WU concrete + flush-mounted boxes in the residential basement - how can this be solved?

I would first like to thank you for the "tip"

How much living space, in percent, do you lose due to the 6-cm front wall?

I just calculated it for my basement, I lose 0.65 m² (out of 27.4 m²) with this measure. It will probably be worth it to me.

My main problem is: they want to start *tomorrow*. The offer and information came today...

Fundamental questions are:
- Who pays for the facing masonry? (I don't really see myself obligated for that...)
- How much does this delay the construction progress?

The loss of space is acceptable, and a Ytong stone also significantly improves the living climate, as it does not radiate cold.

[*]If there is no standing, pressing groundwater, professionally installing UP boxes is not a problem, as long as not a whole series of boxes are installed in the wall. Three per wall would be the limit. [*]A 45mm deep box should be used here

Sorry, this expert is an idiot. A hole is a hole

Sorry this expert is an idiot. A hole is a hole

I have now received the same statement from three independent people who have no connection to the construction: If it is done professionally with a box drill and takes place at a depth of around 45mm, waterproofness is guaranteed, provided that groundwater is not constantly pressing. How do you come to your statement?

It's more about the statement maximum 3 holes why should it become leaky with e.g. 4 or 5 holes?

My main problem is: they want to start *tomorrow*.

Don't let it stress you! In a year, you won't even remember exactly when your house was finished, but you will know very well whether it was done properly.