I am renovating my laundry room and taking part of the garage to also accommodate a sauna/shower, possibly a small toilet. Currently, I have an M60 LK pump/mixing valve and will add a loop for this (about 20m2).
What I need help with is how should the construction be built? Should one have a capillary breaking plastic in the construction, or is geotextile enough?
Currently, the construction looks as follows:
Tile
Cast slab with an extreme slope about 10-15cm
Sand 1cm
Coarse cast concrete slab on the ground
Sand/stone
My idea is to chisel out the slab as well as the lower slab and excavate to make room for the following.
Surface layer
Waterproofing
Concrete slab with waterborne underfloor heating (let cure for a month before covering)
Insulation 10cm + 10cm
Geotextile/filter fabric
Stone 8/16
Place a plastic sheet between the layers of the cell foam and tape it to make it tight. Then proceed as you planned, perhaps with a levelling compound if needed.
Geotextile underneath against the existing ground. Then 0-32 or similar that is compacted, possibly 0-18 on top which is easier to smooth out. 8/16 is not needed. It is indeed capillary breaking, but the insulation does that too. The plastic is only needed if you have radon ground.
