RA8-18 Multiple-Family Dwelling District Setback Requirements

In the RA8-18 Multiple-family Dwelling district in Arlington County, the front setback must be the larger of 25 feet from the street right-of-way or 50 feet from the street centerline. Side and rear setbacks for multi-family structures start at a minimum of 10 feet and increase based on the building's height, while interior lots require a specific minimum rear yard of 25 feet [§3.2.6.A].

General Setback Requirements for RA8-18

The RA8-18: Multiple-family Dwelling district in Arlington County follows the placement and setback regulations established in the general "Bulk, Coverage, and Placement" standards unless specifically modified by the County Board through site plan approval [§6.3.4.B].

Front Setbacks (Street Placement)

The placement of any building or structure in the RA8-18 Multiple-family Dwelling district relative to the street is determined by the following standards:

Structure Type	Required Front Setback
Standard Residential (Multi-family)	The larger of 50 feet from the centerline of any street OR 25 feet from any street right-of-way line [§3.2.6.A.1(d)].
One-family Detached Use	Minimum of 25 feet from the street right-of-way line. This may be reduced to the average distance of existing structures on the same frontage, provided it is at least 15 feet [§3.2.6.A.1(e)].

Side and Rear Setback Requirements

Arlington County regulates side and rear yards in the RA8-18 Multiple-family Dwelling district based on both the lot type and the total height of the proposed building.

Setback Type	Standard Requirement for RA8-18 District
Side Yard (Standard)	10 feet base, plus 1 additional foot for each 2.5 feet of building height above 25 feet [§3.2.6.A.2(e)].
Rear Yard (Interior Lot)	Minimum of 25 feet from the rear lot line [§3.2.6.A.2(e)].
Rear Yard (Other Lots)	10 feet base, plus 1 additional foot for each 2.5 feet of building height above 25 feet [§3.2.6.A.2(e)].
Side Yard (One-family Use)	10 feet, though one side may be reduced to 8 feet. The aggregate of both side yards must be at least 30% of the lot width [§3.2.6.A.2(b)].

Permitted Encroachments into Setbacks

The Arlington County Zoning Ordinance allows specific features to project into required yards and courts within the RA8-18 Multiple-family Dwelling district subject to certain limitations [§3.2.6.A.3]:

18 Inches: Bay and oriel windows (without floor space) and chimneys.
4 Feet: Balconies, eaves, trim, fascia boards, window wells, areaways, stoops, and unattached decks/patios (if the deck/patio is at least 8 inches above finished grade).
Porches (Interior Lots): May encroach 4 feet into the required front and rear yards, provided they remain at least 21 feet from the street right-of-way line.
Stairs and Steps: May encroach to within 5 feet of any lot line. If they are less than 8 inches above grade, they may extend all the way to the lot line.

Special District Exceptions (Fort Myer Heights North)

If an RA8-18 Multiple-family Dwelling district site is located within the "Revitalization Area" of the Fort Myer Heights North Special District, the County Board has the authority to modify standard setbacks [§9.3]. Through a special exception site plan approval, the Board may approve variations in setbacks to achieve a design that preserves historic buildings or significant trees, or to meet specific affordable housing goals outlined in the Fort Myer Heights North Plan [§9.3.5].

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