What Is a Soffit Vent?

Attic ventilation is a low-to-high system. Cool air enters at the soffit, travels up under the roof deck, and leaves through ridge, box, or gable exhaust at the top. Soffit vents come as continuous strips, individual rectangular or round vents, and perforated soffit panels. The openings have to stay clear, so baffles set between the rafters keep attic insulation from packing against them. Building codes size ventilation by net free area against attic floor area, commonly one square foot per 150 square feet, with a more lenient ratio allowed in some balanced setups.

A rep can check the intake side from the driveway. A glance up at the soffit shows whether it is vented, solid, painted shut, or stained, and a quick look through the attic hatch shows whether insulation is blocking the path. Homeowners with hot upstairs rooms or winter condensation often have an exhaust problem that is really an intake problem. Intake upgrades usually fall outside an insurance scope and belong in the upgrade conversation.

Adding more exhaust without adding intake is the common mistake. Another is mixing up the terms: the soffit is the finished underside of the overhang, and the soffit vent is just the part of it that breathes. Paint, solid panels swapped in during a siding job, and insulation blown over the openings all shut intake down without anyone noticing.