Many contractors contact NTCA technical advisers regarding acceptable tolerances for floor tile installations, but our trainers also tell us that with the increased use of large format tile being specified for walls, it is becoming increasingly challenging for tile contractors to successfully install these products without lippage. Contractors should be aware that the tolerances for both floors and walls are the same, and that this issue should be addressed before installing the tile. Many applications in dry areas are to be installed directly over gypsum board or drywall, and there is little opportunity with the adhesive to make up for imperfections in the surface. Lighting can also wreak havoc on a tile installation on a wall, making the edges appear to be even more uneven and imperfect. Industry tolerances for both floor and wall tile applications state that the substrate should have a maximum variation of /14” in 10’ from the required plane, nor more than 1/16” in 12” when measured from the high points in the surface. If a builder wants a tile installation to be flush with no or minimal lippage, they need to make sure the framing and drywall contractors are delivering a surface that meets tile industry tolerances. If the tile contractor doesn’t check for this, and accepts the substrate as is, they run the risk of having a serious issue take place that can cost everyone money and time.
For more information on this subject, you can order the TCNA Handbook or ANSI A108 Book for tile installation on the NTCA website at www.tile-assn.com