What is a continuous ridge vent?
Short answer. A continuous ridge vent is an exhaust vent that runs along the peak of the roof over a slot cut in the decking, letting hot, moist attic air escape along the whole ridge. Most today are shingle-over vents made of rigid plastic or fiber mat and covered with ridge cap shingles, while older homes may have exposed aluminum ridge vents.
The main types
- Rigid plastic shingle-over vent: molded sections, often 4 feet long, with internal baffles and an external baffle lip. Holds its shape under foot traffic and cap nails, and is the most common choice on asphalt shingle roofs.
- Rolled fiber mat vent: a roll of nonwoven mat that conforms to the ridge, quick to install, with built-in filtering. Performs well when nailed as specified and not crushed.
- Exposed aluminum ridge vent: a metal cap with louvers, common on homes from earlier decades. Visible from the street and more prone to letting in driven rain and insects.
- Metal roof ridge vents: profiled closures or vented strips under a metal ridge cap.
What separates a good one
- A published net free area per linear foot, so it can be sized.
- An external baffle that turns wind into suction.
- Filter fabric or internal baffles to stop insects and driven rain.
- End plugs for the rake ends.
- Approval by the shingle manufacturer, since system warranties are simplest when the ridge vent belongs to the same system as the shingles.
What it is not
A continuous ridge vent does not fix a bad attic by itself. It needs intake at the eaves, at least equal to its exhaust, and it should not share the attic with other exhaust vents. Roof pitch matters too; very low slopes and some hip roofs need specific products. See ridge vent vs box vents and roof anatomy explained.