new floor structure in the old building ground floor

Hello everyone!
I am new here and yesterday I bought a house (built in 1953) that is now going to be renovated.
In most areas I already have ideas and plans except for the one mentioned in the topic.
The structure is very good and everything is dry.

Here are some details about the house:
Masonry 25cm NF brick
Partially basemented (this is what it is about)
Currently gas heating
no [WDVS]
Double glazing from around 2000

The non-basemented part of the house has a strip foundation and the floor is built on wooden beams in slag.
I would like to insulate the basement ceiling and the floor of the non-basemented part.

What would you advise me for the floor construction in the non-basemented part of the house (without gaining height)?

Thanks and best regards!
Rene

Hello first of all, welcome to the forum,
congratulations on the new old house.
That sounds like completely undamped with floor joists and floorboards (possibly already worn through)?
And underneath a view of the slag and into the partial cellar?

Hello first of all, welcome to the forum, congratulations on the new old house. That sounds like completely undamped with floor joists and floorboards (possibly already worn through)? And below a view of the slag and into the partial basement?

Yes and no, the basemented part of the house has a floor structure without joists. The floor was laid more or less directly on the concrete. The basement also protrudes about 70cm from the ground. That is why the non-basemented part of the house is backfilled with slag and contains joists. I want to avoid raising the beams, so it would be great for me if I can keep the floor buildup as low as possible. I would level the concrete of the basement ceiling, insulate the basement ceiling, and I am still unclear about what to do with the non-basemented part of the house. Maybe remove the joists, lay a foil, XPS, and concrete? Or remove the joists, foil, bound backfill, and screed? Does that exert pressure on the walls? Is that possible? Thanks!

You will do us a great service in all planning and qualified advising by clarifying the substance with floor plans and sections (possibly from the building file). Both the 1950s and the 1960s were each about three decades in terms of construction technology. In 1953, Schmalhans still improvised a lot; even in the West, those were clearly post-war years in construction terms. I only believe in a "good substance" within the meaning of "not rotten." After all, at that time the lack of fine materials was compensated with much less botching than today. But it is indeed a year of construction with objects that are not cheaply made without reason.

You will do us a great service for all planning and qualified consulting by clarifying the substance with floor plans and sections (possibly from the building file). Both the 50s and the 60s were each about three decades from a construction-technical perspective. In 1953 Schmalhans still improvised a lot, those were still clearly post-war years construction-wise even in the West. I only believe in a "good substance" in the sense of "not rotted." After all, the lack of fine materials was compensated back then with much less botching than today. But it is a construction year with understandably cheap objects.

I will of course gladly provide you with the original plans later, the house was built by the master builder with a quality that is good even by today's standards.

You will do us a great service for all planning and qualified consulting by clarifying the structure with floor plans and sections (possibly from the building file). Both the 50s and the 60s each represented about three decades in construction technology. In 1953, Schmalhans still improvised a lot; even in the West, these were clearly post-war years from a construction perspective. I only believe in a "good structure" in the sense of "not rotten." After all, the lack of fine materials was compensated back then with much less botched work than today. But it is definitely a construction year with not coincidentally cheap properties.

Attached is now the plan (which, however, has little to do with reality).
As you can see, the house is only partially basemented; I have now inspected the non-basemented part more closely and it looks as follows:
the floorboards rest on wooden beams that lie on a simply torched concrete slab, with slag in between.

Thanks again for the help!