Floor construction with high load capacity?!

Hello, I need some advice regarding the floor construction. The problem is that I need an extremely large amount of filling material. The room was completely gutted and now it's time for a new floor construction. From the concrete floor to the finished floor height, it is 29 cm! I have planned again to use a bloated clay filling, foil, screed, and finally a leveling compound. Whether the floor will ultimately be tiled or just laminate, I don't know yet. I have calculated 1.5 cm for tiles or laminate/vinyl including the leveling compound. 6 cm screed Then 21.5 cm filling height remains. The room is 3.9 m² I have informed myself about the Liapor 8/16 filling since it can be used in unlimited height. According to calculations, I would need 15 bags, which corresponds to about €300 here in our hardware store!! Screed with a thickness of 6 cm is around €50, which is manageable. Are there any alternatives or improvement tips? The price for the filling material has really shocked me. I could simply increase the screed thickness to save on the filling material, but that would mean significantly more effort and a lot more carrying upstairs... The plan is to start with the filling on the 24th. So I am a bit stressed with the organization. Best regards

Just realized that the existing heating pipes are already 20cm above the concrete floor. So thicker screed is not possible....

Hello questioner.
Assume that with a ground-contacting slab you would also need thermal insulation. Possibly even a sealing layer, as far as it is ground-contacting.
Sure, you write nothing about that.
If it is an upper floor on which the concrete slab rests, then it would be further to consider whether it is a multi-family house.
You do not write any of that, but those would be important details for a construction recommendation.
Basically, a bonded filling to increase the buildup is a sensible option.
The screed thickness of 60mm is, in my opinion, oversized.
45mm installation thickness with F4 as the flexural tensile strength of the mortar is completely sufficient.
You can still consider which construction you choose.
For example
- sealing layer
- bonded filling
- intermediate layer (MDF/HDF)
- thermal or impact sound insulation
- PE foil layer as separating and sliding layer
- conventionally installed cement or calcium sulfate screed
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Good luck: KlaRa

Thank you for your response. I am on the upper floor. It is a multi-family house. The rest of the apartment is old stock and nothing will change quickly with the floor construction. The plumber and electrician will probably lay their pipes on the concrete floor. Can I lay Styrofoam panels around the first 10cm and then about 10cm of screed? Later then a separating foil and after that the screed? That would save me quite a bit of screed.

Thank you for your answer. I am on the upper floor. It is a multi-family house. The rest of the apartment is old stock and the floor construction will not change that quickly. The plumber and electrician will probably lay their pipes on the concrete floor. Can I lay Styrofoam panels all around the first 10cm and then about 10cm of loose fill? Later then a separating foil and after that the screed? That way I could save a lot of loose fill.

Now with these additional notes, we have everything needed for a proper construction. In a multi-family house, you get significant problems in your home if you do not consider soundproofing!!! Since the electrician and plumber attach their trades on the raw floor, only the following procedure remains for us to meet the normative requirements: - Installations (on the raw ceiling) - bonded loose fill applied evenly up to the top edge of the highest elevation (of the installations) - even covering of the bonded loose fill (3-5mm MDF panels, loosely laid together) - 2 x 25mm impact sound insulation, upper layer rotated 90° to the lower insulation layer - PE foil, joints overlapping at least 25cm and taped to prevent slipping, the foil pulled up at the walls at least 5cm above the height of the later surface covering and cut flush after the covering has been installed - cement or calcium sulfate screed, 45mm thick for conventional installation --------------------------- Note: whoever saves money in the wrong place basically builds twice (because they have to rebuild everything later) and “as a bonus” gets to deal with trouble with the other tenants for free. Good luck: KlaRa