Undersole insulation 80 mm or topsole insulation 120 mm

Hello house building community,

I have noticed that different floor insulation is advertised in the various construction descriptions.

On the one hand, there is the undersole insulation (80mm) and on the other hand, the upper sole insulation (120mm).

Which insulation actually makes sense?

I look forward to your answers.

Best regards

Both make sense because both insulate. ;-)

I once read somewhere that it depends on the wall structure, i.e., whether the vertical insulation ends at the base slab (as is the case, for example, with filled clay bricks) or can be extended beyond it (for example, with an ETICS). In the first case – also in my opinion – the base insulation makes sense, in the second case the under-slab insulation does. However, both are possible in any case.

Best regards

K1300S