Control and expansion joints. Anti-fracture, crack-isolation and crack-suppression membranes all fall within the same family of products. The problems that occur most frequently lie in the treatment(s) employed to protect tile and dimensional stone over control joints.
Control joints should be used as a guide for placing the tile or stone in a crack-free position. In addition, a soft joint should be installed -- even when using a membrane. Some membrane manufacturers have systems that they say will work over control joints. However, the Tile Council of America (TCA) does not recommend a method for tiling over joints with a membrane.