Basement made of WU concrete or Poroton?

Hello and first of all, thank you for the answers.
I am currently a bit helpless.

According to the soil survey, it appears to be accumulating seepage water.

The shell construction company was sought by the developer after the tender, and presumably the cheapest one was chosen, that is the assumption.
This company either cannot provide a waterproof concrete shell or thinks it is not possible in terms of time. However, I strongly suspect that it was ordered too late.

So far, we have not been offered a credit note regarding the "less valuable basement," rather the statement was that the costs of the Poroton basement would be more expensive and better.
According to the developer, the energy value could have been achieved with both.

According to the contract, however, a waterproof concrete shell was agreed upon, but according to the developer only for the walls that are in the ground.
A question occurred to me: is it even sensible to build half a basement out of waterproof concrete and the rest out of Poroton blocks? Due to expansion and movement of the material?

I am attaching the plans that I have. I hope you can make some use of them.

According to the contract, however, a white tank was agreed,

Then the matter is settled.

According to the soil report, it is probably accumulating seepage water.

Insist in writing on the fulfillment of the white tank.

Yes, that's great - then just take half of the white tank!

Tell us who is actually building now - GU-GÜ-developer-you yourself as the client?
As already wrote - a lot depends on what and from whom you actually have claims....

Hi, I totally overlooked it, it is a [GÜ].

According to the soil report, it is probably due to accumulating seepage water.

You can assume that on the slope. With the WW you are on the safe side.

The shell construction company was sought by the developer after a tender and presumably the cheapest was chosen, that is the assumption. This company either cannot provide a white tank or thinks it is not possible in terms of time. But I also strongly suspect that it was ordered too late.

You can assume that the WW is more expensive and not included in the company's cheap offer. The difference is gladly taken as profit by the developer.

Currently, no credit has been offered to us due to the "lower-quality cellar," rather the statement was that the costs of the Poroton cellar would be more expensive and better.

As an entrepreneur, I would claim that too. Here a verifiable cost reduction change order is required.

According to the developer, the energy value would probably have been achievable with both.

Technically, that is easy to achieve.

According to the contract, however, a white tank was agreed upon, but according to the developer only for the walls that are in the ground. Now I have a question: is it even sensible to build half a cellar from WU concrete and the rest from Poroton blocks? Due to expansion and the working of the material?

If that is contractually stipulated, then technically there is no objection. That is state of the art. Whether the entrepreneur will endure that for warranty reasons can be doubted.

I am sending you the plans I have as an attachment. I hope you can make something of it.

Thanks, that helps.

In the plan of the basement, no half WW is shown.