White tank and ring drainage for our house?

Hello everyone,

I have a question about the optimal sealing of the basement against water and moisture. We are currently building a semi-detached house and the basement is already done. Basement dimensions 8 meters by 12 meters. We built with a white tank and have applied or had applied a bitumen layer and thermal insulation on the outside. The architect has planned a ring drainage. The earthworks contractor says it is not necessary. For the basement light wells, he can install seepage grates. What can you advise me?

Thanks and regards Berhane

Hello,

by bitumen layer you mean a thick coating with which the insulation was glued, right? So not a welded membrane.. (Just for understanding)

Then you also need to know how the white tank was constructed. There are differences regarding water guidance.
Regarding the geometry, I would say at first that no major problems should occur. Do you have pictures of how the connection between the base slab / wall was made?

In my opinion, a ring drainage is not necessary for a proper waterproof construction. What groundwater levels do you have?

If you need further help, feel free to contact me, I have some experience in the field of waterproof construction.

Best regards, Jann Stöter

Hello Jann, thank you very much for the feedback.
Yes, it is a WU basin with a thick coating of bitumen and the thermal insulation glued on top.
Attached I am sending you some photos. The connection between the base slab and wall is sealed with a bitumen sheet, see photos.
I have now decided against a ring drainage. I am having infiltration blocks installed under the light wells.
The groundwater level is well below the basement floor.

Is my decision correct?

Thanks and regards, Daniel

Hi,

Yes, that was, in my opinion, correct. The joints seem to be well done. The [lichtschächte] are not connected to the drainage but the water is supposed to infiltrate? Then it was sensible to increase the infiltration capacity underneath.

Have fun with it. Feel free to get in touch if you have any other questions. I do this professionally.

Best regards, Jann

Hello Jann,
thank you very much for the advice.
It helped me a lot.
Best regards Daniel

Fits. You didn't need the thick coating, but double protection is better.