As you may have guessed, curling shingles are not a good sign for the integrity of your roof. But, why are your shingles curling in the first place? Below are a few reasons this could be happening:
Improper ventilation. When working properly, a roof ventilation system pulls outside air in toward the bottom of the roof and displaces it toward the top of the roof. If the ventilation system is not working properly, moisture and heat can become trapped in the attic. This warmer temperature can then cause the bottom of your shingles to prematurely curl.
Improper installation. Shingles have a proper and an improper way of installation. It is important that you choose a licensed contractor that knows how to install the roofing system properly, including knowing how many nails to use per shingle, what type of nail to use, and what type of weather is adequate for installation. If the manufacturer specifications for installation are not followed, not only when this increase the chance of your shingles curling, but your manufacturer warranty may also be void.
Defective product. Shingles may curl if they were manufactured incorrectly.
Installing shingles over an existing layer. If you install new shingles over an existing layer of shingles, you are likely to encounter many problems, including curled shingles. This is because new shingles are unlikely to line up exactly with the old ones, preventing them from sealing properly. Moreover, if there is mold or rot on the existing roof, this will cause problems on the new roof installed above it.
Aged shingles. Shingles may also begin to curl when they are at the end of their lifespan. If your shingles are old and beginning to curl, it is time to contact a trusted roofing contractor.