White tank, drainage, when do you need what?

Hello everyone, can someone explain to me when a "weiße Wanne" is needed? We had a representative here a few days ago. He said it depends on many factors whether this measure is necessary. In his opinion, it would be unnecessary if the drainage can be fed into the sewage system. When is it specifically needed and can I have this clarified before buying the house? Can someone explain this to me?

There is a soil report for this. It is not decided by the construction company but by a geologist what is necessary for your property and the existing soil conditions.

Hello,

When is it actually needed and can I have this clarified before buying the house? Can someone explain this to me?

Water can affect the exterior surfaces of buildings in the form of soil moisture, as non-puddling seepage water, as temporarily accumulating seepage water, as pressing or non-pressing water. The choice of sealing depends on the type of water exposure, the type of soil, the type of stress, and the planned use.
Two basic types of building waterproofing are the “black tank” and the “white tank.”

Black Tank

The building parts to be sealed receive a continuous waterproof membrane on all sides according to DIN 18195 with the black tank. Sealing membranes made of bitumen or plastic are applied to the outside of the building (external sealing) and are pressed by the attacking water against the building walls or floor.

White Tank

With the white tank, no additional sealing membranes are required due to its construction. The floor slab and exterior walls are made as a closed tank of concrete with high water impermeability according to DIN EN 206-1 and DIN 1045-2. This concrete is also called waterproof concrete or WU concrete. For the construction of the buildings, reference is made to the guideline “Waterproof Structures Made of Concrete” of the DAfStb. The white tank is usually built story-high, either from cast-in-place concrete with system formwork or from prefabricated element walls (triple walls).

Whether your soil conditions require special waterproofing of the basement is stated in the soil survey, which you should definitely have prepared by a soil expert before the start of construction!

...In his opinion, it would be unnecessary if the drainage can be fed into the sewage system.

Having an opinion is like believing in church. The seller can – assuming he has already built in the development area – make a guess; but nothing more. I have often experienced that for one semi-detached house plot the soil conditions were fine, but for another – only a few meters away – problems occurred; in case of doubt, this can be quite expensive, but in any case, it will exceed the estimated additional costs.

Best regards

Hello everyone, my experience with BUs is truly alarming. We had discussions with 6 companies. Only 2 companies pointed out in advance to have a soil survey conducted! One representative stated that first the soil should be removed and then you can see if a WW is necessary. That really makes you feel well advised

Hello everyone, According to his opinion, it would be unnecessary if the drainage can be fed into the sewage system.

Then just ask if it not only CAN but also MAY

Hello,

I had to plan with a WU basement due to upcoming water.
Next week the basement ceiling and walls will be backfilled.

Afterwards, I will apply the perimeter insulation myself.
However, I have very different opinions regarding the bonding.

The basement is half embedded in the slope, so the front will be level with the ground and open.
I have already found out that I need two types of insulation boards here (with and without honeycomb for plaster).

But the bonding itself – the basement is clean and perfectly smooth (started setting up last Friday).

My builder says to apply bitumen with a notched trowel and that’s it.
My building materials dealer says a special foam would be more economical, less messy and adheres just as well to clean concrete.

A customer also suggested securing the boards with dowels in the visible area (because of plaster) due to weight.
But dowels in a WU basement? I’m not going to drill into my ship’s hull.

Overall, I have generally chosen the option with bitumen – does that stuff need an activator or something?

Does doing it with foam make sense? It would probably be easier.

But is it really such a problem with the boards in the visible area and the weight of the plaster that will be applied later?
If the boards are glued cleanly to the wall and rest on the gravel bed at the bottom, NOTHING SHOULD sag (by the way this concerns the north side).

Thanks for tips
Regards
Chris