Tim S wrote:
Hi,

Took some old vinyl flooring up at the bungalow, and, not surprisingly[1],
there were large patched of black mould.

[1] 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[2] 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.

[2] Marmox is a closed cell waterproof foam, with both faces finished in
polymer+cement impregnated fibreglass mat

http://www.marmox.co.uk/products_board.asp

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

Tim

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).

Youre putting down a vapour barrier - why would you want two. The one
issue I see is picking a glue for under the marmox that will be ok
permanently damp.


NT