A.Tom Meehan, a tile-setter who owns and manages Cape Cod Tile in Harwich, Mass., with his wife, Lane Meehan, responds: There are two ways to approach tiling a room with radiused walls. I think the old-fashioned way — a mud job done with wire and cement — is best. With this approach you need a layer of felt paper, galvanized wire mesh, a scratch coat of cement, and then a full coat (around an inch) of cement; it requires the skill of a professional tile-setter experienced in mud-bed jobs.
The easier method is to apply two layers of 1/4-inch cement backerboard to the framing over a layer of felt paper, staggering the boards at the joints and bonding them together with a thin coat of nonlatex thinset mortar spread with a 3/16-inch V-notch trowel.
to read the full article.