Took some old vinyl flooring up at the bungalow, and, not surprisingly, there were large patched of black mould.
 The floor is known to be (by digging a holes): 4" concrete on earth, no DPM, and 1.5-2" sand/cement screed. Vinyl laid direct on screed.
Finally, I have made up my mind what flooring to lay:
Bedrooms: 15-20mm Marmox tilebacker board glued to screed, then floating wood floor on top.
Other rooms: 20-30mm Marmox board, glued down, then ceramic/stone/similar tiles glued with flexible adhesive to Marmox.
 Marmox is a closed cell waterproof foam, with both faces finished in polymer+cement impregnated fibreglass mat
Now, the Marmox board will act as a damp barrier (except the joints) and I would glue it down with cementous tile adhesive which isn;t bothered by damp.
So, the question: Do you reckon I would be better off applying a liquid DPM to the screed before sticking this down, or not?
And if so - which one? Most of them (eg Synthaprufe or Aquaseal <random>) look like they are basically bitmen based - in which case would I be weakening the bond to the Marmox board? Would blinding with sand help?
Or - are there any other products that sink in to the surface of the screed? In the USA, there seems to be some references to a polyuretha/ene DPM - which soaks in - but I can't find anything like that here.
Builders' Merchants round here have loads of Thompson products - but they all seem to be aimed at driveway block sealing, brickwork sealing and suchlike...
Cheers and TIA
PS - I decoded against the floorheater.co.uk UFH panels. Marmox is stonger, more rigid and I don't have to worry about wasting money to warm the worms. 20-30mm of Marmox will add to the comfort of the floor, and is a guaranteed energy efficiency measure (how much, I don;t know, but at least it's better than now).