long story short-i have been ripped off by a builder and i'm now left trying to pick up the pieces on a now tiny budget.
my first query (of many no doubt) is, i've got/will have a 3x3 metre utility room. foundations done and walls up. in the inside is currently a long standing concrete walkway (1/4 of width) and long standing (with no movement at all or cracks) 3 inch thick paving sitting directly on top of gravely clay.
would it be possible to use this as a base for the concrete slab floor? if i've got it right, put on top a layer of sand, then the DPM, then insulation, then the concrete (unsure of depth) followed by a screed. would that be ok or does it all need digging up and using hardcore etc? also, i've been searching through info and have seen mentioned a few times about 2 lots of DPM, do i need 2?