Tips for Identifying Intentional (Advertent) Damage to Asphalt Shingles – General Principles – Part 2

Posted by in Roof, Shingles | April 22, 2013

In our last post we discussed the increased frequency in the number of intentionally (advertently) damaged shingle roofs that we have evaluated over the years.  In this post we discuss the method of evaluating shingle roof damage with regard to intentional (advertent) manual damage.  Since this method is based on the application of principles rather than the identification of specific characteristics of intentional damage, this method may also be applied to the evaluation any other type of damage suspected of being intentional.   In this post we will introduce the fundamental principles for identifying intentionally (advertently) damaged shingle roofs.  In following posts we plan to the describe principles in more detail.

An evaluation of damage to asphalt shingles begins with a comparison of the subject damage with the characteristics of what is known to be legitimate hail or wind damage.  If the damage is not consistent with these, we then compare the damage to the known characteristics of other common damage producing mechanisms, such as manufacturing defects, inadvertent damage from human activity, normal wear and tear, etc.  The known characteristics of both of these have been described in other posts, so we will not discuss them here.

But what if the damage is not consistent with either the known characteristics of legitimate hail or wind damage or the known characteristics of other common damage producing mechanisms?  As Sherlock Holmes explained to Dr. Watson during a walk along a country road, “We look for consistency. Where there is want of it, we expect deception.”

Webster defines intentional as “done by intention or design.” Thus, intentional damage is done by design, that is, fashioned, created, or applied according to a plan. Intentional manual damage that appears to mimic hail damage is comprised of man-made indentations and/or surface marks. The indentations or surface marks are mechanically made with a tool or other hard object.  Intentional manual damage that appears to mimic wind  damage is comprised of man-made lifting, creasing, fracturing, tearing, or dislodging.

Those things fashioned, created, or applied according to a man-made strategy (design) commonly exhibit an artificial pattern that is distinguishable from the natural pattern produced by natural damage producing events. The dispersed and relatively random order of indentations or surface marks or the lifting, creasing, fracturing, tearing, or dislodging produced in asphalt shingles by natural causes are difficult to imitate. It is rare that the “designer” of intentional manual damage is able to apply indentations and/or surface marks in the natural pattern of hail damage or produce lifting, creasing, fracturing, tearing, or dislodging in the natural pattern of wind damage. Rather, hand produced damage commonly exhibits an pattern that evidences common human movements or activities.

In our review of industry publications and articles and our evaluation of physical evidence we have come to recognize three fundamental patterns that may be used to distinguish intentional manual damage from naturally occurring hail or wind damage.  These fundamental patterns are:

  1. Natural Order vs. Unnatural (Artificial) Order
  2. Sufficiency vs. Insufficiency
  3. Compatibility vs. Incompatibility

The consideration of these patterns in the evaluation of damage to shingle roofs usually distinguishes intentional manual damage from naturally occurring damage.  I say “usually” because there may occasionally be times when the evidence is such that the result is not conclusive enough to be able to render a professional opinion within a reasonable degree of engineering certainty.

In our next blog we plan to describe Natural Order vs. Unnatural  (Artificial) Order.

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