What is a dormer?

• A. A framed window unit projecting through the sloping plane of a roof.
• B. A curved ridge vent.
• C. A ventilation opening near the gutter.
• D. The underlayment used at the roof hip.

Answer: (A)

A dormer is a framed window unit that projects through the sloping roof plane, creating usable space and letting in light in an attic or upper level. It usually has its own vertical wall that rises above the roof line and often carries a small roof of its own. This definition matches the description of a window unit that sticks out from the roof, which is precisely what a dormer is. The other options describe different roof features: a curved ridge vent runs along the roof peak to vent air; a ventilation opening near the gutter refers to an eave or soffit vent; and the underlayment used at the roof hip is part of waterproofing at the hip line, not a projection through the roof. Dormers also require careful flashing where they meet the roof to prevent leaks, since they extend through the roof plane.