ᐅ Insulation under the ground floor slab to gain additional ceiling height on the ground floor?

Hello everyone,

I’m currently reviewing our construction description and uncertain about one point. The design of the ground slab has been changed to the following version (previously, only insulation on the ground slab was mentioned):

- Sealing of the concrete base according to DIN 18 195 part 4, for example with a bitumen membrane

- On the ground floor, a floating cement screed approximately 60mm (2.4 inches) thick on top of 80mm (3.1 inches) thick impact sound and thermal insulation with a thermal conductivity of 0.035 W/(m·K) and a 60mm (2.4 inches) sub-slab insulation

This results in a U-value of 0.23 W/(m²·K) for the ground slab.

The reason for the modified design is our desire for increased ceiling height on the ground floor while limiting the eaves height to 4m (13 feet).

Does this make sense?

Kind regards

Tapp2014 😕

Tapp2014 schrieb:
....
- On the ground floor, a floating cement screed approximately 60mm (2.4 inches) thick on top of 80mm (3.1 inches) thick impact sound and thermal insulation with a thermal conductivity of 0.035 W/(m·K) and a 60mm (2.4 inches) thick sub-slab insulation.... This results in a floor slab with a U-value of 0.23 W/(m²·K)... Does this make sense?

Only if moisture-free conditions are guaranteed below the building slab level! Otherwise, the effort is pointless, as the thermal insulation effect approaches zero. If necessary, the insulation effort for the slab can be reduced, since it usually only accounts for a small percentage of the total heat transmission losses. Any deficits can typically be compensated at other, much more effective points => compliance with energy saving regulations/KfW optimization.

Best regards