Thinset

When used regarding ceramic tiles, thinset is a process that uses a special adhesive to attach tile to a substrate such as water resistant gypsum wallboard or glass reinforced cement backer board. When hardened, fresh grout is then forced into the spaces between the tiles with a rubber trowel and wiped clean.

As opposed to thinset, the conventional method is to have a thick layer of wire reinforced grout, perhaps over a layer of waterproof asphalt paper. When this grout has hardened sufficiently, another layer of grout is put on top of that and tiles are pushed into this to the proper depth, adjusted and cleaned. The result is heavier and thicker overall.