The development of fiberglass-based asphalt shingles, another 1970s innovation, has resulted in asphalt shingle products with an even higher fire rating. And, through the years up to the present time, asphalt shingles are the most widely used roof covering for new home construction and remodeling — used on four out of five U.S. homes.

Roofing Grades

The basic grades of roofing asphalt are:

1. Saturant-grade asphalt, a nonoxidized or oxidized asphalt used to manufacture saturated felt piles used in the construction of BUR systems, organic felt shingles, and other roofing materials, such as roll roofing;
2. Coating-grade asphalt, an oxidized asphalt used to manufacture roofing materials for a variety of roofing systems, such as asphalt shingles, polymer-modified bitumen roofing, reinforcing and underlayment felts, and roll roofing product; and
3. Mopping-grade asphalt, an oxidized asphalt that is melted and used in the construction of BUR and modified bitumen systems.

Asphalt Shingles

Popular in the early years of the 20th century, fulfilling a need for an economical fire-resistant roof covering. Over the years, asphalt shingles have increasingly become recognized as an economical, fire-safe and aesthetic product with a combination of beauty, durability, longevity and value.

The “standard” asphalt shingle is the square butt strip shingle, elongated in shape and available with one or three tabs. This product is made of a base mat or organic material (cellulose fibers) or inorganic material (glass fibers). The organic mat is saturated and coated with asphalt and then surfaced with ceramic-coated opaque mineral granules.

The saturating process is not necessary for fiberglass-based asphalt shingles, which require only a coating asphalt. The coating asphalt provides weatherproofing qualities. The mineral granules protect the shingles from the sun’s ultraviolet rays and give the shingles color and added protection against fire.

The characteristics have earned asphalt roofing its leading position include the following:

• Weather Resistance.Asphalt roofing products are proven to resist sunlight, heat, cold, water and ice.
• Fire Resistance. Asphalt roofing products are manufactured to comply with ASTM International and/or Underwriters Laboratories (UL) standards for fire resistance.
• Wind Resistance.Asphalt roofing products comply with the wind-resistant standards of Underwriters Laboratories.
• Efficient, high-volume production plus relatively low cost of application result in economies that are difficult for competing roofing materials to match. Moderate installed costs combined with long service life gives asphalt roofing products a very low annual or life-cycle cost.
• Ease of Application.Asphalt roofing is considered to be the easiest of all standard roofing materials to apply.
• Because of their flexibility and strength, asphalt roofing products can be applied on a wide variety of roof styles.
• Asphalt roofing is available in many appealing colors, shapes and dimensional depths that provide bold roof appearances. The wide range of asphalt roofing products introduced in recent years offer much greater flexibility in choosing the appearance of a building’s exterior than is available with most other types of roofing material.
• Style Suitability.Asphalt roofing is completely “at home” with most architectural styles, whether contemporary, modern or traditional.
• Low Maintenance. Properly chosen and applied, asphalt roofing products require little or no upkeep and are easily repaired, if damaged.