MARKETPLACE

The Essential Element: Is Zinc Finally Catching On In The American Building Industry?
Zinc is an essential part of our environment. It’s in the rocks, soil and water. Every single organism on the planet needs it to live. In humans, it’s vital to our immune system, fertility, and sense of taste and smell. It’s also a highly sustainable, recyclable building material.

In Europe, architects have utilized zinc roofs, gutters and walls for a couple hundred years, according to George Vary, executive director of the American Zinc Association, Washington, D.C. However, its major use in the United States and around the world is as corrosion protection for steel.

“It forms a very tough physical barrier against corrosion,” Vary said. “It also provides what’s called ‘sacrificial corrosion protection.’ If you get a bare spot or a hole, the zinc will corrode before the steel does at that spot, much like [how] skin flows across a cut to heal itself.”

Vary said solid zinc, or what might be thought of as nearly pure zinc, is used in the U.S. only on “very upscale, one-off projects.” He said attempts have been made in the past to incorporate more zinc into the industry, but the infrastructure and experience working with it simply wasn’t there. It’s more expensive than galvanized steel, and while it’s deeply integrated into European aesthetics, it has not been part of the architectural tradition in the states.

That may be changing.

According to figures provided by Jarden Zinc Products, Greenville, Tenn., the largest North American producer of solid zinc strip and zinc-based products, zinc usage grew in the U.S. by 13 percent in 2007 due to increased knowledge of the material by architects and builders.

Advantages and Disadvantages

In light of the “green” push that’s becoming increasingly popular in building today, zinc offers several advantages.

Zinc is 100 percent recyclable. According to Jarden Zinc Products Regional Sales Manager Grady Chafin, more than 90 percent of the zinc used in the building industry is recycled, putting it far ahead of many other materials that are just taking their first steps in recycling. It can also last as long as 40 years in an aggressive urban environment and 100 years in a protected rural environment.

Because zinc is a self-healing metal, this makes zinc roofing and wall panels virtually maintenance free, according to Chafin. The material is also applied in strips and can therefore adopt any shape. It can be bent to fit curves with low radiuses and form complex shapes, which are difficult to realize with other materials.

Laurent Heindryckx, technical manager for Umicore Building Products USA Inc., Raleigh, N.C., points out that because of its lifespan, the use of zinc reduces carbon emissions.

“Painted steel is recycled, which is great, but then another installer will have to remove the steel and put a new roof on it. That costs a lot of energy,” Heindryckx said. “All the equipment to remove the panels, bring in new panels, that’s one of the considerations the green movement is having. How much pollution will a product bring directly or indirectly? In the case of zinc, we have a very favorable life-cycle analysis, which takes into account, from cradle to grave, all the aspects of a given product.”

Using zinc can also help earn LEED points, Heindryckx said, however not as many as you might think.

“Right now if you use concrete or zinc, it’s the same as far as recyclable content. Concrete, though, you can’t do too much with at the end of its life,” Heindryckx said. “Metals can go back to the furnace. That’s what’s missing in the LEED certification.

“It takes much less energy to melt zinc than other metals. That makes the second life of zinc much more favorable, and that’s when the green aspect comes back stronger.”

As central to the environment as zinc may be, it’s not necessarily always good for it. Dr. Andrew Green, director of environment and sustainability for the International Zinc Association, Durham, N.C., branch, says runoff—the material that comes off a surface, such as a roof, during rainfall—must be assessed.

Green said the concern with any material when you have rain is that the materials will come off the roof and enter the soil or water nearby. He said that is why most large construction projects, such as a new condominium development, tend to have retention ponds.

It’s very rare, according to Green, for zinc to negatively affect humans. In fact, he said it’s more likely for someone to have a zinc deficiency, which is a major problem causing disease in developing countries. Zinc could, however, be toxic to animal life, such as fish.

“There’s a common phrase, ‘dose makes the poison,’” said Green. “All materials have benefits and negatives. On the one side, zinc is one of the most essential elements out there … but if you get too much there can be issues.”

Aesthetics are a large part of zinc’s appeal, as well. Its dark-gray, matte finish gives it a distinctive look and provides another color for the architect’s palette. If an architect wants gray, zinc will stay gray even after years of exposure.

“What architects tell us usually is that zinc marries pretty well with other products, such as brick, stone and wood. Unlike painted steel, zinc has a very matte finish, [it] doesn’t reflect light,” Heindryckx explained. “Reflectivity [in zinc] is very similar to brick, stone and wood. The architect can mix different products but still have a contrast. It blends together in a sense that if it were painted steel the contrast would be too big.”

Trends

Heindryckx believes the building industry is very traditional. He said the use of copper in the U.S., for instance, goes back to Revolutionary War hero Paul Revere, who was a pioneer in copper production. In Europe, zinc is part of the area’s tradition, and Europe must continue to use it to match what is already there.

There is also sticker shock associated with zinc compared to galvanized steel, but Heindryckx said when looking at zinc’s return on 100 years of use, it may be worth it.

“I think there’s going to be a trend to have buildings that will last longer, especially for institutional buildings,” he said of the future of zinc in the U.S. “There’s a trend from the 19th century.

All these Ivy League universities were made with brick, limestone, copper, and then newer buildings came in made of painted steel. Now I feel there is a revival for products that have a longer lifespan, and that’s when zinc is very in tune with that trend.”

Rediscovery

According to the American Zinc Association, centuries before zinc was discovered in its metallic form, its ores were being used for healing wounds and sore eyes. By 1374, zinc was recognized in India as a new metal—the eighth metal known to man at that time. Paracelsus declared it a new metal in Europe in the 16th century, and zinc went into production in the U.S. in 1850.

Today, 7 million tons (6.3 million metric tons) of zinc are produced worldwide, much of it for construction purposes, according to the American Zinc Association. While it hasn’t been wholeheartedly embraced in its more pure form yet in the U.S., with its environmentally friendly nature and the industry’s continual push towards going green, zinc may be ready to be discovered all over again.

Source: Metal Architecture, March 2008