Floor construction & height adjustment in old buildings (underfloor heating)

I have to admit, unfortunately I can't give you a definitive and well-founded statement on this either. My insulation supplier and screed installer also mentioned back then that it is best to work with 2 layers (which makes sense because you can insulate the joints), of which only one should consist of impact sound insulation (DES).

Your studded plates indeed have EPS DEO processed on them. So you can put the maximum possible thickness of EPS DES impact sound insulation underneath.

I would like to briefly join this thread, as our question points in the same direction. We also have an uneven floor with wooden ceiling beams in the old building. We want to level it with a leveling fill and then lay panels over it, which will subsequently be finished with tiles or laminate. The heating is not in the floor. Now the question: Are there special materials to maximize fire resistance here? We would like to rent out and want to minimize the fire hazard.

Perlite should be the right choice here, although they usually require a minimum installation height of around 30mm.

We have no problems with the height, the rooms are over 4m high. Perlite are noted.

In this case, maybe also consider impact sound insulation made of mineral wool. Or do you not live below?

In this case, maybe also consider impact sound insulation made of stone wool. Or do you not live below?

I would like to cautiously suggest that stone wool is not impact-resistant. But oerlite alone at this construction height already achieves quite a lot.