A mansard (roof) encompasses a four-sided gambrel style hip roof with two distinct slopes. The steeper slope with windows can be found on one side creating an additional floor of habitable space, known as a garret.
The upper slope of the mansard roof may not be visible from street level when viewed from proximity to the building.
Pierre Lescot gets credit for the earliest known example of a mansard roof on a section of the Louvre in Paris built around 1550. The design was later popularized in the early 17th century by François Mansart, an accomplished architect of the French Baroque period. Thus, the term “mansard” was born. It became especially fashionable in the mid-1800s during the Second French Empire of Napoléon III.
The mansard roof style also became prevalent during the historical development of the City of Boston in both large and small buildings.