What causes exposed nails on roof shingles?
Short answer. Exposed nails on roof shingles usually come from one of four things: nail pops, where a nail backs out of the deck and pushes up the shingle above; nails placed too low during installation; face-nailed repairs; or shingles that slipped or blew off and left the nails below uncovered. The final ridge cap is the only spot where a sealed, visible nail is normal.
Match what you see to the cause
- Nail pops: a small bump in a shingle, or a nail head poking through it. The nail has worked its way up out of the deck, often because it missed solid wood, went in crooked, was too short, or the deck shrank and swelled with the seasons.
- Low nailing: nail heads lined up along the bottom of a course, in the part of the shingle meant to be exposed. That is an installation error repeated wherever that crew member worked.
- Face-nailed repairs: random nails surrounded by blobs of sealant, where someone fastened a replacement shingle from the top.
- Missing or slipped shingles: a row of nail heads where a shingle used to be, often after wind.
- Ridge cap: one or two sealed nails on the last cap piece are normal.
Why Georgia roofs see nail pops
Wood decking swells in humid months and shrinks in dry ones, and attic temperatures swing widely. Over years that movement can ratchet poorly seated nails upward. Houses with poor attic ventilation, where the deck gets wetter and hotter, tend to show more pops.
How serious it is
Every exposed nail is a path for water straight into the deck, and a popped nail also tears the shingle above it, which can break the seal and invite wind damage. One or two pops are a simple repair. Rows of exposed nails, or pops across the whole roof, point to an installation or deck problem that deserves a closer look. See common causes of roof leaks and OSB vs plywood roof decking.