By Bud Coburn
The advantages offered by eyebrow dormers, and dormers in general (such as shed dormers), are a mix of aesthetics and function; they provide a curvaceous, subtle way to bring light into a building and ventilate the top-floor space while breaking up the monotony of an otherwise angular roof or flat, interior ceiling. Through these design features, occupants can gaze across their yard or see who is coming up the driveway. Occupants also enjoy additional headroom in certain areas without having to raise the building’s primary roofline. And, as with any design feature that adds elegance and utility to a home, eyebrow dormers typically improve the home’s resale value.
Eyebrow dormers are not usually problem areas, although shoddy roof work is probably more likely here than at the rest of the roof due to the expert handiwork required to put them together competently. Leaking might be an issue because eyebrow dormers are often shingled separately from the rest of the roof, so it’s possible that the connection between the two is a weak point for running rainwater. They can be inspected for water intrusion around the interior and exterior of the window. Note the chipped paint and general wear suffered by the eyebrow dormer in the photo to the right. Any water intrusion should be reported to an InterNACHI inspector during the next scheduled inspection so that the location can be inspected for mold and damage to building components. Inspectors and roofers should be extra careful while traversing roofs that include eyebrow dormers, as their undulating slope can allow for a deadly loss of footing.
Specialty dormers are usually quite expensive. In construction, anything that deviates from a straight line will cost extra. If the window is an unusual shape, it’s going to need to be custom-made and it will cost even more. In addition to the expense of a curved window, the inside of the eyebrow will need to be finished, and the exterior must be roofed around a tricky geometric shape. An eyebrow may cost the homeowner more than $10,000 if it’s a large retrofit, although the price will be somewhat less if it is incorporated into the building’s original construction. Regardless, eyebrows will typically cost several times as much as a skylight, a common design alternative.