The injured employee was working with two other individuals on a V-shaped roof to repair exhaust fan ductwork. The injured employee walked backward up the roof to confirm alignment of an exhaust vent and stepped off the edge of the roof, landing 14.5 feet below onto the next roof level. He landed on his feet, then fell backward, striking his head on a window. The injured employee was hospitalized with a fractured right ankle. Fall protection was not worn at the time.