Can moisture from the sand and aggregate under a slab cause rising damp?
...radon barrier and insulation on an existing slab of concrete to raise it up to meet the level of another part of the house?
If so – I would skip the sand, lay a bit more clear stone, level it and run a plate packer across it, lay down 2 inches of EPS foam (which is a vapor barrier) as you mention, then your radon barri...