jim wrote:
Hi, i will soon be laying karndean vinyl floor planks in my house, it
is a 1946 semi and i am concerned whether it has a dpm under the
concrete floor, it has old black tiles down at the moment which i found
under the carpet not sure what they are made of but they are brittle
and blown on the corners (white dust around the edges), they seem quite
well fixed to the concret floor, it looks there is bitumen on some of
the tiles, does anyone know the likelihood of ther e being a dpm under
the concrete for this age of house. I dont have any damp problems other
than the white dust around the edges of these old tiles, which i think
is due to damp of some sort, and i dont want to lay new floor without
treating the concret first. would bitumen do the job if i spread sand
over the top before i put self level compound down?

Im planning to lift the tiles ,self level with latex, and lay the floor
with pressure sensitive adhesive. do i need to prime the concrete
before latex if so what with? and then do i need to prime the latex
before the adhesive?
Also can i lay the latex in two parts ( i have all downstairs to do)or
does it need to go down all at once. Any advice would be much
appreciated. Thanks

The white dust is probably from the carpet adhesive - fiber to backing.
If the old tile is 9" square it is highly likely it is asbestos tile.
If it is 12" tile, it could be but probably not.
Asbestos is like many other "hazardous" materials. If 100 people had
the same exposure, much less than 10% would be affected. It all
depends on how your body reacts to it.