Mansard roof A mansard or mansard roof (also known as a French roof or curb roof) is a four-sided gambrel-style hip roof with two slopes on each side, the lower of which is punctured by dormer windows and is steeper than the upper. The steep roof with windows adds an extra floor of habitable space (a garret) and lowers the roof's overall height for a given number of habitable storeys. When viewed from close proximity to the building, the upper slope of the roof may not be visible from street level. There are a few other characteristics that distinguish a mansard roof. Dormers, or windows that protrude from the roof, are a common feature. This allows architects to convert the attic space into a bedroom or other livable space by bringing light into the space. One of the greatest advantages of the mansard roof is the ability to convert the attic into living space. It's also worth noting that the lower part of the mansard roof can be straight, convex (curving or flaring outward),...