1504.1 Except as exempted by Subtitle C §§ 1504.2 to 1504.4, a penthouse or rooftop structure shall be set back from the edge of the roof upon which it is located, measured from a point where a line extending from the top of the roof intersects with the outside face of the building enclosing wall, as follows:

1. (a) A distance equal to its height from the front building wall of the roof upon which it is located;
2. (b) A distance equal to its height from the rear building wall of the roof upon which it is located;
3. (c) A distance equal to its height from a side building wall of the roof upon which it is located if:
4. (1) The side building wall is not located on a property line;
5. (2) The side building wall faces a public or private street or alley right-of way, or a public park;
6. (3) The adjacent property along the shared side lot line has a lower permitted matter-of-right building height; or
7. (4) The adjacent property along the shared side lot line is improved with a building that is a designated landmark or contributing structure to a historic district with a height at least ten feet (10 ft.) below the maximum height permitted in its zone;
8. (d) A distance equal to its height from building walls that border all sides of an open court on the property; or
9. (e) A distance equal to two (2) times its height from any building wall of the roof upon which it is located which fronts onto Independence Avenue, S.W. between 12^th Street, S.W. and 2^nd Street, S.W., or fronting onto Pennsylvania Avenue, N.W. between 3^rd Street, N.W. and 15^th Street, N.W., subject to any constraints on penthouses or rooftop structures contained within adopted PADC Guideline documents.

1504.2 The front, rear, side, and open court setback requirements of Subtitle C §§ 1504.1(a)-(d) shall not apply to features meeting the following conditions:

(a) Parapets;

(b) Roof membranes, and green roof mediums that do not exceed a height of two feet (2 ft.), measured from the surface of the roof upon which they sit;

(c) Roof decks, platforms, or other rooftop features that do not exceed a height of twelve inches (12 in.) maximum above the roof, measured from the surface of the roof upon which they sit;

(d) On the roof of any building or structure not noted in Subtitle C § 1504.3(c), solar panels not attached to or hanging down from the side of a penthouse, rooftop structure, or parapet, that do not exceed a height of four feet (4 ft.) maximum above the roof, measured from the surface of the roof upon which they sit;

(e) Guardrails required by the building code for a deck not located on the highest roof of a building;

(f) Guardrails or privacy fences on the top of a one- (1) story accessory building, provided the total height of the building including the guardrail or privacy fence does not exceed the height permitted for an accessory building in the zone; or

(g) Mechanical equipment or screening for mechanical equipment on the roof of a public school, recreation center, or library.

1504.3 In addition to the exemptions of Subtitle C § 1504.2, the rear, side, and open court setback requirements of Subtitle C §§ 1504.1(b)-(d) shall not apply to features meeting the following conditions:

(a) For a rooftop deck on the highest roof a building, guardrails required by the building code that do not exceed a height of three feet, six inches (3 ft., 6 in.), when the façade is not facing a public or private street or a public park;

(b) Gooseneck exhaust ducts serving kitchen and toilet ventilating systems, roof mounted antennas, trash chutes, plumbing vent stacks, HVAC compressors, or other similar mechanical equipment;

(c) On the roof of a one (1) family dwelling or flat, or an accessory building to those uses, solar panels not attached to or hanging down from the side of a penthouse, rooftop structure, or parapet, that do not exceed:

(1) For rooftop-mounted panels, a two feet (2 ft.) maximum height

above the roof, measured from the surface of the roof upon which they sit; or

(2) For parapet-mounted panels, a one foot (1 ft.) maximum height above the top of the side wall parapet.

(d) Roof hatches that do not exceed a height of four feet (4 ft.), measured from the surface of the roof upon which they sit; or

(e) Skylights that do not exceed a height of two feet (2 ft.), measured from the surface of the roof upon which they sit.

1504.4 The open court setback requirements of Subtitle C § 1504.1(d) shall further not apply to a rooftop access stairwell or elevator.

SOURCE: Final Rulemaking published at 63 DCR 2447, 2712 (March 4, 2016 – Part 2); as amended by Final Rulemaking published at 64 DCR 22 (January 6, 2017); as amended by Final Rulemaking published at 64 DCR 6110 (June 30, 2017); as amended by Final Rulemaking published at 68 DCR 013834 (December 24, 2021).