IBHS is investigating whether large quantities of small hail can lead to notable granule loss on asphalt shingles that would accelerate the decline of a roof’s service life. Preliminary results of this study indicate the following:

• More granules are lost after weathering of panels vs. storage of panels
• Granule loss was visible by human observer and could result in a claim
• Cumulative granule loss per panel after impact by a high concentration of small hail far exceeded individual granule loss by a single 2-in. impact on the same product
• Granule loss could shorten the roof’s life span and make it more susceptible to future hail events
• No immediate threat of water entry was indicated