Because the Zoning Regulations contain several provisions regarding the regulation of Accessory Buildings, the Office of Zoning Administrator has summarized these regulations in RF zones for clarity:
RF Zone Accessory Building Regulations – Excerpts of 11 DCMR Subtitle E, Chapter 50
E-5002 HEIGHT
5002.1 The maximum permitted height for an accessory building in an RF zone shall be twenty feet (20 ft.) and two (2) stories, including the penthouse.
E-5003 LOT OCCUPANCY
5003.1 The maximum lot occupancy for an accessory building in an RF zone shall be the greater of thirty percent (30%) of the required rear yard area or four-hundred and fifty square feet (450 sq. ft.).
E-5004 REAR YARD
5004.1 No minimum rear yard is required for an accessory building in an RF zone except when abutting an alley, where it shall be set back at least twelve feet (12 ft.) from the center line of the alley.
5004.2 An accessory building shall be permitted in a required rear yard of a principal building pursuant to the following conditions:
(a) The accessory building is less than ten feet (10 ft.) in height; and
(b) The accessory building is less than one hundred square feet (100 sq. ft.) in gross floor area.
5004.3 If the required rear yard of the principal building in which the accessory building will be placed abuts an alley, the accessory building shall be set back at least twelve feet (12 ft.) from the center line of the alley.
Narrative of Zoning Administrator Interpretation
Both Sections E-5003 and E-5004 requirements apply to the siting of Accessory Buildings in the Rear Yard, but they are distinguished as follows:
The Section E-5003.1 provision is actually a Maximum Accessory Building Footprint limitation [The Zoning Administrator believes that the “Lot Occupancy” title label is a misnomer], and the provision denotes a limit that references 30% of the required rear yard area, which is irrespective of the location (whether or not such Accessory Building is actually within the required rear yard or not). Also, the Zoning Administrator notes that the proposed accessory building area (from E-5003.1) is added to the building area or building footprint(s) on the lot, for an overall maximum permitted lot occupancy.
The Section E-5004.2(a) provision limits an accessory building height to 10 feet when it is located in the required rear yard; outside of that required rear yard area, or elsewhere in the rear yard, such an accessory building may be built up to the 20 foot, 2-story limit accessory building height limit under E-5002.1.
The Section E-5004.2(b) provision essentially limits an accessory building gross floor area [GFA] when it is located in the required rear yard; which is measured form the rear wall of the principal building out towards the rear property line. The effect of this regulation (and subsection (a) noted above) is to allow only a small storage shed-like accessory building in this required rear yard, [within the 20 foot required rear yard as measured from the principal building’s rear wall in a RF zone] but beyond that, if there is room on the lot, then a larger accessory building that may be suitable for a dwelling unit can be sited – typically closer to the rear lot line, and to an alley, if one is present.