Is aluminum-coated EPS 80mm over welding membrane sensible?

Hello.

In the basement, EPS (80mm) is currently planned above the welding membrane.

Is it sensible/recommended to choose an aluminum-coated variant (PUR) here, or is it unnecessary? Costs would be twice as much.

In principle, the welding membrane should actually seal anyway. Can moisture still come through?

Thank you very much.

When moisture occurs, the PUR board does not help either, [allukaschiert] is intended for reflecting the heat from the underfloor heating upwards.

Yes, it is superfluous. The seal is provided by the black line/welding membrane. In front of that, insulation protects this sealing. In front of that comes the dimpled membrane, which in turn protects the insulation. Are you sure it is EPS? For perimeter insulation, XPS is usually used because of the pressure and durability of the material. I would also consider making it a bit thicker, provided the basement is not just meant to be a utility basement.

I think he is talking about insulation under the screed, right? But you mean the perimeter insulation from the outside.

Correct. I mean insulation on the floor slab. Under the floor slab there is already XPS.

ah okay, I read it wrong