The SkyDome's roof retracts completely. The roof consists of four gigantic steel plates. The back plate stays in place while the rest slide back underneath it.
The steel plates themselves are reinforced for strength. Trusses made of steel are covered with an outer layer of steel. The outer layer is then covered by a plastic coating that helps the steel withstand the weather.
The SkyDome's roof is approximately 8 acres in size, and a 31-story building could sit underneath it when it is closed. Although it weighs more than 11,000 tons, it is able to open or close in 20 minutes.
