Observations Regarding Wind Damage to Shingles

Posted by in Shingles, Wind Damage | November 02, 2015

Just because a tree or portion of a large tree has been felled by wind doesn’t necessarily mean that the shingles have been damaged by wind (See the photos below of the undamaged shingles on the roof near a fallen tree).  It has been our observation that shingles that are reasonably well sealed or even partially sealed are usually capable of withstanding approaching wind speeds of 60 to 70 MPH without damage.  This observation is based on non-destructive testing on hundreds of shingle tabs and shingle strips and applying wind uplift principles presented by J. A. Peterka et al. in Wind Uplift Model for Asphalt Shingles.

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We have found in our observations that shingles that exhibit wind damage were usually unsealed by other mechanisms prior to the wind storm, were nailed poorly thus making the shingle strips susceptible to nail pull through, were inadequately nailed and thus they were not adequately fastened to the wood deck, developed a crease from repeated lifting over the years by high but not excessive winds, and/or were weakened previously by aging or unfinished repair work.

This does not mean that reasonably well sealed shingles in reasonably good condition cannot be damaged by wind, but that the winds need to be of significant speed (at least over 60 MPH, probably over 70 MPH) or need to have been directed toward the subject roof through a channel formed by a line of other dwellings and/or trees that funnel the wind toward the subject roof.  We have observed that the roofs over dwelling that are located at the end of a street are usually the first and often the only roofs to exhibit shingle damage after a wind storm.  But we note that we have also observed shingles damaged by excessive winds.

There are many factors that assist in determining whether or not shingle tabs and/or strips were damaged by excessive winds or some other mechanism.  This space is too small to get into the deatils for an evaluation of wind damage to shingles.  We recommend searching for and reading other shingle and/or wind damage articles on this website for more information regarding this.

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