White tub - Water exposure class W2.2-E

It would be great if the "normal" light shafts would fit and not these incredibly expensive special solutions.

And here again the section. I'm already half convinced of the white tub. In the end, I'm the layman and have to rely on the experts, and as you write... what are already the 11K€ if in the end there's the big trouble with water damage and so on.

I think unfortunately it fits in this case as the expert wrote it.

This concerns temporarily accumulating seepage water that runs down the slope into the filled cellar pit and can accumulate at the cellar. Limestone is present at the bottom; whether it really exists everywhere as gravel or if it was only crushed by the drilling... I would also not risk bypassing the sealing there with drainage.

Although... how did they classify the gravel chronologically, or describe it? Is it a Quaternary terrace/river gravel, etc.? Or is it limestone weathering (Muschelkalk, etc.)?

To be honest? 11k is the surcharge for the white tank? Do it.

What do you do during heavy rain? Vineyards hold 0.0 water, as unfortunately seen in the Ahr Valley. In just a few minutes, thousands of liters of water run down the slope, and your drainage, which was made possible because it was Muschelkalk from the Spättertiär and not Kalkmuschel from the Frühkarbon... the drainage won't help you at all at first.

And in such a case, everyone here in the forum will also keep quiet if you open the thread "Help, my basement is flooded, what nonsense did you advise back then?"...

Judging by the drilling profiles, you really can't avoid a watertight concrete shell [weiße Wanne], Cronos is right about that – especially if it’s more than just a thin layer of sand-lime brick. Then your excavation pit acts like an artificial basin. The basement window wells can be made watertight against pressurized water even without concrete; there are proven solutions for that. If your general contractor (GU) builds in element construction and you use the basement for residential purposes, external monitoring is required since you then fall into the corresponding usage class, but that's just a side note. Generally, you should also familiarize yourself with the topic of element walls in WU construction. We have that too, and it has some disadvantages compared to pure in-situ concrete methods, which only became clear to us afterwards. You should record in the construction contract which technical regulation the construction method of the basement should comply with, i.e., whether it is built according to DIN standard or WU guideline, etc. In the case of element construction, the WU guideline will be applied 99% of the time. It is also important that it is documented that the construction method "agrees" with the soil report or at least does not conflict with it. Later on, no one will want to take responsibility again ;-)

Also talk to your GU about the sealing concept for the basement. That means any penetrations of the basement walls or floor slab. Which sealing method is used for each penetration, etc. There are usually different options for execution (masonry collar, ring space sealing, etc.). You should try to focus on avoiding penetrations and plan with maximum safety for those that are absolutely necessary. For instance, in our case, this led to raising the sills of the basement windows, placing the core drilling for media connections as high as possible, and executing it watertight against pressurized water with a Doyma multi-utility house penetration system, etc.

I would claim that many construction defects in WU basements could have been avoided with comprehensive, forward-looking planning. The basement later forms the foundation of the house and should remain dry for the lifetime of the house. This does not happen by chance but comes about through meticulous planning and conscientious execution. Such a basement is built in almost two weeks and, in my opinion, requires much more attention than most give it. The composition of the rock in the ground usually does not change, but the saturation with water can, sometimes, although many ignore that.

In our region, a new dam was built a few years ago, resulting in the groundwater level rising by half a meter. Since then, thousands of basements have been damp or flooded and, in part, had to be sealed afterwards.