Greener Roofing Options

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Although polymer-composite roofing offers some environmental benefits up front, no infrastructure exists currently to support the reclamation and recycling of these materials at the end of their useful lives. Robert Falk, Ph.D., one of the original designers of the product, says he eventually would like to see a buyback system put in place to promote the return of used composite building materials to companies for re-manufacture.

Fiber-cement shingles, made by blending Portland cement with finely ground sawdust (from recycled sources), sand and clay, are another composite product. Known for their durability in warmer climates, they typically carry a 50-year warranty. Unfortunately, fiber-cement shingles absorb water, which may weaken the shingle due to freeze-thaw cycling in cold weather. Some products, however, have coatings or polymer constituents to minimize water absorption.

Metal Roofs

Metal roofing can be made with up to 25-percent recycled steel from scrapped automobiles. This form of roofing is the lightest medium available, weighing a fraction of slate or clay tiles. Additionally, metal will not rot or crack, is noncombustible and designed to resist hurricane-force winds. Metal roofing also reflects more radiant sunlight than it absorbs, which saves you money on heating and cooling, and it comes in a wide spectrum of materials: steel, stainless steel, aluminum, copper and zinc alloys. Each has different properties that affect durability, price and appearance. Prices range from about $1.80 to $6 a square foot, which may seem expensive, but its long life, minimal maintenance and reduced installation labor makes it proportionately affordable over the long run. It’s lightweight and durable, with a life expectancy of 20 to 50 years, and you can sheet right over an existing roof with it.

Metal roofing does have a few drawbacks. Some types of metal roofing such as aluminum make more noise during rain or a hailstorm and can dent. Long-term issues include paint finishes that can peel, chip, fade or scratch.

Photovoltaic Roofs

The last word in eco-friendlier roofs may be the introduction of photovoltaic (PV) roofing shingles and thin-film laminates that both serve as a protective roof cover and energy powerhouse. When the sun strikes the solar cells embedded in the their matrix, electricity is produced. These types of shingles may even produce power on partly cloudy days. According to the National Renewable Energy Laboratory, solar shingles provide the same durability, flexibility and protection as asphalt shingles. Most are warranted to produce power for at least 20 years.

United Solar Ovonic’s Uni-Solar shingles incorporate directly onto the roofing surface and usually integrate well with conventional asphalt shingles. The company estimates that replacing a 450-square-foot section of conventional shingles with solar shingles can meet a third of a typical household’s annual electricity needs. Atlantis Energy System’s SunSlate PV tiles can be incorporated with tile, shake, metal or asphalt-composite roofs.

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