Gable vs. Dormer — What's the Difference?

A gable is the triangular section of a wall between the edges of intersecting roof pitches. The shape of the gable and how it is detailed depends on the structural system used, which reflects climate, material availability, and aesthetic concerns. A dormer, on the other hand, is a roofed structure, often containing a window, that projects vertically beyond the plane of a pitched roof.

Gables are often seen in traditional residential architecture; they can be covered with various materials to match the rest of the house. Dormers are used to increase the usable space in the loft of a building, to create window openings in a roof plane, and to add character to the dwelling. Both elements have been used in architecture for centuries and can be found in various styles across the world.

While a gable is an integral part of the roof, giving structure and often contributing to an attic's ventilation, a dormer provides natural light and may increase headroom in an attic or upper floor. A gable is typically seen from the side of the house and is a significant part of the house's overall appearance. In contrast, a dormer is viewed from the front or back and can change the aesthetic and functional aspects of the roof.

The construction of a gable is generally simpler, as it is part of the roof framing itself. Dormers, however, are more complex as they involve cutting into the roof to add extra framing, which can be a more complicated process during construction or remodeling.

Gables and dormers both alter the exterior appearance and interior space of a home, but they do so in different ways. Gables affect the outline of a home's roof and are a major architectural feature, while dormers are secondary structures that serve more practical purposes, such as adding light or space.