Floor construction without screed for solid wood planks - experiences

My current plan is that we will have a "standard" concrete slab under the house; additional insulation would still be possible. From my experience with a house with a basement, I had planned to lay a foil as a barrier on the raw floor (this time without a basement). On top of that, a beam layer or cross layer and insulation fill in between (cork, perlite, hemp-light clay fill; this was also the statement from the executing craftsman). Now I inquired at a specialist company for such insulation materials and they sowed some doubts that the foil on the raw floor might possibly prevent moisture, which could have settled downwards from the indoor air in the worst case (through wooden floorboards, insulation fill), from "draining" there because of this foil. Therefore, the advice was to lay the beams only on foil to protect the wood from direct contact with concrete/moisture and to apply the insulation fill directly on the raw floor. That, in turn, in my opinion carries the risk that residual moisture might penetrate from below upwards into the insulation area and the problem would then exist just in reverse. The possible solution would be to use foam glass gravel during the initial construction of the concrete slab; however, again I do not know whether my general contractor will implement this and whether it makes sense. I was basically clear about this topic already, but since there is no basement under the living rooms in this construction, it now makes me a bit thoughtful. Ultimately, I want to avoid screed precisely for this reason of moisture. Does anyone have more experience/knowledge about this? you have such a construction; could you tell me your exact structure (foil, insulation etc.)? Do you have a basement? What kind of concrete slab do you have? What height of beams did you use? S(sorry for the many questions).

Aren't you getting underfloor heating?

Hello, here is a brief overview... a strip foundation was created for the exterior walls. On top of that, a floor slab, which is not specially insulated underneath. A sealing was glued and welded onto the raw floor (entire room, not just under the wood). For the beam layer, wood pieces of about 10x10 cm were used, which rest on blocks. Unevenness was compensated with plastic wedges (I personally didn’t like that... but our construction company assured that they last forever...). In between came this yellow insulation felt, and finally the floorboards.

I never thought that condensate could collect on the floor slab. We also don’t get condensate on the walls... it would be similar, wouldn’t it..? I hope this helps..

Aren't you getting underfloor heating?

No, I don't like it that much.

Thank you very much for the information. It should be something like this here, although I am planning an insulation screed.

That is interesting, unusual, and uncommon.

May I ask what advantages you expect from this floor construction?