Best possible floor construction

Hello everyone,

I have a question about the floor construction of a wooden beam ceiling and hope that I am in the right place here! My father built an addition and a story up about 6 years ago, but since then the upper floor is still a "shell". The area in question is about 10x10m (old house) and consists of a wooden beam ceiling with 6x20cm beams and a clear span of 50cm. Currently, there is a 2cm plywood/OSB board on the beams. The floor construction now needs to be aligned with the height of the newly built areas (the house was extended on 2 sides). At the moment, the difference is still 6cm (new building to OSB board).

It is mainly about the acoustics; it should be insulated as well as possible so that footsteps are not transmitted either within the apartment or downwards.

An image for illustration is attached.

My favorite is "Situation 1" because I can probably add the most material and use the most volume here. This means the most work, however, I prefer doing it properly than regretting it later. But I have a big question here: how are drywall partitions installed? Are they then screwed directly onto the beams beforehand?

Regarding "Situation 2": Of course, easier because the OSB boards can initially remain as they are, but the floor construction is then not as high. Only about a 3cm infill can be added, and the rest would be balanced out by dry screed boards.

For your information: A structural engineer and various craftsmen will definitely come for assessment; I just want to know in advance who will try to fool me and who really knows what they are talking about.

Which option is the most sensible now? For other possible variants or ideas, as well as any advice, I am very grateful!!

Thanks in advance and best regards,

Phillip

Loose filling is no longer the state of the art. In the installed condition, leveling layers must/should be in bonded form. 4 cm screed is also unnecessary. I would work with EPS DEO boards and 2 cm dry screed on top.

Thank you for the answer, but isn't that far too little? Currently, when walking on the floor, the entire ceiling vibrates slightly. Not strongly, but you can definitely notice it. If I then just lay "Styropor Platten" and dry screed on it, nothing will change, right?

so if it swings, loose fill is even less suitable. If something bends there, the loose fill can shift. But the ceiling should not swing. I would have a specialist take a look before any measures are taken.