An eyebrow dormer is a type of curved window that extends through the surface of a roof. This type of design detail originated with the Queen Anne or shingle style of architecture from the 19th century, and may date back even further to windows found on early English cottages. An eyebrow dormer serves as a shallow, rounded version of the traditional rectangular dormer window. Not all of these dormers incorporate a window, but on those that do, this glass opening is known as an eyebrow window. Roof eyebrows vary in size and design, and can be used to complement many types of building design.
Eyebrow dormers typically feature either a half-round or shallow circular shape. Those with an ocean wave style extend up from the roof in a wave-like pattern, and are often used in a series or pattern along the length of the roof. These dormers may also incorporate a dome or geometrical shape rather than a round one. They typically contain either a window or some form of ventilation grill. Those with built-in windows may be operable to let air in, or inoperable, in which case they can be used to bring in light or simply add aesthetic appeal.
The process of constructing an eyebrow dormer is extremely complex, and requires the work of a skilled carpenter. Some manufacturers make pre-fabricated eyebrow dormer units, but even these are difficult to install correctly. Both types of dormers must be properly joined to the existing roof covering, and are highly prone to leaks and roof failure due to their unique shape and profile. Homeowners should seek the help of a professional installer when adding either a pre-fabricated or traditional eyebrow dormer.
When installed correctly, eyebrow dormers provide numerous benefits. They help to break up a boring roof line, and make the facade of the building appear much more interesting. When equipped with a window, the eyebrow dormer also brings light into the attic or the upper floors of a house. Those that are operable also bring in fresh air, and can be used to improve ventilation and prevent moisture issues. Like all dormers, these units add extra headroom to small spaces, and may make them appear larger.
The primary disadvantage to adding an eyebrow dormer is its high cost. Due to the complexity of designing and installing these units, most users will be unable to save money by installing the window themselves. Finally, the majority of eyebrow dormers require not only a time-consuming custom design process, but also require a customer window to fit within the curved profile.