I laid some sticky vinyl floor tiles, over old flooring in the kitchen when I moved in. They were red clay ( I think) brick like floor tiles, and hard on the feet as there's no heating and was a cheap way of coping. But a few months ago, the grooves and shape of the old tiles began to show through the newer vinyl covering, which makes it look untidy. Should I have prepared the floor somehow beforehand?

Open Question: How do I stop old floor tiles from showing through a layer of self-adhesive vinyl floor tiles? for the full Yahoo Question / Answer.