What size roofing nails are used for asphalt shingles?
Short answer. Asphalt shingles are fastened with galvanized roofing nails at least 12 gauge with a 3/8 inch head, usually 1-1/4 inches long for a new roof on standard decking. Overlays on an existing layer need longer nails, often 1-3/4 to 2 inches, and hips and ridges also take longer nails because of the extra layers.
By situation
- New roof, 3-tab or architectural, on 7/16 or 1/2 inch deck: 1-1/4 inch.
- Starter strip: same as the field shingles, nailed per the instructions so the sealant stays clear.
- Thick designer or impact rated shingles: often 1-1/2 inch.
- Hips and ridges: 1-3/4 to 2 inches, or longer through a ridge vent if the vent maker says so.
- Overlay on an existing layer: long enough to reach 3/4 inch into the deck through both layers, often 1-3/4 to 2 inches. Many manufacturers and local codes limit or discourage overlays.
- Repairs: match the original length; replacing one shingle usually means hand nailing under lifted courses.
The code baseline
The International Residential Code calls for galvanized steel, stainless steel, aluminum or copper roofing nails with at least a 12 gauge (0.105 inch) shank and a 3/8 inch head, long enough to penetrate 3/4 inch into the deck or through it. Shingle makers can require more, and their instructions control the warranty.
What not to use
Most shingle makers do not allow staples, and the code's shingle fastener section lists nails. Bright, uncoated nails rust. One inch nails rarely meet the penetration rule on a modern deck. Screws are for metal panels, not shingles.
See roofing over existing shingles and roof anatomy explained.