What does a ridge vent with a baffle mean, and is it different from attic baffles?
Short answer. A ridge vent with a baffle has a raised lip along its outer edges, called an external baffle, that deflects wind up and over the vent, creating suction that pulls air out and keeps rain out. Attic baffles are different parts entirely: chutes stapled under the roof deck at the eaves that keep insulation away from the soffit vents so intake air can reach the ridge.
External baffles on the ridge vent
- How they work: wind hitting the roof slope runs up to the ridge. The baffle bends that wind upward, which lowers the pressure at the vent openings behind it. Air is pulled out of the attic instead of pushed in.
- Rain: the same deflection carries driven rain past the openings rather than into them.
- Which vents have them: most rigid shingle-over vents. Some rolled vents and many older aluminum vents do not, and unbaffled vents are more prone to letting in wind-driven rain.
Attic baffles at the eaves
- What they are: foam, cardboard or plastic channels, also called rafter vents or vent chutes.
- What they do: hold insulation down and back, keeping at least 1 inch of air space under the deck, as the residential code requires at vent locations.
- Where they go: in rafter bays over vented soffits.
Why a good system has both
The external baffle makes the ridge vent an effective exhaust. The attic baffles make sure intake air reaches it. A baffled ridge vent over soffits buried in insulation still moves little air, and open soffits feeding an unbaffled ridge vent can leak in storms.
How to check yours
From the ground, a baffled vent's edges show a slight raised lip under the caps. In the attic, look for baffles at the eaves in each vented bay. See roof ventilation basics and ridge vent vs box vents.