More Curves, Material Options Top List of Trends in Metal Roofing
Many building owners seeking long-term roofing solutions are insisting on metal roofs that offer both curb appeal and exceptional performance.
The growing emphasis on style, for example, has ushered in a new category of roofs shaped to give them asymmetrical curves. It’s an increasingly popular option in many parts of the country, especially for retail stores, commercial buildings, schools, and public buildings, suggests Rob Haddock, Director of the Metal Roof Advisory Group of Colorado Springs, Colo.
A leading technology for producing curved panels involves a process in which a computerized two-way press bends panels precisely into the desired radii and angles of curvature without damaging the panel’s finish.
Roof slopes are becoming steeper
Haddock has also identified a trend toward steeper slopes, a development that originated in the ‘80s and ‘90s. “Flat and very low-slope roofs were the rage in the ’60s and ‘70s, but the desire for buildings with more curb appeal has led many building owners and architects to conclude that steeper is better,” Haddock says. “And there’s nothing to suggest that this trend won’t continue to gain momentum.” In addition, some building owners eager to be design trendsetters are now opting for roof fascias that are overstated, extended or molded to increase their dramatic appeal.
Value conscious end-users, according to Haddock, are also gravitating toward metal roofing products because they provide long years of reliable performance and ensure the best possible return on investment. Carbon steel, the dominant metal in commercial construction, is the most economical metal option, and features excellent structural characteristics. And, like other metals, it requires little maintenance, provides long service life, has a low life-cycle cost structure, and offers ample design flexibility.
To ensure life spans of 40 years or longer, sheet steel used for roofing is protected from the elements by aluminum-zinc, zinc, aluminum or lead-tin alloy coatings. These coatings provide a continuous, impervious barrier that prevents moisture from contacting steel. And without direct moisture contact, steel cannot corrode.
The most common thickness of steel roofing used in commercial construction is 24-gauge, though 26-gauge is used on some occasions. (The lower the gauge number, the thicker the material.) In areas prone to hurricanes, 22-gauge steel with a .030 inches minimum thickness may be preferable.
Crafted roofing materials can last centuries
Owners of high-end or historical buildings often favor softer metals such as copper, lead and terne-coated stainless steel, according to Haddock. These “crafted roofing” materials may be somewhat more expensive, but their life expectancies can be measured in centuries.
Titanium zinc, another of the so-called crafted metals, is just beginning to attract attention in the U.S. as it has in many parts of Europe. The soft gray metal is available in different surfaces finishes, including pre-weathered, and comes in thicknesses of .7 mm and .8 mm. It never requires re-painting or re-coating and can provide virtually maintenance-free service for a century or more.
Terne, a tin-lead alloy coated steel, is another option for owners seeking a quality metal roofing material, according to Haddock. It has a moderate cost and long life-expectancy, but requires some maintenance, mainly periodic painting. Because of the material’s resemblance to tin, terne roofs are commonly referred to as “tin roofs.”
Meanwhile, terne-coated stainless steel requires no maintenance, but like zinc, lead titanium, and lead-coated copper, it tends to be among the more costly metals. Terne generally comes in 28 and 30 gauge panels, while terne-coated stainless steel is typically available in 26- and 28-gauge panels.
Another roofing material option that is catching on with commercial and institutional building owners is architectural titanium. This attractive metal has an inorganic finish, a very low thermal coefficient, and excellent strength, durability, and corrosion resistance. It typically comes in four-foot wide 28-gauge panels, but is also available in custom lengths.
Aluminum is a viable option in coastal areas
For salt-water coastal environments, high tensile aluminum has become a viable, cost-effective option, Haddock suggests. Aluminum can be easily painted, and organic color finishes can be added inexpensively. Moreover, since the application of an aluminum roof is virtually identical to that of a steel roof, it is easy to find qualified contractors who can work with this metal. The most common thickness for aluminum roofing is .032 inches, with .040 inches running a close second.
Though metals continue to gain in popularity and are being specified increasingly on commercial and institutional roofing projects, Haddock suggests that some knowledge and understanding of the basic elements of system design and installation can greatly improve the success of a roofing project. “An educated owner is the key to making intelligent decisions,” he says.
For more information on metal roofs, log onto The Metal Initiative website – www.themetalinitiative.com
