The Town of Islip set out the word usages and definitions to be used in their zoning requirements. All accessory buildings must be restricted to one story in height. Building height is determined by looking at the vertical distance from the average grade of the ground at the base of the structure to the highest point of roof, excluding chimneys, spires, and other permitted projections. For any single-family homes in a special flood hazard area, the building height shall be measured from the average grade of the ground at the base of the structures or at the minimum elevation necessary to meet the prerequisites for federal flood insurance. The Commissioner of Planning shall be responsible for any interpretations concerning average grade and/or base flood elevation.