The fix
How are blistered shingles fixed?
The fix follows the cause. Replace damaged shingles, correct attic airflow, and use cement sparingly. Widespread blistering on an old roof may call for a bigger decision.
For a few shingles, a roofer can replace the worst ones. That is the roof repair our roof repair page covers. The cause still needs attention, though. If heat is the cause and the attic is poorly vented, new shingles will face the same heat, so the vent area, the balance between intake and exhaust, and any blocked soffits all deserve a look. ARMA recommends a balanced system, with about 50 to 60 percent of vent area at the soffit and the rest at or near the ridge.
If the cause was too much roofing cement, the fix is mostly about workmanship on future repairs. Atlas, ARMA and CertainTeed all say to use cement in small amounts. Our guide to ridge caps blown off shows where cement is used on hips and ridges.
If blisters are spread across slopes and the roof is old, the bigger question is replacement. Our guides on signs you need a new roof and shingle roof cost cover that path, and roof repair cost covers the smaller one. Whether you repair or replace, ask who will check the attic vents. A roof is only as long-lived as the air under it.
Who does what. A roofer looks at the shingles and the attic and does the repair. The shingle maker, not the roofer, decides what its warranty covers, so ask for the maker's wording in writing. Coastline can show you the roof and the attic in a written photo report, and tell you what the photos show. Timing matters too. Heat is the driver, so the weeks before summer are a better time to look than the middle of a July heat wave, and a repair is easier before hurricane season than after it. If a storm has already hit, see our storm damage repair page.
The short version
Blisters usually trace to attic heat or too much cement. Photograph them, check the vents and get a written look before you spend on anything.
