I am a huge fan of Mansard roofs. They look so unique on a home or on any structure. Lots of apartment buildings in Paris have these type roofs. A Mansard roof allows for living space to be built into attic areas with less work than a total renovation. These roofs will accomodate dormer windows to allow for sunlight to enter the attic.
The style was named after a French architect, Francois Mansart (1598-1666). He used this style roof on a lot of his buildings. The style first became popular before his time and he revived it. Parts of the roof of the Louvre are Mansard style.
The roof itself has two slopes on each side of the building. The lower slope is steeper than the upper. I just adore these buildings. Very romantic look to me. Seems almost like a fairy tale house. I can almost see Goldilocks coming out the door of the top one. As to the one on the bottom, can’t you see having a spot of tea with a friend on the closed in porch on a pretty spring day?