Why Use Metal Roofing?

Metal is experiencing a renaissance of sorts. As knowledge of metal’s suitability for walls and roofs grows, it increasingly is being used on a variety of building projects, including schools, warehouses, health care facilities and office buildings, among others. Facilities executives are recognizing benefits such as durability and longevity, and this has led to wider use, say industry sources.

According to Toy Henson, director of education and market development with The Metal Initiative (TMI), metal’s share of the commercial building market has about doubled over the last 20 years. While no firm statistics exist, Henson estimates that metal currently accounts for 20 to 30 percent of the market. What’s more, about 70 percent of specifications for building materials issued by the federal government include metal, says Henson.

A life-cycle cost analysis conducted by Ducker Research Company in 2004 helps explain the growing popularity for metal as a building material. When analyzing roofing systems, researchers found that the expected life of a metal roof is 40 years. By comparison, the average built-up roof lasts 10 to 15 years and single-ply roofs last about 20, according to the study.

Because metal roofs need to be replaced less frequently than most other roofing systems, the total cost of the roof, when measured over its expected life, becomes much lower. The Ducker study estimated that the expected life-cycle cost per square foot for a metal roof is 30 cents. In contrast, the life-cycle cost per square foot was 57 cents for single-ply roofs.

Metal does have a higher first cost than other building materials, says Scott Kriner, technical director with the Metal Construction Association (MCA). However, Kriner cautions that it’s difficult to make broad generalizations given the wide range of metal substrates and finishes on the market.

Even so, the initial price disparity for metal roofing and wall systems can often be made up in savings in the costs of other construction materials, say industry insiders. That’s because metal is significantly lighter than other roofing materials.

According to Green Seal, a nonprofit organization that promotes the manufacture of environmentally responsible products, metal weighs between 50 and 270 pounds per 100 square feet. That compares with 250 to 400 pounds per 100 square feet for built-up roofs. Because of metal’s lighter weight, support columns and footers needed within the frame of a building can be spaced farther apart. This can reduce the cost of construction materials.

It’s important to note that metal’s lighter weight doesn’t compromise its strength, says Dick Bus, president of ATAS International and president of the Metal Construction Association. “Pound for pound, metal is stronger than other materials.”

In addition, a metal roof can be part of the building’s structure, rather than an addition to it, says Joel Voelkert, vice president of Rigid Building Systems and chair of TMI’s market development committee. Commercial metal roofs may not require a separate deck, although an architect may request one as part of the roof design. In contrast, a built-up roof system is placed atop a deck.

Another benefit of metal building systems: The installation work often can proceed more quickly than with other materials, such as brick, says Jeff Irwin, chief executive officer with MeTecno/Benchmark and incoming president of MCA. That’s because it is installed in sheets that can measure 36 inches wide.

Finally, metal building systems can be installed in most types of weather. This reduces the risk of a delay in construction due to snow, rain or other weather extremes.

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