Why do red tiles peel easily?

This material is of poor quality and is easily affected by weathering. Red tiles are made of clay and calcined at high temperature by adding crushed sedimentary shale components. Generally, it is fragile, and the reason for peeling is poor material and easy to weather. Red tile appeared in the early 1970s, which belongs to a kind of machine-made tile, and its cost is much lower than that of traditional blue tile.