We study errors in construction. Why do cracks appear in foam concrete walls?

In one organization, where I often visit, I drew attention to the extension to the warehouse:

A small room was built from blocks of foam concrete, plastered, gutters installed. But if you look closely, cracks appeared on the wall:

This crack is not similar to the consequences of deformation of the foundation. But, as they say, not a fact. Perhaps the point is this:

Pay attention to the characteristics: strength class and average shrinkage mm / year. Foam concrete has up to 3 mm / year per 1 m of the wall.

It is these two characteristics that distinguish autoclaved aerated concrete from foam concrete. Although, there are many "specialists" who do not distinguish them at all and even give out one after another.

It is possible that due to the low strength and increased shrinkage, a shrinkage crack has formed in the wall. And the foundation has nothing to do with it. During the shrinkage of the foam concrete wall, deformations concentrated in one place and formed a crack. But often there is a whole network of small cracks.

In addition to the cracks on the wall, plaster fell off in places. But this suggests that the walls were plastered immediately after laying. The moisture contained in the foam concrete could not come out, because plaster is a more waterproofing material, accumulated on the border of foam concrete-plaster and in places peeled off the plaster. It is recommended to withstand the masonry for a year without external plaster. This also applies to aerated concrete.

When choosing wall materials, one must rely not only on the price (foam concrete is cheaper than aerated concrete) and on the fact that the neighbor said that he was "warm". It is necessary to look at the strength characteristics.

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Photos of the author (c)

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