Mansard ROOF, also known as a French ROOF, is a type of roofing system characterized by two slopes on each of its four sides. It is named after the French architect Francois Mansart (1598-1666) who popularized the design. The lower slope is typically much steeper than the upper slope, and the ROOF often has dormer windows built into it. This type of ROOF is often used in residential buildings to create additional living space in the attic.