Horizontal sealing of the base slab

Why should a PE foil have been laid under the floor slab in this particular case? Floor slabs do not necessarily have to be, but are still usually equipped with steel reinforcement. Where is the PE foil supposed to be then? And what will it look like when the iron worker has marched over it dozens of times and sharp-edged reinforcing steel bars have been pulled across it? Who wants to take responsibility for the PE foil, if it was even installed at all, not being perforated, torn, and also overlapped at the sheet edges? All speculations resembling a look into the blue crystal ball. However, the German construction landscape with its technical rules does not stand for such residual risks.
----------------------------------
Regards: KlaRA

@ "joho78":
Tip: Save the money for the alternative sealing (the correct term), as no success can result from this!
Because the installations that are routed over the raw ceiling must be secured against slipping.
Means: Forced drilling of the base slab, through the sealing.
This perforates it and it cannot fulfill its intended tasks.

Hello KlaRa, I want to ask a question: What you write here is logical, the sealing will then be damaged by the pipe fastenings. How does one ideally seal so that this does not happen, only under the exterior and interior walls?

Hello "Paulus16". The whole problem in construction actually begins already at the planning stage. Surely you are not the only client in Germany asking yourself such questions! Unfortunately, the usual case is that installations are laid crisscross, sometimes overlapping, forming significant high points clustered like knots on the raw ceiling. In extreme heights, the concrete ceiling is chiseled to "bury" some of the empty conduits; and if the screed installer is a bit lucky, these installations are even fixed to the raw ceiling (and not hanging in the air at the slightest touch). A state-of-the-art approach is to rework this tangle with a bound fill, which means leveling up to the top edge of the highest installation. This now level surface is used for the flat waterproofing layer (sheet material). At exterior walls, the waterproofing is pulled up to the horizontal barrier in the masonry. This can be directly below the first row of bricks, but more often it is above it. Sealed in this way, we then move on to thermal insulation, PE foil, and wet screed. This is how a proper build-up would look amid the chaos of the installations. However, often the necessary build-up height is missing, so artistic carving-like work with the thermal insulation becomes necessary to adapt the insulation material in a height-saving way to the chaos of the raw ceiling. Correctly observed: there is no space for the waterproofing layer there, or the waterproofing applied on the (visually masking the chaos) thermal insulation is technically incorrect. --------------------------------------------- Regards: KlaRa

Thank you for the quick response.

So the base slab will not be sealed initially, but the installations will be attached to it, then the whole thing will be backfilled until we have a level surface, which is only then sealed, have I understood correctly?
What material does the bound backfill consist of?

The fillings can consist of different (that is: the most varied) materials. For example, PERLITE is a volcanic, thus mineral filling that binds firmly only due to the friction forces between the little beads (thus bonded). Then there are cement-bonded styrofoam beads from THERMOZELL, and the company KNAUF offers the SCHUBO system for low surface weight (for example, on wooden beam ceilings). The only decisive factor is that the system is moisture-resistant, as it is used between the floor slab and the sealing.
-------------
Best regards: KlaRa

Thank you KlaRa, so sealing directly on the base plate is a waste of money, right? At least that's what an acquaintance of mine (mason by profession) thinks.