Penthouses or roof structures or the housing of elevators, stairways, tanks, ventilating fans or similar equipment required to operate and maintain the building and fire or parapet walls, skylights, towers, steeples, flagpoles, chimneys, smokestacks, personal television antennas, water tanks, silos, churches or similar structures, may be erected above the maximum height permitted in each district. No structure or penthouse shall be allowed for purposes of providing additional floor space. (Ord. 2433 § 2, 2000)