The advent of cement backer board has made it possible for do-it-yourselfers to lay tile like a pro. The reason: For most installations, it eliminates the need to set tile in a thick bed of mortar.

Q. I embarked on a simple caulking repair around my bathtub that’s now turned into a quest. While pulling out old caulk I discovered loose tile. After removing four rows of tile up from the top of the ...