How do you replace a roof ridge vent?
Short answer. To replace a roof ridge vent, remove the ridge cap shingles and the old vent, inspect and correct the slot and the decking around it, install the new vent centered over the slot with the manufacturer's specified nails, and cover it with new hip and ridge cap shingles. The job is a good chance to upgrade to a baffled vent and to fix a slot that was cut too wide, too narrow, or too close to the ends.
Step by step
- Set up safely: use roof anchors or a harness, and work in mild weather when shingles are neither soft nor brittle.
- Remove the caps: pry up the cap shingles and pull their nails. Old caps rarely survive and are not reused.
- Remove the old vent: pull its nails and lift it off. Clear debris, nests, and old sealant from the slot.
- Inspect the slot: check its width against the new vent's instructions, confirm it stops short of the ends, and look for soft or rotted decking along the edges.
- Correct the slot: widen a slot that is too narrow, add decking strips where it was overcut, and close any section that runs to the rake edge.
- Install the new vent: center it, join sections as directed, and install end plugs.
- Nail properly: use the longer nails the manufacturer calls for so they penetrate the deck, without overdriving.
- Recap: install hip and ridge cap shingles at the specified exposure, working from the end opposite the prevailing wind.
Choosing the replacement vent
- A shingle-over vent with an external baffle and weather filter handles wind driven rain best.
- Check the net free area rating so the new vent supplies enough exhaust.
- Matching the vent and caps to your shingle manufacturer may matter for warranty coverage.
Cap shingle matching
New caps on a weathered roof may look slightly different at first. If the field shingles are near the end of their life, folding the vent into a full replacement avoids paying for the ridge twice. See ridge vent vs box vents and signs you need a new roof.