Nails missing the rafters after a reroof: how many is too many?

Shingle nails are supposed to come through. The International Building Code and the International Residential Code require asphalt shingle nails to sink at least 3/4 inch into the deck, or to pass all the way through a thinner one, according to NRCA's Professional Roofing magazine. The magazine notes that the Asphalt Roofing Manufacturers Association wants at least 1/8 inch of point showing below a thin panel deck. An attic full of short points under a half-inch deck means the shingles were nailed right.

The nails that matter are the longer ones fastening panels to rafters, and they only change if the deck was replaced or renailed during the job. A sheathing nail that misses the framing is called a shiner. Under Table R602.3(1) of the residential code that Atwater, California, began enforcing in 2023, roof panels 3/8 to 3/4 inch thick take 8d common or RSRS-01 ring-shank nails 6 inches apart at panel edges and at intermediate rafters. In the 48-inch band along roof edges and ridges the spacing tightens to 4 inches for Exposure B sites with design wind speeds above 130 mph, or Exposure C sites above 110 mph.

A miss is not automatically a code violation. In a December 2022 informal interpretation, the Building Officials Association of Florida said shiners are acceptable provided enough other nails are properly embedded and the fastening schedule is met. It added that crews normally pull shiners or clinch them flat so they cannot migrate up through the shingles and start a leak. Count per rafter: a whole line of misses along one rafter leaves that rafter short of nails.

Bare points also collect frost. Reuben Saltzman of Structure Tech, a Minnesota home inspection firm, writes that moist house air leaking into an attic condenses on cold surfaces such as roof nails and drips when it melts, and that the fix is air sealing and exhaust fans vented outdoors, not roof work. Ask the roofer whether the deck was renailed, with what nail and pattern, and have misses backed out and redriven into the rafter.