Is the old soil report still usable?

Hello, I had a soil survey conducted 7 years ago (2x 8m 1x 6m 1x 4m) on our property. Now the construction company wants a new survey because the DIN has changed and the groundwater level has risen. Does that make sense? The soil has not changed after all. To be honest, I feel this is just a money-making scheme.

Honestly, I find that to be a money grab.

Why? The construction company doesn't make any money from that. In my opinion, it must be correct, see warranty.

Hi,
I guess this concerns DIN 18533-1 for building waterproofing (Abdichtung von erdberührten Bauteilen von 2017).

It is about whether your house needs to be sealed against pressurized water or only against soil moisture.

This depends on
- the soil type (sand/gravel = permeable, clay/loam soil = less permeable)
- the water level (distance of the base slab to the groundwater)
- and thus also on your foundation (basement or slab) and the embedding depth

from these factors, the water impact on the building is determined.

The groundwater level can of course always change (in summer up to one meter lower than in autumn), so the waterproofing must be properly chosen.

In general, I would ask the soil expert if he can adapt the building waterproofing to the planning. That should not be too expensive. I also consider it pointless to conduct further borings.

You can post soil type, water level, and planned foundation.

Regards

Why? The construction company does not earn anything from it. In my opinion, it must be correct, see warranty

What should have changed in the ground conditions in 7 years?