A section of the roof at the 256,000 sq ft St. Charles, Ill., headquarters of pond construction company Aquascape crumpled to the ground on Sunday, the Chicago Tribune reported.
No one was injured in the collapse, which company officials said was likely the result of an ice dam forming and preventing melting snow from draining off the roof. The section, about 50 feet wide, ran the length of the building and extended over a parking lot.
The LEED silver-rated building housed a warehouse and offices.
Aquascape vice president Ed Beaulieu told the Tribune that he didn’t know whether the weight of the roof’s six inches of lightweight soil contributed to the collapse.
“I honestly don’t think we can make that assessment yet,” he said. “I do know that the structural members were greatly increased over what would be used in a standard building.”
Green roofs are roofs planted with vegetation to absorb rainwater and help regulate temperatures. In Chicago, more than 600 green roofs have been or are being built, the city Department of Environment said.
“There’s really nothing about the inherent design of a green roof that should make it more susceptible to this kind of collapse,” Joseph Clair, director of energy and sustainability at the Illinois Institute of Technology, told the Tribune. “Green roofs have been installed in this country and other countries that have snow for hundreds of years.”