What Causes Roof Blisters and How to Fix Them

Your roof is one of the most important parts of your home. It protects you from rain, sun, wind, and extreme temperatures. But when small bubbles or raised areas appear on your roof’s surface, they could signal a problem. These bubbles are called roof blisters. Left unchecked, they can grow and lead to leaks or more serious damage.

What Roof Blisters Look Like

Roof blisters appear as raised bumps that often form on asphalt shingles or flat roofing systems. These bubbles can range from small spots to large areas that peel or crack over time. Blisters are most noticeable during hot weather when heat causes trapped air or moisture to expand.

Unlike cracks or punctures, blisters may not immediately leak, but they weaken the surface and can open up over time, especially under foot traffic or during temperature changes.

What Causes Roof Blisters

Blisters usually form due to trapped air or moisture between layers of the roofing material. When the sun heats the surface, the trapped material expands. Since there’s no way for the air or moisture to escape, it pushes upward, creating a bubble.

There are several reasons this may happen:

Poor Ventilation

A roof needs proper airflow to keep heat and moisture from building up under the surface. Without it, warm air gets trapped, which increases the chances of blistering.

Improper Installation

If shingles or roofing layers are not applied correctly, gaps or pockets can form. These spaces allow air or moisture to get stuck between the layers, which later form blisters when heated.

Moisture in Roofing Materials

Roofing materials must be dry before installation. If wet materials are used or if they get damp before the roof is sealed, the moisture becomes trapped inside. That trapped water will later expand with heat, causing blisters.

Age and Wear

Older roofs are more likely to develop blisters. Over time, the bond between layers weakens. Heat and sunlight can break down the materials, especially if the roof is already nearing the end of its lifespan.

How to Fix Roof Blisters

Fixing roof blisters depends on how severe they are. Some small blisters may not need immediate attention, but larger or open blisters should be repaired quickly to avoid water damage. Here’s how you should proceed:

Inspect the Roof

Look for raised areas, cracks, or places where the roofing material is peeling. If the blister has burst, check for soft spots or exposed areas underneath.

Remove Damaged Materials

For larger blisters, a roofing professional will cut away the blistered section. The area must be cleaned and dried completely before repairs begin. This prevents further moisture problems.

Apply New Material

Once the damaged section is removed, new roofing material is added. The new layer is sealed tightly to avoid future blistering. In some cases, a patch may be used, while in others, a full replacement of the affected area may be needed.

How to Prevent Roof Blisters

Prevention begins with proper installation. Make sure roofing work is done during dry weather and that materials are stored correctly. Good attic ventilation also plays a major role in preventing heat and moisture buildup.

Regular inspections can help catch early signs of blistering. If you see bubbles forming, contact a professional before they grow larger. Keeping your roof clean also helps. Dirt and debris can trap heat and moisture, making blistering more likely.

Don’t let small issues turn into costly repairs. Whether you’re dealing with roof blisters, storm damage, or planning a full roof replacement, we at Braswell Construction Group bring experience, quality materials, and trusted craftsmanship to every project. Contact us today.