Is purchasing a house and complete renovation affordable?

With our house from the 1950s, we also had sand in the ground and wood parquet / floating screed on top.
This was probably more common in Bavaria/Franconia.

Where did you dispose of the sand back then?
I once calculated it. There must be 10 cubic meters of sand in the house.

10 cubic meters is not that much. You could spread it on the lawn if it is big enough. Is the sand in the [OG]? Then it serves as sound insulation and usually works better than all the systems you can buy nowadays for a lot of money. You could also consider leaving it inside if it is structurally possible.

This is simply filler material for insulation and soundproofing, for us it is slag. We left it in the upper floor and attic (only on the ground floor it is now gone because we installed underfloor heating, screed, and insulation there). Otherwise, it is only disposed of with great effort and something else is put in at the end.

Where did you dispose of the sand back then? I once calculated it roughly. There should be 10 cubic meters of sand in the house.

We also left it in the ground floor and applied leveling compound and decoupling mats on the wooden floor. We also once calculated it roughly and decided against it because of the effort, as we would have had to do it everywhere and consequently would have had to remove existing screeds as well. However, due to money/effort, we also did not retrofit underfloor heating.

The sand in a wooden ceiling serves to reduce vibrations (sound insulation and stability) and must not be removed under any circumstances. Ideally, the house is somewhat sound-permeable (structure-borne and airborne sound); in the worst case, you have structural problems. Glass wool or lightweight fillings are not suitable for this purpose.

Where the sand or the partially coarse-grained material lies, it is a concrete ceiling. On the first floor, I opened the floor today and here the sand also lies on the concrete ceiling. I would like to remove this material in order to install underfloor heating and screed. The room height from the concrete ceiling floor to the ceiling is 2.54 m. What do you think about removing the material and installing underfloor heating and screed?