Photograph 1: Hail impacts cause blemishes that vary in size, shape, and characteristics.

Tips for Identifying Intentional Roof Damage – Part 2

DonanEngineering Articles, Commercial & Residential Roofing, Forensic Engineer, Forensic Engineering, Hail and Wind, Registered Roofing Consultant, Roofing Investigations

Photograph 1: Hail impacts cause blemishes that vary in size, shape, and characteristics.

Photograph 1: Hail impacts cause blemishes that vary in size, shape, and characteristics.

Part 2: Suspicious Damage Characteristics Not Caused by Hail

An important tip for identifying intentional roof damage, which is made to mimic hail damage to a shingled roof, is to observe the characteristics of individual blemishes on the roof.  Examining close-ups of high resolution digital images is a useful method of determining whether a blemish was caused by hail, or was intentionally made to mimic hail damage.

Each damaging-sized hail impact to a roof creates blemishes that exhibit one or more of the following characteristics: granule loss, exposed asphalt mat, fractures that have a softened depressed area, or tears.  Cumulatively, the hail-caused blemishes on the roof will exhibit all of these characteristics, due to the variability of the size, speed, density, and direction of the hailstones (Photograph 1).

Photograph 2: Creating damage with a ball peen hammer creates blemishes that are uniform size, shape, and characteristics.

Photograph 2: Creating damage with a ball peen hammer creates blemishes that are uniform size, shape, and characteristics.

Depending on the type and age of shingle, ¾-inch to 1 ¼-inch diameter hail is required to cause functional damage to a shingle.  The blemishes that are caused by damaging-sized hail are approximately the same diameter as the impacting hail.

Functional hail damage to a shingle reduces the water-shedding capabilities and/or reduces the expected service life of an originally sound shingle. Intentional damage, which is made to a roof to mimic hail damage, creates blemishes that exhibit one or more of the following characteristics: symmetry, crushed or scratched granules, and gouge or tool marks in the asphalt mat.  The shape of a hailstone is not symmetrical and an impacting hailstone does not cause symmetrically shaped blemishes.

Shingle granules, which are made of crushed rock particles and have a colored ceramic coating, are too hard to be crushed by a hailstone. A ball peen hammer is commonly used to create intentional damage (Photograph 2).

Photograph 3: Viewing a circular-shaped blemish made with a ball peen hammer.

Photograph 3: Viewing a circular-shaped blemish made with a ball peen hammer.

A ball peen hammer creates symmetrically shaped blemishes, which are too small in diameter to be caused by hail (Photograph 3). The blemishes that are created with a ball peen hammer are uniform in size and appearance, which is uncharacteristic of hail damage.

Coins are commonly used to create intentional damage to shingles.  A close-up view of a blemish caused by a scraping a coin, such as a quarter, shows the marks of the striated edges of the quarter in the asphalt mat of the shingle (Photograph 4).

Photograph 4: The imprint of the coin edge is evident in the asphalt mat.

Photograph 4: The imprint of the coin edge is evident in the asphalt mat.

Scraping a shingle with a coin, or striking it with a tool such as a hammer, can displace, scrape, or crush the granules.  Scrape marks, light-colored surfaces on the granules, and granule dust on the blemish are indications that the shingle has been intentionally damaged by a scraping tool or a hammer-type tool (Photograph 5).

Intentional damage is also commonly made with other items, such as the end of a steel pipe, claw hammers, and screwdrivers.

Photograph 5: Scrapes on the granules and granule dust are evident on the blemish.

Photograph 5: Scrapes on the granules and granule dust are evident on the blemish.

Gouge marks in the asphalt mat are an indication of intentional damage.  The gouge marks displace granules and leave indented scrapes in the asphalt mat (Photograph 6).

By viewing high resolution digital images of roof blemishes and knowing the appearance of blemishes that are made with ball peen hammers, coins, or other implements, a conclusive determination can be made whether the damage is caused by hail or by intentionally-made damage to mimic hail damage.  The pattern and locations where blemishes are found on the roof can also be studied to confirm intentional damage[1].

It is compelling evidence that roof damage is intentional when the characteristics of the blemishes are suspicious and they are oriented in suspicious patterns.

Photograph 6: Viewing gouges made with a coin in the asphalt mat.

Photograph 6: Viewing gouges made with a coin in the asphalt mat.

 

 

 


[1] Donan, “Tips for Identifying Intentional Roof Damage, Part 1: Suspicious Damage Patterns Not Caused by Hail”, https://www.donan.com/knowledge-base/article/tips-for-identifying-intentional-roof-damage/