BUILDING HEIGHT - The vertical distance (measured from the grade level) to the highest level of the roof surface of flat roofs; to the deck line of mansard roofs; or to the mean height between eaves and ridge for gable, gambrel or hip roofs. Except where specifically provided in this Ordinance, building height does not apply to portions of buildings extending above the general roof line and comprising an aggregate area not greater than twenty-five percent (25%) of the total roof area, or to structures other than buildings.
I found this on a town zoning site that had some definitions. -Steve