From the ordinance
Building, height of, means the vertical distance measured from the level of the curb or the established curb grade opposite the middle of the front of the building to the highest point of the roof if a flat roof; to the deck line of a mansard roof; or to the mean height level between the eaves and ridge of a gable, hip or gambrel roof; for buildings set back from the street line, the height shall be measured from the average elevation of the ground surface along the front of the building.