Minecraft wiki entry for Roof_types, associated text: A mansard roof is similar to a gambrel roof. It has two or possibly three distinct roof pitches. Most of the roof is steep, but it always has a shallow or flat section higher up, and like a hipped roof it has slopes in both the North-South and East-West directions. Some mansard roofs may use curved roof sections, more commonly on the lower portions. Hence the usable volume under the roof is greatly increased. Very large buildings may have several floors under a mansard roof.