Quick definition
An exhaust vent installed along the roof ridge that lets warm, moist air escape from the attic.
Hot, moist air rises to the top of an attic. A ridge vent lets it out along the whole length of the roof peak, and it's nearly invisible once it's covered with cap shingles.
What is a ridge vent?
A ridge vent is an exhaust vent installed along the ridge, the horizontal peak of the roof. The installer cuts a slot through the deck on each side of the ridge, fastens the vent over the slot, and covers it with ridge cap shingles or matching metal.
How does a ridge vent work?
Ridge vents work as half of a system. Cooler outside air comes in low, through soffit vents at the eaves, and warm air leaves high, through the ridge vent. Wind blowing across the ridge also helps draw air out. Without intake at the soffits, a ridge vent can't move much air.
What does a ridge vent do?
- Releases heat that builds up in the attic, which matters in hot climates.
- Carries out moisture that would otherwise condense on the deck and framing.
- Helps keep the roof deck colder in winter, reducing the conditions that cause ice dams.
- Vents evenly along the whole ridge, without a row of separate box vents.
What are the types of ridge vent?
| Type | What it is | Notes |
|---|---|---|
| Shingle-over (rigid) | Molded plastic sections covered with cap shingles | The most common type on asphalt shingle roofs |
| Shingle-over (roll) | A flexible, filtered roll covered with cap shingles | Follows uneven ridges |
| Metal | A vent built into a metal ridge cap | Used on metal roofs |
| Baffled | Any of the above with an external baffle | Helps resist wind-driven rain and snow |
What problems happen with ridge vents?
- No intake: without soffit vents, the ridge vent may pull air in through itself or barely work.
- Mixed exhaust vents: a ridge vent combined with gable vents, power vents or box vents can short-circuit the airflow. Shingle and vent manufacturers generally advise using one type of exhaust.
- Slot not cut or too narrow: the vent is installed but air can't reach it.
- Weather getting in: low-quality or poorly installed vents can let in wind-driven rain or snow.
- Short ridges: hip roofs may not have enough ridge length for the exhaust area they need.
What it means for you
What Ridge Vent means for homeowners
If your attic is very hot in summer or damp in winter, ask a roofer to check whether the ridge vent has enough soffit intake to work, and that it isn't mixed with other exhaust vents.
Frequently asked questions
Sources
- International Residential Code, Section R806: Roof Ventilation. International Code Council.
Tier 1 authority 路 code - Shingle and ridge vent manufacturer ventilation guidelines. Technical Reference.
Tier 1 authority 路 manufacturer - Residential Asphalt Roofing Manual. ARMA.
Tier 2 authority 路 industry - The NRCA Roofing Manual: Steep-slope Roof Systems. NRCA.
Tier 2 authority 路 industry