Blisters on asphalt shingles are not as common as they used to be, thanks to improvements in manufacturing technologies and stricter quality control. However, it doesn’t mean it won’t happen from time to time.
What Causes Asphalt Shingle Blisters?
Asphalt shingles are made of two layers: the asphalt-soaked backing material and the granule layer. The backing material can be “composition” (made of fiberglass) or “organic” (made of paper and fabric pulp). The granules are made of crushed colored rock mixed with ceramic. Some asphalt shingle products may have additives in the granules, such as copper, which helps prevent algae growth. The granule layer provides color and protects the backing material from damage caused by ultraviolet (UV) rays.
During manufacturing, large rolls of backing material are soaked in hot asphalt multiple times. After the last soak, a layer of granules are press-rolled on one side of the still-wet sheets and then cooled. The shingles are then cut to size, bundled and packed in boxes for shipping. Standard or three-tab asphalt shingles feature one layer while architectural shingles feature two layers cut asymmetrically.
Humidity levels are carefully monitored during manufacture because moisture can end up trapped between the asphalt and granule layers, which won’t evaporate even after the shingles are installed. As the roof becomes exposed to heat from the sun, the moisture expands between the shingle layers, which results in blisters.
Can Asphalt Shingle Blisters Be Fixed?
Since asphalt shingle blisters are a manufacturing defect, the only way to fix them is to call your residential roofing services provider and have them replaced under warranty. Blisters typically occur within the first few years after a roof is installed. Therefore, your roof should be well within its warranty period if it happens. It’s important to note that certain warranties may not cover labor costs.
Another thing worth noting is that shingle blisters and damage caused by hailstones look almost the same when seen from the ground. The main difference between the two is that blisters are covered by warranties while hail damage is not. It’s not uncommon for hail damage claims to be denied because an insurance adjuster mistook one for the other. This is why it’s important to have your roofing contractor inspect your roof in case of either: it helps ensure accuracy and minimize the likelihood of a denied claim.
Renovation Team is your leading provider of home improvement services, including exterior siding installation. Give us a call at (636) 428-3634. You can also fill out our contact form to schedule an appointment. We serve customers in St. Louis and St. Charles, MO, as well as the surrounding communities.
