Tile Laying Tricks for Uneven Surfaces
- The best solution to an uneven tiling surface is to cover it with an even surface. Cement board (a much harder version of drywall) is the standard today for laying most kinds of tile, and should be used for tiling whenever possible. Install 1/2-inch cement board for floors and 1/4-inch for walls. It's installed with thinset mortar and screws, and arranged in staggered rows, like drywall. Fill in the seams between the boards with thinset mortar and scrape them smooth to get a solid, flat, unbroken surface for your tile.
- Sometimes you can't install cement board, because the surface isn't conducive to it or it will raise the level of a floor too much (one example would be an existing tile floor that you want to tile over). In those cases, a combination of a liquid leveler and a thick mortar bed can solve the problem. Levelers are mixed to a watery consistency, then poured over the surface to settle into the dips and cracks, eventually drying rock-hard. Using a thicker layer of mortar than usual to lay the tiles will also help obscure the unevenness of the surface.
- Sometimes no amount of preparation work will fix an even surface in preparation for tiling (a patched-up, wavy concrete patio, for example). At that point, it may be time to invoke an old carpenter's axiom: If you can't fix it, make it look like you planned it that way. Many types of tiles are made to look random and uneven, including tumbled travertine, Mexican saltillo and roughcut flagstone. When installing these tiles on an uneven surface, it's still a good idea to use extra mortar, so you don't get air pockets underneath that could loosen them.