Roof is the cover of any building. The term also includes the materials that support the roof. Climate often determines the design of roofs. Ancient Syrians and Egyptians used flat roofs because of the hot sun and the lack of rain. Steep, sloping roofs covered the homes of central Europe, to help drain off heavy rains.
There are many variations of flat and sloping roofs. A gable roof has two sides sloping up to a center ridge. The hip roof has four sides sloping up from all four walls. The lean-to is a single slope over a small building, usually set against a larger building. A gambrel roof has two added ridges parallel to the center gable ridge, making steep slopes below each side of the upper, flatter slopes. Mansard roofs also have ridges below the center one, but on four sides, like the hip roof. Water is drained beyond the walls of a building by the eaves (overhang) of the roof.
