ACCESSORY BUILDING, STRUCTURE OR USE shall mean a building, structure or use which is customarily associated with and is subordinate and incidental to the principal building, structure or use and which is located on the same lot therewith, including, but not limited to, garages, carports, barns, kennels, sheds, non-portable swimming pools, guest houses and all roofed structures. Any accessory building attached to the principal building shall be considered part of the principal building.