact that blocks that have absorbed moisture begin to collapse under the influence of frost.
Requirements for plaster
From all of the above, it follows that the plastering of aerated concrete on the outside should level out all the shortcomings of this building material. In particular, good water repellency is a basic requirement. In addition, the finish must have a high coefficient of vapor permeability.
Given the properties of aerated concrete, plaster must also have the following characteristics:
- Good adhesion to the base;
- High frost resistance;
- Compressive strength.
Advice!
In addition to plastering, the aerated concrete facade can be clad with siding or another type of ventilated facade.
The choice of plaster
Having dealt with the basic properties that a finishing material should have, now consider the types of compositions that fit these requirements. It should be said right away that traditional cement-sand plaster is absolutely not suitable for these purposes. Also, it is impossible to finish with polystyrene boards and paint the facade with film-forming paints.
Therefore, for the finishing of aerated concrete, a special plaster mixture is used, which is modified with water-retaining components and other elements. Such a coating absolutely does not interfere with the natural ventilation of the walls and copes well with protective functions.
The price of such mixtures can vary significantly depending on the properties and type of composition. However, all of them are designed for the features of this building material.
Aerated concrete wall plastering technology
Foundation preparation
Having figured out how to plaster aerated concrete from the outside, now let's take a closer look at how this process is performed, since it has some of its own nuances.
Work, as usual, begins with preparation:
- First of all, it is necessary to prepare the surface - remove dust and dirt.
- Then cracks and chips should be repaired with mortar.
- Next, the surface of the walls in two layers is covered with a primer containing water-repellent components. The second layer is applied after the first has dried.
Advice!
It is advisable to dilute the primer applied with the first layer with water and apply at a temperature of at least 10 degrees Celsius to ensure the maximum effect of the composition.
Plastering
After the primer dries, you can start plastering. This process takes place in several stages.
The instruction looks like this:
- A plaster mesh made of fiberglass is fixed on the prepared surface of the walls.
- Then the solution is diluted in accordance with the instructions on the package and infused for 10 minutes.
- Next, the composition is applied with a narrow spatula on and applied to the surface with a thin layer. For different mixtures, the permissible layer thickness may be different, but on average it is not less than 5 and not more than 15 millimeters. If the layer thickness is 15-20 mm, then the plaster must be reinforced with a metal mesh.
- After the coating on the walls dries, the facade must be covered with a layer of vapor-permeable elastic paint. A good option is to use a rubber coloring compound.
This completes the process of finishing the facade with your own hands.
In the photo - the plastered facade of an aerated concrete house
If the plaster was incorrectly selected or the technology was violated during its application, then defects such as cracks (horizontal, vertical or cobweb), peeling, swelling, dark spots, etc., may appear on the surface of the walls.
To prevent this from happening, you should familiarize yourself with some of the nuances of the work:
- Before purchasing a plaster mixture, you should make sure that it has a high vapor permeability coefficient.
- If the solution began to dry out, do not try to dilute it with water, as it will lose its properties.
- If cracks nevertheless appeared on the surface of the plaster, the walls can be covered with a layer of putty. If the flaws are serious, then it is better to stick the reinforcing mesh with special glue, and then putty the fiberglass.
Output
Due to the high "breathing" abilities of aerated concrete, living in a house built from this material is close to living in a wooden building in terms of comfort. However, in order for the dwelling to be not only comfortable, but also durable, it is necessary to perform it correctly.
Therefore, when doing the work, you should adhere to the recommendations given above. Additional information on this topic can be obtained from the video in this article.
