ᐅ Moisture Behind the Dimpled Membrane – What Could Be Causing the Issue?

Created on: 25 Feb 2024 17:39
C
crion
Hello everyone!

We moved into our house in November 2020. Around the foundation slab (unfortunately, we do not have a basement), there is a relatively tall dimpled membrane.

My wife recently noticed that it is quite damp behind the dimpled membrane in some areas, see the attached photos.

Where is the problem/what is going wrong here, how did the moisture get in there, and how can we get rid of it?

Best regards,
Christian
Exterior view: glass door left, beige wall, black gravel path with rectangular stone slabs.

Outdoor area: gravel path with concrete slabs, red gloves lying on a stone slab in front of the window.

Close-up: finger touching silver metal plate with round dimples at the foundation, gravel.

Hand with work glove placing perforated metal sheet against the building foundation over gravel.

Exterior view: perforated metal step next to a rough white wall; gravel lying beside it.
C
crion
9 Apr 2024 13:46
Hello WilderSueden!
WilderSueden schrieb:

What type of ground do you have? The winter was relatively wet, and maybe the house is now standing in a swampy area?

Otherwise, the dimpled membrane with filter fleece was installed correctly with the fleece facing the "soil." For me, the question is why use such a membrane at all. Water drains through the gravel almost as well as through the filter fleece. With a simple dimpled sheet with the dimples facing the house, there would at least be more air circulation between the membrane and the wall.

Thank you for your response as well!

We basically have no soil.
Almost the entire house is built on a thick gravel base.
It is slightly sloped, but even at the lower end, it still rests on gravel...
Underneath, there is clay at some depth, but it was never swampy and still isn’t.

Behind the terrace, there is an area that occasionally becomes slightly swampy, but the gravel is far away there — also, the three arborvitae trees used as privacy screening towards the neighbors now absorb the water quite well.

Yes, we tried to buy “good” dimpled membrane and installed it correctly with the right side facing outward.
But does it even make sense?
Because it doesn’t extend very far down; there is some gravel and a few slate pieces on top of it, and that’s about it.

Would a simple dimpled sheet also have to extend that far out (and look ugly!) and cause everything behind it to potentially mold?

Best regards,
Christian
T
tumaa
9 Apr 2024 15:54
The dimpled sheet, whether single-layer or triple-layer, only serves the purpose of providing mechanical protection; it does not offer waterproofing at the base.