Tiles is one of the best surfaces to tile onto, though a wee sandpaper to the glaze never does any harm. As a rule of thum so long as its neither flaking nor too porous then its ok. Bal are one of the best around. I used them for my floor gorut as they are one of the only people who do a good fully waterproof grout for extra wide gaps (I layed randon Slate tiles). Sovereign, who do all sorts of products such as damp proof chemicals etc are also excellent. If yuo have a local independant tile merchant the go with their recomendation. They are not going to sell you rubish. You can get 2 equally good types, one which is adhesive other, the other does for grout too, both types come in a tub. I prefer to use the adhesive only and then mix up my own grout from powder, but thats a personal preference. Calum Sabey (Newark Traditional Kitchen 01556 690544)