I'm concerned about the tiles I found under the carpet in the room which is
going to be our new kitchen. They've probably been there since the house was
built around 1955, and are practically impossible to get up. (We've had a
little success using a wallpaper scraper and a steamer, but its extremely
tedious, and could never be finished in time for the kitchen units being
fitted).
We are having floor tiles fitted, ceramic or porcelain, and I'm worried that
they won't bond well enough to the old tiles beneath. The builder says he
will roughen them up thoroughly, and use Polybond, which I believe is a
PVA-type adhesive, in the tile cement.
Does this method sound ok? Has anyone any experience or suggestions to
share?

Also, any opinions regarding printed ceramic tiles (cheaper), versus
porcelain tiles (nearly double the price, but harder wearing I hear).
Thanks!