Buckled or wavy shingles, also called shingle ridging, are shingles that ripple, hump or lift instead of lying flat. ARMA traces most buckling to two causes: underlayment that took on moisture and wrinkled, and wood decking that moved with moisture, often because panels were installed tight or the attic is damp. Uneven decking, structural movement, bad nailing and debris under shingles cause the rest. The pattern tells you which: lines that follow deck joints point to the deck; random ripples point to the underlayment. The fix starts with the cause, then flat reinstallation. This page is general information; your roofer makes the final call on your home.
On this page: Signs · Causes · Reading the pattern · Repairs · Basis · When to call
Signs of buckled shingles
- Ripples or humps across a slope, easiest to see in low sun.
- Straight ridges running across or up the roof at regular spacing.
- Random wrinkles that do not line up with anything.
- Shingle edges lifting at the high spots, sometimes with worn granules.
- A new roof that never quite flattened out after a cold-weather install.
What makes shingles buckle
- Wrinkled underlayment. Felt that absorbed moisture and wrinkled before or after the shingles went on.
- Deck movement. Wood panels or boards swelling and shrinking with moisture; see swollen or buckled decking.
- Tight deck joints. Joints not spaced at least 1/8 inch apart.
- Plank decks. Adjacent boards moving at different rates.
- Poor attic ventilation and moisture. Damp attics drive deck movement.
- Other causes: uneven decking, nails not driven flush, shingles damaged in storage, debris left under shingles, or structural movement.
Reading the pattern from the ground
- Pick a low-sun hour and look across each slope with binoculars.
- Straight lines repeating every 4 feet or 8 feet suggest the deck panels, which are usually 4 feet by 8 feet.
- Random ripples suggest wrinkled underlayment.
- One big, obvious hump or dip can mean framing or structural movement; see structural roof problems.
- In the attic, look for damp or swollen panels and signs of attic frost. In Colorado, check again after a cold snap with snow on the roof, when frost in a damp attic is easiest to see, and remember that your local building code sets the attic ventilation the shingle maker expects.
Repairs
| Repair | When it fits |
|---|---|
| Wait through warm weather and recheck | A new cold-weather install that has not fully flattened |
| Fix attic moisture and ventilation | Deck-pattern ridges with a damp attic |
| Remove the affected shingles, flatten or repair the underlayment, reinstall flat | Random wrinkles in one area |
| Replace sheathing and the roof section | Decking is damaged or misaligned |
Fixes that fail: nailing down the humps through the shingle face, adding more shingles over the ripple, and ignoring a wet attic.
Manufacturer basis
ARMA’s Plain Facts About Buckled Shingles (March 2024) names wrinkled underlayment and deck movement as the main causes, explains that deck-moisture distortions line up with panel or board joints while underlayment wrinkles are random, calls for deck joints at least 1/8 inch apart and staggered, and says undamaged shingles can be reinstalled flat once the root cause is corrected. Owens Corning’s cold-weather bulletin (Pub. 10022497-A) notes cold-installed shingles may take longer to lie flat and calls for end joints gapped no more than 1/16 inch so shingles do not buckle against each other when they warm. Owens Corning also publishes a bulletin on repairing wrinkles in self-adhered underlayment.
When to call
Call when ripples appear on a roof less than a few years old, when ridges follow a grid, or when buckling comes with attic dampness. Related guides: thermal splitting, nail pops and the roof problems guide.
Ask us what the ripples mean
Integrity Roofing and Painting is veteran-owned and family-run since 1990, an Owens Corning Platinum Preferred contractor with 650+ Google reviews. We photograph the pattern from the ground and the deck from the attic, then explain the likely cause in writing. Colorado Springs area: (719) 488-2800 or a free inspection. Denver metro: (303) 209-0152 or a free Denver inspection. Austin: (512) 610-5897 or a free Austin inspection. Same-business-day reply.
Sources: ARMA, Plain Facts About Buckled Shingles (March 2024); Owens Corning, Cold Weather Shingle Installation technical bulletin (Pub. 10022497-A); Owens Corning, underlayment wrinkle repair technical bulletin.
