Insulation of basement vestibule

Hello everyone,

I am currently facing the question of how best to insulate the windbreak of our new building and how the overall structure should be constructed.
First of all, here is the cross-section:


As you can see, there is a basement room under the windbreak, which is heated.
Since the top edge of the finished floor of the windbreak should be the same as in the hallway, the total build-up height is unfortunately only 10 cm.
For the flooring, I would prefer a natural stone slab. However, this probably won’t work because it could crack without a thick mortar bed or similar. Therefore, I was now thinking of large terrace tiles.

For the build-up, I am currently considering the following overall:
1. Bituminous membrane or liquid waterproofing (0.5 cm)
2. Terrace insulation board BauderPIR FA TE (8 cm)
3. Tile adhesive (0.5 cm)
4. Terrace tiles (0.9 cm)

Is this feasible? Do you have any tips and suggestions?

Since the windbreak is covered, I think a slope can be omitted. So far, the windbreak has always been dry during the construction phase, even during the heavy rainfalls of the past days.

Thank you and best regards

For understanding: is your [Windfang] outside the house? Normally, the [Windgang] is inside the house between the outer door and the vestibule/hallway.

Exactly. Maybe "Windfang" is the wrong word. Here is also the excerpt of the floor plan related to it

In the meantime, it has become clear to me that the construction I originally considered above is not possible.

Therefore, it might possibly work like this:

1. Bitumen waterproofing membrane or liquid waterproofing (0.5 cm)
2. Resol rigid foam board (4 cm)
3. Cement screed (4 cm)
3. Tile adhesive (0.2 cm)
4. Terrace tiles (0.9 cm)

Maybe I can also use dry screed and thus gain more height for the insulation. Fermacell, for example, offers the product Powerpanel TE for this. However, it is not clear to me whether I can simply place a Resol rigid foam board underneath it. How would these layers be bonded together?