Adding an Eyebrow to Your Roof

Imagine cutting a horizontal slit in your roof and then, from underneath, pushing on the uphill side, raising a little wave in the plane of the shingles. That's the shape of an eyebrow window—a curvaceous way to get some light and, perhaps, ventilation in a top-floor space while distinguishing a building's facade.

The first eyebrows appeared on medieval thatch-roofed cottages. They were popularized in America in the second half of the 19th century by Boston architect Henry Hobson Richardson, the father of the Shingle style. "Richardson's eyebrows—sometimes called eyebrow or eyelid dormers—were long, narrow slits with short windows," says Stephen Holt, the architect of the Shingle-style This Old House television project in Manchester, Massachusetts. "They added undulating curves to his large, expansive roofs."

Today, eyebrow windows aren't restricted to the roofs of Shingle-style replicas. They're found on buildings as varied as Post-Modern beach homes and the converted-garage guest cottage shown here. Most require a custom-made sash (fixed or hinged), and all involve tricky framing and roofing. They can be designed in shapes and sizes from soft Richardsonian sine curves to tall half-rounds. According to Morristown, New Jersey, architect Nick Bensley, who puts eyebrows on many of his residential projects, "They really break up the monotony of a rectilinear roof or flat interior ceiling. Besides, curves are sexy."