Five Reasons You're Dealing With Curling Shingles on Your Roof

Scott Dylan Westerlund
Reviewed by Ami Feller
Updated June 2, 2022
The gable of a large renovated house
Photo: bgwalker / E+ / Getty Images


  • Shingle curling can happen on roofs of all ages.

  • Curly or wavy shingles are never a good sign.

  • Improper installation is a common cause of shingle curling.

  • Weak roofing materials can also be to blame if the manufacturer cut corners.

  • Check your roof warranty to see if you’re covered for this problem.

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If you see your asphalt shingles curling on your roof, you may wonder what’s going on. Like any common roof problem, curling asphalt shingles should be taken seriously. Fortunately, there are some telltale signs that can help you get to the root of what’s causing your wavy roof shingles. Here's a look at the five likely causes behind the issue.

1. Poor Attic Ventilation

Your roof ventilation system works by pulling in outside air from intake vents located on the roof's lower portion before displacing it to higher areas of the roof. When venting is inadequate, you get moisture and heat trapped in your attic. It might be time to make sure there's enough airflow to prevent roof issues that ultimately indicate your home is also at risk for mold damage.

“Underventilated roofs also cause shingles to not last their full lifetime expectancy,” says Ami Feller, Expert Review Board member and owner of Roofer Chicks in New Braunfels, TX. “Many builders underventilate their homes. You should have 1-square-foot of ventilation for every 300 square-feet of attic space, and that 1-square-foot should be split evenly between intake and outtake vents. Since most vent openings are expressed in inches, you will need to convert to inches when calculating the amount of ventilation needed. There are many ventilation calculators available online. Don’t forget to add your garage space in the the attic space square feet. Most two-car garages add 400 square feet.

2. A Bad Roof Installation

If your shingles look suspect, it’s probably time to call in some local roofing companies near you. Roofing manufacturers have strict guidelines regarding how their products must be installed. One slip up in following the guidelines could void a warranty.

Storing shingles at improper temperatures before installation can lead to trouble. If any moisture gets absorbed into the shingles or decking before installation, it could create curling.

If you're wondering about the cost to repair an asphalt shingle roof because your shingles are peeling after you did a DIY roof installation, it may be time to seek advice from local roofers before the issue gets worse.

3. Defective Shingles

A worker replacing a roof’s shingles
Photo: Huntstock / Brand X Pictures / Getty Images

When it comes to curly shingles, blame could fall on the shingle manufacturer. It's possible that your roof shingles were simply made with flaws. In this case, make sure you have a roofing pro document the issue on your behalf, for warranty purposes.

4. Your Current Shingles Were Installed Over Old Ones

Roofers and homeowners sometimes layer new shingles over old shingles. While this isn't typically a code violation, it's generally a bad idea. The reason why is simply that new shingles can't seal properly when they're placed over old shingles. It also covers up other hidden problems that may be lingering in the original roof.

This shortcut frequently causes roof shingles to blow off in strong winds. Yes, it can also increase the chances of curling. If your roof has been overlaid, it's likely that the manufacturer may also void their warranty.

5. Your Shingles Have Reached Their Max Lifespan

Your roof shingles may simply be curling their way into retirement. Most asphalt roof shingles last from 15 to 30 years. However, architectural shingles represent some of the types of asphalt shingles that go up to 50 years.

If you're in an area with a harsh climate of either extreme, your roof may make its curtain call sooner than expected. Always have a pro come in to help you assess whether it's smarter to repair or replace your roof under the circumstances before you start peeling off your shingles.

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