What size roofing nails should you use?
Short answer. Use 1 1/4 inch galvanized roofing nails for most shingle work over 7/16 to 1/2 inch decking, 1 1/2 inch or longer for ridge caps, hip caps and thicker decks, and 1 3/4 to 2 inches anywhere the nail passes through extra layers. Underlayment gets cap nails, and drip edge and step flashing go on with the same roofing nails used for the shingles.
A quick guide by task
- Field shingles on 7/16 to 1/2 inch decking. 1 1/4 inch.
- Field shingles on 5/8 to 3/4 inch decking. 1 1/4 to 1 1/2 inch so the nail reaches 3/4 inch into the wood.
- Ridge and hip caps. 1 1/2 to 2 inches, depending on cap thickness.
- Starter strip. Same as field shingles.
- Synthetic underlayment. Cap nails with plastic disks, at the spacing the underlayment maker prints on the roll.
- Drip edge. Roofing nails no more than 12 inches apart.
- Step flashing. One roofing nail per piece, high on the roof side so it is covered by the next shingle and never through the part against the wall.
- Pipe boots and vents. Roofing nails or the screws supplied, with exposed heads sealed.
Quick checks
- Every shingle nail should be at least 12 gauge with a 3/8 inch head.
- Points should show slightly through decks thinner than 3/4 inch.
- Galvanized for steel and aluminum flashing, copper nails for copper.
- Ring shank for better holding where available.
On a repair
When replacing a few shingles, match the nail length to the roof that is there. Thicker old decking, extra layers, or board sheathing can call for a longer nail than a new roof. Never nail through the exposed face of a shingle as a shortcut.
Get the bigger picture in architectural vs 3-tab shingles, drip edge explained, and roof flashing explained.