How do you use roofing nails correctly?
Short answer. Use corrosion-resistant roofing nails with at least a 12 gauge shank and a 3/8 inch head, long enough to go at least 3/4 inch into the wood deck or through thinner decking, and drive them straight and flush in the manufacturer's nailing area. The residential code requires at least four nails per strip shingle, and more where the manufacturer calls for them, such as on steep slopes.
Choosing the nail
- Material: galvanized steel, stainless steel, aluminum or copper under the residential code. Galvanized steel is standard for asphalt shingles.
- Gauge and head: the code minimum is a 12 gauge shank and 3/8 inch head; many roofing nails are 11 gauge with larger heads.
- Length: enough to reach 3/4 inch into the deck or fully through thinner decking. That often means 1 1/4 inch nails in the field and longer ones at ridge caps and doubled areas.
Placing the nail
- Drive within the manufacturer's nailing area, so the nail passes through both layers of a laminated shingle and is covered by the course above.
- Keep nails the specified distance from shingle ends.
- Do not nail into the sealant strip or into a cutout gap.
Driving the nail
- Flush: the head should sit snug on the shingle surface.
- Not overdriven: a head sunk into the mat cuts it and weakens the hold.
- Not underdriven: a raised head keeps the shingle above from sealing and can wear through it.
- Straight: an angled nail leaves one edge of the head up.
Pneumatic nailers need the right air pressure, and good crews adjust it as the day warms, because hot shingles are softer.
Mistakes that show up later
High nails let shingles slide and blow off in storms, exposed nails rust and leak, and nails driven into gaps between old deck boards hold nothing. Nail tips showing in the attic are normal when penetration is correct. See wind damage to roofs in Georgia and roof anatomy explained.