A mansard roof has two slopes on each of the four sides. The lower slope is steeper than the upper slope. Dormers are often set in the lower slope. The upper slope is usually not visible from the ground.

Illustration from ArtToday.com

The term "mansard" comes from the French architect François Mansart (1598-1666) of the Beaux Arts School of Architecture in Paris, France. Mansart revived interest in this roofing style, which had been characteristic of French Renaissance architecture, and was used for portions of the Louvre.

Another revival of the mansard roof occurred in the 1850s, when Paris was rebuilt by Napoleon III. The style became associated with this era, and the term Second Empire is often used to describe any building with a mansard roof.

Mansard roofs were considered especially practical because they allowed usable living quarters to be placed in the attic. For this reason, older buildings were often remodeled with mansard roofs. In the United States, Second Empire -- or Mansard -- was a Victorian style, popular from the 1860s through the 1880s.

Architecture Glossary