Architectural zinc is a natural metal valued as a construction material since antiquity. Modern architectural zinc is specified for roofing, rain management, wall cladding and architectural details. It can be fabricated into a variety of panel styles, sizes and shapes. Today’s zinc material options also offer different colors and coatings, complemented by numerous installation techniques and systems.
Vaughan Metropolitan Centre Subway Station, Vaughan, Toronto, Canada. (Photo courtesy of RHEINZINK)
Architectural zinc building products have a potential lifespan of 80 years or more with basic maintenance. Throughout its long lifetime, a dynamic aesthetic evolves as the zinc material’s patina is influenced by the project location’s unique climate and protects this ecologically friendly material for many generations.
Zinc is the 24th most abundant element in the earth’s crust. Research indicates zinc resources should be available for at least the next 700 years, without taking recycled zinc scrap into account. Recycled content in architectural zinc products reaches up to 40% for pre-consumer and 10% for post-consumer. Zinc building products are infinitely recyclable without loss of the metal’s chemical or physical properties.
Pure zinc is somewhat brittle and works best as a building material when alloyed with small amounts of titanium and copper. ASTM B69-20 Standard Specification for Architectural Rolled Zinc details Type 1 and Type 2 architectural rolled zinc, where Type 2 has a higher copper composition and a graphite-gray patina.
Supporting environmental and human wellness, the metal alloy used by industry-leading architectural zinc manufacturers does not contain lead, iron, cadmium, selenium, manganese, magnesium or chromium-6. Energy-efficient, low-emission production is part of what makes zinc building products ecologically friendly.
Zinc’s natural attributes may contribute to meeting criteria of green building programs such as the U.S. Green Building Council’s LEED rating systems. Product and material testing and documentation are necessary to support sustainability claims. When assessing an architectural zinc product, request a third-party verified, environmental product declaration (EPD). When considering the entire life cycle, the Cradle to Cradle Products Innovation Institute’s evaluation differs from other certifications in its focus on safe, sustainable products for a circular economy.
Installed properly, zinc building products will resist air and water infiltration. For regions with high winds and hurricane conditions, zinc roof and wall cladding systems have been tested to withstand high winds as required by codes and local jurisdictions. In environments which are susceptible to fires, zinc also provides a non-combustible solution.
Zinc’s inherent metallic properties allow the material to deliver low-maintenance and long-lasting performance. No paints, varnishes or sealants are required. Runoff is minimal, non-staining, and does not adversely affect the environment as the zinc material’s patina naturally forms.
The natural patina will form to a soft blue-grey or graphite-grey color, depending on the alloy type. To achieve this vintage look at the time of installation, some architectural zinc manufacturers can accelerate the patination process under factory-controlled conditions before the material is fabricated. Additional color and coating options for architectural zinc include pickling, phosphating or color coating. All these coloring techniques will eventually fade and give way as the material continues to naturally weather and form its unique patina.
Charles (Chip) McGowan is the president of RHEINZINK America Inc., Woburn, Mass., and draws from more than three decades of experience working with architectural, specifications and installation professionals on projects featuring metal building products. He is a member of ASTM B02 Nonferrous Metals and Alloys Committee and represents RHEINZINK’s membership in the Metal Construction Association (MCA), U.S. Green Building Council (USGBC), and the American Institute of Architects (AIA). McGowan can be reached at charles.mcgowan@rheinzink.com.