How is a ridge vent installed?
Short answer. A ridge vent is installed by cutting a continuous slot through the decking along the peak, stopping short of the ends, then nailing the vent centered over the slot and covering it with hip and ridge cap shingles using the longer nails the manufacturer specifies. The exact slot width and end clearances come from the vent's instructions and depend on whether the roof has trusses or a ridge board.
Step by step
- Check the attic. Confirm there is soffit intake and plan to close any competing gable vents, box vents, or fans.
- Measure and mark. Snap chalk lines on each side of the peak to the slot width the vent specifies. On truss roofs, one major manufacturer calls for about 1 inch per side, or 2 inches total. With a ridge board, the slot is typically cut about 1 inch beyond the board on each side, though some products allow more.
- Set end stops. Stop the slot short of the ends, commonly at least 6 inches from the rake edge or an end wall, and farther from chimneys and hip intersections, as the instructions specify.
- Cut the slot. Use a circular saw set just deep enough to cut the decking without cutting rafters or trusses. Remove the cut strips and debris.
- Install the vent. Center it over the slot, join sections as directed, and install end plugs.
- Nail it. Use the nail length the manufacturer calls for, long enough to penetrate the deck, and do not overdrive and crush the vent.
- Cap it. Install hip and ridge cap shingles over the vent at the specified exposure, starting at the end opposite the prevailing wind.
On a full replacement this happens as part of the shingle work. As a stand-alone retrofit, it is often a half day job.
What it costs
Installed during a reroof, a ridge vent is a modest line item. As a retrofit, many homeowners see quotes from a few hundred dollars to around $1,000 or more, depending on ridge length, pitch, and cap shingles. See what to expect on roof replacement day and ridge vent vs box vents.