Noob here on the forum.
Rowhouse from '79 with a foundation of concrete slab + vapor barrier (apparently only partially) + 50mm foam plastic + floor chipboard + surface layer of original vinyl flooring and click flooring.
Ongoing renovation of the ground floor including, among other things, changing the surface layer of the floor and taking down some interior walls.
First part of the interior wall demolished. Studs directly on the slab, no vapor barrier, but the adjoining foam plastic has a partial vapor barrier underneath. Under the part of the floor with a vapor barrier, there seem to be air channels, see image:
However, these are filled with wood shavings and some black crushed stone, see next image:
Are these construction residues that shouldn't really be in this air gap, or is it simply not an air gap but something with a different function? I'm aware that the flooring solution as such is a risk construction, but moisture measurements have shown that it seems OK. Probably not much ground moisture here in the north. Very grateful for any info on what these air channels in the slab could be and whether I should try to remove what seems to be construction debris or not?
