• Sue Nassiri

Why Roof Shingles Blister and What to Do About Them

Asphalt shingles are well-regarded among roofing contractors and homeowners because of their reliable performance and cost-effectiveness. They are common in many households in the U.S. and can be found in most construction supply stores. However, there are certain issues that asphalt shingles face, and one of them is blistering.

In this article, we share why asphalt shingles blister and what you can do about the problem. Why Do Asphalt Shingles Blister? Asphalt shingles blister due to several reasons, including:


  • Trapped moisture - Moisture can get trapped in the shingles during the manufacturing process. The trapped moisture in the asphalt shingles makes them blister when your roof gets heated up by the sun. Continuous exposure to the sun causes the shingles to absorb a lot of heat, and the trapped moisture within the shingles evaporates and rises, causing them to blister. This is most common in areas that experience heavy rainfall, followed by hot and sunny weather.

  • Poor attic ventilation - Poor attic ventilation can cause the attic space to become hotter, causing damage to the shingles above it. While blistering is a common sign of a poorly ventilated attic, other issues can also result from attic heat buildup, such as warping, granule loss and cracking. Overheating attic can lead to recurring issues, which means you may frequently need roof repair.

  • Bad shingles - Sometimes, the problem isn't with the environment or your home's roofing system. It can also be due to poorly manufactured shingles. When there are inherent flaws in the shingles themselves, they tend to blister and fail after they are installed and exposed to the elements.

  • Aging roof - Roofing systems that are nearing the end of their expected service life tend to show many signs of failure, and blistering can be one of them. Asphalt shingle roofs typically last between 20 to 25 years, and if your roof has been around that long, then it's probably time to get a roof replacement.

Are Blistering Shingles a Problem? The answer to this depends on the current condition of your asphalt shingles. Generally, blistering is not a problem as long as the shingles still have a significant amount of granules. Blistering shingles reduce the appeal of your roof. But apart from being an aesthetic issue, it doesn't pose a serious threat to your roof. Regardless of the amount of blisters on your shingles, your roof will still be fine. However, blisters can become a problem when they pop. Popped blisters cause granule loss and expose the asphalt of the shingle to the heat of the sun, which can cause significant damage to your roof and affect its performance and longevity. Blisters typically pop due to foot traffic or impact from debris, but they can also pop due to extreme weather conditions, such as excessive heat and strong winds. If you're not sure whether you have blistered or hail-damaged shingles, you should call a roofing contractor to take a look at your roof.

How Do I Fix Blistered Shingles? The most important thing you should remember is that blistered shingles won't cause harm to your roof unless they pop. That said, the best thing to do is to avoid popping them by preventing foot traffic on your roof and trimming trees surrounding your property. Falling twigs, pine cones and other debris can easily pop the blisters if they fall onto them or get hurled at them with enough force. Small animals that can climb to your roof can also pop the blisters accidentally. Cats, squirrels and birds can easily get up on your roof and step on the blisters. Some things may be out of your control, so it's important to monitor the blistered shingles through regular inspection. Once the blisters pop, you can be proactive and ask your roofer if it's a good idea to replace your shingles. You can also do this as soon as you or your roofer discovers the blisters. By replacing the blistered shingles before their condition even worsens, you can save yourself from constantly worrying about when the blisters will pop. Improving your attic ventilation is also a good way to keep your shingles from getting damaged further. Make sure your roofer addresses all the underlying problems before installing the new roof so you can avoid the same issues from recurring.

The Importance of Granules The granules of asphalt shingles are part of the roof's defense against the sun's heat. They reflect heat and radiation, and help lessen the retained heat from constant exposure. Aside from that primary function, they also provide a layer of protection and fire resistance to your roof. There are many kinds of asphalt shingles on the market. The most common ones provide adequate protection and performance while others have thicker layers of granules or have specific properties that make them more resistant to the elements. Some roofing companies even recommend shingles that have added impact resistance to prevent the loss of granules, especially in areas that frequently experience hail.

The Difference Between Roof Blisters and Hail Damage Some homeowners find it hard to tell whether they have roof blisters or hail damage since they look similar to one another. However, there are easy ways to determine whether you have blistered or hail-damaged shingles:

  • Check the pattern of the blisters. If your roof has blisters and some of them have popped, then there must be some unpopped blisters around certain sections of your roof. If all of them look popped and there are no unpopped blisters on any section of your roof, then those are signs of hail damage.

  • Consider the location of the blisters. If the issues are only present on one section of your roof, it's most likely hail damage. Blistering shingles have a more random pattern and can appear in different sections of your roof. Hail damage looks more uniform and tends to be seen on only one slope or area of the roofing system.

  • Look for divots or small dents. If these are present on your roof, then you're dealing with hail damage. The impact of hailstones can dent or gouge out small sections of your shingles. Blistering shingles don't have any of these. Aside from that, blistering causes parts of the shingles to rise while hail damage doesn't.

If you need roof repair, A1 Quality Roofing, Inc. is a reputable roofing company that can give you the roofing services you need. From roof repair to replacement, we guarantee excellent workmanship and great value. Our crew always works hard to meet or exceed our clients' expectations. We also offer roof maintenance, re-roofing and waterproofing services. To learn more about our services, call (951) 877-4406, or fill out our contact form.

10 views0 comments