Permitted exceptions. Chimneys, cooling towers, elevators, bulkheads, fire towers, gas tanks, grain elevators, solariums, steeples, penthouses, stage towers or scenery lofts, tanks, water towers, ornamental towers or spires, communications or radio or television towers or necessary mechanical appurtenances may be erected as to their height in accordance with ordinances of the City, provided no tower other than a church spire or tower of a public building shall exceed the height regulations by more than 25%. No tower shall be used as a place of habitation nor shall an advertising device of any kind whatsoever be inscribed upon or attached to any chimney, tower, tank or other structure which extends above the height limitations.