Help!: Bitumen and vinyl tiles

[suej]

Hi
We have a bitumen floor which we think is also acting as a damp proof membrane in our bathroom and want to tile over this with thick vinyl tiles. (We've been advised that it's safer to leave the bitumen where it is and cover it rather than try to lift it as the danger from the asbestos content would then be non existent). A previous thread on your forum recommended a screed of Portland and SBR on top of the bitumen but didn't say what the mix should be. Also wondered whether this would work for vinyl tile adhesive as well as for ceramic. Any help would be gratefully received - the more I google the problem the more confused I become!
Thanks

[SandyFloor]

If your bitumen floor is firm you can screed over but unless you want it at least 40mm thick don't use portland cement. If 3mm is more like it you can use Ardex or F.Ball products.

Ardex ......P51 primer and K11 screed
F.Ball ......P131 primer and Stopgap 300 screed

Apply the primer neat with a brush (for non porous surfaces) and allow to dry to a tack (about an hour) , mix screed with water as instructions and pour and spread evenly. If done right it should give a smooth level surface ideal for vinyl tiles.

If you're unsure I would get a flooring pro in with experience of vinyl tile preparation as it needs to be smooth.

[suej]

Thanks so much for this reply - it's really clear and fantastically helpful!