Why Do Asphalt Shingles Blister at Home?

Asphalt shingles are a popular roofing material due to their affordability, durability, and aesthetic appeal. However, even with their resilience, they can experience issues like blistering over time. Blistering occurs when small raised areas form on the surface of the shingles. Understanding the underlying causes can help homeowners prevent and address this problem effectively.

Deschutes Roofing & Insulation explains what you need to know.

Moisture Absorption and Vapor Retention

One of the primary culprits behind asphalt shingle blistering is the absorption of moisture. When shingles are exposed to high humidity or experience rain or snow, they can absorb water. If the shingles don’t dry out properly due to poor ventilation or trapped moisture, the absorbed water can create pockets of trapped moisture within the shingle layers. As the sun heats the shingles, the trapped moisture turns into steam, causing the shingles to blister and deform. A great preventative measure for blistering, especially in wintertime, is professional snow removal. 

Manufacturing Defects and Poor Quality Control

Blistering can also result from manufacturing defects or inadequate quality control during the production of asphalt shingles. If moisture becomes trapped within the shingle layers during the manufacturing process, it can lead to blister formation over time. This highlights the importance of choosing reputable manufacturers that prioritize quality control to minimize the risk of defects.

Improper Installation and Ventilation

Incorrect installation practices and poor ventilation can contribute to shingle blistering. If shingles are not properly aligned or are overexposed to direct sunlight during installation, they can absorb excess heat, accelerating the moisture-to-steam conversion process. Moreover, inadequate ventilation in the attic can lead to the accumulation of hot, humid air, which can cause shingles to blister from beneath.

Home Age and Wear

Asphalt shingles, like any roofing material, have a limited lifespan. Over time, they can become more susceptible to various issues, including blistering. Even with regular snow dam removal, the combination of weather exposure, temperature fluctuations, and wear and tear can contribute to the deterioration of the shingles’ structure, making them more prone to blistering.

UV Radiation and Weather Exposure

Long-term exposure to intense UV radiation and extreme weather conditions can weaken the integrity of asphalt shingles. UV rays break down the asphalt’s composition, making it more susceptible to moisture infiltration. Blistering can occur when compromised shingles allow moisture to penetrate the layers and become trapped, leading to the formation of blisters.

Addressing Asphalt Shingle Blistering

Recognizing the factors that contribute to asphalt shingle blistering empowers homeowners to take proactive measures to prevent and address the issue and prolong the lifespan of the home roofing system. 

If you’re in Bend, OR, do not hesitate to contact Deschutes Roofing & Insulation. We are a GAF roofer with a team of trained professionals ready to assist with all your roofing concerns. Call us today at the following numbers: (541) 241-5720 (Bend), (503) 967-9590 (Portland), (541) 246-6860 (Eugene), (503) 468-7663 (Lake Oswego), or (503) 928-8750 (Beaverton). You can also fill out our convenient online form for a free estimate.