Work plans and responsible for inspection on construction?

On the other hand, there is currently a thread here where the base slab was obviously poured too small.

Here the case is different, here it is assumed in the threads "L-Steine" or "zwei Lagepläne" that it is not poured too small, but rather eighty centimeters too high (or was it ninety?) – HOWEVER, this is a point that should be checked and, if necessary, rejected as the responsibility of the builder!

The in the china shop again... I deliberately held back and hope for the best.

The @11ant in the china shop again... I held myself back on purpose and hope for the best.

I hope for the best too, but you were the one who first pointed out that I chose too harmless an example earlier. Of course, the height specifications are part of the consistency to be checked between the plan and the agreement, and this strange point definitely needs clarification before approval.

The sentence is common. As a builder, one should know what is being built. A few days ago, a window was measured incorrectly or the plan was changed without the [BH] noticing.

I assumed that especially with a prefab house, the dimensions would be checked at the factory and am now worried whether the responsibility for the house not standing straight in the end or showing cracks or collapsing, because a few millimeters or centimeters are missing or too much somewhere, will be transferred to us.

The word millimeter is a foreign word in construction. It is impossible to guarantee anything to you there. Even accuracy to the cm is sometimes difficult. But the house will not collapse because of that. It is more about the fact that a 3m wide room will be 2.95m wide in the end due to various tolerances, plaster application, etc. Measuring again is quite simple: measuring tape or some cheap laser distance meter for 20€. A colleague had to find out after moving into the prefab house that a drywall was installed 20cm incorrectly. Such things happen if no one measures again. Errors creep in; it is not the malice of the craftsmen. If it had been recognized in time, the wall could still have been corrected.

When masonry, the tolerance for window openings is actually 15mm per side, meaning top and bottom as well as left and right. When I heard that, I was shocked. That my father-in-law, a window installer by profession, confirmed this only did little to improve my state of mind. It is really sad when the masons themselves are unable to adhere to these tolerances. But I shouldn’t have been surprised anymore...