Is granule loss considered damage?

As hail season kicks off, we will see a recurring theme – granule loss and hail damage.

The question, ‘Is granule loss considered damage?‘ will arise on a regular basis. Hopefully, this will serve as a guide for homeowners, real estate agents and inspectors alike:

Hunt's Construction - photo of defective shingleLet’s begin with a looking into how shingles are made and the purpose of granules on a composition shingle:

Granules have multiple main purposes:

  • to protect the asphalt coating from UV rays
  • to add aesthetic beauty (color of shingle)
  • and to provide fire resistance

All asphalt shingles have granule surfaces that will lose adhesion qualities over time. The older the shingle becomes, the more adhesion qualities will dissipate, resulting in granule loss. Hail, wind, rain, foot traffic and a host of other factors can contribute to granule loss.

In the shingle manufacturing process, up to 40% more granules than are necessary are applied to the shingles. Many engineers have estimated that 12-15% of the granule surface of a new shingle will erode before the adhered granules are even exposed.

To say it a different way, 12-15% of the granules on a new shingle are not securely attached to the shingle. They may be interlocked with embedded and adhered granules, but are not adhered themselves. These granules are commonly referred to as “hitchhikers”.

Hunt's Construction - photo of defective shingleShould you have the inclination, purchase a pack of shingles and open it. You will discover a fair amount of unattached granules in the packaging itself. Now remove a shingle or two and shake them to simulate the installation process. Many more granules will dislodge, yet the shingle itself is still undamaged (unless you shook it hard enough to damage it).

After a weather event, be it hail, wind or heavy rain, it can be observed that a seemingly abnormal amount of granules have accumulated in gutter systems. The newer the roof, the more granules one will typically observe as present in the gutter systems.


Hunt's Construction - photo of defective shingle

Granule loss does not always indicate damage – it is simply an indicator that weathering has taken place. Shingles are designed to weather. An example presented by one roofing assessment service spelled it out nicely:

“Consider the following: an individual makes a routine maintenance check on his property and decides to clean out the gutters. A recent hail storm had occurred and a collection of shingle granules were discovered. The overall appearance of the roof remains the same, but now there may be a concern of roof failure. The amount of granules collected from the gutters filled two gallon containers. A gallon of roof granules weighs approximately 15 lbs. An average size house has a roof square footage of about 3,000 square feet or 30 squares of shingles. There are about 86 lbs. of granules in a square, which would be a total of about 2,580 lbs. of granules. If you collected two gallons of granules in the gutter system (30 lbs.), it would take 86 YEARS to lose all the granules from the roof providing the same hail storm occurs every year! This scenario is extreme and unlikely, but provides enlightenment to our discussion. So, does granule loss automatically determine roof failure and constitute roof replacement? No! Granule loss is part of the natural aging process of a shingle and is recognized as such by the roofing industry.

Credit to AAA Roof Technologies, Hendersonville, NC

The point is that granule loss does not necessarily point to “hail damage”. The shingles, by design, shed granules over their useful life cycle. As the shingles age, the adhesive bond between the substrate and the granules will deteriorate and release granules more easily.

If the only indicator that you see when checking your roof is granule loss in your gutters and no impact marks on the shingles then you likely do not have damage – the shingles are simply weathering and losing shake (granules) by their intended design.

A uniform pattern of granule loss is considered “normal wear and tear” by shingle manufacturers, forensic engineering firms and insurance carriers. Impact points, crushed granules and exposed and cracked or bruised substrate are considered “hail damage”.

It should be noted that there are ALWAYS exceptions to the rule, and an exceptionally severe small sized hail event accompanied by heavy rains could theoretically erode a sufficient amount of granules to justify a roof replacement.


Excessive patterns of granule loss can point to a defect shingle.  In this scenario recovery from the shingle manufacturer can be a route of recovery to replace a defective roof.  Manufacturer defect is ALWAYS excluded in insurance policies and so turning in a claim for a roof with excessive granule loss from manufacturer defect will be denied coverage (i.e. not paid).

We can assist in determining, documenting and submitting a warranty claim to the manufacturer for defect shingles.

Hunt's Construction - photo of defective shingle 

The shingles to the left were covered for replacement under the manufacturer’s warranty, which we helped facilitate.

Granule loss due to a manufacturing anomaly will typically display a distinct pattern.  The granule loss exposes the mat to weather and the shingles are considered compromised. Defective shingles will continue to shed more granules exposing even more of the mat.

Improper granule adhesion is a variation in the manufacturing process and if the shingles are within warranty then they often can be replaced by the manufacturer.  Of course, not all shingles are within warranty and some defective shingles have already been settled in class-action suits, which are now considered over and unrecoverable.

If you are unsure as to whether your shingles are aging normally, have adverse weather in the form of hail or wind or are deteriorating from manufacturer defect, please contact us for a FREE ROOF INSPECTION.