You must know what the contract says and what the soil report states!
Of course I know what the soil report says and what the contract addendum states. It's now more about the term White Tank. We have pressing water and need sealing according to DIN 18195, and the Aquasafe from Glatthaar meets that.
Okay, I took a look at the structure, it is not the classic ww as you know it. It is a double sealing from the outside, it will work. Glatthaar actually has a good reputation.