The pilot moved the airplane from his hangar to go flying. The airplane was positioned about 20 ft from the edge of the hangar. The pilot stated that he initially had trouble starting the engine, so he advanced the throttle to full, and the engine started. The pilot stated that he held the brakes while he was starting the airplane and after the engine started, the airplane rolled into the edge of the hangar. The fuselage and left wing of the airplane sustained substantial damage during the collision. The pilot estimated that the entire event lasted about 2-3 seconds from engine start to the collision with the hangar. The airplane pilot operating handbook stated that the brake should be set before engine startup. The pilot reported that there were no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operation. Inspection of the airplane’s brake and throttle systems did not reveal any pre-accident anomalies.