Steel and other metals make the grade for the green building market

March 2012- Commercial metal roofing is at 22 percent market share and growing quickly, says Scott Kriner, president of Green Metal Consulting Inc., Macungie, Pa., and technical director of the Metal Construction Association. He believes the uptick in the use of metal roof products is largely because of the design community’s appetite for durable, long-lasting products and its increasing awareness of metal as a sustainable, robust option. Green Metal Consulting helps companies and organizations gain footing in the green building market by helping them keep pace with technology and initiative changes in renewable energy, alternative energy, zero-energy building design and whole building or system-performance criteria. The company also supports manufacturers in their development of new products for the construction sector that are sustainable and environmentally responsible.

Durability
“Metal has quite a track record,” says Kriner. “You can reduce the waste stream and lower costs if you don’t have to replace metal roofing every 10 to 15 years as with some of the other roofing products on the market.” Metal roofing, he explains, is a term that covers a family of products ranging from zinc, copper and aluminum to unpainted and coated steel. “The variety of metals gives designers a lot of flexibility in terms of aesthetics,” he says. “More importantly, these metals allow designers and manufacturers to integrate components into roof systems that help to improve energy efficiency. Metal also is an ideal platform for photovoltaic applications.”

Photovoltaic (PV) or solar cells produce electricity when exposed to sunlight, are environmentally friendly and need little maintenance because they have no moving parts. Standing seams on a metal roof can double as racking systems for PV products. “With a modular PV unit or PV coating, we’re able to reduce the weight and cost associated with other roof systems,” says Kriner. “Leaks and the need for weatherproofing are eliminated. PV units are lasting 25 to 30 years. Since metal roofing can outlast the PV unit, we’re able to reduce costs even further.”

According to Kriner, steel is the most-recycled product in the world and actually can be used for the same application again once the metal reaches the end of its first life. “Steel’s capacity to be fully recycled and reused eliminates landfill,” says Kriner. Cool metal roofing made with special pigmented paint systems is another green product able to deliver reduced heating and cooling costs without the premium price tag. “With metal products, architects are realizing they have the whole package—access to a rainbow of colors, different shapes, design flexibility, longevity, sustainability and durability,” Kriner says.

Solar power
Kriner also is the founding chairman of the Cool Metal Roofing Coalition and works with companies like Drexel Metals Inc., Ivyland, Pa. Drexel is a leading supplier of equipment, materials and technical support to roofing contractors worldwide and specializes in solar and cool metal roofing products. The company’s cool metal roof products integrate solar technologies that use above sheathing ventilation for additional energy efficiency. Suited to commercial and residential applications, the roof system is also available in a configuration that combines solar energy with hybrid solar hot water collectors. These collectors attach to the back of modular crystalline PV panels and are designed to collect the heat that builds up on the PV system and transfer it to a solar hot water tank. In addition to keeping PV panels cool, the system provides 90 percent of domestic hot water needs.

“Solar and metal roofing are the perfect marriage,” says Tony Spaw, product technician for Drexel Metals. “Metal lasts more than 50 years and is recyclable. It’s not cost effective to have to rip a roof off in 20 years to reinstall solar panels. By combining solar and metal roofing, we give customers the whole package upfront.”

The corrosion-resistant coatings on steel are Galvalume (a 55 percent aluminum-zinc alloy coating) or galvanized (zinc coating). Galvalume is sourced prepainted from the mill. “Drexel Metals provides roofing contractors with Galvalume coils as part of its metal roofing on-demand initiative,” says Spaw. “The coils reduce the potential for damage, eliminate shipping costs and help the contractor boost its bottom line when compared to conventional factory-formed manufacturing for these types of products.”

“Architects are looking for warranties of at least 20 years on the materials they consider using,” adds Frank Oswald, warranty inspector for Drexel. “These roof products are engineered and designed to meet rigorous requirements. They can easily meet the design community’s warranty needs when installed to our specifications.”

According to Kriner, steel roofing products also lend themselves to retrofit projects on existing buildings. “With metal, you don’t have to pull the existing roof off,” he says. “By introducing a steep slope metal roof using an engineered framing system, you can create space between the old and new roof and introduce elements like solar water heating and enhanced ventilation for greater energy efficiency. Since you don’t have to remove the old roof, there’s no debris going to a landfill. As the demand for green, sustainable products in the building and construction markets continues to grow, steel and other metals are proving their worth.” MM