Lippage is the vertical displacement between two adjacent tiles of a ceramic, glass, or stone installation. When excessive, this can lead to numerous problems, ranging from chipped edges to snagged furnishings and appliances to safety hazards.
Specifiers typically select the grout for their tile project based on general performance characteristics, color, warranty, and cost. Despite this, less-than-optimal products are often used. Some do not fully understand the changes in grout technology and do not realize they have a choice. Not all grout is the same, and, of course, color is only one small factor in the overall performance.
When there is a tile or stone failure, a contributing factor is often the lack of properly installed movement joints. Just like concrete sidewalks and bridges, tile and stone need to have movement joints to control the anticipated movements within a structure. Tile and stone will expand and contract when it is subjected to heat/cold or moisture/dryness. It is critical for architects to properly specify the design, materials, and layouts of movement joints.
Exterior decks and balconies, and interior showers and bathrooms, have historically been problematic areas for the installation of ceramic, glass, and stone tiles. Typically, problems are due to installer error, not using appropriate materials, or not providing clear enough specifications. In each case, it is the result of not following industry standards.
Whether it is a shower or an exterior deck or balcony, the waterproof membrane surface must be sloped to drain or away from the building. Shower pans or receptors are supposed to have a pre-sloped mortar bed installed over the base substrate before installing the waterproof membrane. The pre-slope needs to have a minimum slope of 6 per 305 mm (1/4 per 12 in.) and be flat within that plane with no more variation out of plane than 6 in 3049 mm (1/4 in. in 10 ft), or 2 in 305 mm (1/16 in 12 in.). Exterior decks and balconies should also have a pre-sloped surface to meet those standards before applying the waterproof membrane.