A single characteristic distinguishes the Second Empire house: its dual-pitched hipped roof. From the eaves, the roof rises steeply, then becomes almost flat (and invisible from below) as it extends to the center of the building. The steeper pitch of the roof typically has multiple dormers so that the attic of the house is essentially a third floor.
This configuration is known as a Mansard roof, getting its name from the seventeenth-century French designer Francois Mansard. Its nineteenth-century popularity, however, owes its occurrence to the Mansard-roofed wings added to the Louvre in the 1850s when Napoleon III was Emperor of France. That brings us back to where we started, as his reign was known as the Second Empire. In America, the design, although based on earlier prototypes, was regarded as a very contemporary echo of a modern Parisian style, rather than an allusion to an earlier one.
The Mansard roof is most often found on two-story houses. The footprint is usually square or rectangular, although some examples are L-shaped and others have a tower at center front. Brackets typically support the eave overhangs and other details resemble those of the Italianate House. The entrance usually features a double door and the windows are tall and narrow, typically two-over-twos.
The Second Empire house became particularly popular in towns and cities. The two main floors plus a tall attic floor produced a surprising amount of living space for the size of the footprint, an efficient design that made the style well suited to narrow in-town lots with limited light and space. These houses were popular in emerging manufacturing cities in the decades after the Civil War. In fact, for some years these houses were referred to as having been built in the “General Grant Style” because of their popularity during U. S. Grant's presidency, when many administrative buildings in Washington, D.C., were built in the Second Empire style.
REMODELER'S NOTES: The typical Second Empire home is large and comfortable, reflecting the growing wealth of the American nation in the years after the Civil War. The roof of a Second Empire house distinguishes it, but that same roof is often an expensive challenge to its owner. Frequently, the roofs were originally covered with multicolored slates or tin plates, both of which are expensive to maintain or replace. Any roof work on a Second Empire House is likely to be expensive. Yet maintaining the original character is important-replacement of an original polychrome roof with asphalt shingles does not do justice to the building, especially if the steeper slope of the roof either flares or curves, as many Mansard roofs do.
At the height of the popularity of the Second Empire house in the 1860s and 1870s, Mansard roofs were also a popular choice for renovating earlier houses. The spaces beneath the tall roof line provided useful living space, so framing a new Mansard roof atop an existing home could add considerable living space to the home.