Lippage – A condition where one edge of a tile is higher than an adjacent tile giving the finished surface an uneven appearance.
When a customer feels there is too much lippage in the tile installation, it is too late. Lippage is something that is discussed with your customer before starting the project, not after the fact. You as a tile expert should know the potential issues involved and address them with your customer or you may be in trouble.
Items to review
Warpage – The 2008 edition of the ANSI 137.1 significantly tightened up the standards of allowable warpage from those in the past. One easy way to see if the tile is warped is to stack the tile face to face and see if there is a gap between the tiles. This could be an indication of problems.
Floor and Wall Flatness – You, as the tile professional, should check site conditions before you accept the surface to be tiled. All substrates should be fl at to within 1/4” in 10’-0” and 1/16” in 1’-0” when checked with a straightedge. Some projects may require a more stringent requirement depending on the tile size and joint requirements.
Joint Size - An educated tile professional should always check the tile for difference in facial dimension before starting the job. The ANSI Specifications state that a grout joint size shall be three times the actual variation of facial dimensions of the tile supplied. ANSI also states that in no circumstances shall the grout joint be less than 1/16”.
Critical Lighting – Always analyze the lighting placement before you install the tile. Moving the lights away from the wall surface can often eliminate the problem. Critical lighting can make otherwise acceptable levels of lippage appear unacceptable. Lippage can be a very unforgiving subject when you don’t educate and inform everyone involved with the project BEFORE starting the project.