Choosing the Right Metal for Architectural Design

“There’s a lot of, shall we say, ‘misinformation’ that gets out there,” he said.

Zahner would know. The president and CEO of A. Zahner Co. has written numerous articles and several books about the use of metal in architecture. He has appeared at SMACNA events many times to discuss the topic. His company, the 125-year-old Kansas City, Mo.-based A. Zahner Co., has done the design, fabrication and installation for some of the most well-known and iconic metal structures around the world — from international corporate headquarters to museums that draw millions of visitors annually.

The company’s employees are experts at making metalwork for high-profile construction projects, whether it’s fabricating gleaming stainless steel pillars or deep brown copper cladding. And since they have extensive experience not just with metal design but also its fabrication, Zahner and other company employees often act as consultants on metal projects worldwide.

Bill Zahner has written seven books on architectural metals. The latest series of five books covers stainless steel, aluminum, zinc, steel and copper alloys. Zahner picked those metals, he said, because they’re the ones most commonly used in architectural projects. Each volume goes into extensive detail on the applications for using the material.

The most recent book in the series, Zinc Surfaces: A Guide to Alloys, Finishes, Fabrication and Maintenance in Architecture and Art, was just published by Wiley.

It’s information that needs to get out to the broader architectural and design community, Zahner said.

“The point of (the series) was to educate designers and artists of the various idiosyncrasies between one metal versus the other and how they can be used in design and fabrication successfully,” he said. “All the books delve into the actual surface of the material, how they’re weathered, how they’re going to respond to the environment, and how you can alter them to create various patinas or custom reflectivity from the surface.”

Echoing some of the information that he covers in greater detail in the book series, Zahner discussed with SMACNews some of the most popular architectural metals in use today, their advantages, and some of the misconceptions architects and designers have about them.

“We use them all,” he said. “What I try to do is shed some light and give real world (examples) and some scientific approaches on why certain things happen.”

Stainless Steel
Zahner has been involved in many noteworthy architectural projects that use this material, including the Petersen Automotive Museum in Los Angeles, which features numerous stainless steel ribbons on its exterior.

“We’re seeing stainless steel being used more and more (because) it’s strong,” he said. “It doesn’t change or change is extremely slow. You can add color to it using an interference coloring technique, which is chromium oxide layers on the surface, or you can use physical vapor deposition, which is a very thin molecular coating of say, titanium carbide or titanium nitride on the stainless steel to give it those colored tones.”

“The biggest trend is using finishes that diffuse the light,” Zahner said, “like a finish that we developed over the years called ‘angel hair’ that has become very popular with architects because of the way diffuse light reflects from the surface. It’s as if light is being generated from the metal itself.” The Petersen Automotive Museum used this type of material.

Despite its popularity, some architects and designers do not fully understand how stainless steel is impacted by environmental factors, Zahner added. “People think stainless steel will never corrode and never rust, but there are certain conditions where it does,” he said. “The prolific use of deicing salts in our cities can damage the surface of stainless steels.”

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