The airline transport pilot was on a Title 14, CFR Part 91, personal cross-country flight when the accident occurred. The pilot reported that during the landing roll at a private airstrip, the airplane started drifting left. He said that right rudder and right brake did not correct the drift, and the airplane exited the runway in a left turn. The airplane struck a building adjacent to the runway with its right wing, and according to the pilot, received substantial damage to the leading edge and rear wing spar. The pilot indicated that an FAA certificated aviation mechanic who examined the airplane told him the tailwheel malfunctioned, and would not turn to the right. The pilot said there were no known mechanical problems with the airplane prior to the accident.