An eyebrow dormer adds light and an attractive architectural element to the roof line of a home, but no living space. An arched window is framed into the roof line of a home, and extends outward and upward only as far as required to build out and flash the window into the roof. The front of the arched window resembles an eyebrow extending from the flat roof plane; the curved roof over the eyebrow dormer is covered with a single piece of rolled roofing. This type of dormer can add light to an existing living space.
The most common style of dormer is the gable dormer. Sometimes called the dog house dormer, a gable-style dormer protrudes through the roof line like the front of a dog house. The dormer features a small roof which is integrated into the existing roof lines and a double-hung or casement window on the front face. This dormer can add light, ventilation and a small amount of floor space to a dimly lit and poorly ventilated attic area.
Half dormers can fit on the front or rear of a home, but most often are integrated into the rear side. Used to add significant floor space into an upper-level home, a half dormer converts an upper attic area into a full-sized suite by creating a full-height second story along one half of the upper level. From the front of the building, the addition is virtually unnoticeable, which makes this dormer very attractive for those who do not wish to change the architectural appeal of the home's front elevation.
Full dormers are similar to the half dormers, but instead of extending across only half of the length of the home, full dormers extend across the entire roof line. Full dormers can be built in such a way that they are flush with the existing walls of the home to blend seamlessly with existing architecture. However, these dormers are often set back from the existing walls. By choosing the set-back style, existing roof lines, lower-level siding, and existing end-of-the-home gable siding areas can remain undisturbed, which lowers the overall construction costs.