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.
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.
Wissi schrieb:
Unfortunately, the statement seems poorly founded... sorry to say it like that. But then another user could come into this forum and claim the exact opposite, and it would cancel out. For example, me: it actually is.
A few references are always helpful in cases like this (no links, as they are not allowed)
- Building physics studies from TU Berlin
- Information sheets from the Concrete Information Center GmbH in Erkrath
- Publications from the German Committee for Reinforced Concrete
These are just three of many sources that confirm this.
Especially your last source states exactly the opposite. From a building component thickness of 20 cm (8 inches) and above, no moisture transport takes place anymore.
Oops, there was another comment on the quote. Even better!
Here is the source anyway:
Excerpt from "Cement Data Sheet for Structural Engineering H10 3.2012 – Watertight Concrete Structures," published by InformationsZentrum Beton GmbH. Authors Dipl.-Ing Thomas Bose, Dipl.-Ing Rolf Kampen, and, in general, InformationsZentrum Beton.
Here is the source anyway:
Excerpt from "Cement Data Sheet for Structural Engineering H10 3.2012 – Watertight Concrete Structures," published by InformationsZentrum Beton GmbH. Authors Dipl.-Ing Thomas Bose, Dipl.-Ing Rolf Kampen, and, in general, InformationsZentrum Beton.
Hm, regarding diffusion again:
Thank you for this clarification! So, am I understanding correctly that with a thickness of 24 cm (9.5 inches), a maximum capillary and drying zone of 8 cm (3 inches) each, there would be a core area of 8 cm (3 inches) remaining?
Now I’m really puzzled. The logic clearly points to choosing a waterproof basement!
Because if with a wall thickness of 20 cm (8 inches) there is (almost) no overlap between the capillary and drying zones, then with 24 cm (9.5 inches) you are definitely on the safe side.
Phew, yes….I think the decision is clear then. I’d rather invest the 3000 euros in perimeter insulation.
Thank you for this clarification! So, am I understanding correctly that with a thickness of 24 cm (9.5 inches), a maximum capillary and drying zone of 8 cm (3 inches) each, there would be a core area of 8 cm (3 inches) remaining?
Now I’m really puzzled. The logic clearly points to choosing a waterproof basement!
Because if with a wall thickness of 20 cm (8 inches) there is (almost) no overlap between the capillary and drying zones, then with 24 cm (9.5 inches) you are definitely on the safe side.
Phew, yes….I think the decision is clear then. I’d rather invest the 3000 euros in perimeter insulation.
That is exactly the source I meant. It states, among other things, "In watertight concrete structures, diffusion in the drying zone slows down over time and practically comes to a halt after the release of internal moisture [5], [12]. Also, in [14], no cases of increased humidity were reported under constant hydrostatic pressure (floating houses)."
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