Heating cracks in the screed / walls.

Today we noticed that we have several partly hairline cracks in the plaster. The cracks were not present yesterday. Since yesterday, the heating program has reached 55 degrees. I know that the cracks can be filled and covered with painter's fleece. But what happens if tiles are applied? What worries me even more is that the cracks go through the partition walls to the other side. We have HBL stones. We have already terminated our general contractor, who was supposed to build the house turnkey, some time ago because he did not want to fix too many defects.

From my point of view, settlement cracks are normal. With us, they mainly appeared during the drying out process in the first year. This occurred both in exterior walls and on both sides of interior partition walls. We have now simply filled them in gradually during the first renovations.

eheliche Risse

However, you should urgently do something about those. ;)

what can we do about it?

were those just cleaning cracks for you or also the masonry?

Today we found that we have several partly hairline cracks in the plaster. .... Since yesterday, the heating program has reached 55 degrees.

55° supply temperature?
That would mostly not matter to the room, except where supply heating pipes are located.
The important thing is the room temperature and humidity.

However, it is crucial that the building does not dry out too quickly inside.
For example, heating up from nighttime temperature (outside) to 22° room temperature.
This will inevitably cause drying cracks.

Settlement cracks are (as already mentioned) rather typical to normal.

Plaster cracks are completely normal. It is difficult to prevent them unless mesh is incorporated, which then relieves the tensions. For exterior plaster, mesh should actually be included, for interior rather not.

Fill in and done. A house shifts anyway, so cracks in the plaster are unavoidable.

Even in drywall with gypsum boards, there are cracks in the filler. Here, too, fiberglass-reinforced mesh can be used.

Since construction nowadays is usually done quickly, it also has to dry quickly. Usually, it does not dry completely, which later results in mold. A house should naturally freeze out in January/February with correspondingly low humidity and cold.
Then it is properly dry. During construction, huge amounts of water are introduced. Often thousands of liters. Especially with screed and plaster.
That water has to go somewhere. Then the polystyrene insulation all around, blocked walls, etc. Where is it supposed to go?