Many homeowners choose to use natural stone tiles in and around their homes for the beauty that comes with every stone tile. Unfortunately, there are several issues that sometimes crop up with stone use, particularly as more and more people are beginning to use larger format stone tiles in their homes. A large format tile is defined as anything larger than 16-inces in size. One of the most common problems that is seen and reported by homeowners using large format stone tiles is lippage.
Lippage is the condition where one tile – often at the corner – lifts up above the surrounding tiles. Lippage can occur to any degree, but is most likely to be a problem when the lift is about the thickness of a nickel or greater.
The cause of lippage is due to poor installation, and is not a problem with the stone itself. Substrates are rarely if ever perfectly level and even. Therefore, when installing large stone tile, the surface it is being installed on needs to be built up slightly to allow the tile to have sufficient mortar to even itself out in. This is known as back buttering and involves placing additional mortar directly onto the backs of the tiles before installation. Often the stone is also beaten into the mortar bed to help achieve level.
On walls, tile lippage can be removed with levelers inserted into the joints. When the levelers are pulled together, the tiles even out and the lippage is removed. All of these steps have to take place during installation in order to avoid lippage.
Once the lippage has occurred, there is little that can be done. If the height difference is less than the thickness of a nickel, often it is recommended that the stones be left alone. If it is higher, the stones can be ground down and repolished to remove the offending ridges.
Proper installation methods can help prevent lippage, which can detract from the beauty of a new stone tile installation.