Having just bought a load of floor tiles & chucked the grotty carpet tiles
out i'm left with some v.old, but soundly fixed tiling which is fairly
level.
I plan to tile on top of this, what prep. would be best to clean off the
various bits of double sided tape, other sticky stuff, muck & gunk etc. on
the old tiles?
Do the old tiles need anything on them to help adhesion with the new tiles?