Asphalt shingle blisters do not occur as often as they used to, thanks to improvements in shingle manufacturing technology and tighter quality control. However, it can still happen from time to time. In today’s post, local roofing contractor D & M Roofing shares an overview of asphalt shingle blisters, and whether it can be fixed.

What Causes Shingle Blisters?
Standard asphalt shingles have two layers — the backing material and the outer granule layer. The manufacturing process involves feeding large rolls of uncut sheets of backing material onto rollers and soaking them in hot asphalt. These sheets can be made from pulp made of paper and fabric (“organic” shingles) or flexible fiberglass (“composition” shingles).
A layer of granules is then pressed on one side of the still-wet sheets. These granules protect the outer layer of the asphalt shingles from UV damage. They also provide the roofing color and other features like resistance to algae. After cooling, the shingles are then cut to size, laminated with another layer if required and packed for shipping.
Humidity levels in the factory are carefully monitored because it can trap moisture between the asphalt and granule layers, which may not evaporate even after installation. Prolonged exposure to heat from the sun will cause the moisture to expand, resulting in blisters.
Can Asphalt Shingle Blisters Be Fixed?
Sometimes asphalt shingles still make their way to roofs, and the only way to fix affected shingles is to replace them. Since shingle blisters usually form within the first few years of a roof’s service life, it should be well within the warranty period, and therefore shouldn’t result in a complete roof replacement. It’s important to note that the costs of labor, which includes tear-off and disposal, may or may not be covered depending on your warranty coverage.
It’s also worth noting that blisters and hail damage look very much alike when seen from the ground. The key difference between the two is that hail damage is usually covered by insurance, while blisters are not. It’s not uncommon for hail damage claims to get denied because an inexperienced insurance inspector mistook hail damage for blisters. Have your roofing contractor perform the roofing inspection to ensure accuracy in the damage report and minimize the likelihood of a denied claim.
D & M Roofing is the leading roofing company serving customers in Akron and Canton, OH, as well as the surrounding communities. Give us a call at (330) 621-5408. You can also fill out our contact form to schedule an appointment.