ᐅ Waterproof Basement – "Fresh Concrete Composite Membrane"

Created on: 13 Jul 2017 09:04
W
Wissi
Hello everyone,

this is about the method our house builder is using to create a waterproof basement. To be honest, I have never heard of this before, and there is very little information available online about it... and what there is mostly relates to commercial or office buildings.

The method is called "fresh concrete composite membrane" (FBVK #waterproof) with double-layer exterior walls 20cm (8 inches) thick.
One step down would be the "WU-basement" with double-layer exterior walls 24cm (9.5 inches), joint flashing. Of course, this option is also cheaper (approx. 3,000 €).

The plan is to set up a home office in the basement. Therefore, we would prefer it to be "properly sealed," ideally without high humidity caused by water-resistant concrete.

A soil report is not available yet!

Are you familiar with the first method? Have you had any experience with it or any opinions?
It would also be interesting to know whether insulation is possible at all if there is a "membrane" facing the soil on the outside.
Wissi6 Aug 2017 18:23
Specifications according to the offer are mentioned in the first post. Here is a summary again:

WU-BASEMENT
  • Exterior walls 24cm (9.5 inches)
  • Foundation slab 25cm (10 inches)
  • Joint sheets in all component joints

Version with FBVB (fresh concrete composite membrane)
  • Exterior walls 20cm (8 inches)
  • Foundation slab 25cm (10 inches)
  • Water pressure-resistant basement windows (up to 80cm (31.5 inches) water column)
  • Sealing with the mentioned membrane
  • Additional cost of about 3000 Euro

Doing it yourself (or having it done) is unfortunately not an option, as this is a prefabricated basement and only available as a complete package
Yilmaz6 Aug 2017 18:27
I would like to know if it is truly a heated ground floor plus ceiling with thermal insulation, or just a concrete basement plus ceiling with thermal insulation.
I believe this is where the problem lies...
Wissi6 Aug 2017 18:33
Oh, by the way: According to the construction and performance specifications, the execution with foil appears to be with normal concrete.
But that’s a good point, I definitely want to ask about that.
Yilmaz6 Aug 2017 18:35
Exactly! WW is built to last forever, while the membrane lasts only 10-20-30 years?
Wissi6 Aug 2017 19:04
I do think that these membrane systems have a long lifespan.

They are also commonly used in higher-quality commercial or public construction projects. However, it’s probably difficult to find detailed information or definitive statements about them—similar to watertight concrete (WU concrete), I would guess. A crack after 10 years, and suddenly water gets in :-/

Still, there are a few things I definitely want to clarify with Schwörerhaus. Thanks again for the feedback!
A
Alex85
7 Aug 2017 06:47
In both quotes, the waterproof concrete seems simply too thin, doesn’t it? It should be 25cm (10 inches), preferably 30cm (12 inches). No wonder they still need a membrane there... There should be a processing guideline or something similar for waterproof concrete; try googling it.