Consider the conditions your roof must endure. First, there is the
intense heat of the sun, which scorches the surface of the roof and
raises rooftop temperatures 50 to 75°F above ambient temperature.
The sun’s rays are relentless, especially during the early afternoon
hours. In addition to heat, the sun is the source of ultraviolet
radiation, which has been shown to degrade and accelerate the
aging of the asphalt layers of the shingle. If not for the protective
layer of colored granules, roofing shingles would fail very quickly.
Other factors such as moisture, pollution and physical effects (roof
traffic, hail, snow loads, tree limbs, etc.) all contribute to the aging
and degradation of your roofing shingles.
Seasonal and weather changes also play a role in the aging of
asphalt roofing shingles. For example, consider the common
situation in which the roof is bathed in the intense heat of the
On such a day the rooftop may reach temperature s in excess of
160°F. Now imagine a cold front sweeping through the area,
bringing with it the violent thunderstorms that are a common
occurrence during the sweltering days of summer. Almost
instantaneously, the rooftop temperature drops 60-100°F as
it’s pounded with a summer shower. Thermal shocks such as this
cause the roof deck beneath to expand and contract, placing a strain
on the shingles.
Year after year this process is repeated, resulting in cyclic fatigue of
In addition to all of the climatic and external variables that can
impact the performance of your roof, consider the internal factors
that negatively influence the performance of roofing shingles.
Research has confirmed that an improperly ventilated air space
inhibits air movement, and under most circumstances this
increases moisture content in comparison with properly vented
attic air spaces. Heat shortens the shingles’ life and moisture causes
deck movement and/or deterioration, which ultimately affects the
performance of shingles.
As you can see, the roofing environment is a hostile one with
many factors influencing the longevity of your roofing shingles.
The natural aging process begins as soon as the shingles are
installed on your roof. Day after day, the shingles are exposed
to the elements—sun, rain, heat and cold. Your roof never has
a “good” day.