Hello Kisska,
The architect says 180mm floor construction on the ground floor. But he did not say exactly how it should be assembled. The same for the attic.
And why don't you ask him then? Insulation, impact sound insulation, foil, underfloor heating and screed lead to an 18 cm construction height. This also means you have to decide which final flooring you want for the rooms later so that the screed installer knows.
And what speaks against informing yourself and making decisions???
That you are an absolute layman?
Building owners make decisions about the floor plan, wall construction, equipment and type of technology. For all other requirements on site, a professional is needed. Since laymen usually cannot manage this nor check the decisions – although many believe that after “x” weeks of searching for a building partner they have become experts – I recommend involving external expertise. This way, possible sources of error can be quickly identified according to the four-eyes principle, and the building owner, who is the client, always knows a competent partner is by their side who answers all questions clearly.
Rhenish greetings