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Most homeowners do not know the term “blistering roof shingles” until they notice some odd peeling and bubbling shingles and search online for answers. Without timely repairs, blistering roof shingles can become a huge expense that lessens the lifespan of your roof. So, what causes this common problem?

Below, one of our roofing experts from Polaris Roofing Systems explains why roof shingles blister and what you can do about it. If you live in or around Flagstaff, Parks, and Williams,

Arizona, and need help with your roof, call us at (928) 699-4840 for a free inspection!

What Are Blistering Roof Shingles?

What Causes Blistering Roof Shingles

Blistering roof shingles are similar to the blisters you might get on your skin. Essentially, the outer shingle material bubbles up and pops, creating a spotty appearance across the entire roof.

Many people confuse blistering roof shingles with hail damage, but these are two different problems. If you want to differentiate the two, consider the following:

  • Indents: Hail damage will leave indentations surrounding the impact area, while blisters will have no depression.
  • Pattern: Hail damage typically leaves uneven destruction patterns, while blisters disperse across the entire surface.
  • Bubbles: Blisters may leave unpopped bubbles, while hail damage will only cause indentation holes.
  • Weather: Hail damage comes after severe storms, while blistering shingles often happen in the heat of summer.

If you have blistering shingles, you must try not to pop any of the bubbles. Avoid walking across the roof surface, and do not place anything heavy on your shingles. If you have tree branches hitting the roof, carefully trim them away.

When blisters pop, they compromise the roof’s weatherproofing. Exposing the inner layers will increase the roof’s risk of water damage and UV exposure, creating more expensive repairs down the line. To resolve the problem before it accelerates, you should call a roofer to help with your shingles as soon as you notice any bubbling or blistering.

What Causes Blistering Roof Shingles?

Blistering roof shingles are extremely common among homeowners. Two main factors typically cause shingle blistering. Often, you may encounter both problems.

Trapped Water Evaporation

Your roof has three separate layers: the backing, asphalt, and granules. In combination, these layers seal off your home from the outside. Sometimes, roof installers or manufacturers may accidentally trap moisture between these layers.

If you have trapped water inside the roof, the water will evaporate when the sun heats up. Water vapor takes up more space than liquid water, causing the interior roof layers to expand. Once the roof layers run out of room, this pressure will push into the shingles and cause them to bubble up and pop from the trapped vapor.

Aside from blistering, trapped water can cause problems in the winter, too. Instead of turning into a gas, the moisture may freeze into ice, which also expands. Ice dams can create roof cracking and other serious issues.

Improper Attic Ventilation


propert attic ventilation

Heat problems do not just come from the sun. If you have poor ventilation in your attic, your home might send too much heat into the roof. Without adequate vents and insulation, not only does your energy bill skyrocket, but your attic will disperse hot air upward (since heat rises).

Now, any liquid that sits between the roof layers will heat up and become vapor, as we discussed above. The gas will expand the roof and create blistering across the shingles.

Do Blistering Shingles Require an Entire Roof Replacement?

If you repair the problem early enough, blistering roof shingles do not require an entire roof replacement. Your roofer can diagnose the severity of the problem and decide to either repair the affected shingles or replace the roof altogether. Typically, if your roofing blisters haven’t popped yet, you shouldn’t need a new roof.

Blistering Shingles Require an Entire Roof Replacement

If you have a lot of open blisters, your roofer may recommend that you go for a replacement.

After enough time without weatherproof sealing, all of the layers beneath the shingles will have severe damage from rain and sun rays.

When Should You Call a Roofing Expert About Your Blistering Shingles?

As soon as you notice any odd textures, bubbles, or dark coin-shaped circles on your shingles, you should call a roofing expert for an inspection and diagnosis. A professional can confirm the issue and offer advice on your best route moving forward.

Can You Avoid Shingle Blistering?

You can avoid blistering shingles by improving your home’s and attic’s ventilation to reduce heat exposure. You can also try selecting a durable and high-quality shingle option the next time you replace your roof so that bubbles do not pop as easily.

Protect Your Arizona Home By Contacting Polaris Roofing Systems

Don’t wait to repair your roof — contact our roofing experts today to prevent further damage and expenses. At Polaris Roofing Systems, we have over 25 years of experience offering professional roof repairs and installations across the region including Flagstaff, Parks, and Williams, Arizona.

If you suspect you may have blistering roof shingles, call us at Polaris Roofing Systems today at (928) 699-4840 for a free inspection!

Justin Young

Justin Young

Justin young has been in the construction trade for nearly 25 years, focusing on insurance restoration and roofing. While attending Arizona State he worked in new construction custom homes until the opportunity came to get back into restoration and roofing. Roofing came full circle and Justin was promoted to General Manager of a local roofing company. As that progressed he ventured out on his own to start his own company, Polaris Roofing Systems. He prides himself on being on the cutting edge of roofing materials, applications and roof quality. Justin enjoys spending time with his 2 young children and wife. Justin prides himself, his company and continued growth on the people around him and the integrity for which it stands for.

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