Stucco for aerated concrete: how to do according to the rules
Facade plaster of aerated concrete walls done quite often. After all, if the thickness allows, then you do not even need to carry out insulation and plastering will be an acceptable finish.
The content of the article
Stucco errors
The technology of plastering walls of aerated concrete worked out by time. And when finishing work on aerated concrete walls is carried out, it is important to understand what errors may occur so that this does not happen. Therefore, it is worth considering the situation by example.
When the construction of the house was carried out, for which gas silicate blocks were used, only window openings were reinforced, but armpoyas and rows were not reinforced. As an alternative to glue, a solution made of sand with cement was used.
Finishing was made in the following order:
- Layer of cement plaster with sand
- Primer coat
- Two-layer putty for facades
- Primer (seeWhy do we need a primer: technological nuances of finishing work)
- Dyeing
Interior decoration:
- Layer of cement plaster with sand
- Primer coat
- Putty was applied in three layers
After one year, or even completely, immediately after the work, multiple cracks appeared in the inner and outer parts ("spider line"), which became especially visible after the rains, although after a while they disappeared again.
Accordingly, questions arise: what to do with this finish? Do I need to delete it if I make a new one? How was it necessary to do it correctly so that this would not happen? The case, in fact, is sad, but instructive.
- Indeed, to carry out the work it took a considerable amount of money to be spent, and nowhere! But such errors happen to many, and quite often. Therefore, before embarking on finishing work, and more specifically on plastering walls from aerated concrete blocks, it is important to understand what’s what, understanding the basic requirements for carrying out this type of work.
- To begin with, you must generally understand that the stands made of aerated concrete blocks, foam concrete or brick - have significant differences among themselves.
- Blocks of foam concrete and aerated concrete - cellular. At first they were used for warming. And only after some time, they began to be used as structural ones. Actually, from the general - this is all between the two materials.
- The production scheme for both materials is completely different. In this case, it is still worth talking about aerated concrete, since we are talking about it. Aluminum chips are the main source of gas formation. That is why it is added to the composition of the solution in the production of blocks from aerated concrete. The crumb of aluminum, reacting with lime, forms the structure of the cells, as a result of which the pores are open in comparison with the foam concrete blocks in which the cells are closed.
- Due to this factor, the vapor permeability property of aerated concrete is much greater compared to brick and foam concrete. Therefore, if it is necessary to carry out finishing works on aerated concrete walls, it is important to consider the vapor permeability factor.
- For example, when building walls of a house is being carried out, it is necessary to take into account the confirmation of the heat engineering calculation, as a result of which it is determined that the thickness of the walls of aerated concrete is absolutely acceptable for the climate zone. In this case, you can plaster the walls immediately, without first insulating them.
Attention: Laying aerated concrete blocks on a composition of cement with sand does not make sense at all.Well, before the plaster, you need to reinforce the walls.
The whole point of reinforcing
The technology of wall plastering from aerated concrete involves the reinforcement of a plane (seeReinforcing mesh for plaster: how to apply) Only this must be done correctly. After all, this is not only to strengthen the coating, but also greatly affect the appearance.
Caution: The load-bearing ability of the masonry reinforcement is independent. It is necessary to prevent “hair” cracks, especially if they have loads on the bends that may occur during the period of uneven movement of the foundation.
In any case, it is necessary to reinforce those walls that will be exposed to plastering, even if only from one of the sides. This can not be done only if the inside of the house will be sheathed with drywall, and with the outside - siding. In this case, it will be necessary to erect monolithic armpoles at the levels where the floors are located, as well as under the farm.
The procedure for reinforcing walls of gas silicate blocks:
- Using a cutter, you need to cut the cutter
- 2 bars of reinforcement with a diameter of 8 mm are laid in the stub. Pre-strobe must be treated with glue. In this way, masonry is made, as well as reliable anti-corrosion protection.
- The reinforcement rods must be installed in the first row, after which the next 4 - block rows. The fittings must be laid so that it is one row lower than the opening, and one row of the bridge support. Between the openings and reinforcement on each side there should be a distance of 90 to 100 cm.
- With the help of a reinforcing cage, designed specifically for the cultivation of narrow, thin joints, it is possible to replace the bars with reinforcement. Their frame consists of strips of high-strength steel with a section of 1.5 * 8, millimeters. They are interconnected by a wire, the diameter of which is 1.5 mm, according to the method of "snake".
Plastering
Plastering a house from aerated concrete is done in several stages. Each is important enough, so do not think about not conducting soybeans, because even then you will lose in quality of coverage.
To do this, prepare:
- The rule with which the screed is made stucco mortar between the lighthouses.
- Profiles of beacons to align the surface of the wall.
- Grater to grout the plaster layer.
- A trowel with which excess mixture is removed.
- A plumb line that allows you to determine the geometry, the evenness of the surface of the walls.
- Bucket, you can also trowel to throw the mixture on the wall.
- Drill with stirring nozzle.
- Capacity in which to make a solution.
- "Plastering a house from the outside is possible only upon completion of the interior decoration, as well as carrying out" wet "cases."
Attention: For example, a serious mistake is to plaster the facade of the house when it is warm (in summer), or inside when it is cold (in winter). After all, that moisture, which will in any case during the work, will come out through the pores of the wall material. And in the cold season, condensation will occur on the verge between aerated concrete and the outer layer of plaster. After which the moisture naturally freezes, and the plaster exfoliates. Therefore, it is better to start finishing work from the inside of the house.
Reasons why cement-sand mortar is not suitable:
- Poor adhesive properties of stucco with wall. Aerated concrete blocks absorb moisture from the solution very quickly, and when the surface dries, it becomes covered with small cracks. Alternatively, you can try priming the wall surface in advance. But there is no guarantee that everything will be fine.
- If you use a solution of cement with sand for gas silicate blocks, the vapor permeability of concrete walls will be significantly reduced. Accordingly, the microclimate is disturbed in the interior of the house. True, this factor is not too important if the house is brick-built or built of foam concrete blocks.Well, if the walls are made of aerated concrete blocks, they may not breathe at all.
Therefore, it is better to choose special, high-quality mixes for aerated concrete. In addition, today on the market you can buy a variety of such domestic products, the quality of which is not inferior to imported mixtures. The price of the composition will depend on the manufacturer, but do not save much, it is worth giving preference to trusted brands.
Decorating the house outside
Plaster for aerated concrete blocks outside the house should be for exterior surfaces. Therefore, before buying, the instructions for the material should be studied. How to plaster walls from aerated concrete on the outside now we will consider in more detail.
Caution: In this case, it is strictly forbidden to use a solution of cement with sand. This is because the multilayer wall should be with good vapor permeability, which increases from the inside to the outside.
Gas-silicate wall plaster is available on the market as a dry powder, in a composition with specially selected additives, contributing to:
- The most basic is, of course, vapor permeability.
- Water resistant, to protect the blocks from getting wet.
- Frost resistance.
- The highest adhesive properties.
- Sustainability to mechanical stress and damage.
- Elasticitydue to which, resistance to cracking is ensured.
- Heat resistance.
Before plastering the walls, they should be prepared by cleaning: from dirt and dust, stains of bitumen, plaster (see How to remove old plaster from walls without problems), paints.
- The solution for plastering should be prepared strictly in accordance with the instructions. Subject to proportions, the mixture is poured into a suitable container. As a rule, 200 mm of water per 1 kg of dry plaster is needed.
- Water needs to be added correctly and as much as necessary according to calculations. The ideal proportion of the composition is cream. It can also be interfered with during the manufacturing process manually. But it is much more convenient, and more likely to do this with a drill with a nozzle.
Instruction - step by step
Wall decoration from aerated concrete plaster should be done in the following order:
- The surface must be coated with a primer made of acrylate siloxane. It has hydrophobic properties, as well as strengthening.
- A grid made of fiberglass, resistant to alkaline solutions, and its density of 200 grams per cubic meter, is attached to the wall surface. m. Such material should not be torn.
- In advance, guiding beacons are installed on the wall, then it is necessary to apply the solution evenly. One layer of plaster should not be thicker than 1.5 cm. If you apply it with two layers, then each of them should not exceed 9 mm.
- Using a plaster rail, you can even out a fresh layer of plaster, and remove any excess.
- When the surface is slightly dry, it must be wiped.
- Vapor permeable paints can cover the walls after at least two days.
Attention: To prevent the tool from deteriorating, immediately after completion of the work it must be washed well.
- Using a long rail (its length should be from floor to ceiling), you need to check how well the plaster layer is applied to the wall of the house. The rail should be attached to be sure in several places. You need to do this both in a vertical way and in a horizontal way.
- If on the surface of the wall there will be even the slightest irregularities, flaws, protrusions, this will immediately be noticeable with the help of the rail attached to the wall. That which is imperceptible to the naked eye is permissible for a flaw error, but such a maximum error can be up to 7 millimeters.
- To ensure that the period of operation of the updated facade of the house lasts as long as possible, it is additionally recommended to process the last, finishing layer using a special agent - water repellent. But before you apply this tool, you should wait time. The walls of the house should dry very well.
Attention: In general, such a layer can be applied even, after a year and a half, after finishing the finishing work (both internal and external). In this case, the water repellent must be applied as thin as possible.
No matter what material you perform the work, it may be ceresit aerated concrete plaster, or any other, never rush and stick to the technology of the work. To do this, you should watch the video in this article and the photo. Having done all the work with your own hands and qualitatively, the finish will not bother you for a long time.
