Guide to
Asphalt Shingles
Are You in need for a New Roof?
Just like people, asphalt shingles gradually change with the passage of time. Signs of this aging process may appear as early as the first couple of years, during what is often called the Curing Phase. At first, you may notice small surface cracks, or a few small blisters. These changes will not affect the ability of the asphalt shingles to protect your roof, and are an anticipated part of the aging process. During the Stable Phase, these signs of aging will slow down dramatically. The duration of the stable phase may last 20-30 years, but is dependent on many factors including the construction of the asphalt shingles, the condition of your roof and roofing ventilation, roof slope, location, materials, design, underlayment, as well as the workmanship of your roofing contractor. Near the end of the expected life of asphalt shingles, the aging process begins to speed up. This is what is called the Final Phase, during which most homeowners start to think about replacing their asphalt shingles.
CURLING:
One of the things you may notice is a slight curling of the shingles along
the bottom edge, particularly during cold weather. This is a normal occurrence
of asphalt shingles and results from the natural loss of the oils from
the asphalt covering the felt. As the asphalt loses its oil, it slowly
becomes more rigid, and may shrink at a quicker rate than the felt.
SURFACE CRACKING:
Just like skin that has been exposed to the scorching heat of the sun,
the surface of asphalt shingles reacts in a similar fashion. Like your
skin, asphalt shingles may develop small surface cracks. This is a result
of asphalt shingles becoming more brittle over time. Thermal shock and
deck movement may also increase the occurrence of surface cracking.
BLISTERS:
As asphalt shingles age, large bubble-like blisters may appear on the surface,
some as large as a quarter.
They may be open, exposing the asphalt, or closed. Blisters are more likely
to appear when there is
inadequate ventilation, or in areas where tree sap drips onto the shingles.
Small “rash” blisters do not
affect the performance of the shingles.