Dormers

Dormers are a structural element that projects from a sloped roof, creating a vertical wall and a window that extends beyond the plane of the roof. They add usable space, headroom, and natural light to upper floors or attic spaces.

There are several common types. Gable dormers have a triangular pediment and two vertical sides with a pitched roof. Shed dormers use a single sloped roof and typically provide the most headroom for minimal roof loss. Hip dormers have roofs that slope on all sides, blending with the surrounding roofline. Eyebrow dormers feature a low, curved profile with little or no vertical wall, while bonnet dormers are box-like with a curved upper edge and a projecting roof.

Construction and design considerations include framing a box on the roof plane, supported by rafters. Proper flashing, underlayment, and waterproofing are essential to prevent leaks, and dormers affect roof loads, drainage, and the overall aesthetic. Exterior cladding should often match or harmonize with the house, and insulation and ventilation are important for energy efficiency and comfort.

Functionally, dormers convert attic or loft spaces into usable rooms, increase natural light, and can influence ventilation. Aesthetically, they contribute to a building’s character and curb appeal, with styles ranging from traditional to contemporary.

History and regulation: dormers have appeared in European architecture since medieval times and became common in many 19th- and 20th-century houses. Modern construction may require building permits and adherence to local codes, and renovations in historic districts may be subject to restrictions on dormer type or placement.

Maintenance considerations include monitoring for leaks, rot, and heat loss, and ensuring continued proper flashing and sealing.