OAR 806-010-0002: Definitions of Building Size Limitations

As set forth in ORS 671.030: (1) "Ground Area" shall be measured to include the total area within all surrounding exterior walls and includes areas not provided with surrounding walls under the horizontal projections of a roof or floor above. Measurements extend to the outside face of the exterior walls and the edge of horizontal projections. (2) "Height" shall be measured from the top surface of the lowest occupiable floor to the highest interior overhead finish of the structure in determining whether a building exceeds the 20 foot height limitation. A basement floor is considered the lowest floor when useable (i.e., storage, garage, etc.)