Large tiles give you so much design freedom. The 12 x 24 is the new 12 x 12. And tile as large as 48” is becoming common. But large tile can be challenging to install.
The Tile Council of North America, Ceramic Tile Education Foundation, and American National Standards Institute have all issued updates to their manuals for LHT or large and heavy tile. It’s a whole new world of tile and needs to be considered differently from regular tile. That includes grout joints.
Grout Joint Size for Large and Heavy Tile
A sufficient grout joint gives the tile room to breathe—so to speak—for building movement and thermal expansion. It also allows for variation in the manufactured tile, different types of application, and warpage that may be present in large tile.
All ceramic and stone large format tile (greater than 15”) requires a minimum 1/16” grout joint according to ANSI. Daltile recommends that large tiles have a 1/8” or 3/16” minimum grout joint for the most successful installation. The difference is not really noticeable visually, but can make a big difference to the quality of the installation.
Grout Joint for Staggered Brick Joint Patterns
Tile longer than 15” tends to have slight variations to it that cause complications for successful installation in a brick joint pattern. If the overlap is placed at 50% like most brick joint patterns, the joint will bring together the ends of the tile (where there is less bowing) and the center to the neighboring tile (where the bowing is at its greatest) and that makes for a floor that will tend toward unevenness.
If the stagger of the brick joint pattern will be greater than 18”, ANSI and Daltile recommend that the offset not be greater than 33% to avoid unevenness. Daltile also recommends a minimum grout joint of 3/16” to decrease any unevenness in large and heavy tile installations.
Beyond the Grout Joint
Installing LHT tile is more than just getting the grout joint right. For more information about installation requirements visit the large and heavy tile webpage at Daltile.