The height limitations of this chapter, as shown in Area and Bulk Schedule B, shall not apply to church spires, belfries, cupolas and domes which are not used for human occupancy nor to chimneys, ventilators, skylights, water tanks, bulkheads and other necessary mechanical appurtenances usually carried above roof level nor to a parapet wall or cornice nor to radio or television receiving antennas, transmission towers and cables or other similar structures, provided that they do not exceed the height limit by more than five feet.