Nail Pop
A condition where a roofing nail backs out of the deck and pushes the shingle above it upward, creating a raised bump that can break the shingle seal and allow water infiltration.
What Is a Nail Pop
A nail pop occurs when a roofing nail backs out of the roof deck over time, pushing the shingle above it upward and creating a raised bump that compromises the shingle seal, exposes the nail head, and creates a direct path for water infiltration. Nail pops are visible as small raised spots on the shingle surface. When you press on the bump, you can feel the nail head beneath the shingle. Left unaddressed, the raised area catches wind, breaks the adhesive seal with the shingle above, and allows water to follow the nail shank into the deck.
Causes of Nail Pops
The most common cause is thermal cycling. The roof deck expands in heat and contracts in cold, and the repeated movement gradually pushes nails upward. Other causes include nails that are too short, nails driven at an angle, nails that hit a gap between sheathing panels, and nails that missed the framing member. New construction with high-moisture lumber is especially prone to nail pops as the framing dries and shrinks.
Nail Pops and Insurance Claims
On their own, nail pops are a maintenance issue that carriers exclude from coverage. However, nail pops become relevant during storm damage claims when they are evidence of an installation deficiency that made the roof more vulnerable to wind damage. If a storm inspection reveals widespread nail pops along with wind-lifted shingles, document both conditions. The nail pops may explain why the shingles failed at a wind speed that should not have caused damage to a properly nailed roof.
Frequently asked questions
Nail pops are caused by thermal expansion and contraction of the roof deck, improper nail length, nails driven into gaps between sheathing panels, or nails that missed the rafter or truss. Over time, the cycling pushes the nail upward through the shingle above it.
Nail pops from normal thermal cycling are considered a maintenance issue and are typically not covered. However, if a storm event causes nail pops by lifting shingles and breaking seals, or if nail pops from a recent installation are part of a broader workmanship claim, coverage may apply.
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