Asphalt Shingles

Asphalt Shingles

As the choice of 4 out of 5 homeowners, asphalt shingles top the list of popular roofing materials in the United States. Besides being affordable, they are favored for a relatively long life that can range from 20 to 30 years depending on type of shingle, slope of roof, location and local weather conditions. Typically, asphalt shingles come in a single piece that has the appearance of three separate tiles. Architectural shingles typically cost more, but have a more interesting appearance, and are generally guaranteed for longer life.

How are Asphalt Shingles made?

Asphalt shingles have been around since the 1800s and came about as a by product of the tar industry. They used to be made of asphalt embedded in cotton or wool felt, and today they are made with fiberglass or organic felt material such as recycled paper. The former is made with fiberglass reinforcement which is then given a coat of asphalt to make it waterproof. The latter are known as composition shingles and have embedded ceramic granules in their asphalt coating that offer protection against the elements.

Types of Asphalt Shingles

Asphalt shingles can be categorized in terms of design types and constitutive elements. They can also be categorized depending on their weight, mat thickness, and type of filler material.

In terms of design, asphalt shingles come in four types including the single piece shingle, strip shingles, laminated shingles, and interlocking shingles. The single and strip types differ based on size. Laminated asphalt shingles, which are made to resemble the three dimensional visual effect of conventional wood and slate shingles, are a comparatively new entrant into the market. Interlocking asphalt shingles are ideal for storm prone regions that experience gale force winds.

Asphalt shingles may be made of fiberglass or organic elements. The fiberglass variety is preferred for its fire resistant property and for its comparative light weight but not for overall performance. They are preferred in regions with moderate to warm climates. Organic composition asphalt shingles, on the other hand, are popular for their durability and value for the money. One rule of thumb when it comes to composite asphalt shingles is that the heavier the shingle, the more durable it is. They are considered more flexible and favored in colder regions.

Warranties on Asphalt Shingles

Warranty periods for asphalt shingles vary according to their type and quality and can fall anywhere between 20 to 40 years and more. Longer warranty periods are normally associated with the high end laminated architectural variety of asphalt shingles that blend durability with decorative features. Warranties normally cover issues such as cupping, curling, thermal splitting, and other problems related specifically to the shingles themselves and not brought on by other defective roof materials. In hurricane prone areas, manufacturer’s warranties may be limited to wind speeds below 50-80 miles per hour. Warranties are generally pro-rated and non-transferable.

Shingle warranties do not typically cover the labor costs associated with replacing the shingles, they are typically pro-rated, and they generally exclude so-called "acts of god", such as severe storms.

Asphalt Shingle Ratings

Asphalt shingle ratings have been formulated by the American Society for Testing and Materials (ASTM). ASTM has set standards for both fiberglass and organic varieties of shingles. Fiberglass shingles with an ASTM D 3462 certification and organic shingles with ASTM D 225 certification comply with ASTM standards. To be certified to these standards, the shingle products must have successfully withstood procedures such as nail-withdrawing and tear strength tests.

Asphalt shingle ratings cover criteria such as fire and wind impact resistance. Fiberglass shingles are normally Class A rated (the highest fire resistance), and organic shingles are usually Class C (the lowest fire resistance). Impact resistance relates to wind damage and those shingles with a Class 4 rating have extra adhesive strips under the tabs which make them the most wind resistant. They also take six nails as opposed to the usual four to fasten them in order to increase their wind resistance.

The Underwriters Laboratory (UL) test specifically tests against wind and hail impact. Only on withstanding 60 miles per hour winds for two hours will shingles win the UL certification. As for hail ratings. the shingles have to remain unscathed under a barrage of steel balls simulating hail stones. Consumers can to check for the ASTM and UL labels on shingle packaging and in product brochures.

Lastly, in addition to fire and weather inflicted damage, shingles also undergo age-related deterioration such as loss of the protective ceramic granule coating and growth of algae. Newer varieties of asphalt shingles come with zinc or copper coating which considerably reduces the problem of algae and staining and helps maintain a shingle’s good looks.

Common problems with Asphalt Shingles

Asphalt shingles fare better in cooler climates than in hotter ones. Ultraviolet rays damage the ceramic granules embedded in the asphalt coating and eventually cause cracks and loss of color. There is also the problem of thermal shock which can happen when asphalt shingles experience dramatic changes in temperature within a short period of time (in the course of a day, for example). Quick expansion in heat of day and contraction in the night time temperatures cause cracks which then get worse when water seeps into them. Moisture can be damaging in the form of leaks as well as in growth of algae. Sudden freeze-thaw cycles also inflict damage on asphalt shingles.

Asphalt shingle problems can be compounded if the roof is low pitched and does not have adequate sloping to encourage water drainage. Insistent leaks may form which in turn can cause damage to other roofing materials (such as wood) and the ceiling.

Improper ventilation can cause a problem with asphalt shingles known as cupping, which occurs when shingle tabs curl under.

Environmental Impact of Asphalt Shingles

"Green" Asphalt Shingle Resources

Over the years two strip type asphalt shingles have dominated the market: the 3-Tab asphalt shingle and the Laminated asphalt shingle, sometimes called an Architectural asphalt shingle. There are several manufacturers of asphalt shingles, however there is not much difference in the makeup and to some extent the design from one manufacturer to another.

Asphalt shingles are generally made of a spun fiberglass mat but can be made of an organic or polyester type mat. Most are saturated with asphalt but can be saturated with modified bitumen. All are coated with ceramic granules. There are several manufacturers of asphalt shingles.

The 3-Tab asphalt shingle is generally 36" long by 12" wide with two cutouts in the lower portion of the shingle making it appear, once installed, as individual shingles. This type of strip shingle is the least expensive roofing material .

The Laminated asphalt shingle is made of two pieces laminated together. One piece is about 36 long by about 6. Another piece is laminated over it commonly called the dragon’s tooth piece because it resembles squared off teeth. This type is more expensive and can be very expensive if marketed by the manufacturer as a 50 year or lifetime roof.

There are a few other styles of strip shingles now available which present a different appearance, sometimes called Architectural asphalt shingles. Some are a one-piece dragons tooth, others have a few layers of differently cut asphalt shingles all laminated together. These are the most expensive types of asphalt shingles.

The manufacturers market their shingles as 20, 25, 30, 35, 40, and even 50 year or Lifetime asphalt shingles as a way of differentiating several 3-Tab or Laminated and Architectural shingles they sell. They make it sound as if they will last that long. There may be differences in the amount of asphalt they use or they may have a thicker mat and look or they might be granulated on both sides and have more self-sealing asphalt for better wind resistance. But in the end, an asphalt shingle still is an asphalt shingle. No matter what little changes they make, they all look similar in that they all are covered with granules and their performance is similar .

When specifying Asphalt Shingles, make sure to state the Manufacturer, the number of years warranted, name of the shingle, color, and type. Example: Acme, 30 year, Wind Star, Sand Dune, 3-Tab Asphalt Shingle. (Made up shingle)

The life expectancy of any asphalt shingle varies in different climates. Around here in Colorado the life expectancy is at the most 20 years for 3-Tab shingles and maybe 25 years for Laminated shingles no matter what their marketing/warranty says. This is because the sun’s intense ultraviolet rays bleach out the asphalt very rapidly compared to other parts of the country. So basically, a 30 year asphalt shingle will last about the same amount of time as a 50 year or Lifetime asphalt shingle roof. After all, they all are made of the same materials.

Asphalt Shingles

  • are the least expensive roofing material to have installed.
  • are the easiest Steep-Roofing materials to install.
  • require the least amount of craftsmanship. A beginning roofer can be taught to install asphalt shingles properly within a few months.
  • are easy to cut using a roofing knife at valleys and around roof protrusions.
  • are a 2 ply roofing system. This means that when drilling a hole anywhere through the exposed surface area of the shingle, there is another shingle layer below that the drill would have to go through before reaching the underlayment.
  • have less chance of leaking than many Steep-Roofing materials because of being a 2 ply roof system.
  • can easily be walked on without damaging the roof when the surface is not hot from the sun.
  • are easier to make repairs on.
  • could last about 20 to 25 years here in the Metro Denver Area barring any damage from hail. (Note: This includes the so called 30 year, 40 year, and 50 year asphalt roofing shingles. They may be thicker, may have more laminates, but they are still made of the same materials. I have yet to see an asphalt shingle roof older than 25 years that still even looks acceptable. Our severe weather and UV rays from the sun will take its toll on any asphalt shingle.)
  • are usually installed as a Class A Fire Rated roof system.
  • are more susceptible to damage from wind and hail than most other types of Steep-Roofing materials.
  • are easier to install on small areas and on difficult cut up architectural areas.
  • will resist snow sliding off better because of the surface adhesion they provide.
  • are medium in weight, from about 2 pounds per square foot to just over 3 pounds per square foot.
  • come in a wide variety of colors and fade little over their life span.
  • are very difficult to match colors when from different runs. A replaced area or shingle will never quite look the same as the rest of the roof if from a different run.
  • colors and shades come and go all the time. The manufacturers change colors fairly frequently except for a few standards they might have.
  • should not be installed in cold or hot weather. They are fracture prone when cold and easily scarred when in the hot sunshine. Care must be taken when ambient temperatures are less than 40 degrees and shingles should never be installed when colder than 32 degrees. Care must be taken when the ambient temperature is above 90 degrees, or less if in direct sunlight, on 4:12 and 5:12 pitch roof slopes. Steeper slopes require even more care.
  • can cautiously be walked on when wet.

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