Florida Certified Roofing Contractor CCC 1334537
What causes shingles to blister and form small bubbles across the roof surface?
A straight answer from a Florida certified roofing contractor — then what you can check yourself and when to call. Free quote: (954) 775-8990.
Shingle blisters are small raised bubbles caused by moisture or gas trapped inside the asphalt layers, which then expand when the sun heats the roof. The usual contributors are moisture in the shingle from manufacturing or storage, installation over a damp surface, and attic heat and humidity that are not vented out.
The nuance is that a few scattered blisters can be cosmetic, while blisters across a whole slope are a sign of a material or ventilation problem. Once blisters pop, they leave small craters that shed granules and expose the asphalt, and that speeds up aging.
Why shingles blister
Asphalt shingles are layers of asphalt, a reinforcing mat and a granule surface. If moisture or air is sealed into those layers, the heat on a sunny roof turns it to vapor. The vapor has nowhere to go, so it pushes the surface up into a bubble. Florida's strong sun and high humidity create exactly those conditions.
Attic ventilation is a major factor. When hot, humid air sits under the deck, the shingles get heat from above and below. That can drive moisture out of the deck and into the underside of the shingle, and it shortens shingle life in general. Blisters often show up first on the slopes that take the most sun.
Installation can play a part. Shingles laid over a wet deck, over trapped moisture or over an older roof layer can hold vapor that has no way out. A manufacturing defect, where moisture or air was in the shingle from the start, is also possible. That is why blisters can appear on a fairly new roof, and why it is worth keeping your paperwork and photos.
What you can check yourself
Look from the ground with binoculars
Check whether the bubbles are scattered or spread across entire slopes, and whether some have popped into dark, crater-like spots. Do not climb up to inspect them.
Check the gutters and downspout outlets
A heavy build-up of loose granules can mean blisters have broken open and the surface is wearing away.
Look in the attic
Notice whether it feels very hot and stuffy, whether the vents are blocked by insulation, and whether the underside of the deck is stained or damp.
Check the ceilings
Water stains or soft spots below can show that the roof is already letting moisture through.
Gather your records
Find the installation date, the shingle brand if you know it, and any paperwork. Take dated photos so the pattern can be compared over time.
When to call a pro
Call a roofer if blisters cover whole slopes, if many have popped and exposed the asphalt, if granules are collecting in the gutters, or if there are stains inside. A pro can tell blisters from nail pops, algae streaks, hail marks or normal granule wear. They can also tell whether the cause is the shingles or the attic.
On licensing, the rule is: "Roofing work in Florida legally requires a licensed roofing contractor and generally a permit from the local building department; a contractor's license is verified on the Florida DBPR website." We are happy to give you a free estimate, and our certification can be checked on that site. You can reach us at (954) 775-8990.
What a pro will do
- Inspect the roof and atticWe look at how widespread the blistering is and whether ventilation, moisture or the installation points to a cause.
- Tear off to the deck when replacement is neededA full tear-off lets the deck be inspected, with rotten plywood and fascia replaced as part of our scope.
- Install the new systemThat means a secondary water barrier where required, architectural shingles rated for Florida wind zones, starter strip, ridge cap, drip edge and valley detailing.
- Correct ventilationWe detail ridge and off-ridge ventilation so heat and humidity are not baked into the new shingles.
- Handle the permit and cleanupPermits are pulled under our own license, inspections are scheduled and passed, the permit is closed out, and the site gets a full cleanup including a magnet sweep.
Related questions
- Are blistered shingles a leak?
- Not by themselves. A blister is a surface defect, but once it pops and sheds granules, the exposed asphalt weathers faster. Left alone for a long time, that can lead to leaks.
- Can blistered shingles be repaired?
- A few damaged shingles can sometimes be replaced individually. Widespread blistering usually means the material or the ventilation is the problem, and patching does not address either. An inspection will tell which applies, and repairs generally need a permit from the local building department.
- Does the replacement shingle need an approval?
- Yes, and it depends on where you are. Miami-Dade and Broward are Florida's High-Velocity Hurricane Zone. Roofing products used there need a Miami-Dade Notice of Acceptance (NOA) for that use; elsewhere in Florida they need a Florida Product Approval (or local approval). Either way the product is installed per its approval.
- How do I get a quote for a blistering roof?
- Call (954) 775-8990 or use the form on the page. We give a free estimate and a written flat rate quote that says what is included.
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