Cracks in the aerated concrete wall: causes and methods of struggle

Cracks in the aerated concrete wall: causes and methods of struggle

We described in detail the properties, pros and cons of aerated concrete, mentioning separately that approximately 20% of all blocks used in the construction of a house crack. Of course, most often the cracks are very small, not critical and there is nothing special to do with them..

External small cracks are perfectly hidden, for example, under plaster or siding, without disturbing the thermal insulation of the house and the bearing capacity of the walls. From the inside, such small flaws in aerated concrete blocks are also usually hidden by the finish and do not lead to serious problems.

And if the crack goes through several blocks and is visible even from afar? If it formed on the most important section of the wall, for example, at a corner and threatens to expand over time?

Cracks in the aerated concrete wall: causes and methods of struggle

Cracks are of two types: caused by shrinkage of the house, exposure to moisture and temperature, as well as mechanical, associated with the applied load.

The reasons for the appearance of cracks in the masonry of aerated concrete can be:

  • Low-quality aerated concrete. Simply defective material, which has no chance to calmly “survive” the coming winter. We strongly recommend purchasing aerated concrete blocks exclusively from trusted suppliers, from manufacturers already known on the market, and not from “bushes”;
  • Wrong choice of block class. Recall that for load-bearing walls, you should choose aerated concrete of modification D500, or better D600 and with a density of B2.5, B3.5–5. Otherwise, the material will simply be unsuitable for high loads and will begin to crack;
  • Foundation problems. Yes, aerated concrete is a relatively light material, especially in comparison with hyper-pressed bricks or good old cinder blocks. However, you cannot save on the foundation! It needs to be reinforced, hydro- and thermally insulated, otherwise frost heaving and uneven subsidence will lead to the appearance of very serious cracks;
  • Laying aerated concrete on poor quality mortar or adhesive mixture. It is better to purchase a special glue recommended by the manufacturers of aerated concrete blocks to prevent problems..

Cracks in the aerated concrete wall: causes and methods of struggle

So, in order to prevent the appearance of cracks in aerated concrete as much as possible, it is necessary:

  1. Choose quality material.
  2. Use material of the correct grade and density.
  3. Purchase high-quality adhesive.
  4. Take care of a reliable foundation, its heat and waterproofing.

That is, in fact, observe the technology of building houses from aerated concrete blocks, paying attention to all the details. There is no guarantee that even in this case there will be no cracks at all, but serious problems will definitely not appear..

Cracks in the aerated concrete wall: causes and methods of struggle

Based on the causes of cracks in aerated concrete blocks, there are several options for eliminating them. For example, in case of problems with the foundation, most often you need to first strengthen, insulate, waterproof it, and only then deal with the cracks themselves..

The crack itself should be fought like this:

  • clean this place from dust, wet with water;
  • prime;
  • cover cracks with putty;
  • use a reinforcing material on top, for example, fiberglass, which will then disappear under the finish.

Cracks in the aerated concrete wall: causes and methods of struggle

Important! Most of the cracks in aerated concrete are formed during the cold season. There is a high risk of large cracks if the house has already been built, but not finished and no one lives in it, that is, there is no heating.

We advise, if the crack is very deep, and the reasons for its occurrence are unclear, contact a specialist. In this case, self-repair of the wall can only aggravate the situation..

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