Error during concreting of the prefabricated basement - consequences? Experiences?

Hello dear forum,

our house construction has gotten off to a good start (sarcasm): the construction crew simply forgot to form the precast parts at the transition to the floor and the concrete leaked out at the bottom again. As a result, it could no longer be safely assumed that there are no voids in the wall structure and that the WU wall 25/30 really fulfills its task and is watertight. As joint tape, no Pentaflex (or similar) was used but only a sheet metal was pressed into the freshly poured floor slab. In response to our inquiry, we received the following answer: "these joint plates are only structural to counteract the negative water pressure from the waterproofing. That means the water cannot flow from the inside to the outside under the walls. This has nothing to do with the actual external waterproofing."

The basement construction company admitted the error of the construction team and therefore executed the basement as a black tank. (However, the ordered execution was no "white tank" but a basement executed with WU concrete and sealed joints corresponding to the soil report.)

My question: Is this execution now worse than the ordered one or ultimately even better? (apart from the fact that we of course do not know how many voids may have formed between the formwork).

Can anyone here assess whether we will have increased follow-up costs, e.g., for filling the excavation pit, as a result of this changed execution as a black tank?

In your opinion, is there any reason why the 5-year warranty might no longer be sufficient?

Thank you very much for your attention

Clarissa

That people ask here doesn’t surprise me, a huge botch job has been created here..

You even want to have an opinion without pictures.

Better get a building surveyor who checks on site

By the way, just because c25/30 concrete is used, the basement is not watertight, even if it were properly cured.

My question: Is this execution now worse than the ordered one or ultimately even better? (apart from the fact that of course we don't know how many cavities may have formed between the formwork).

I think only "even better" we can deny with the utmost certainty from the bottom of our hearts. How could this happen?

Since the house manufacturer does not offer basements, but we need one due to the slope, we ordered this from a renowned prefabricated basement manufacturer

I think we can definitely and loudly deny just "even better." How could that happen?

How could that happen? The actual foreman was on vacation – so the crew (none of whom spoke German) poured the basement walls by themselves – unfortunately, they thought the concrete was thick enough and probably wanted to save time by skipping the stripping. The joints were even sealed with construction foam (which, according to my research, is not allowed under WU guidelines). By chance, the inspector was on site... and he and the concrete supplier spoke to the three workers, telling them that it would leak again... but they probably didn’t understand. When it did start leaking, they panicked and quickly stuffed battens underneath. If our inspector hadn't been there by chance, we would have never found out. I have to give the basement builder credit for not trying to downplay the mess but instead immediately offering the black tank system.

That people are asking here doesn’t surprise me, a huge botch job has been made here..

You even want to have an opinion without pictures.

Better get yourself a building surveyor who checks on site

By the way, just because c25/30 concrete is used, the basement is not tight despite that, even if it were properly stripped.

We had a building surveyor on site, thank God, because he happened to be there when the mess happened.
I don’t know how you’re supposed to tell from pictures how tight the wall is now?

There is absolutely nothing sealed. An absolute complete disaster for you. I am sorry.