Underfloor insulation to achieve more room height on the ground floor?

Hello everyone,

I am currently working on our construction description and am uncertain about one point. The structure of the floor slab was changed to the following variant (previously, only insulation on the floor slab was mentioned):

- Sealing of the concrete base according to DIN 18 195 part 4, e.g. with a bitumen welding membrane

- In the ground floor, floating cement screed approximately 60mm thick on 80mm thick impact sound and thermal insulation WLG 035 and a 60mm sub-base insulation

This results in the floor slab achieving a U-value of 0.23 W/(qm x K)

The reason for the changed structure is our desire for more room height on the ground floor, while limiting the eaves height to 4m.

Does this make sense?

Best regards

Tapp2014:confused:

.... - On the ground floor, floating cement screed approx. 60mm thick on 80mm thick impact sound and thermal insulation WLG 035 and a 60mm sub-slab insulation....This results in a U-value of 0.23 W/(sqm x K) for the base slab...Does this make sense?

Only if moisture-free conditions are guaranteed at the level below the BPL! Otherwise, this effort is pointless, as the thermal insulation effect => 0. Possibly the insulation effort of the BPL can be reduced, as it is usually only responsible for a small percentage of the total transmission heat losses. Any deficits can usually be compensated for elsewhere, in a much more effective way => Energy Saving Ordinance/KfW optimization.

v.g.