What is a soffit vent, and should a soffit be vented?
Short answer. A soffit vent is an opening, louvered strip or perforated panel in the underside of the roof overhang that lets outside air into the attic. A soffit should be vented wherever it opens into a ventilated attic, because it is the intake half of the system; soffit sections over porches, along gable rakes or under sealed spray foam attics can stay solid.
Why intake goes in the soffit
- Lowest point: intake belongs low so air travels the full height of the roof before leaving at the ridge.
- Sheltered: the overhang keeps rain from blowing straight in.
- Even coverage: soffits run along every eave, so each rafter bay can get fresh air.
Where soffits should be vented
Any eave where the soffit cavity connects to the open attic, with baffles above the wall so insulation does not block the air.
Where soffits can stay solid
- Gable rakes, the overhang along the sloped edge, which usually does not feed the attic the same way.
- Porch ceilings and overhangs separate from the main attic.
- Homes with sealed, spray foam attics.
- Spots right next to bath, kitchen or dryer exhaust outlets.
Common mistakes
- Vented panels installed over solid wood.
- Paint clogging the louvers.
- Insulation filling the eave cavity.
- Too few individual vents for the size of the attic.
Quick check for your house
Stand under the eaves and look for louvers, a strip vent or perforated panels. Then look from the attic on a sunny day: light showing at the eaves in each rafter bay means the soffit vents are doing their job. A vented look outside with no light inside usually means solid wood or insulation is blocking them.