How to Install a Ridge Vent

RIDGE vents are the unsung heroes of a long-lasting roof assembly. By allowing hot, moist air to escape at the highest point of your home, they prevent ice dams in the winter and keep your shingles from cooking from the underside in the summer. When done well, the roof looks sleek and uniform, and your attic temperature stays within a few degrees of the outside air. Installing a ridge vent is high-stakes work because you are intentionally cutting a hole in your roof. Success depends on precision: you need enough gap to move air, but not so much that you expose your roof rafters to the elements. Focus on a clean line and sealing the edges properly, and your roof will breathe efficiently for decades.

1. Mark Your Cut Line. Measure the distance from the roof eave to the peak to find the exact center. Use a chalk line to snap a straight reference line along the entire length of the ridge.
2. Slice Through the Ridge. Set your circular saw depth to match the thickness of your roof sheathing, typically 5/8-inch. Cut along the chalk line, stopping roughly six inches short of the gable ends or hip joints.
3. Clear the Opening. Use a pry bar to lift the cut plywood pieces away from the rafters. Ensure no jagged wood edges remain that could snag the vent material.
4. Secure the Vent Strip. Roll out the ridge vent material over the gap, centering it exactly. Fasten the vent to the roof deck using the manufacturer-provided roofing nails.
5. Crown the Ridge. Install ridge cap shingles directly over the vent material. Use long, galvanized roofing nails to secure the caps through the vent and into the underlying roof sheathing.
6. Seal the Ends. Apply a bead of exterior-grade roofing cement to the exposed ends of the vent where it meets the gable trim. This keeps wind-driven rain from entering the attic.