by L. Wiliam Zahner

"Perforated" is the designation given to a body of metal surfaces that have been pierced or cut with the purpose of removing portions of the body of the sheet. Perforated metal is available in a vast array of hole sizes, shapes, and grids. Patterns can be staggered, gridded, random, or custom.

Perforated metal creates a textural appearance on surfaces. From a distance, the perforations look slightly darker than the metal surfaces. The holes do not reflect light back to the viewer so they tend to darken the overall surface appearance. When light from behind is allowed to show through, the holes tend to lighten the surface appearance.

Metal can be perforated economically on a large gang-punching machine. An entire series of rows across the width of a sheet can be created at one time. This method limits the flexibility but keeps the cost down. Gang punching can also be performed on selected portions of the sheet to limit the area of transparency.

Custom perforation is also possible. Custom perforation offers the designer tremendous flexibility. Holes can be pierced any place on the sheet and in any configuration imaginable. The surface takes on a textural quality and an intriguing pattern as light passes through. Custom perforation requires the use of computer-numerically controlled (CNC) machines that punch or cut a hole in a specific, predetermined location.   >>>

Discuss this article in the Architecture Forum...

Light penetrates the perforated ceiling panels at the entryway of the de Young Museum of Art, San Francisco, designed by Herzog and de Meuron. Photo: Courtesy of L. William Zahner Moiré patterns are created by overlaying two perforated surfaces in the Nelson-Atkins Museum of Art parking facility, Kansas City, Missouri, designed by Steven Holl. Photo: Courtesy of L. William Zahner   Click on thumbnail images to view full-size pictures.