CTEF Tile Tip: Lippage and Flatness Standards for Ceramic Tile Installations
Two of the most common ceramic tile workmanship complaints from customers are lippage and flatness issues. To avoid these, contractors must know and meet the industry standards for allowable lippage and allowable deviation from perfect flatness.
<br /><br />Lippage is the difference in height of adjacent tiles. In general, the installer is allowed 1/32” lippage between two adjacent tiles in addition to whatever amount of warpage (curvature) is in the actual tile being installed. If the grout joint is ¼” or larger, the installer is allowed 1/16” lippage. For flatness, the installation should not have any more than ¼” variation in 10’. This is typically checked by placing a 10-foot straightedge on the installation to find high and low spots.
<br /><br />Although the installer has a lot to do with how much lippage will be present in an installation and how flat the installation will be, the specific tile and pattern chosen and the existing substrate also play a major role. The contractor may need to flatten the substrate to meet or exceed the flatness and lippage standards. The contractor should show the customer any areas of concern and explain the potential for installation issues if the decision is made not to flatten a less-than-ideal surface. The larger the tile, the more likely the substrate needs to be fixed. Additionally, make sure the customer understands if the tile or the pattern chosen could cause more lippage. Brick-joint (running-bond) patterns accentuate any warpage present in tile.
<br /><br />Communicating, and more importantly documenting, your recommendations and the customer’s decisions will be your best aid in avoiding complaints, because the only way to meet a customer’s expectations is to manage them.