The short answer
What Causes Shingles to Curl
Shingles curl when they lose moisture and flexibility. In hot weather, the sun's UV rays break down the asphalt in asphalt shingles, causing them to dry, shrink, and lift at the edges. Wood shingles can also curl if they dry unevenly, especially if the roof deck lacks proper ventilation.
Age is another major factor. As shingles get older, they become brittle and less able to expand and contract with temperature changes. If the shingles were installed in cooler weather and then exposed to intense heat, the expansion stress can cause edges to curl upward. The same happens when shingles are nailed too tightly, which restricts natural movement.
How Heat Affects Your Roof
Heat alone can cause shingles to curl, but the damage often goes deeper. When shingles lift, they expose the roof deck to water during rain or snow. In a mild coastal climate with wet winters and dry summers, curled shingles can let moisture seep in and cause rot or mold.
You might notice granules from asphalt shingles collecting in gutters, which is a sign that the surface is breaking down. If the curling is widespread, the roof's ability to shed water is compromised. That can lead to leaks inside your home, staining ceilings, and damp insulation.
- Check for visible gaps under the edges of shingles
- Look for granules or debris in gutters
- Inspect attic for water stains or dampness
- Feel for soft spots on the roof deck
- Note if shingles are brittle or crumble when touched
- See if curling is worse on south or west facing slopes
What to Do About Curled Shingles
If only a few shingles are curled, you might be able to replace just those. But if many are affected, a full roof replacement is often the practical choice. The pros can assess the condition of the roof deck underneath and advise whether repair or replacement makes sense.
Do not wait too long. Curled shingles let water in, and once moisture reaches the wood deck, the damage can spread quickly. If you suspect water has already gotten inside, a water damage inspection can help you understand the extent before you commit to a repair plan.
- Replace individual shingles if curling is isolated
- Consider full replacement if more than 20% of shingles are affected
- Ensure proper attic ventilation to reduce heat buildup
- Use lighter colored shingles that reflect heat
- Have a professional check the roof deck for rot
- Keep gutters clean to prevent water backup
Preventing Future Curling
Prevention starts with good installation. Shingles need to be nailed loosely enough to allow for expansion, and the roof deck needs adequate ventilation to let heat escape. In hot climates, choosing shingles with higher temperature resistance can make a difference.
Regular maintenance helps too. Trim overhanging branches to reduce leaf litter, and check your roof after heat waves. Keep an eye on the south facing slopes, which get the most afternoon sun. A quick visual check each summer can catch curling early.
When to Get Professional Help
If you see widespread curling or any signs of water damage, it is time to have a professional look. The pros can safely inspect the roof, identify underlying issues, and recommend the right course of action. They can also check for moisture in the attic and walls.
A roof that has curled shingles may already have small leaks that are not visible from inside. A water damage inspection can reveal hidden moisture, and structural drying may be needed if insulation or wood has gotten wet. Acting quickly can prevent more costly repairs later.
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Call Now (425) 407-5186Frequently asked questions
Can I fix curled shingles myself?
If only a few shingles are curled and the roof is otherwise sound, you can replace them with matching shingles. But if curling is widespread or you see water stains inside, leave it to the pros. Working on a roof is dangerous, and a professional can spot problems you might miss.
How do I know if curling has caused water damage?
Look for dark spots on ceilings, damp insulation in the attic, or a musty smell. You can also check the roof deck from the attic for soft or discolored wood. If you notice any of these signs, a water damage inspection can confirm the extent of the problem.
Will roof replacement solve the curling problem?
Replacing old, curled shingles with new ones usually fixes the issue, provided the roof deck is in good condition. Proper ventilation and nailing during installation help prevent recurrence. If the deck has rot, that must be repaired first to avoid future problems.