ᐅ Dimple membrane waterproofing is missing under the floor slab.

Five years ago, we purchased a terraced house from Interhomes in Cologne. It has now come to light that the company forgot to install the dimpled membrane in the floor, which is causing moisture to enter the base of the walls. All buyers in this row believe this is a defect and should be repaired by the company under the warranty. Interhomes, however, argues that the buyers themselves should have installed this membrane when they extended the terraces. Could someone please offer advice on how to proceed in this situation? How can the absence of this membrane be identified in a completed building? Isn’t a house supposed to be delivered “waterproof”?

Hello,

holweide1 schrieb:
How can you tell from a finished building that this membrane is missing? Isn't a house supposed to be handed over as "waterproof"?

You can't tell from the finished building; the answer is in the building specifications!

Kind regards

Bauexperte schrieb:
Hello,

Not on the finished building; the answer is in the construction description!

Best regards

Hello!
I have some doubts about that. The dimpled membrane costs practically nothing – and you can’t address every little detail.

However, it can be assumed that a dimpled membrane is not part of the house itself, but rather belongs to the exterior landscaping – and if these were not included in the contract, then the matter is settled.

Regards,
Tom.

TomTom1 schrieb:
Hello!
I have my doubts about that. The dimpled membrane costs practically nothing – and you can’t regulate every little detail.

However, you can assume that a dimpled membrane is not part of the house itself, but belongs to the exterior landscaping – and if that was not included in the contract, the matter is settled.

Regards,
Tom.

Hmm, as a layperson I would probably see it that way too. There are so many standards, industry guidelines, and generally accepted construction practices that cover almost everything and are often cited. This topic is not covered there?

Hello...

I was under the impression that the dimpled membrane is only a mechanical protection against backfill and has nothing to do with waterproofing.
We have a precast concrete basement with external wall insulation and the dimpled membrane in the ground-contact area.

Best regards

Good morning,

TomTom1 schrieb:

I have my doubts about that. Studded membranes cost practically nothing – and you can't specify every little detail.

I agree with you that a building brief doesn’t need to specify every single detail; otherwise, it would probably be like a tender document. However, I don’t consider the detail about separating the basement from the surrounding soil (e.g., rising damp) to be a "minor point." Following this argument, a building brief could consist of only two pages, namely covering the essential requirements for the above-ground structure. Everything else would then follow automatically from the applicable technical regulations.

TomTom1 schrieb:

However, you can assume that a studded membrane is not part of the house but belongs to the external works – and if these were not part of the contract, then the matter is settled.

No.

Studded membranes have their fixed place in building construction and have nothing to do with external works. They primarily serve to protect insulated underground components against, for example, rising damp and also to prevent damage from backfilling. External works are indeed "only" external works: internal access routes, driveways, terraces, garden landscaping.

Source: my website

Best regards, Bauexperte