tiling bathroom

[johnbikemad]

i intend to re-tile my bathroom ,on top of the existing tiles. which type of adhesive do i paint on first ? im sure its a pva type.

[buildersmate]

If you must do it, then there's no need to put any coating on - you just spread the new adhesive onto the old tiles. But you won't get as good a finish as starting with no tiles.
PVA is sometimes used to seal a porous surface like plaster, but there's no point on top of impervious tiles.