NATIONAL REPORT—Metal roofing has a long, successful history in the United States and the world. Its proven track record spans all types of projects—commercial, industrial and residential, new construction and remodeling. With today’s heightened interest in and demand for ecologically-sound building materials, metal roofing is an ideal choice. In fact, The Metal Construction Assn. says metal roofing should be included on all lists of environmentally friendly or “green” roofing materials.
Metal roofing’s durability can virtually eliminate the need for future raw materials to be used to produce roofing. Other roofing materials are heavily affected by weather extremes. Metal roofing, however, is unaffected by the hot-cold/wet-dry weather cycle that breaks down other materials. In addition, it is known for its ability to hold up against other weather extremes including windstorms, hail, ice, and snow. No other roofing material has greater ability to withstand a wider range of weather conditions than metal.
There are many handmade metal roofs still in existence that date back to the 1800s. Commercially-produced metal roofing systems have been available since about 1910; numerous profiles and types have been produced since then and there are examples of these roofs across the country. While some metal roofs are long lasting and durable with exposed metallic surfaces, modern technology has also brought quality paint systems that beautify metal roofing and are warranted for as long as 50 years. If necessary, many years in the future, metal roofs can be repainted for additional life.
As consumers, many of us are careful to collect our recyclable materials and turn them in for collection. In reality, though, we are offered very few consumer products where we can “close the loop” by purchasing products that are high in recycled content. Metal roofing, however, offers that option to consumers by allowing them to choose a significant building product on the basis of its recycled content.
Metal Roofs Include Recycled Content
Most metal roofs have recycled content ranging from 25 percent to 95 percent. This is in stark contrast to conventional roofing shingles that have much shorter lives and use oil-based products as their primary raw material. The recycled content of metal roofing has been reason for several state and local entities such as solid waste districts and departments of natural resources to include metal roofing on their lists of green and recycled content products.
While metal roofing is known for its extremely long life, it does have the added benefit of being 100 percent recyclable if it is ever removed in the future, perhaps as part of a building renovation. Whereas other old roofing materials are disposed of by the ton in landfills across the country each year, the steel, aluminum, and copper used in metal roofing can be recycled in their entirety, potentially even to become another metal roof.
Depending upon the product chosen, metal roofing has a weight that is one-third to as little as one-eighth the weight of conventional roofing shingles. In comparison to heavy tile and slate roofing, the weight of metal roofing is virtually miniscule. This low weight serves several valuable purposes. First, it puts less weight load on a structure. This helps extend the life of buildings and it also provides invaluable protection against roof cave-in threat in the event of seismic activity.
With retrofit applications, many metal roofs can be installed over the old roofing material. This has a very positive benefit by preventing the need to remove the old roof and fill up valuable landfill space. Each year, about 20 billion pounds of old composition roofing shingles are dumped into U.S landfills. Metal roofing is the way to avoid this. Additionally, metal’s low weight and high strength presents an ideal way to cover and encapsulate existing asbestos roofing shingles rather than pose a health risk by removing them and putting them in a landfill. State EPA offices support this practice of asbestos shingle encapsulation.
A Safer Roofing Alternative
Metal roofing and the finishes used on it are inert, safe materials that do not pose a health risk. Additionally, metal roofing is noncombustible and that provides additional fire protection. Of course, one roofing material that has turned out to be very dangerous is the asbestos shingle roofing. This material was used extensively many years ago and now, having realized the health hazards it poses, we’re spending many dollars each year to get rid of it. This worry does not exist with metal.
Many consumers with chemical sensitivities are turning to metal roofing and finding that it does not have the allergy problems that are associated with other roofing materials. Today’s commercially-produced metal roofing systems are carefully tested on an ongoing basis for performance, wind resistance, fire resistance, and hail resistance. They are listed with various building codes and entities including Underwriters Laboratories, International Congress of Building Officials, Dade County, Florida, Southern Building Code Congress International, and others.
Metal roofing is rapidly gaining acceptance as a very energy efficient material. Property owners have reported energy savings of as high as 20 percent and even more after installing metal roofing. The reflectivity and subsequent energy efficiency of metal roofing has been confirmed in studies done by Florida Solar Energy Center, Florida Power and Light, Oak Ridge National Laboratory, and other independent organizations. Ongoing studies are being conducted to continually substantiate and quantify the energy efficiency of metal roofing.
Many available metal roofs are being documented to meet Energy Star requirements. Prepainted metal roofing can display solar reflectance of at least 65 percent and thermal emittance of 80 percent. This can have a tremendous impact on energy usage by reducing air-conditioning costs and the smog and pollution that are created by the production of that energy. Additionally, the low thermal mass of metal roofing means that it dissipates heat very quickly once the sun goes behind a cloud or sets for the day. Other roofing materials have greater thermal mass and will continue to radiate captured heat into the structures beneath them even when the sun is not shining.
In light of the above benefits, the Metal Construction Assn. strongly encourages metal roofing’s consideration and inclusion on lists of green building products. Many state green programs have already included metal roofing products on such lists that they publish. Roofing is a major component of any structure and it is a component where the product chosen can have a dramatic effect on the building’s life cycle and energy costs. Metal roofing’s many benefits, including sustainability, recycled content, recyclability, low weight, and energy efficiency, far outweigh virtually all other roof systems from an ecological standpoint.