86a-3-tab fiberglass-mat asphalt shingle, intentional coining 2  Warren

Tips for Identifying Intentional Roof Damage

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

Part 1: Suspicious Damage Patterns 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 locations and patterns of the damage.  The patterns can be observed by circling each damaged location and then connecting the locations together with chalk lines.

Photo 1: Actual hail damage varies in size and characteristics, and is located on the entire roof slope, including the roof edges.

Photo 1: Actual hail damage varies in size and characteristics, and is located on the entire roof slope, including the roof edges.

The location of hail impacts to a roof is random.  Hailstones commonly accompany weather events with high winds, which cause the hail stones to impact the roof in the direction of the wind.  The directionality of the wind-driven hail stones causes the hail impacts to predominantly impact roof slopes facing in one or two adjacent directions.  Hail impacts occur on the entire area of the affected roof slopes.  The damage is commonly obvious enough to be observed from a distance (Photograph 1).  Hail impacts do not cause damage to partial areas of a roof slope, unless the roof is obstructed, such as by an adjacent higher roof or building.  The location of hail impacts within individual shingle tabs is random.  Hail-caused blemishes and fractures to shingles are not uniform in size or shape, due to the variable size and density of the hailstones.

Photo 2: Intentional damage centered on a shingle tab.

Photo 2: Intentional damage centered on a shingle tab.

Blemishes found on a roof that do not have these characteristics, were probably intentionally made to mimic hail damage and were not caused by hail impacts.  Common objects, such as hammers, coins, and screwdrivers, are used to create intentional damage[1].

One characteristic of intentional damage is that the majority of the damage locations are centered, or approximately centered on individual shingle tabs (Photograph 2).

Photo 3: Intentional damage located in straight lines.

Photo 3: Intentional damage located in straight lines.

The damaging of numerous shingles in the same relative position on the tabs is the result of the human subconscious tendency of repeated motion and for things to be ordered and symmetrical.  This same tendency commonly results in damage being made in straight lines along rows of shingles (Photograph 3).

Another characteristic of intentional damage is a pattern that is oriented perpendicular to the roof ridge (Photograph 4).  These patterns are made when an individual creates them while walking upslope or downslope on the roof.

Photo 4: Intentional damage perpendicular to the ridge.

Photo 4: Intentional damage perpendicular to the ridge.

Damage patterns are made on the roof in the form of arcs when an individual stops in one location on a roof and rotates while creating the damage locations (Photograph 5).

Blemishes, which are not present on an entire roof slope, are indicative of intentional damage (Photograph 6).  On a moderately sloped roof, this is commonly a result of the

damage being created by someone who is unaware of the characteristics of hail damage, or was done in haste by the damage-causing individual who is seeking to escape detection.

Photo 5: Intentional damage in an arc pattern.

Photo 5: Intentional damage in an arc pattern.

On steep-sloped roofs, individuals commonly avoid creating damage at inconvenient or dangerous locations on the roof, such as at the edges of a roof.  For this reason, it is not uncommon for an individual to create damage that is no closer than 6 feet from the edge of a steep roof, such as is shown at the far edge of the roof in Photograph 3.  In contrast, actual hail damage is visible at the edges of the tall, steep-sloped roof in Photograph 1.

Photo 6: Intentional damage made on a small area of the roof (within the red border).

Photo 6: Intentional damage made on a small area of the roof (within the red border).

Marking patterns of damage on a roof with chalk lines is a useful method to document strong visible evidence of intentional damage.  Chalk-lined suspicious damage patterns are readily distinguishable as intentional damage, even by individuals who are not trained in identifying roof damage.  Intentional damage to roof shingles can almost always be identified by a trained professional.



[1] Donan, “Tips for Identifying Intentional Roof Damage, Part 2: Suspicious Damage Characteristics Not Caused by Hail”,  https://www.donan.com/knowledge-base/article/tips-for-identifying-intentional-roof-damage-part-2/