What causes roof shingles to lift?
Short answer. Shingles lift when the adhesive seal strip that bonds each course to the one below breaks or never bonded in the first place. Strong wind gusts, installation in cool weather, nails placed too high, deck movement and aging, brittle shingles are the usual causes, and once a tab is loose the next storm can tear it off.
How shingles are supposed to stay down
Each asphalt shingle has a strip of heat-activated sealant. After installation, the sun warms the roof and the strip glues the shingle to the course below. That bond, plus four to six nails, is what lets a shingle resist wind.
Why the bond fails
- Wind. Gusts that get under an edge flex the shingle until the seal cracks. Once unsealed, it flutters in every breeze after that. This is the most common wind damage adjusters look for.
- Cool weather installs. Shingles installed in late fall or winter may not seal until warm weather arrives, and dust or pollen on the strip can keep it from ever sealing.
- High nailing. Nails placed above the nailing zone let the bottom of the shingle pivot. Manufacturers mark exactly where nails go.
- Nail pops. Deck movement or short nails let nails back out, pushing the shingle up from below.
- Age and heat. Old shingles lose flexibility and the sealant dries out, so edges curl and lift.
What to do about lifted shingles
A few lifted tabs on a younger roof can often be resealed with dabs of roofing cement under the tab, or replaced. Widespread unsealed shingles after a storm can be wind damage worth documenting; adjusters commonly check by gently lifting tabs to see whether the seal is broken and the shingle is creased. Do not pry tabs up yourself on a very hot or cold day, since that can crack them. See wind damage to roofs in Georgia and signs you need a new roof.