water absorption of tiles

Water absorption of tile is controlled by the selection of raw material used for the body and the manufacturing process. It is the body that absorbs the water not the glazed surface. (In fact the glaze may be sawed away from the surface while running the test.) The water absorption determines the classification of tile. Wall tile has from 7-20% water absorption (that’s right, it’s a lot). That’s why you shouldn’t use wall tile outside where there can be freezing temperatures. The water goes into the body when it rains, snows, from pools and fountains, and even condensation, and then it expands when it freezes and the tile cracks. So don’t put this tile outside in most places in the U.S. Even Florida and California have some freezing days in most parts of the state. The same holds for “Saltillo” tile that rough looking hand pressed Mexican tiles. These can have water absorption up to 30%.