Sometimes, things aren’t quite what they seem.
According to multiple media reports, four patrons at Willis Tower’s Skydeck in Chicago Wednesday night saw the floor crack below them while standing in the “Ledge”—a glass and steel box that extends out of the building more than four feet and 103 stories above the city.
Naturally, the event caused some undesirable excitement, but after everyone stepped back, things were cleared up. The glass that cracked was actually a protective layer that sits on the structural glass, and while it may have frightened the patrons, they weren’t in real danger.
“The Ledge was designed with a protective coating that completely covers all glass surfaces to protect against scratches,” a Willis Tower spokesperson said in a statement Thursday, following a surge in media attention regarding the matter. “This coating does not affect the structural integrity of The Ledge in any way. Occasionally, the coating will crack, as it is designed to in order to protect the surface of the glass.”
Lyle Hill was president of the contract glazing company that built the Ledge. He explains that the “coating” being referred to is actually a quarter-inch of clear tempered glass called a “sacrificial lite” which did what it was supposed to do—take one for the team.
During the Ledge project, using a film on the floor was considered. But instead, they opted for the sacrificial lites for longevity purposes, though it was understood that the protective lites would need to be replaced from time to time due to scratching and scuffing.
In fact, Hill says in the past, Skydeck has had extra pieces in stock to periodically replace the used ones every so often, adding that he remembers one other time—roughly two years ago—the sacrificial lite on the floor cracked.
“I believe the last time one broke, a tourist dropped a metal souvenir on it,” he says. “It’s not the first time.”
The Willis Tower says Skydeck remains open, but its four Ledge boxes were temporarily closed for inspection as of Thursday afternoon.