How to plaster the walls of the foam block

The so-called foam concrete blocks, familiar even to non-professionals, have long been successfully used in modern construction. Building materials of this class are significantly superior to similar materials in a number of parameters and are characterized by the following indicators:

• relatively light weight
• low thermal conductivity
• convenience and ease of processing.

Immediately, we note that it is possible to realize all of the above advantages only after becoming familiar with how to plaster the walls of the foam block. Thus, well-organized wall decoration is the main condition for improving the wear resistance and durability of the outer coating.

The advantages of plaster

Plastering surfaces from foam blocks allows you to realize all the previously listed advantages of this material and provides the following benefits to the prepared coating:

1. Increases its thermal insulation characteristics.
2. It protects the building from dampness and dirt, which can lead to its destruction over time.
3. Reduces the impact of the main climatic factors that determine the maximum lifetime of the structure.
4. It creates normal conditions for effective outflow of moisture from the inside walls (increases their vapor permeability).

Preparation for plastering

Immediately before plastering walls from foam concrete blocks, the entire surface of the latter is necessarily primed. For these purposes, so-called deep penetration mixtures are used, which act as a base under the plaster and are applied to the treated surface in two layers.

To improve the quality of plastering the exterior walls of a building, it is recommended to use primers, which include hydrophobic substances. In addition, the top layer of plaster is recommended to process a special water-repellent impregnation. Such an operation helps to prevent the spread of cracks along the outer layer of the coating, which may also cause cracking of the plaster located under it.

In addition, to increase the adhesion of the surface of the foam-coated concrete immediately before plastering, a special reinforcing (fiberglass) mesh, which is characterized by increased resistance to aggressive alkaline media, is attached to it. Such reinforcement of the structure significantly increases the strength of the surfaces being formed and is usually used only on problem areas (in the joints of adjacent surfaces, in window and door openings, etc.).

Constructions of foam concrete blocks do not need a thick layer of plaster; in this case, the thickness of the finish can be no more than 2–3 centimeters.

Quality requirements for plastering

The main condition for obtaining high-quality protective coating is the use of plaster mixture that meets the following requirements:

1. Durability and durability.
2. High adhesion with foam concrete.
3. Resistance to sudden temperature fluctuations.
4. Good water repellency.
5. Good vapor permeability.

These requirements are fully met by special plaster mixes designed to finish the walls of foam blocks.

Packages with mixes for foam concrete are usually marked with a special marking, indicating that the solution prepared on the basis of them can be used for finishing surfaces with a cellular structure. As for the price, these mixtures are somewhat more expensive than classical finishing compositions. But in this particular situation, you will have to come to terms with the costs, since it is only with the help of these mixtures that you can get high-quality coverage.

Distinctive features of plaster for porous bases are clearly presented in the following video:

Plastering walls from foam blocks

As for how to plaster the walls of the foam block, the sequence of operations, which should be followed in this case, may look like this:

1. First of all, the plastered surface is treated with a primer composition that is suitable for cellular structures.
2. Immediately before plastering, a glass fiber mesh is mounted on the surface of the walls, which allows to strengthen the finishing layer (increase its contact with the surface of the base).
3. Following this, you can proceed to the finishing of the facades with plaster mixture, prepared on the basis of your chosen dry composition.
4. A small amount of plaster, prepared in the right proportion, is applied with a trowel on the primed surface and carefully leveled.

After the mortar “grabs”, you can evenly distribute it over the entire surface to be trimmed with light smoothing movements.

We recommend to read:

• leveling the walls with drywall;
• how to glue the ceiling plinth.