soffit

Soffit refers to the underside of a structural element that projects from a wall, most commonly the horizontal underside of a roof overhang or eave. It can also describe interior applications where a ceiling or wall is dropped or recessed to conceal ductwork, plumbing, or structural components.

Exterior soffits cover the gap between the exterior wall and the roof edge, protecting exposed framing such as rafter tails from weather and pests. They often play a role in attic ventilation; vented soffits have perforations or mesh to allow air into the attic, where it can escape through ridge or roof vents to regulate moisture and temperature. Common exterior soffit materials include aluminum, vinyl, wood, and fiber cement. Non-vented soffits are used when ventilation is unnecessary or when moisture control is addressed by other means.

Soffit is typically paired with fascia, which is the vertical finishing edge along the roofline. The soffit provides the horizontal underside, while the fascia forms the boundary for the gutter and roof edge.

Interior soffits are used to conceal mechanical systems or to create architectural interest. They may conceal ducts, pipes, or wiring, or serve as decorative features along walls or ceilings.

Maintenance and considerations: soffits should be kept clean and free from moisture buildup. Damaged or poorly vented soffits can allow water intrusion, pest entry, or mold growth, necessitating repair or replacement. Proper installation and appropriate ventilation help maintain roof integrity and indoor comfort.