Blistering on architectural shingles is a common issue where small, bubble-like bumps form on the surface of the shingles. This happens due to trapped moisture or air pockets beneath the shingle’s outer layer, often caused by manufacturing defects, poor ventilation, or improper installation. When moisture from the roof deck or attic gets trapped, it expands with heat and creates these blisters. Over time, blistering can cause shingles to weaken, crack, or even fall off, reducing the roof’s effectiveness. To spot early signs, look for raised areas or bubbling, especially after hot or humid weather. A simple DIY check involves inspecting your attic for proper ventilation and checking for signs of moisture, such as damp insulation or mildew odors.
If you see blistering, first verify that your attic is well-ventilated—good airflow prevents moisture buildup and can stop further damage. Ensure gutters are clear and shingles are clean and dry before inspecting. Blistering might void some warranty terms, so it's smart to review your shingle warranty before proceeding with repairs. If blisters cover a large area or shingles are cracking and curling, it’s time to call a professional roofer. When you do, ask, “What is causing the blistering in my roofing, and how will you fix the underlying issue?” Also, inquire, “Will repairing or replacing these shingles affect my existing warranty?” These questions help ensure the roofer addresses the root cause and respects your warranty coverage.