After high-temperature firing, the material structure of flat clay tiles changes, the impurities in the clay are decomposed, the internal pores are reduced, and the density of the tiles is significantly increased. This high-temperature firing process gives flat clay tiles a higher waterproof ability.

The water flow intensity of high-pressure water guns is very strong, especially when the water flow is directly aimed at the edges or gaps of tiles, which can easily cause tiles to crack or break. Especially when the wrong water pressure or nozzle angle is used, the surface of the tile may be eroded, weakening its protective layer.