In the early 2000s, as the green-building movement reached its tipping point, the roofing industry’s contributions to sustainability focused on increasing energy efficiency, improving long-term durability and addressing the heat-island effect. In the years since, significant strides have been made in all three of these areas for commercial and residential buildings.
In recent years, increasing attention has been given to the benefits and challenges of recycling roofing materials at the end of their useful life. This is no trivial task: Owens Corning estimates asphalt shingles alone comprise up to 5 percent of building-related landfill waste. This doesn’t take into account other roofing materials, including EPDM, thermoplastic PVC and metal.
Not surprisingly, rising removal costs, coupled with the growing demand in some areas of the country to legislate landfill content, are putting pressure on contractors and building owners to seek alternatives to traditional roof construction scrap and tear-off disposal methods.
In response, greater numbers of roofing manufacturers and contractors are driving strategies to avoid the landfill. A general review of emerging trends across the roofing industry suggests manufacturers and contractors increasingly are turning to recycling to steer these materials from the waste stream.
Metal roofing’s sustainable attributes are significant. Industry experts cite its ability to improve a building’s energy efficiency, and metal today contains anywhere from 25 to 95 percent recycled material.
On its website, the Chicago-based Metal Construction Association (MCA) encourages installing metal roofing directly over an existing roof, thus eliminating the need to dispose of the original materials. But when an older metal roof or new-construction debris must be removed from a site, contractors and owners in most regions of the country can quickly identify scrap yards that take metal.
“Steel is the most recycled material in building construction today,” says MCA Technical Director Scott Kriner. “There’s an infrastructure that supports it, and metal in general is virtually 100 percent recyclable.” Kriner notes MCA supports recycling as part of the metal industry’s overall commitment to environmental sustainability and transparency in business.
PVC has been used in roofing systems since the 1960s, and the post-consumer recycling of roof membranes began in North America in 1999—a nice symmetry when one considers roofs in terms of 30-year life cycles.
In general terms, the recycling of PVC roofing is a relatively straightforward process. The material is sliced into long strips, rolled up, lifted off the roof and transported to a recycling center. Recyclers run the PVC through a conveyor system, where fasteners and other metal objects are removed.
Initially, the recovered membrane was ground into powder for reuse in molded roof walkway pads. More recently, some manufacturers have been incorporating a granulated form into new PVC roofing membranes, exclusively on the backside to avoid aesthetic issues with color variations. The first installations of membrane produced with post-consumer recycled composition occurred in the mid-1990s. So far, its field performance has matched that of PVC roofing produced with virgin raw materials.
The Vinyl Institute, Alexandria, Va., says close to 1 billion pounds of vinyl are recycled at the postindustrial level yearly. “The vinyl industry has a history of supporting recycling,” the institute reports on its website, “and this effort continues as companies, alone and through their trade associations, expand existing programs and explore new opportunities to recover vinyl products at the end of their useful life.”
Ethylene propylene diene terpolymer is used extensively on low-slope commercial buildings. Yet even this durable synthetic rubber membrane must eventually be replaced, and today recycling is a viable option.
The removal process generally involves power-vacuuming off the stone ballast, where present, to expose the EPDM membrane below. The membrane can then be cut into manageable squares, which are folded and stacked on pallets, loaded onto a truck and transported for recycling. The recycler grinds it into crumbs or powder, depending on the end use. A growing number of recycling centers nationwide now handles EPDM.
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