Is a vapor barrier required in the basement with waterproof concrete and underfloor heating?

The vapor barrier should of course only be applied on the floor and only 20 cm up the walls, which corresponds to the floor construction height.

Then it’s only half as funny as I first thought. Whether it makes sense, you have to decide for yourself depending on how long the floor slab was allowed to dry. Some experts even believed that no barrier is basically needed with WU concrete. But I am also torn, especially considering that the barrier is perforated multiple times by subsequent trades. Regards Nika

The basement floor slab has been drying since November, so it should be nicely dried through. Additionally, it is insulated at the bottom. I just asked my heating engineer and received the advice to have a vapor barrier applied. No matter how many people you ask, in the end, it is a 50:50 matter. At least that's my impression.

No matter how many people you ask, in the end it’s a 50:50 matter. At least that’s my impression.

That’s exactly how it is. Even experts don’t have a strong opinion on that. However, I haven’t read anything stating that it is considered mandatory at WU. The general sentiment is rather that caution is the parent of safety. I would make it dependent on the amount of the costs. Regards, Nika