I'm about to ceramic tile my hallway floor which is covered with 12" square
vinyl tiles at the moment. These are well stuck to the concrete underneath
with some sort of black adhesive. Can I tile directly on top of the old
tiles or do I need to remove them.
Another related question............. when you "comb" out the tile adhesive
on floors or walls, anyone got any tips on how to keep the "ridges" even ,
where one "comb" overlaps the next one?

many thanks.... Geoff