ᐅ Insulating the basement floor

Hello everyone,

we are going to build a house with a basement. The basement will be a waterproof concrete shell. In addition, an external insulation of 10 cm (4 inches) is planned. The basement floor is supposed to consist of 4 cm (1.5 inches) screed plus underfloor heating. Our design architect said that this is sufficient. However, our sales contact suggests that it might be useful to install a floor height increase of 16.5 cm (6.5 inches) for an additional 3,500 euros as extra insulation. What do you think? Is it worthwhile or not?

Thanks!

Do you plan to use the basement as living space? Are the 10 cm (4 inches) also under the basement? What kind of screed is that? At 4 cm (1.5 inches), it might not even provide the necessary coverage.

BeHaElJa schrieb:
Do you want to use the basement as living space? Are the 10 cm also under the basement?

No, they are only on the exterior wall, not underneath. The large basement room, about 35 m² (375 sq ft), will be a "playroom" with a Playstation and projector as well as a hobby room where we will sometimes spend evenings. However, it won’t be used daily.

Is that even possible considering the energy saving regulations? You would essentially be heating directly into the ground. Are you sure that there isn’t any insulation planned beneath the screed and that you are only referring to the insulation under the footing?

I am asking again for clarification. According to the statements made today by the sales representative, only the exterior wall was intended to have insulation.