Bitumen coating despite finished exterior plaster

Hello everyone,

this seems to be a somewhat unusual question, at least my search on the topic yielded nothing even on Google. Regarding my case:

our house itself is finished and the exterior plaster is completely completed as well. Now we are planning the outdoor area. Here we want to raise the ground in one spot higher than originally planned. Therefore, part of the plastered wall will disappear under the soil.

Now to the question:

Is it sufficient to use the typical dimpled membrane [Noppenbahn] between the soil and the wall at the already finished plaster to protect the wall from moisture, or should one still apply a bitumen coating on the plaster?

Regards
Toni

Normally, the seal should go 15cm above the ground; I do not know how finished plaster is protected. Maybe can help.

Yes, [Noppenbahn] is not a waterproofing. It is only a mechanical protection. Whether you can apply bitumen directly onto the exterior plaster depends on its composition and technical data. If you compare the technical data sheets of both building materials, it may already indicate to a layperson whether they are compatible.

Another waterproofing layer can also be applied to the plaster. There are various mortars from the plaster manufacturers that can be used for this. It is important where the waterproofing connects in the soil, so that no moisture can migrate behind it. This is difficult to assess with the limited information available. You should definitely do something; the dimpled membrane is just the minimum to prevent the soil from having permanent contact, but it is rather to be seen as protection for the waterproofing.

Thank you all already.

maybe the attached picture will help a bit more. Below (the partial Mohne structure at the split, here the dimpled membrane comes and is plastered under the plaster. I would now like to go up half a meter to one meter higher with the soil.

Hello,

I faced the same question when my basement garage was bricked up and then the driveway was filled with soil. At that time, we used bitumen thick coating plus insulation and studs. If you fill soil against the plaster, I would also use bitumen thick coating plus studs here, then you're safe. The thick coating is not UV resistant. So it is really only protective where it is covered with soil. There is also something like bitumen IS, be careful about what the small print says. Often it states that there is no permanent protection against moisture, which doesn’t help you. I once made this mistake and was lucky that the architect clarified it.