Retrofitting With Metal Offers Potential Long-Term Savings
Building owners who balk at the cost of a new metal roof or wall system ought to think hard about the potential long-term savings, industry experts say.
Although upfront costs are usually higher than a membrane roof, a metal retrofit can last 40 to 60 years, or more, depending on the substrate, says Scott Kriner, technical director of the Metal Construction Association. That compares favorably to the typical 17 to 25 years for a conventional roof.
The capability of retrofitting metal roofs onto existing buildings has been around for at least 30 years, Kriner says, but it has gained popularity in the last decade: "You don't even have to tear off the existing roof in many cases."
But even now, it can be difficult to get building owners to buy into the idea of life-cycle cost, although the potential economic benefits go beyond simple replacement expenses, he says. In addition to long life, metal offers many design possibilities, can contribute to energy efficiency and needs very little maintenance.
Ken Buchinger, vice president of business development for MBCI, says that schools and governments like metal roofs because of their life-cycle costs. "They don't sell their buildings," he says. "They're in them for a very long time." Commercial building owners, he says, are sometimes more reluctant to make the investment, but many schools have found that they can retrofit a sloped metal roof over the old flat one, add insulation, save money on maintenance, and "use that painted metal roof as an aesthetic element to the building," perhaps painted in the school's colors.
"We're looking for building owners who are going to maintain the structure for a long period of time," says Jim Bush, vice president of sales at ATAS International. Product is typically warranted for 30 to 35 years, he says, "but it's generally accepted that it's going to last much longer."
The Metal Construction Association is conducting a detailed study of how existing roofs have fared in different parts of the country. Buchinger says the first results, from a 33-year-old Galvalume roof in Colorado, reveal that the aluminum-zinc alloy coating and the steel substrate have not deteriorated, and the seals of the seams still meet specifications.
Beyond the first installation, says Bill Croucher, manager of engineering for Fabral Metal Roof and Wall Systems, if a metal roof begins to show signs of wear, a building owner can get another 10 to 20 years out of it with a new coat of paint. In some cases, "a metal roof can outlast the life of the building," he says. Case in point: Many hand-made copper roofs have survived for centuries.