How to plaster aerated

Currently, in the construction of buildings of various profiles, aerated concrete blocks, which are a type of the so-called cellular building material, are increasingly used. Outwardly, such blocks resemble artificial porous rock with uniformly distributed voids of uniform shape throughout its volume. Products of aerated concrete are in high demand among interested users, which is explained by the following remarkable material properties:

• high strength characteristics;
• low volumetric mass, which significantly simplifies all the working procedures associated with laying blocks;
• low thermal conductivity;
• simplicity and convenience of processing.

When finishing the buildings, the walls of aerated concrete blocks are closed with a layer of plaster, due to which it is possible to get rid of such defects of porous material as poor waterproofness and nondescript appearance. But before plastering aerated concrete, you will need to familiarize yourself with another feature of this material, which allows you to maintain a healthy microclimate inside the building. The fact is that this material has a good vapor permeability, the effect of which can be maintained only in the case of proper selection of the composition of the plaster and the thickness of the finishing layer.

Requirements for the quality of plaster and its choice

To form a high-quality protective coating (layer of plaster), the mixture used for its preparation must have the following characteristics:

• have high strength properties;
• ensure good adhesion with aerated concrete;
• be resistant to sharp climatic (temperature) fluctuations;
• provide the necessary water-repellent effect;
• differ in vapor permeability, and also resistance to strong frosts.

Most modern plaster mixtures intended for finishing cellular materials fully comply with all listed requirements.

When choosing a suitable plaster for your conditions, first of all pay attention to the special markings applied to the bags with the dry mixture and indicating that they can be used to work with cellular structures. The price of such mixtures is slightly higher than the cost of ordinary finishing compositions, but in this situation one should not try to gain something, since any attempt to save could lead to unpredictable consequences.

Interior finish

Plastering of the internal surfaces of walls assembled from aerated concrete blocks is performed in the following order:

1. Immediately before plastering, the surface of the blocks must be thoroughly cleaned from contamination.
2. After this, you should correct all visual defects of the seams. In this case, you can use small fragments of insulation and mounting foam.
3. The walls prepared for decoration are then covered with a layer of special putty.
4.  Immediately after it dries, you can proceed to the priming of the surface of the blocks.
5. And only after the primer is completely dry, you can proceed to plastering the walls.
6. To do this, they are applied to a layer of plaster prepared in the desired consistency, which is then carefully leveled along the entire surface to be treated.
7. After a light setting of the mortar with smooth smoothing movements of the grout, the surface should be completely leveled (having previously moistened it with water).

Exterior finish

For external plastering, the following procedure should be followed:

1. First of all, the surface of the facade is treated with a special soil composition, designed specifically for cellular concrete.
2. After that, a small layer of mortar is applied to the wall.
3. Then the reinforcing mesh made of fiberglass is pressed into the solution.
4. After this, you can proceed to the finishing of the facades with a pre-prepared plaster mixture having a high vapor permeability index. The thickness of the applied layer should be approximately half as much as in the case of internal plastering.
5. All operations for the final alignment of the plaster layer are made similar to the interior decoration.

Work organization

The order of work on the finishing of the facades is somewhat different from the generally accepted one, since the plastering of aerated concrete blocks from the outside can be started only after completing all the procedures related to interior finishing and after complete drying of all coatings.

To understand the reason for this order of finishing is not difficult at all. The fact is that residual moisture, which is always present in the finishing mixtures, can form condensation on evaporation on the outer surface of the blocks. Its freezing at low temperatures leads, as a rule, to detachment of the plaster applied on top of it and to the destruction of the entire coating.

Video

Master class on aerated concrete plaster: