Without proper application of mortar coverage tile will begin to slip and break. Correct installation is critical to avoid these costly mistakes.
Often times we see failures of this type. In this case the tile installation was around 7 years old. Much of the grout was breaking apart or being pulverized by the movement of the delaminated tile work.
The previous contractor installed 1/4" Comply Plywood and direct adhered the tile to the plywood with thin set. The notch pattern was not correct and trapped air. Tiles were not back buttered and it appears the thin set was allowed to "skin over" or surface dry. When this happens the thin set mortar does not make connection (coverage) with the tile. ANSI requires that there is at least 85% coverage on tile and 95% in wet areas. Many of these tile had less than 5%.
Wood expands and contracts around 10x more than tile or stone. This differential of thermal movement delaminates tile over time. The replacement was DITRA by Schluter uncoupling membrane and porcelain tile.
