Blistering
Definition
- Related pages
- 4
- Last revised
- 23 August 2026
Blistering is a manufacturing or service defect of asphalt shingles: small raised bubbles in the asphalt layer, formed when moisture or volatiles trapped in the shingle expand in heat. An intact blister is a dome; a popped blister is a pit with a rough bottom and a ring of lifted granules around it. Blisters form on the sunniest slopes, often in clusters, and a roof with poor attic ventilation blisters more.
They matter in a hail claim because a popped blister looks, at a glance, like a hail bruise. The differences are diagnostic: a blister pit has a crater rim and no soft or fractured mat beneath it, it sits on the hottest slopes rather than the windward ones, and the same roof usually carries intact blisters nearby. A roof attributed to hail on the strength of blisters is a common form of mistaken hail claim, and distinguishing the two is a standard part of an inspection.
Blistering is not a weather event and has no place in the storm record. The record bears on it indirectly: a roof whose marks are being attributed to hail on a date for which the record holds nothing near the property is a roof whose marks deserve a second look.
In the report
How the document prints it
Blistering is a condition of the roof and does not appear in the report, which describes what reached the address and when. A reader separating blisters from hail marks uses the document for the date question: the Findings say whether hail is on record near the address inside the window and with what confidence, and the Records say what size was measured on the ground on each day. A roof attributed to hail on a date the report shows nothing for has a question the report has put plainly.
Related
The terms this page uses and the guides that go further. Each is shown against its own example from the record.
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Term
Bruising
A soft, sometimes fractured spot in an asphalt shingle where a hailstone struck and displaced granules, the mark inspectors look for first.
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Term
Functional damage
Damage that shortens the service life or impairs the water-shedding of a roof covering, as distinct from damage to its appearance.
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Term
Prior storm
An earlier storm that reached the same property before the one a claim is about, and the usual reason a hail claim is disputed.
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Guide
Which storm caused it: attributing damage across several storm days
Most roofs in the hail belt have been under more than one storm, and a claim is rarely argued against a blank record. It is argued against the other days: the one before the policy began, the one the last carrier paid, the one nobody noticed. This guide sets out what the law asks when storms compete for the same damage, how an appraisal panel reads the record, and why the calendar has to be on the table before the argument starts.
Sources
The primary references. Each opens on the agency's own site.
The glossary defines the word. The report is what uses it.
Everything above is definition: what the word means in the document, and what it does not. None of it says what reached one roof.
Run the address and the archive is searched at the property: the storm, the date, the measured size, the distance and bearing from the roof, and the federal record each figure came from, in a document that states its own method. About a minute.
How this page is made
- The text
- Written by the editors and last revised 23 August 2026. It explains the record and how the report reads it; it contains no figure of its own.
- The example
- The archive holds nothing this page could show yet, so no example is printed. One appears, computed rather than written, as soon as the record holds a relevant day.
- Measured and detected
- A report from a person or an instrument is measured. A radar-derived size is detected, not measured, and is marked as such, here and in every document we issue. The two are never added together.
- What this is not
- A definition of a word the report uses. It is not a report on any property, and it states no opinion about one. The coverage page states what the record holds, by kind and by year.
About this record
Everything here is reproduced from public federal and volunteer weather records, as the agencies and observer networks that publish them released it. Titan Weather compiles the record; it does not observe the weather, and it is not affiliated with any source it cites.
No archive holds everything. Storms cross places where nobody is standing, instruments and spotters cover some areas better than others, sources revise their records, and recent reports can take weeks to arrive and settle. Where this page shows nothing, nothing was found in the sources searched, within the period and area it states. That is not a finding that no weather occurred.
These pages describe the public record near a place or on a date. They do not establish what reached any particular property, and nothing here is insurance, legal or engineering advice.