The eyebrow window, or eyebrow dormer as it is often referred to since it is most commonly found in roofs, is a small arched window that projects into the roof to allow light into an upper story.
Unlike larger dormers styles the eyebrow window doesn’t typically provide headroom for living space, and often doesn’t even function as an operable window. Its main purpose is to allow light into dark attics and provide architectural interest to what would otherwise be a blank rectangular roof.
The architect who popularized eyebrow windows in the late 19th century in America was Bostonian Henry Hobson Richardson 1838-1886. Richardson was closely associated with the Richardson Romanesque style which was named after him.
I may be a bit partial to eyebrow windows since I have them on my own house! Architecturally what makes them so unique is their curves. Their incorporation into historic buildings with nothing but straight lines provides a welcome relief to the large empty mass of a rectangular roof.
The complexity of building round items from straight pieces of wood requires more art than science for most carpenters and forces us to use different pieces of our geometry skills from just figuring out the 3:4:5 triangle.
Installing an Eyebrow Window
I won’t go over the installation details of putting an eyebrow dormer into your house, but there are some careful considerations you should make if you are considering this project.
Proper massing is important. These windows should almost always be subordinate to the floor below them. They are designed as small features and to have an eyebrow window larger than a window a flight below will cause the structure to look top heavy and out of balance.
Flashing is key. If you are installing a curved element on a sloped roof then you have to ensure proper flashing. Using regular step flashing won’t work because of the curves. Unlike many other dormers an eyebrow window doesn’t have siding on its sides. It is simply a window that looks as if it is peeking out from the roof covered with shingles.
Match existing windows. Your house inevitably has existing windows so the eyebrow windows should match the style and pattern of the existing windows. Remember these are utilitarian in their function so ornate styles like stained glass are usually not called for. Follow the lead of the existing architecture of the house.
Once you know what they are it’s pretty difficult to miss eyebrow windows since they are so unique and they appear on many different style homes.
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I love old houses, working with my hands, and teaching others the excitment of doing it yourself! Everything is teachable if you only give it the chance.
A new roof is going on and I would like to add an eyebrow because I like them!!! It does not have to be functional. Is this expensive to add????