Ballpark: The building and use authorized by Zoning Commission Order No. 06-22.

Basement: That portion of a story partly below grade, the ceiling of which is four feet (4 ft.) or more above the adjacent finished grade.

Bicycle Parking: See Parking Space, Bicycle.

Blockface: The entire front lot line of all building façades of a square between two (2) streets.

Board of Zoning Adjustment (Board): An independent quasi-judicial body empowered to grant relief from the strict application of the Zoning Regulations (variances), approve certain uses of land (special exceptions), and hear zoning appeals.

Boarding House: A building or part thereof where, for compensation, lodging and meals are provided to three (3) or more guests on a monthly or longer basis.

Boathouse: A building or structure designed and used to store and provide water access for non-motorized watercraft, including racing shells, kayaks, canoes, sailboats, rowboats, and similar boats.

Building: A structure requiring permanent placement on the ground that has one (1) or more floors and a roof supported by columns or walls. When separated from the ground up or from the lowest floor up, each portion shall be deemed a separate building, except as provided elsewhere in this title. The existence of communication between separate portions of a structure below the main floor shall not be construed as making the structure one (1) building.

Building, Accessory: A subordinate building located on the same lot as the principal building, the use of which is incidental to the use of the principal building.

Building Area: The maximum horizontal projected area of a principal building and its accessory buildings. Except for outside balconies, this term shall not include any projections into open spaces authorized elsewhere in this title, nor shall it include portions of a building that do not extend above the level of the main floor of the main building, if placed so as not to obstruct light and ventilation of the main building or of buildings on adjoining property.

Building area shall not include: Building components or appurtenances dedicated to the environmental sustainability of the building; cornices and eaves; sills, leaders, belt courses, and similar ornamental or structural features; awnings, serving a window, porch, deck or door; uncovered stairs, landings, and wheelchair ramps that serve the main floor; and chimneys, smokestacks, or flues.

Building, Attached: A building that abuts or shares walls on both side lot lines with other buildings on adjoining lots.

Building, Detached: A freestanding building that does not abut any other building and where all sides of the building are surrounded by yards or open areas within the lot.

Building Envelope: The maximum three (3) dimensional space on a lot in which a building may be built as limited by the applicable development standards and other relevant limits and conditions of this Title.

Building Façade: An exterior vertical plane, face, or side of a building, exclusive of any permitted projections.

Building, Height of: In other than R, RF, RA, RC-1, CG-1, and D-1 zones, the vertical distance measured from the level of the curb, opposite the middle of the front of the building to the highest point of the roof or parapet or a point designated by a specific zone district; in Residential (R) zones the vertical distance measured at the existing grade at the midpoint of the building façade of the principal building that is closest to a street lot line to a point designated in the zone district. Berms or other forms of artificial landscaping shall not be included in measuring building height.

The term “curb” shall refer to a curb at grade. When the curb grade has been artificially changed by a bridge, viaduct, embankment, ramp, abutment, excavation, tunnel, or other type of artificial elevation or depression, the height of a building shall be measured using Rules of Measurement for Height (Subtitle B § 308).

Building Height Measuring Point (BHMP): The point used to measure building heights in R, RF, and RA zones.

Building Line: A line beyond which property owners have no legal or vested right to extend a building or any part of the building without special permission and approval of the proper authorities; ordinarily a line of demarcation between public and private property, but also applied to building restriction lines, when recorded on the records of the Surveyor of the District of Columbia.

Building, Principal: The building in which the primary use of the lot is conducted.

Building, Semi-detached: A building that abuts or shares one (1) wall, on a side lot line, with another building on an adjoining lot and where the remaining sides of the building are surrounded by open areas or street lot lines.

Building, Separate: Structures that are separated from the ground up by common division walls or contain multiple sections separated horizontally, such as wings or additions, are separate buildings. Structures or sections shall be considered parts of a single building if they are joined by an enclosed connection that is fully above grade, is heated and artificially lit; and either a common space shared by users of all portions of the building, such as a lobby or recreation room, or space that is designed and used to provide free and unrestricted passage between separate portions of the building, such as an unrestricted doorway or walkway.

Build-to Line: A front setback line that the front façade of the principal building of the lot must abut.

Bulkhead: A retaining wall or protective structure along a shoreline whose primary purpose is to stabilize, hold, or prevent earth or backfill from eroding or washing away. For purposes of this definition, the term bulkhead does not differentiate between and includes bulkheads, seawalls, and revetments.