What are the ridge vent installation instructions, step by step?
Short answer. The general steps are: confirm there is enough intake, mark and cut a slot along the ridge to the vent's specified width while stopping short of the ends, shingle up to the slot, center the vent over it, then nail cap shingles through the vent with the specified fasteners. The exact slot width, nail length and end details come from the instructions for the specific vent.
Before you start
- Check the attic for intake: open soffit vents with baffles, or another intake route. Without intake, a ridge vent does not work.
- Decide what happens to existing exhaust; most manufacturers advise against mixing a ridge vent with box vents, turbines or gable vents in the same attic.
- Roof work is dangerous. Use fall protection, and avoid hot afternoons when shingles scuff and soften.
General steps
- Mark the slot. Snap chalk lines on each side of the ridge at the width the vent specifies, commonly about 1 inch from center on trusses, or 1 inch beyond each face of a ridge board.
- Set the saw depth to cut only the decking without touching rafters or trusses.
- Cut the slot, stopping where the instructions say, often about 6 inches from gable ends and about 12 inches from walls, chimneys or intersecting ridges. Clear debris from the attic side.
- Shingle to the slot so field shingles reach the edges of the opening.
- Install the vent centered over the slot, running the full ridge length, and join sections as directed.
- Set end plugs at both ends.
- Nail the cap shingles through the vent with nails long enough to fully penetrate the deck, without overdriving and crushing the vent.
Common DIY mistakes
Cutting into a truss chord, cutting the slot too wide, using short shingle nails that let the ridge blow off in a storm, and installing the vent but forgetting to cut the slot at all. If any of that feels uncertain, this is a job for a roofer. More context in ridge vent vs box vents and the roof maintenance checklist.