External perimeter insulation floor slab, basement mold risk

Hi,

for our house with a basement, both construction providers have only calculated insulation on the floor slab. An additional cost for the external insulation is about €3400 ([WLG035, 10cm]).

The basement will mostly be used as storage space, the hallway and a large room will be heated by underfloor heating. Would you carry out this insulation to avoid/minimize thermal bridges in the corners and thus the risk of mold?

Regards Daniel

What does your planner's calculation say about whether this insulation measure is necessary? He has also carried out the energy saving ordinance calculation and can tell you if it might even be unavoidable. Apart from that, I am puzzled by an "insulation on the floor slab." Either the floor slab is insulated, then it is the UNDERNEATH - or the floor slab is not insulated and you try your best to fit a few centimeters into the floor construction under the screed. Then you still have the thermal bridges of the wall foot points and the exterior walls... -ks

Hello,

An extra charge for the external insulation costs about €3400 (WLG035, 10cm).

If a basic assessment has been carried out for the property, the additional effort can be economically evaluated. The system technology also plays a major role. With a brine heat pump as the heat generator, the impact on heating energy costs will be rather minor, whereas with a gas condensing boiler it will be considerably more significant.
Overall, financially not a "huge" additional effort, so it should definitely be used. It may be possible to eliminate a solar thermal system, which is usually uneconomical in single-family homes, through this.

Best regards.

With a brine heat pump as a heat generator, the impact on heating energy costs will be rather minor, whereas with a gas condensing boiler it is significantly more pronounced.

*oops* is the kWh price really so different for these two options in Brandenburg? For me, it's about 1:1 :confused:

Can someone explain the abbreviations to me?

According to their calculations, it is not necessary for either to achieve Kfw70. The insulation on the floor slab is already the insulation under the screed that you described in the floor construction. I now also have the exact price from the second provider.

About 2500€ for the insulation and 1100€ for the modification of the grounding ([Edelstahlerdung]).

Ah ok, thanks. We will build with LUWA heat pump.