Occasionally, we come across a brand new stone tile installation where the tiles are not level, or simply one tile is laid higher than other adjacent tiles creating a level of lippage which is unacceptable by the homeowner or even by industry standards. In the image above, although the level of lippage seems minimal, it failed the credit card test.
What is the Industry Standard?
According to the Terrazzo, Tile & Marble Association of Canada, an acceptable level of lippage varies depending on the size of the grout joint.
For grout joints of 6 mm or greater, the acceptable level of lippage is 1.56 mm or 1/16 of an inch. For smaller grout joints of less than 6 mm in width, the acceptable level of lippage is 0.78 mm or 1/32 of an inch.
Since a credit card is about 1/32 of an inch, a credit card is often placed against the tile to do a spot check and evaluate lippage.
How to Correct Lippage?
If only one or two tiles are considered to have lippage, the most economical solution would be to remove the affected tile or tiles and to install new tiles.
However, if lippage is rampant throughout the tile installation and you are dealing with a large area, you may be considering ripping out the brand new install, purchasing new stone and re-installing new tile. This option carries very high costs as a result of having to remove and dispose of the original material, to pay for stone, mortar and grout material again and having to hire a second contractor to do the job right. To live dissatisfied with a substandard install for years to come, is also not a viable solution.
Few people are aware, including contractors, that a more affordable solution exists. With natural stone installations, it is possible to grind down the surface of the stone using industrial diamond abrasives to create a smooth, level and uniform surface. Of course, after the affected tiles have been grind down and the surface is level, the stone must be brought back to its original finish and lustre.