WHAT ARE THEY?
Asphalt shingles come in two basic types: glass fiber (a.k.a. fiber glass) and organic.
Organic shingles consist of an organic felt material which is generally paper saturated
with asphalt to make it waterproof. A top coating of adhesive asphalt is then applied and
the ceramic granules are then embedded. Organic shingles contain around 40% more asphalt
per square (100 sq. ft.) than their glass fiber counterpart which makes them weigh more
and gives them excellent durability and blow-off resistance.
Glass fiber shingles have a glass fiber reinforcing mat manufactured to the shape of
the shingle. This mat is then coated with asphalt which contains mineral fillers. The
glass fiber mat is not waterproof by itself. It's purpose is for reinforcement. What makes
the glass fiber shingle waterproof is the asphalt. However, the asphalt itself will not
stick to the mat. For this reason, "fillers" are used. The fillers in the
asphalt cling to the glass fibers in the mat. The asphalt then encapsulates the glass
fibers, fills all of the little holes and voids in the mat rendering it waterproof. After
this cools a bit, an adhesive asphalt is used to cover the mat and the ceramic granules
are then embedded.
The ceraminc granules are there for two reasons. The primary reason is to protect the
shingles from the sun. The sun's UV rays are very damaging to asphalt and cause it to
deteriorate prematurely. This is one of the same reasons that gravel is used on built-up
roofs. The second and more obvious reason for the granules is aesthetics. Asphalt shingles
are available in a wide variety of colors to match almost any facade or landscape.
So which type is better? By far, the more popular shingles are the glass fiber ones.
This may be attributed to the fact that they are cheaper and easier to manufacturer than
organic shingles making them more cost effective to the homeowner, or it may be that they
are easier to work with, or they may simply be a personal preference of the roofing
HOW LONG DO THEY LAST?
The lifespan of asphalt shingles depends highly upon the environment. Shingles in cooler
climates such as the northern United States seem to last longer than those installed in
the warmer climates. Studies have shown that the average lifespan for a 20 year shingle in
Phoenix, Arizona is around 14 years. In Minneapolis, Minnesota the lifespan was 19.5
years. And in Reading, Pennsylvania, the lifespan was 20.8 years. From this data it seems
obvious that the hotter the environment is, the shorter the service life of the shingles.
One thing that's very damaging to shingles is Thermal Shock. Thermal Shock is what roofing
materials experience when the ambient temperature changes dramatically within a very short
period of time - usually 24 hours. For example, in Yreka, California, the temperatures
during a summer day can often reach 100 degrees and at night, they'll often drop below 50,
sometimes as low as 40. Roofing materials are unable to expand and contract to accommodate
such a dramatic temperature change in such a short period of time so cracks and splits in
the materials start occurring. Water can then enter the materials and damage them further
in two ways. One is the damage water does to asphalt materials in general. It's not that
water hurts asphalt, but algae and fungus do and the continuous presence of water will
permit algae and fungus to grow on asphalt materials. Another way water damages is the
freeze-thaw cycle. In the cold months, water will get into the cracks and then freeze at
night. Water expands as it freezes so the more this occurs, the bigger the cracks or
splits become. This is why most roofing contractors and consultants are such big advocates
of sloped roofs. The better the roof sheds water, the less problems it will usually
Still another factor affecting asphalt shingle roofs is attic ventilation. Proper roof
ventilation has been known to extend the service life of a roof. Whether it is because it
has a direct effect on the shingle themselves or on the other components such as the roof
deck is uncertain. For more information on attic ventilation, click
WHAT ABOUT SHINGLE WARRANTIES?
Shingle manufacturers provide product warranties against manufacturing defects ranging
from twenty (20) to forty (50) years and beyond. The warranties will cover defects such as thermal
splitting, some cases of granule loss, cupping, and curling. It is very important that you
ask for and receive a copy of the manufacturer's written material warranty before making a
decision on whose material you'd like to use. Warranties are generally for materials only.
Labor is rarely included so if your roof materials fail, you'll have to pay a roofer to
install the new shingles. Warranties rarely, if ever, cover what are known as
"incidental and consequential" damages resulting from material failure.
"Incidental and consequential" damageas are those that occur to the interior of
the building. If anything on the inside of the building gets damaged, you or your
insurance company will have to pay for it. Warranties are also commonly prorated and
non-transferable. This means that if you have twenty year shingles and they fail after ten
years, you'll be reimbursed for half the cost of the materials. Non-transferable means
that if you sell your house, the warranty will be voided.
Some shingle manufacturers are offering NDL (No Dollar Limit) warranties for added
costs of around 4.5 cents to 6.5 cents per square foot. These warranties may or may not
cover all damages and labor costs.
Shingle manufacturers will not warrant their products against "Acts of God or
Nature" such as hurricanes, hail storms, severe winds usually in excess of 50 mph,
tornadoes, earthquakes, etc. Nor will shingle manufacturers honor their material warranty
if the products are improperly installed, if there is improper roof ventilation, if there
is equipment installation or structural changes after roof completion, or if there is
heavy foot traffic on or over the roof.
For specific warranty information, ask your contractor to provide a sample warranty of
the materials he installs.
Types of asphalt shingles include, but are not limited to:
Click on the following links for more information on Asphalt Shingles.