QUESTIONI have greatly enjoyed reading your articles in Tile Talk. Thanks for such informative resources. I was recently conversing with a contractor about two of your 2016 articles about tile and stone lippage and wanted to confirm a couple of points.
1. First, if a tile with one side longer than 15 inches is installed on shower walls with, on average about a 1/16th inch grout joint, such an installation would NOT meet industry standards, correct? Is this a correct application of ANSI A018.02? (According to your article ANSI A108.02 states for running bond tile patterns using tiles where any tile side is greater than 15” (380 mm), the grout joint size shall be on average a minimum of 1/8” (4 mm) wide for rectified tiles, and a minimum of 3/16” (5 mm) wide for calibrated tiles. The grout joint width shall be increased over the minimum requirement by the amount of edge warpage on thelongest edge of the tiles being installed.)
2. If long format tiles are installed with a 1/16th inch grout joint, there will be a risk of increased perception of lippage (depending on warpage of tile) and also such a grout joint is too narrow to adequately fill to full depth and can result in grout failure later.
3. If the grout joint of ceramic tiles is 1/16th of an inch and warpage is less than 1/32, the maximum allowable lippage in accordance with industry standards is less than 1/16th, correct? (ANSI A108.02-201304.3.7)
ANSWERANSWER - ANSI A108.02-2013 standards say that the grout joint width should be at least 3 times the actual variation of facial dimensions, but never less than 1/16” wide.
ANSI A108.02 says that the grout joint width should be at least 3 times the actual variation of facial dimensions, but never less than 1/16” wide.
Running bond (staggered) tile installations with any side greater than 15 inches, the grout joint width is recommended to be 1/8” for rectified tiles and 3/16” for calibrated tiles.
The minimum grout joint width should be increased by the amount of edge warpage it has; assuming it doesn’t exceed the standard maximum.
Allowable lippage in a floor tile with a grout joint of 1/16” to less than ¼” wide is 1/32” plus the inherent warpage of the tile. Not what it is allowed to have per ANSI, but what that specific tile you are measuring actually has.
- ANSI standards are recommendations. Having a 1/16” wide grout joint is acceptable, but not recommended on a tile with an edge larger than 15” set in a running bond pattern.
- There is a greater propensity to have actual, or the perception of, excessive lippage, and it may not be possible to fully fill the grout joint with grout.
- If the grout joint is 1/16” wide, then the allowable lippage is 1/16” plus the inherent warpage. If the warpage is 1/32”, then the allowable lippage is 3/32”. If the warpage is 1/64”, then the allowable lippage is 5/64”. From a standard-of-care point of view this allowable lippage might be considered excessive lippage and not acceptable for certain types of tile, applications, and installation methods.