Tips for Identifying Intentional (Advertent) Damage to Asphalt Shingles – The Pattern of Compatibility – Part 5

Posted by in Roof, Shingles | May 13, 2013

We have been discussing three fundamental patterns that may be used to distinguish intentional manual damage  from naturally occurring hail or wind damage.  These fundamental patterns are:

Natural Order vs. Unnatural (Artificial) Order

  1. Sufficiency vs. Insufficiency
  2. Compatibility vs. Incompatibility 

In our last two posts we discussed the first two fundamental patterns that may be used to identify intentional manual damage: there is usually an artificial Order and Insufficiency to the damage that is not consistent with the more complex order produced by a natural weather event. In this post we will discuss the third and final fundamental pattern of intentional damage, Incompatibility.   

Incompatibility describes the details in the features of the damages and/or surface marks with the features of legitimate hail damage. That is, man-made indentations and surface marks exhibit features that could not have been produced by hail impacts, but which are consistent with features produced by man-made impacts from a tool or other hard object.   

Genuine hail damages are produced by the impact of frozen water of the consistency somewhere between a slush ball and an ice cube. This means that the hail stone usually deforms and/or fractures upon impact, unlike a tool or hard object.  Thus, damage from impacts by tools or other hard object are not compatible with impacts from hail stones.  Damages or marks caused by tools or other hard objects impart a surface damage that is distinctly different from a slush or ice ball.   

Genuine wind damages are caused by a relatively uniform, but somewhat varying, distributed uplift pressure.  This means that the entire exposed surface of a shingle is being lifted in varying degrees.  When a shingle strip or group of strips are uplifted manually, a concentrated force is applied at an edge, end, or corner.  The concentrated force often results in localized damages that cannot be produced by exposure to high wind pressures.  Thus, intentionally mimicked wind damage differs from genuine wind damage.

We would provide examples here, but we would rather not assist in the education of those who may be reading this information for nefarious purposes.  If you are a client of ours and are interested in examples, please email us at engineering@prugarinc.com and request the remainder of the blog article for Compatibility vs. Incompatibility.

This blog article closes the discussion of identifying intentional manual damage to asphalt shingles.

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