In the construction of houses, aerated concrete blocks are used more and more widely as a building material. They have an open cell structure. Finishing methods largely depend on this property, the most common of which is the plastering of aerated concrete walls. If the technology is violated, the microcirculation of the walls may change and adversely affect the quality of construction work.
Wall Features
The structure and composition of aerated concrete differs from the usual material and the absence of gravel inside it. Steam and air freely pass through this material, thanks to which the walls can “breathe”. Structurally, the material is a concrete base with spherical voids evenly spaced inside, the diameter of which is 1-3 mm.
Ways of internal plastering of walls
There are 2 ways of interior decoration of aerated concrete walls. In the first case, plaster is a material that allows air and moisture to pass through along with the walls. When the exterior cladding is made, it is not recommended to use a cement-sand mortar, since moisture leaves it into the walls and, when dried, the surface becomes covered with cracks. Even the subsequent primer and putty does not help here. In high-rise buildings, the facades are made according to the required technology, and the owners of the apartments have to deal with internal plastering.
Incorrectly selected plaster composition for interior decoration worsens comfortable conditions. The unique ability of the walls to “breathe” brings their properties closer to wood and improves the microclimate in the rooms.
Another way of finishing is the maximum possible vapor barrier on the inside of the walls. Then the microclimate of the room will not differ from ordinary reinforced concrete houses. As a result, the plaster coating of the facade will serve for a long time. The aerated concrete wall acquires an equilibrium humidity and the amount of steam coming from the inside is significantly reduced. This is of little concern to the owners of apartments, since they have exhaust ventilation.
How to do interior cladding
Builders mainly choose a material specifically designed for aerated concrete walls. It's better here gypsum plaster mix. Various materials from crushed minerals can be used as a filler. Moisture and gases pass freely through such plaster.
The quality of the solution is influenced by the fractional size of the components. Manufacturers have created well-applied formulations that are also easy to rub and have perfect whiteness. They contain polymer additives that improve properties.
The porous structure of aerated concrete requires the use of a large amount of primer. It should not be saved, as this will negatively affect the strength of the connection of the plaster with the walls.
Preservation of useful properties of aerated concrete
Any material for plastering walls made of aerated concrete is more expensive than traditional ones. But in general, it can be cheaper, since the consumption is 3-4 kg / m2. Also, the exact dimensions of the blocks and the quality of the masonry contribute to reducing consumption. Properly selected internal plaster will allow the outer protective layer to last at least 15 years without repairs.
To finish walls made of aerated concrete, the following rules should be followed:
- only special compositions corresponding to the material of the walls are used;
- the house should stand for some time without finishing, until the humidity of the blocks decreases and you can start lining inside;
- finishing works are carried out within the temperature range from +15C to +30C;
- fiberglass meshes are attached as required by the technology.
The choice of materials for finishing aerated concrete
The selection of plaster mixtures is carried out according to the following indicators.
- For reliable adhesion of the plaster to the blocks, the adhesion should be about 0.5 MPa.
- Proportions for diluting mixtures are indicated on the packaging. The dry composition is sold in bags weighing 30 kg. It consumes about 8 liters of water. The preparation process consists in adding water to the dry mixture and mixing with a drill with a nozzle or a construction mixer.
- The layer thickness is 2-15 mm. If it is large, the mixture is applied in several layers. In this case, fiberglass mesh is often used. By itself, aerated concrete does not hold coatings very well. Optimum flow is achieved at a thickness of 2 mm. At the same time, one package of 30 kg is enough for plastering an area of 8 m2.
- The shelf life of the finished solution should be 3-4 hours. Then it can be applied without haste.
- The mixture is best used universally or for interior wall decoration.
Technology of internal plastering of aerated concrete walls
The process is exactly the same as with conventional finishing work. First, irregularities (excess glue, sagging) are removed from the wall and it is cleaned. Then applied primercorresponding to the purpose of the premises, the materials of the walls and plaster.
Beacons are vertically mounted on the wall - profiles of a certain thickness. They are installed parallel to each other, and the distance between them does not exceed the length of the rule.
After drying, a coat of gypsum mixture is thrown onto the wall with a trowel. The layer thickness should not exceed 4-8 mm. If it is more, the composition may collapse. Work is carried out from the bottom up, to the very ceiling. Then, as a rule, a layer of raw plaster is stretched, supported by lighthouses. If the composition exfoliates, the voids are immediately sealed.
After the composition dries, the beacons are removed and the irregularities are repaired. The wall is leveled with a metal spatula. Movements are made in an arcuate manner. During the shift, 3-4 beacons are passed. Particular attention is paid to the work in the corners. Here you can use reinforcing mesh.
The quality of work is checked using a rail, the length of which is equal to the distance from the floor to the ceiling. Defects are found by applying it in different places horizontally and vertically. Permissible errors are 6-7 mm.
Gypsum plaster does not require a special finishing composition and holds well if the rooms are dry. In a humid environment, for example, in a bathroom, the wall is treated with special agents that reduce the effect of moisture on the plaster.
An absolutely flat surface is obtained by smoothing a day after the wall dries. In this case, the blocks are moistened with water. Further painting of the walls is allowed.
Interior decoration will serve the longer, the higher the quality of building and finishing materials.
Conclusion
Finishing aerated concrete walls is different from wood and brick. If you do not take into account the special properties of this material, then the service life of the plaster will be low. It will swell, peel off, and cracks appear on the surface. In addition, the poor quality of the plaster can affect the humidity of the blocks, which will degrade their thermal insulation properties. It should easily pass moisture and air. Then the plaster will be reliable and durable, and the house will be dry and warm.
