Building Site Assessment: Expert and Developer Disagree on Basement Plan

Hello everyone,

first of all, a big compliment for the forum. As an interested party, I have been reading here for several weeks. Now I need your help with my own construction project:

I am planning to have a solid single-family house (approx. 170 sqm) with a basement built. For this, I have had a preliminary geotechnical report prepared (see attachment). As a non-geologist, I did not get much out of the document. However, the expert personally explained to me that we can quite easily build our single-family house with a basement on the building ground. The basement would have to be protected against moisture (DIN 1045), but nowadays this is not a big effort. Everything is fine so far.

I showed the report to the builder I plan to work with. He disagrees with the expert and calculates significant (additional) costs for the basement (soil has to be transported in, water has to be directed, the basement has to be protected against water ingress). He questions whether a basement is still worthwhile at all considering the expected extra effort.

Now I am caught in the middle and cannot make an informed statement about the content. Therefore, I look forward to feedback:

[*]how the initial situation for a basement actually is
[*]how complex (approximately!) the transporting in of soil, directing of water, and protection against moisture can be in our case. Basically, these points sound to me as if they would occur in any basement construction.

I am grateful for any input!

Thank you very much!
Wombat

I showed the report to the builder I plan to build with.
Wombat

Contract already signed?

Aside from the fact that I would not base a decision of such magnitude on random comments in a forum: - according to DIN 1045 nothing can be sealed, apart from that the standard is no longer valid - a WU construction is certainly state of the art (and probably also what is meant here) but cannot be described as "not a big effort"... - the subsoil is certainly suitable for a basement, but it can't really be much worse.

Contract already signed?

No, nothing is signed yet, why?

- The building ground is certainly suitable for a basement, but it can't really get much worse.

What exactly is so bad about the building ground?

No, nothing has been signed yet, why?

because you definitely clarify such things beforehand ) and for example you can also ask another company. with property + soil survey, every seller will engage with you.

Good evening,

Now I’m caught between two stools and can’t make a well-founded statement on the content.

I don’t understand, your currently preferred general contractor has already given you the right answers, hasn’t he?

[*]how elaborate (approximately!) the earthworks, the water management and the protection against moisture can be in our case. Fundamentally, these points sound to me as if they would also occur with any basement construction.

NRW is large; the prices differ. Where, in NRW, are you going to build?

Rhineland greetings