TRICKS OF THE TRADE SEAL STRIPS ASSESSMENTS .pdf

TRICKS OF THE TRADE
(Published by the Building Envelope Science Institute in their April 2017 issue of their periodical)

Starting shortly after Hurricane Camille (August 1969), I became amazed by how little formal education and or formal training
adjusters had in actual training in knowing how to “spot” signs of subtle or latent property damage. Believing that I must be
missing a part of a bigger picture, I applied for and was approved to attend Lenard’s School of Adjusting, where I learned how to
measure the size of a roof and what the various parts of a policy were, essentially explaining that a policy was many
“endorsements” (changes) to a base endorsement, along with some Declaration Pages. Essentially, I learned that most
adjusters were not denying claims to save their employer money, it was more of a case where they were either operating a) off
misinformation passed down to them by a more experienced, yet also all but clueless person, on forensic matters or they were
essentially winging it.
The following are some of the tricks of the trade I have learned from professionals with vast knowledge in various roof systems
that their company manufacturers or installs, or have significant education and or formal training, and or experience with certain
roof systems. I was fortunate early on to grow up as the son and grandson of contractors. I always admired the men called “field
engineers” where were the guys that essentially “saving the day’ by figuring out how to make something that worked on paper,
work in the field. Accordingly, I obtained an “Applied Engineering” degree from Mississippi State University, designed to perform
as a “field engineer” and parlayed that into working for 2 major engineering and construction firms, which offered what I
considered to be the best ‘OJT’ (on the job training) I have ever been exposed to. It is the application of my education, training
and experience in construction and property damage forensics that has guided me to amass a collection of hundreds of
thousands of pages on what evidence to look for and what it means. Starting with Asphalt Shingles, I offer the following:
The most common damage to composition shingles is called ‘wind damage’ or more specifically, ‘wind lift damage’. If you are
going to access a roof for ‘wind lift damage’, you will not likely be able to fully determine the scope if you do not remember that
the initial damage will always be ‘seal strip violations’. The ‘classic’ rating for most 3-tab shingle seal strips in 60 mph on most,
with some being given a 70-mph rating, UNDER IDEAL CONDITIONS. I have found many 3-tab shingles have failed in what
was ‘supposedly’ only 40 mph for the ‘published’ wind speed. Regardless as to what the actual wind speed was ON THE
SURFACE OF THAT ROOF, if there is reason to believe that there were ‘damaging winds’ during the event (large branches
broken, trees blown over, or a few shingle tabs in the neighborhood), these are ‘indicators’ of a roof that deserves a closer look.

Phase 2 - Partially
pulled out nails
Phase 1 – deformed
upward corners
Phase 2 –
fracture line

Phase 3 –
broken back

Initially, evidence of wind lift damage can be
spotted where the corners of the shingles are
not laying flush on the lapped over shingle face.
I refer to this as ‘Phase 1’ in the adjacent upper
photo. You will likely need binoculars to detect
this from the ground. The “fracture line”
identified as ‘Phase 2’ in the lower photo show
the next step in destruction of the roof. This
fracture line is evidence that this tab has
fluttered enough to fracture at the ‘natural fold
line’. The next step I identify as ‘Phase 3 – is
“broken backs”. When the fluttering is intense or
long in duration and or occurring over several
events, the fracture line will advance to a point
where there is little to no resistance to folding
back the row above and the only thing keeping it
from blowing off the roof is the reinforcing fibers
in the center of the tabs. The next phase is
what I refer to as ‘Phase 4’, whereby the tabs
are blown away entirely.
A little-known step in evaluating the seal strips is
when is the best time to perform such an
assessment. Many manufacturers agree that to
get the most accurate results is to check them
when conditions are about equal to when the
shingles are exposed to a severe wind storm.

Phase 4 –
missing tab

Seal strips are “heat activated” and will try to resist uplift when they are hot even if they been violated before. Conversely, if the
seals are broken after a few years, they will not likely be able to resist significant uplift when they are cold or cool. The
chemistry of the seal strips breaks down over time, impairing their ability to resist a ‘normal’ amount of uplift when they are cold.
If it is too hot to catch them when they are below 70o, catch them before the morning sun gets to them and use a hose or bucket
of water to cool them first and then approach the assessment using the classic ‘1-finger test’, starting at the corners. The
performance difference is huge.
If you can lift the entire tab by sliding your finger across under the tab (regardless as to any ‘token’ resistance (denoted by the
‘crackling’ sound being created as you go) those seal strips can no longer perform to any acceptable level during the more
severe wind & rain storms that will occur every year. There are other considerations involved if one is to make a case for this
being storm damages but, one needs to initially determine whether there is a considerable number of seal strips that are
impaired before considering what the causation was.
______________________________________________________________________________________
Lewis O’Leary has served as both a forensic consultant and restoration
contractor since Hurricane Camille (1969). He has a degree in the
fields of Mechanical Engineering and Architecture, is a member of the
Roofing Consultants Institute and is a design/build, commercial and
residential General Contractor licensed in North Carolina and writes the
initial draft for engineering firms involved with wind damages from
hurricanes and tornadoes. He can be contacted at 919-577-0907 or
via e-mail at probuil@aol.com