Where Metal Really Shines

Nov. 10, 2005
Dispelling the four most common myths about metal roofs and walls

Metal. One of the most dazzling building materials available today, it is also one of the most under-rated and misunderstood by buildings professionals. A recent focus group comprised of experienced facilities managers confirmed this perspective:

  • “Metal [roofing] is for a warehouse application and is inexpensive.”
  • “My vision is that [a metal wall panel] is for industrial and light commercial, and that it is low in cost. We would probably give it the least consideration because it’s the low-end, least durable, and least pleasing.”

As illustrated throughout the following pages, metal is anything but. Yes, it is affordable - particularly with respect to its life-cycle and maintenance costs - but the bottom line is that metal is a high-end design material that has proven its longevity. Just think: The Chrysler Building’s chrome, nickel, and steel roof looks as stunning today as it did in 1929. And thanks to continuing advances in coatings and corrosion resistance, today’s metals offer even greater durability.

Earlier this year, The Metal Initiative (TMI), a coalition of manufacturers, individuals, and associations in the metal industry, launched an extensive educational and promotional campaign to increase the use of metal in the commercial construction market. Included in the campaign are roundtable meetings with top-tier building owners, industry symposia and forums directed at leading owner-executives and architects, public relations and advertising efforts, conference sessions and continuing education classes, and more. In addition to promoting the use of metal in building projects, TMI’s efforts are also focused on addressing - then dispelling - the most common misconceptions about metal roofs and walls. Rick Mowrey, director of market development for TMI, spoke with Buildings to offer further insight into the four most common myths about metal roofs and walls.

Myth #1: “Metal is not green.”

Consider the facts:

  • Metal contains post-industrial recycled content. Specifically, the recycled content for steel used in metal roofs and walls is at least 25 percent by weight, which also helps earn points in the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) Green Building Rating System®. The recycled content of domestically produced, flat-rolled aluminum construction products is approximately 80 to 85 percent. Additionally, the average recycled content of all copper and zinc products is 44 percent and 9 percent, respectively. Copper roofing contains approximately 75-percent recycled material.
  • Metal is recyclable. Steel, aluminum, copper, and zinc used in metal roof panels is 100-percent recyclable, contributing to future products’ recycled content. Of the metals used in roofs and walls, steel is the most recycled. The annual recycling rate exceeds 70 percent, and its recovery rate is even higher - near 90 percent. Easily separated from other materials via magnetics, steel is reclaimed through a vast collection and processing network. Like steel, aluminum building products can be repeatedly recycled back into similar products with no loss of quality.
  • Metal is sustainable. Metal roofs and walls are extremely durable and have long service lives. Metal roofing, for example, is unaffected by the hot-cold/wet-dry weather cycles and weather extremes that can break down other roofing materials. Metal roofing also has the ability to hold up against other weather forces, including wind, hail, ice, and snow. Also contributing to the extended service life of metal roofs and wall panels are today’s generation of metal coating systems that not only protect and beautify, but are also warranted for 20 to 30 years. Another sustainability plus: Metal roofs can be installed over old flat roofs. This eliminates the need to remove the old roofing material and helps preserve valuable landfill space.
  • Metal roofs are “cool.” Metal roofs with heat-deflecting coatings can reduce energy consumption by lowering cooling loads. In fact, cool metal roofing can achieve reflectance values over 70 percent and emittance values as high as 90 percent. An Oak Ridge National Laboratory study showed painted metal roofs maintain 95 percent of their reflectance value over time - an important finding, considering that many building codes assume reflective performance of all roof materials degrades at the same rate. Additionally, cool metal roofing can reduce the urban heat island effect by reducing ambient temperatures.

According to Mowrey, “With the recycling of aluminum and steel so prevalent in our society, [the ‘metal is not green’ myth] was the one misconception that most surprised us. When we pushed a little into that perception, we had a few building professionals say, ‘We know metal can be recycled, but when you paint it, you can’t separate the paint from the metal so the [material] would probably go to the landfill.’ That’s simply not true. For years, formal recycling centers have been heating the metals and using scrubbers; the coatings are emulsifying, and all the metals are 100-percent recyclable at end of life - no matter what substrate or coating.”

Myth #2: “Metal doesn’t offer enough design flexibility.”

The facts speak for themselves:

  • Metal roof systems offer a wide choice of substrates, shapes, styles, profiles, colors, seam types, module widths, and rib patterns.
  • Metal wall systems offer a wide choice of products, panel sizes, profiles, colors, finishes, textures, and vertical and horizontal installations.

While many owners think that metal is only corrugated or ribbed, entirely vertical, or marred by unsightly screws, the reality of design options is entirely different, says Mowrey. “There are 15 different substrates, 10 different textured finishes that can be applied to those substrates, painted and unpainted, 57 different shapes, profiles, shadows, and sight-lines - and double that when they are used horizontally and vertically. And I can’t think of any one of the panels or metal curtainwall systems that are used on new construction that could not also be used on a renovation.”

Metal roofing is available in both structural (low- and steep-slope) and architectural applications. Both curb appeal and exceptional performance are an owner’s goal for any system, according to TMI, with the coalition noting a growing trend toward steeper slopes and overstated, extended, or molded roof fascias.

Myth #3: “Metal rusts and has a short service life.”

Fact: Today’s highly durable protective coating systems are designed to last for decades - and have proven their longevity.

Says Mowrey, “We started putting metal cladding on structures in 1910, continued that into our industrial era in the ’20s, ’30s, and ’40s, and a lot of those [buildings] are still around - even though the quality of protective coatings wasn’t as good. That is where some of the misconceptions rest. Thirty-eight years ago, Kynar was developed, which gave us [the resin technology] to develop high-quality coatings to protect the metal so it won’t chalk, fade, or rust.”

Most finishes are applied during the manufacturing process in a controlled environment to help ensure even greater protection and longevity

Myth #4: “Metal is too costly.”

TMI notes a number of facts to dispel this myth:

  • Metal can reduce construction costs. Metal roof and wall systems are light in weight, which can reduce structural requirements. Metal systems also install quickly because they are not affected by weather conditions. This reduces labor costs, minimizes construction delays, gets the building closed-in quicker, and speeds up completion.
  • Metal can reduce maintenance costs. Non-coated natural materials are virtuallymaintenance-free. As noted earlier, the highly durable coatings applied to metal skins to protect the panels are designed to last for decades.
  • Metal can reduce operating costs. Cool metal roofs lower energy costs by reducing cooling loads. Insulated panels lower energy costs by providing uniform performance.
  • Metal roofs are a cost-effective roofing system, confirmed by a 2004 study from Bloomfield Hills, MI-based Ducker Research Co. (See Life-Cycle Cost Analysis results, page 54.)

“In our research with owners and architects,” says Mowrey, “they felt that to get quality metal, it was too expensive. Before we had good craftsman and certified installation, [and] before we had good warranties, that may have been more true. However, today’s systems are developed with less pieces, and certified installers are ensuring high-quality installations.

“A very important aspect of the [Ducker] research was in determining [the total cost of ownership] - from installation through service life. As the numbers indicate, metal is a good value, both initially and long-term.”

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