My wife and I are planning on installing new ceramic tile floor in our kitchen/dining room. We have removed the old flooring, (carpet in DR/ancient early '70s kitchen linoleum...and yes, we were careful), and are left with the concrete slab on which our home was built in 1974. The room is an irregularly shaped "L," almost a "C", the largest dimensions being 27' by 20'. The narrowest dimension, in the "riser" of the "L" is about 10'. Our tiles are square measuring 13 1/8 inches. Plumbers recently jack hammered a roundish 1 and a half foot hole into the slab, which I repaired. Could we install the tiles directly onto the concrete or must we use cement backerboard? If we must use the backerboard, what thickness should we use? How should it be attched to the concrete? What about this new material I've heard abou that is used in place of backerboard? Any help would be valuable.

I know (from reading the forums) that I can install a kitchen tile backsplash on wallboard and where it was painted, I should "rough it up" for adhesion. But... what about where it was painted over old wallpaper? The old wallpaper is not going to come off easy so then, since this is above a 4 inch corian backsplash and really for looks more than function (in other words it's probably not a "wet area") the big question - will it stick? thanks