What are Asphalt Shingles?
Asphalt shingles are the most common type of roofing material in North America. They are budget-friendly, lightweight, durable, and come in a variety of styles. Asphalt shingles come in two varieties–fiberglass and organic mat-based. Fiberglass shingles are made of a woven fiberglass base mat, covered with a waterproof asphalt coating, and topped with ceramic granules that shield the shingles from harmful UV rays. Because of the composition of the fiberglass mat, less asphalt is needed to give the shingles their durability and strength. The result is a lighter weight and thinner roofing material. Fiberglass shingles also have a higher fire rating than organic varieties and generally carry a longer warranty.
Organic mat-based shingles are made from a recycled layer of felt paper (asphalt-saturated for waterproofing) and coated with adhesive asphalt into which the ceramic granules are embedded. With 40 percent more asphalt than their fiberglass counterparts, the traditional organic mat-based shingles are heavier, thicker, and more costly. While organic shingles are considered more rugged and more flexible, they are also more absorbent and can warp over time. Regardless of whether they are fiberglass or organic-based, asphalt shingles generally measure 12 by 36 inches and are commonly manufactured in two different types:
- Three-tab shingles are distinguished by cutouts—tabs—made along their long lower edge. The result is that each shingle looks like three separate pieces when installed, but it’s only one.
- Architectural asphalt shingles contain no cutouts, but their lower portions are laminated with an additional asphalt layer. This creates the contoured, dimensional look that gives them their name. Asphalt sealant bonds the layers, reinforcing the shingles’ waterproof capability. Though durable, architectural shingles are not recommended for low-sloping roofs, which are more vulnerable to wind-driven rain.
Style and Color of Asphalt Shingles
Installed properly, asphalt shingles are no longer easy to identify. Some are made to convincingly mimic the look of slate, cedar shakes, or even tile. Color choices are also more varied than ever. You’ll generally find tones ranging from pale gray, medium gray and dark gray to beige, reddish and medium brown to dark brown, plus shades of blue and blue green. You can also create a polychromatic look by mixing light and dark tones.
Are Asphalt Shingles Right for Your Climate?
Manufacturer warranties currently guarantee asphalt shingles a 15- to 30-year useful life. The large variance in those warranties are typically based on climate, weather, and other environmental factors. Homeowners in areas enduring long summers with high heat may need to replace roofing sooner than homeowners in cooler regions. In areas known for severe winters, ice may aggravate tiny cracks and fissures. Algae and fungus growth can also be potentially damaging for roofing in perennially damp or subtropical areas. Algae-resistant shingles are available. The ceramic granules on the shingles are coated with leachable copper to prevent discoloration and long-term damage from algae and moss growth. Keep in mind though, this protective treatment can add 10-15% to your materials budget.
Cost of Asphalt Shingles
Asphalt shingle pricing is influenced somewhat by geography but mostly by regional differences in labor cost. Generally speaking, the average cost of asphalt shingle roofing is $.80 to $1.20 per square foot for the materials. For a medium-pitch roof, the average cost will be somewhere between $100 and $200 per square for the shingles alone. Making asphalt shingles even more desirable is the fact that they can be applied directly over old shingles, providing the roof deck is in good condition. If there are already two or more shingle layers on your existing roof though, it is HIGHLY advisable to remove the old layers before applying new shingles.
Asphalt shingle manufacturers are also adopting energy-saving, cool-roof technology to help reduce the amount of heat absorbed by the roof. Look for shingles with Energy Star ratings and you can significantly reduce the cost of cooling your home.
Common Concerns with Asphalt Shingles
Though your asphalt shingle roof should last 15-30 years, it is not necessarily a great environmental choice. Traditional roofing products contribute an estimated 20 billion pounds of waste to U.S. landfills on an annual basis. Asphalt shingles do offer the possibility of being reused with uses in hot mix asphalt, cold asphalt patching, and as a fuel in cement kilns, but asphalt naturally contains polycyclic aromatic hydrocarbons, some of which are carcinogenic and may put recycling workers at risk. If your existing roof has less than two layers of shingles on it, you can reduce the amount of waste generated by your upgrade (not to mention the demolition cost) by layering your new roof on top of the existing structure.