Asphalt shingles that develop blisters are not as common as they used to be, but it does happen once in a while. But what causes asphalt shingle blisters, and what can be done to fix them?
How Asphalt Shingles Are Manufactured
To understand what causes asphalt shingle blisters, let us first take a look at how asphalt shingles are manufactured. The first stage of manufacture involves spooling large sheets of backing material on a series large rollers. Depending on the product being manufactured for the batch, the sheets can be made of fiberglass (“composition” shingles) or pulp made from paper and fabric (“organic” shingles).
The sheets pass through poured hot asphalt multiple times, and then a layer of granules are pressed on one side of the still-wet backing material. The granule layer protects the backing material from damage caused by ultraviolet (UV) rays as well as provides its color. Commercial bitumen roof systems are manufactured in a similar manner. The cooled sheets are then dusted to stop them from sticking, cut to size, laminated (if architectural shingles are being manufactured) and packed in boxes for shipping.
What Causes Asphalt Shingle Blisters?
Roofing manufacturers carefully monitor humidity levels at the factory because moisture can become trapped between the asphalt and granule layers. If these asphalt shingles end up being installed on the roof, the moisture will expand when exposed to heat from the sun, resulting in blisters.
Is There a Fix for Asphalt Shingle Blisters?
Repairs for asphalt shingle blisters involve replacing the defective shingles. Since it’s considered a manufacturing error, and they usually manifest in the first few years after installation, asphalt shingle blisters should be covered by your roofing warranty. Note that some roofing warranties may not cover labor costs.
It’s also worth noting that damage caused by hailstones can be misidentified as asphalt shingle blisters. This can be a problem if you are filing an insurance claim because insurance providers do not cover manufacturing defects. To avoid a denied claim, it’s always a good idea to have your roofing contractor perform a thorough roofing inspection after a hailstorm.
Certified Roofing Solutions, LLC is your leading provider of roofing services, including installation of silicone roof coating systems. Give us a call at (888) 910-3746. You can also fill out our contact form to schedule an appointment.