Roofing Nails for Shingles

Roofing Nail Types and Sizes

Roofing nails are the primary fastener for asphalt shingles. The standard roofing nail for new construction is a hot-dipped galvanized steel nail, 1.25 inches long, 11-gauge or 12-gauge wire diameter, with a head at least 3/8 inch across. Ring-shank nails have ridges along the shaft that grip the wood fibers and resist withdrawal better than smooth-shank nails. Screw-shank nails twist as they are driven, providing even more holding power. Most manufacturer specifications accept smooth, ring-shank, or screw-shank nails, but ring-shank and screw-shank are preferred in high-wind areas. Stainless steel nails are required in coastal environments where salt air would corrode galvanized nails. Electro-galvanized nails have a thinner zinc coating than hot-dipped and are acceptable for standard applications but not recommended for high-moisture environments.

Nail Placement and Pattern

Every shingle manufacturer specifies a nail line, which is the zone on the shingle where nails must be placed. On a standard 3-tab shingle, the nail line is approximately 5/8 inch above each cutout. On architectural shingles, the nail line is marked or described in the installation instructions, typically just below the adhesive strip. Nails placed on or near this line pass through two overlapping shingle layers, which is what gives the shingle its wind resistance. The standard pattern is 4 nails evenly spaced across the shingle for normal wind zones. In high-wind zones, 6 nails are required, with the two additional nails placed near the ends of the shingle. Each nail should be driven flush with the shingle surface, not overdriven into the mat and not left proud above the surface.

Common Nailing Defects

High nailing is the most widespread installation defect in the shingle roofing industry. When a nail is placed above the manufacturer's nail line, it passes through only one shingle layer instead of two. The overlapping shingle above is not secured at all. In a wind event, the unsecured shingle lifts, breaks the adhesive seal, and blows off. Overdriven nails are another common problem. A nail driven too deep tears through the fiberglass mat of the shingle, leaving only the granule surface holding the shingle down. Underdriven nails sit above the shingle surface and prevent the overlapping shingle from sealing flat, creating a bump that wind can catch. Pneumatic nail guns set to incorrect pressure are the primary cause of both overdriving and underdriving.

Nailing and Insurance Claims

When shingles blow off during a windstorm, the nailing pattern on the blown-off shingles and on the exposed nail heads on the roof tell a story. If the nails are in the correct location and the shingles tore away from properly placed fasteners, the damage is consistent with wind. If the nails are high, the shingles were never properly secured, and the failure is an installation defect. Insurance companies and forensic engineers routinely examine nail placement on wind damage claims. Contractors who document their nail line compliance during installation protect themselves and the homeowner. Adjusters should photograph exposed nail patterns on the deck and examine any recovered blown-off shingles for nail hole location relative to the nail line.