Sticking Karndean flooring over thermoplastic tiles

[Midge]

Just about to tile our kitchen with Karndean flooring.

The existing flooring is thermoplastic tiles (previously covered with cusionfloor) stuck to the concrete floor using some sort of bitumen adhesive. Whilst there are one or two bits around the edges which have broken up over time due to the uneveness of the concrete near the walls, the tiles are otherwise stuck down well and I'm planning on tiling over them (I've repaired some areas around the edge with leveling compound).

I've no experience of the type of acrylic adhesive used for Karndean/Amtico, and was just a bit wary of trying to stick it directly to tiles that could have absorbed a bit of dirt/grease over the years. I have some Evo Bond PVA I was going to use as a primer but it doesn't indicate the suitability/dilution for this sort of job. Thoughts?

TIA, Midge.

[Rob Graham]

You may well find that PVA would do the job very well. I'd use it full strength. It's very adhesive indeed, although it doesn't appear to be when you put some between finger and thumb.

However, I wonder what will happen after a few years of use. Will you be able to see the outline of the old tiles through the new flooring? In the days of lino, when people put old newspaper down as underfelt, you could sometimes see the outline of just one sheet of paper after a time. OK, so you're not using lino, but the question is worth considering.

Rob Graham

[Midge]

Thanks Rob - that shouldn't be an issue. The thermoplastic tiles are laid dead flat and you can't even feel the joints. The Karndean tiles are 3mm thick and as tough as hide so I'm not expecting anything to show through (the surface is textured to look like slate too which will help).

Midge.