Four industry experts — Robert Anderson, metal product manager, Firestone Building Products; Jim Bush, vice president of sales and marketing, ATAS International; John Pierson, engineering services manager, The Garland Co.; and Gary Zigler, metal manufacturing product manager, American Construction Metals — discuss the state of standing-seam metal roofing:

Why do some say metal is the next cool or green roofing system?

Metal roofing systems similar to this one on the Blaine County Administration Building in Hailey, Idaho, are gaining popularity among architects and specifiers because of their flexibility in design æsthetics and environmental benefits, according to Robert Anderson of Firestone Building Products. (Photograph courtesy of Firestone Building Products)

Anderson: The concept of metal as a cool roofing system is relatively new. Because of pigment changes within the last five years, colored metal panels are now more reflective. More reflective panels help reduce heat gain in buildings, truly making metal a cool roofing product. As for green roofing systems, metal is one of the original green roofing systems. Metal is 100 percent recyclable, and many metal roofing panels come from already recycled materials. The range of recycled content can vary: steel generally consists of about 31 percent, aluminum can range from 30 percent to 70 percent, while architectural grade sheet copper has more than 90 percent recycled materials.

Anderson

Bush: Metal offers inherent benefits that other competing products cannot offer, such as high reflectivity and emissivity values, high recycled content, recyclability at the end of its useful life, and, according to new information, ventilation between the roof material and the substrate. This new "above sheathing ventilation" issue addresses cooling of the roof surface in hot climates, as well as offering benefits during the heating season in colder climates.

Bush

Pierson: Metal roofing systems have a life expectancy of more than 20 years. They contain recycled material and can be completely recycled at the end of their serviceable life. Additionally, they reduce the energy demands of buildings and use no volatile solvents or chemicals in their installation.

Pierson

Zigler: Metal roofing is cool and green. Many coatings manufacturers offer elastomeric acrylic coatings that turn a metal roof into a cool roof. These coatings offer high reflectivity and emissivity, meaning they reflect much of the sun's energy and then radiate away much of the heat that the roof does absorb. This not only keeps the building cooler during hot weather, reducing energy use and costs, but also helps lessen the urban heat island effect, in which solar energy is absorbed into pavement and rooftops, making urban and suburban areas warmer than the surrounding rural areas. In some cases, a metal roof can be installed over an existing asphalt roof, so the old asphalt doesn't end up in the landfill. The metal is so lightweight that you can place an underlayment between the asphalt and the metal and then simply fasten the metal through the asphalt to the decking below. Unlike many other roofing systems, metal is recyclable. A metal roof will last for decades, but when its life-cycle has eventually run its course, the metal can be broken down, recycled, and reused in other products.

Metal requires a different skill set for traditional roofers. Is the industry offering enough training?

Zigler

Anderson: Metal roofing systems are gaining popularity among architects and specifiers because of their flexibility in design aesthetics and environmental benefits (they contribute to lower cooling costs and are recyclable). It is important to ensure more traditional contractors are knowledgeable in the application of metal roofing. While there are some training options for contractors, there is a definite need for more.