No building shall be erected to a height in excess of 35 feet above average curb elevation on adjacent street; provided, however, that this limitation shall not apply to churches, public buildings, flagpoles and monuments, nor to domes, cupolas and chimneys, air-conditioning enclosures, provided that the aggregate horizontal area of such parts shall not exceed 10% of the ground area covered by the main building. Radio and television antennas, poles, masts or towers shall not exceed 50 feet in height above ground level measured from the structure on which located.