Case Study: Hand Torn Shingles

Posted by in Case Studies, Shingles | September 12, 2016

The dimensional shingles on the roof exhibited many torn and dislodged shingle strips (see featured photo).  The shingle strips were well sealed and when they were lifted, the underside of the mat adhered to the underlying shingle (Figure 1).  In fact, they were so well adhered, the strips had to be pried up with a tool, as evidenced by the tool marks on the backside (Figures 2 and 3).

Figure 1 Plug of asphalt and mat pulled from underside of overlying shingle.

Figure 1 Plug of asphalt and mat pulled from underside of overlying shingle.

Figure 2 Plug of asphalt and mat pulled from underside of overlying shingle.

Figure 2 Plug of asphalt and mat pulled from underside of overlying shingle.

Figure 3 Tool marks under tab that is partially torn.

Figure 3 Tool marks under tab that is partially torn.

Small pieces of the strips were also lifted and/or torn (Figure 4), sometimes in multiple directions (Figure 5).

Figure 4 Small piece broken at corner of shingle strip.

Figure 4 Small piece broken at corner of shingle strip.

Figure 5 Multiple tears in shingle strip.

Figure 5 Multiple tears in shingle strip.

This pattern of damage occurred on slopes facing north, south, east, and west.

This is not wind damage.  Winds well over 70 MPH would be required to unseal these well sealed shingle strips: no other damage was reported or observed in the immediate area. Wind does not lift up and bend back small pieces of a strip, but lifts a strip relatively uniformly: a broken corner or a tear resulting in a small piece of shingle is due to a concentrated force such as hand lifting.  Wind does not causes deep and heavy scratches on the underside of the shingle strip: these are from the scrapes of a hard object, such as, a tool. The damage on slopes facing all four directions is not characteristic of high winds, possibly a tornado, but not high winds or a gust.

These damage were due to hand lifting.

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