ᐅ Laying a waterproof membrane on the bathroom floor to protect against water?

Hello. Our tiler recommended laying some kind of membrane in the bathroom to protect the screed from water damage in case of a leak. Many insurance companies reportedly would not cover claims without this membrane/waterproofing. I have never heard of this before and couldn’t find any information about it online.
Is what he says true, or is he just trying to make money?
We have planned to install vinyl flooring in the bathroom, which will be glued down.

A liquid waterproofing membrane is applied to seal everything. The tiler spreads it over the substrate and the base of the skirting board. After it dries, the tiles are installed.

Is this liquid waterproofing membrane required? I mean for the entire bathroom, not just the shower area? Regardless of whether it’s tiles, vinyl, or other flooring? I can understand its use in the shower, of course.

Tx-25 schrieb:

Is this liquid waterproofing membrane actually required?

For walk-in or level-access showers, yes, throughout the entire room. Otherwise, not to my knowledge.
The type of flooring doesn’t matter since none of it is waterproof.

Yes, waterproofing in bathrooms is mandatory according to DIN 18534.
Depending on the shower design (without a tray, with a partition, etc.), there are different requirements for walls and floors.
Light and dark gray areas indicate the waterproofed surfaces.

Okay, this is a clear overview, perfect, and thank you.
Can you also tell me how it would look in an insurance case?
This seems to refer to the following:
- Water leaking from the shower or bathtub + no waterproofing on the entire bathroom floor = trouble (damage will not be covered)
With waterproofing, it would be covered unless it is due to negligence, etc.

- What happens if there is a defect/fault in the pipe from the washbasin or toilet when I don’t have waterproofing? Will the damage be covered then?