Foam glass gravel yes/no?

Not for that SirSydom .... I think you don’t have to go along with every nonsense ... even if I can’t scientifically prove this nonsense (note, before someone comes at me again with missing evidence). Sometimes plain common sense is enough in my opinion

Rhenish greetings

Insulating against the soil makes sense - at least on the sides. Under the slab, in my opinion, it is also nonsense and I agree with the building expert on the pressure load, which I simply do not trust based on gut feeling.

According to the energy saving regulation calculation, a certain amount of heat flow already passes through the floor slab, moreover, there are only 12cm EPS between the warmest spot in the house, the underfloor heating pipes, and the cold floor slab. Between the hot water circulation and the floor slab, there is even less insulation. I was doubting that because, mathematically, that was already a considerable heat flow. But if you practitioners say so

I think you are basically right about the pipes - but one must differentiate between with and without basement (normally there are no/ hardly any pipes on the basement floor, but more on the ground floor). Numerically, we solved this with PUR to avoid "damaging" the floor construction - whether 12cm EPS will be sufficient will have to be determined by the thermal protection calculation.

I would have really liked to have foam glass gravel (SGS) as perimeter insulation.. (and have done without all that Styro... stuff) What you read about SGS sounds brilliant to me. However, our planner reacted like almost everyone here. In the sense of: oh no.. we've never done that before. Where are we supposed to tack the underfloor heating pipes on then? Actually, you can find a lot of information on the internet. I also saw prices from the manufacturer "Veriso" (per cubic meter.. you then have to calculate the price per square meter based on the thickness, plus VAT). Of course, it’s more expensive.. the only downside..
Best regards, Steffi.

PS. You insulate an exterior wall best from the outside and not from the inside. I imagine it similarly with the floor slab, it’s better to insulate directly under the floor slab than on top of it (but that is just my "gut feeling").

For our bungalow, the floor slab is to be placed on a strip foundation. The energy saving ordinance consultant has proposed insulation below and on the floor slab. But how should the foundations be dealt with then? They are not insulated after all. Does that even make sense?