Roofing Glossary

Shingle Blistering

Blistering appears as small raised bubbles — usually a quarter-inch or less — across the shingle surface. When the bubbles pop, they leave tiny pockmarks with missing granules. It is unsightly, and it is a sign something is wrong with moisture, heat, or both.

Blisters form when moisture trapped in the shingle or the deck below expands as vapor in heat. Common causes include shingles installed over damp decking, manufacturing moisture, and — most often — excessive attic heat from poor ventilation baking moisture out of the system.

Popped blisters expose small spots of asphalt to UV, which accelerates local deterioration. Widespread blistering on a young roof can indicate a manufacturing issue; on an older roof it usually points to ventilation problems.

Why It Matters

Blistering itself rarely causes immediate leaks, but it signals conditions — trapped moisture, overheated attic — that shorten roof life. The underlying cause deserves investigation, not just the symptom.

What to Watch For

• Clusters of small raised bumps on shingle surfaces
• Pockmarks with missing granules where blisters popped
• Blistering concentrated on the hottest slopes

Questions about your own roof? Request a free estimate or call Nucci Brothers Roofing at (301) 458-1003.