Arlington County C-1-O Limited Commercial-Professional Office Building District Setback Requirements
In the C-1-O Limited Commercial-Professional Office Building District of Arlington County, structures must adhere to a front setback that is the greater of 50 feet from the street centerline or 25 feet from the street right-of-way line. Side yard requirements start at a minimum of 10 feet but must increase based on the height of the building, while rear yards for interior lots are strictly required to be at least 25 feet deep.
Primary Setback and Yard Standards
The Arlington County Zoning Ordinance establishes the following placement requirements for the C-1-O Limited Commercial-Professional Office Building District. These standards ensure appropriate spacing between structures to facilitate light, air, and safety [Section 3.2.1].
| Setback Type | Minimum Requirement |
|---|---|
| Front Setback (from Street) | The larger of 50 feet from the street centerline OR 25 feet from the street right-of-way line [Section 3.2.6.A.1(d)] |
| Side Yard (Base) | 10 feet minimum [Section 3.2.6.A.2(e)] |
| Side Yard (Height Adjustment) | For buildings taller than 25 feet, add 1 foot of side yard for every 2.5 feet (or fraction thereof) of height above 25 feet [Section 3.2.6.A.2(e)] |
| Rear Yard (Interior Lot) | 25 feet minimum [Section 3.2.6.A.2(e)] |
Specific District Application
While Article 7 of the Arlington County Zoning Ordinance contains the specific provisions for commercial and mixed-use districts, Section 7.9.3.B explicitly states that bulk, coverage, and placement requirements not listed within the C-1-O district's specific section default to the general measurements and standards found in Article 3 [Section 7.9.3.B].
Unlike many other commercial districts in Arlington County, the C-1-O district is specifically excluded from the "no side or rear yard required" allowance. This highlights its intended function as a low-intensity transitional district where building placement must more closely resemble residential patterns [Section 3.2.6.A.2(a)].
Visual Clearance and Street Frontage
In addition to standard setbacks, the C-1-O Limited Commercial-Professional Office Building District is subject to safety-related placement rules:
Visual Clearance at Corners
On any corner lot within the C-1-O district, no building or obstruction is permitted between a height of one foot and 10 feet above the curb level within the sight triangle. This triangle is formed by the street right-of-way lines and a diagonal line connecting those lines at points 10 feet from the intersection [Section 3.2.6.A.4(b)].
Minimum Street Frontage
Every building erected in Arlington County, including those in the C-1-O district, must be located on a lot with a minimum of 30 feet of frontage on a public street [Section 1.5].
Permitted Encroachments
Arlington County permits certain architectural features to extend into the required setbacks and yards:
- Architectural Features: Chimneys, bay windows, and oriel windows without floor space may encroach up to 18 inches into required yards [Section 3.2.6.A.3(a)(1)].
- Unenclosed Features: Balconies, eaves, trim, fascia boards, window wells, areaways, stoops, and decks/patios (at least eight inches above grade) may encroach up to four feet into required yards, provided they remain at least five feet from any property line [Section 3.2.6.A.3(a)(3)].
- Mechanical Equipment: Air conditioning units and similar mechanical equipment may be placed in side or rear yards, but must be at least eight feet from a side lot line and 10 feet from a rear lot line [Section 3.2.6.A.3(b)].
Sections Cited
- §1.5 Street Frontage Required
- §3.2.1 Purpose (Bulk, Coverage and Placement)
- §3.2.6.A.1 Setbacks from any street
- §3.2.6.A.2 Side and rear yards
- §3.2.6.A.3 Encroachments allowed into required yards and courts
- §3.2.6.A.4 Visual clearance (corners)
- §7.9.3.B Bulk, coverage and placement (C-1-O District)