(1) Where doubt exists as to height of fences, hedges, masonry or retaining walls, etc., provided for in this Title, height shall be measured from the average finished grade of the yard or yards in which fences, hedges, masonry or retaining walls, etc. are located.

(2) The height limitations of this Title shall not apply to church spires, belfries, cupolas, or domes not used for human occupancy, nor to chimneys, ventilators, skylights, water tanks, silos, cornices without windows, antennas, radio towers, or properly screened mechanical appurtenances usually carried above the roof level of a building; except in no case shall it be lawful to construct, build, or establish a building, tree, smokestack, chimney, flagpole, wire, tower, or other structure or appurtenances thereto which may constitute a hazard or obstruction to navigation or landing and take-off of aircraft at a publicly used airport. Regulations established by the Federal Aviation Agency shall be considered to be the minimum acceptable standards for facilities in such an area.