Sheet Metal & Air Conditioning Contractors’ National Association


A. Zahner fabricates facade for National September 11 Museum

Jun 15, 2015

Outside envelope recalls stars and stripes of American flag

National September 11 Museum, New York City
A. Zahner Company, Kansas City, Mo.

IMG_9089The stunning architecture of the National September 11 Memorial and Museum was designed to evoke the contrasting emotions of absence and presence, reflection and hope.

SMACNA contractor A. Zahner Company of Kansas City, Mo., reflected that promise of hope in creating the building’s striking façade. Zahner designed, engineered, and manufactured the museum’s building envelope, outer roof, and paneled walls.

Custom-designed and fabricated entirely in their extensive shop, the façade consists of numerous striated stainless steel panels. Their surfaces alternate from reflective to muted and perforated to uniform. The façade evokes the stars and stripes of the American flag.

911-museum-detail2The National September 11 Memorial and Museum Pavilion were constructed at the site of the World Trade Center’s twin towers in New York City. Two footprints mark where the two towers once stood, consisting of two square pools lined with cascades of falling water subtracted into the earth. The National September 11 Museum was erected in the space between these two reflective pools. 

The museum design was originated by the acclaimed Norwegian architectural firm Snøhetta. The museum was designed to offer an image of hope. As visitors look down to reflect upon the water cascading down into the two memorial pools, they also look up to the museum pavilion to reflect upon the present and the future with hope.

IMG_9054The architects worked closely with Zahner’s Design Assist Group, a dedicated think tank where the project's facade was translated into a constructible scheme. 

Zahner fabricated the metal systems in Kansas City and then shipped everything to the jobsite in lower Manhattan for installation. The prefabricated units allowed the installers to quickly place the panels.

IMG_0097The panels were tested for wind loads and water permeability at a special testing facility. Zahner’s NS11 panel mockups were tested for high moisture and winds. The panelization method used for the project also required welding studs to the reverse side of each panel. Fabricators welded with the engineered settings so the studs didn’t show on the face of the panels.

The surface of the metal shell alternates between a matte GB-60™ surface and a semi-reflective stainless steel surface. The matte surface is glass bead blasted stainless steel, which provides a non-directional surface with ambient reflectivity on the metal. The alternation of matte and reflective panels repeats itself down along the metal and glass surfaces of the building envelope, appearing striped. They represent the stripes of the American flag,

911-wind-water-testingThe envelope protects both the interior environment and facilitates climate control. The building envelope is also responsible for the visual shape of the building. The museum houses a collection of artifacts, photographs, audio, and videos about the world Trade Center’s history and of the events of Sept. 11, 2001.

The National September 11 Memorial Museum stands as a tribute to the past and a symbol of hope for the future.

Learn more about how the A. Zahner Company created this remarkable façade on their blog.IMG_9071

You may also read the Architectural Record article, “First Look: National September 11 Memorial Museum.”

A. Zahner Co. is a fourth-generation, internationally acclaimed engineering and fabrication firm known for its specialized use of metal in art and architecture.

IMG_9100SMACNA contractors who also worked on the National September 11 Memorial Museum include Celtic Sheet Metal Inc., Congers, N.Y., and International Testing and Balancing Ltd., Seaford, N.Y.