Why I do not grind the seams in aerated concrete masonry and do not recommend doing it

The work of most teams and self-builders when laying walls made of aerated concrete presents the following picture:

Smeared masonry seams. This is considered the norm.

Another thing is when the laying is carried out on glue-foam and there is no such smearing on the facade and inside - they are perfectly clean.

I lay the masonry using the combined method: horizontal seams with mineral glue, vertical - with glue-foam (foaming vertical grooves). Why this particular method will be a separate article (there are good reasons).

Despite the use of mineral glue, I try to avoid smudges and do not cover up the seams. Why do most builders resort to covering up seams - let's figure it out.

When laying aerated concrete walls on mineral glue, it is very difficult to achieve a sealed vertical seam for several reasons:

• the geometry of the blocks is not ideal and one edge fits snugly, and the other forms a gap (there are also trapezoidal blocks);
• it is especially difficult to qualitatively combine blocks in vertical edges with a tongue-and-groove system. The glue gets hammered into the groove or remains on the “spike” protrusion and there is a gap between the blocks;
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• covering up smudges.

Builders try to fill the cracks, cover them with glue after the block is in the masonry. Well, and on the horizontal seams, the formation of smudges is by itself, in a hurry, to lay as much volume as possible during a working day. There are examples when a team builds a floor in three days. At this rate, smudges are inevitable - and they are covered up.

Some bricklayers build from aerated concrete as they used to, like from brick: on a thick seam with mortar. The solution is cold bridges. And then the point is to build from aerated concrete?

Because the hollow seam is smeared over - then there is no visible marriage (gap), although in fact the problem remains. It is better to honestly leave such seams and mark them for further work to eliminate it. Ideally, the outside seam is embroidered 10-15 mm deep, foamed and plastered. Thick empty seams can be simply foamed.

To apply glue, I use just such a carriage. It allows you to avoid smudges (they happen only in places of chips). And it speeds up the process. In the corner blocks, I gently apply with a notched tile trowel.

Covering up hollow joints does not solve the problem of heat loss. When viewed in winter with a thermal imager, it is clear that large heat losses occur through such seams:

A snapshot from a thermal imager of low-quality aerated concrete masonry. Problems can be solved, but if you smear such places, then you can find them only with a thermal imager.

I solve the issue during masonry like this:

Sibit blocks have grooves on the side faces. The vertical seam is dry, but sealed with adhesive foam. The seam becomes airtight. This has been confirmed by tests with the manufacturer.

Yes, with such subtleties, the work is progressing more slowly. But the quality of work is above all for me. I will grind small smudges and the facade of the house will have a more attractive appearance. This is also important because without front finishing, a house can stand for several years.

Comments of aerated concrete manufacturer's experts on this topic at the link: https://vk.com/@zavodsibyt-pochemu-ne-nuzhno-zatirat-shvy

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