The pilot reported that, after landing he taxied back up the runway to the north. As he reached the end of the runway, and approached the most northerly taxiway, he had to maneuver around another airplane that was parked partially in the taxiway easement and on the runway. As he began to make a right turn onto the taxiway, the airplane was blown sideways about 15-20 ft as a result of the wind from the operating propellers (prop-wash) from a turbo-prop airplane performing a full engine run at a maintenance hangar. The pilot stated that his airplane was dropped onto its left wing and subsequently was spun to the south. Despite the pilot’s attempt of using full brakes to keep the airplane in place, the airplane slid backward and was temporary lifted airborne before it collided with the ground. As a result of the impact, the airplane sustained substantial damage to the left rear spar and aileron. The pilot reported that there were no preimpact mechanical failures or malfunctions with the airplane that would have precluded normal operation.