Disaster Safety Review 2013 Vol. 2 | Page 9

Most of the effects are detrimental to
ensuring robust sealing of the shingle
tabs.
• It was invariably difficult to get the
shingle tabs to develop a robust seal
when the conditioning was limited to
the temperature range and exposure
time specified for preparing samples
to be evaluated using the ASTM D
3161 test.
• More work is needed to ensure that
this test protocol produces products
that are robust enough to perform
their intended function after being
subjected to variations that occur
as the products progress along the
supply chain as well as potential
installation imperfections and
irregularities that may arise even if
the product is installed following the
manufacturer’s installation guidance.
This should include assessment of
likely improvements in initial weak
seals that are likely to occur as the
shingles are naturally heated to
higher temperatures during summer
months.
• Large granules embedded in the
adhesive strips of some products, fine
particles used to keep the shingle
ribbon from sticking to rollers in
other products and installation
issues kept a number of products/
samples from developing robust
sealing of the entire shingle on a
particular test specimen even when
the conditioning temperature was
increased beyond those specified in
ASTM D 3161.

throughout most of the U.S.) and
poor sealing was eliminated for the
few shingle tabs that still did not seal
well (by surface nailing down the tab
along the sealant strip), many of the
shingle products were capable of
resisting winds in excess of 110 mph
for two hours. Several specimens
withstood wind speeds, generated
using the ASTM D 3161 test method,
between 140 and 160 mph for a full
two hours.
• Once a robust seal was created,
shingle tabs that partially or
completely lifted frequently exhibited
failures within the shingle itself rather
than having the sealant material fail.
Some shingles exhibited cracking
along the sealant strip where the tip
of the shingle tab folded back. These
performance observations indicate
clear physical limits for these shingles
regardless of sealant type, strength
or condition. These kinds of limits are
not currently recognized in the ASTM
performance protocols; but, they
would likely be classified as failures in
post-event assessments.
• Protocols for verification of shingle
sealing and for retrofitting to seal
any shingles that remain partially or

completely unsealed after installation
on homes and businesses are needed
to ensure improved performance
of most existing asphalt shingle
products in real-world applications.
• Polymer modified asphalt
composition shingles may be
able to survive sealing failure
without damage to the shingle that
necessitates replacement. This may
be an acceptable alternative to
ensuring complete robust seals on
all shingles provided the assembly is
able to keep water out and products
are not damaged as a result of the
shingles lifting.

CONCLUSION
Ensuring that the tabs on shingles develop robust seals to the tops of shingles below and are kept well-sealed throughout
the time they are on the roof is critical to
enhancing the wind performance of most
asphalt composition shingles on the market today. Durable shingles that can survive loss of seal to the shingle below without needing to be replaced, and are part
of an assembly that ensures water does
not enter the building, may provide an attractive alternative to requiring complete
sealing of all shingles.

PHYSICAL LIMITS AND REAL-WORLD
PERFORMANCE ASSURANCE
• When robust seals were produced
by conditioning shingles at higher
temperatures than specified in
the ASTM standards (shingle
temperatures that are routinely
exceeded during summer months

© Insurance Institute for Business & Home Safety

Bubbling of the shingle surface at a high wind speed (130 mph) when wind pressure built up
under the shingles. Note the fish mouth lifting of the middle of the shingle at the lower RHS of
the specimen where the tab had not sealed well for a distance in the middle.

Disaster Safety Review | 2013

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