Except as provided elsewhere in this title, the minimum side yard shall be as set forth in this section.
Side yards for a detached or semi-detached building containing one (1) or two (2) dwelling units shall be a minimum of eight feet (8 ft.). No side yards shall be required for a row building containing one (1) or two (2) dwelling units.
Except as provided in Subtitle F § 208.2, the following side yard rules apply:
A side yard shall not be required along a side street abutting a corner lot in any of the RA-1, RA-2, RA-3, RA-4, and RA-5 zones.
Existing conforming side yards shall not be reduced to a nonconforming width or eliminated.
In the case of a building with a non-conforming side yard, an extension or addition may be made to the building; provided, that the width of the existing side yard shall not be reduced or eliminated; and provided further, that the width of the side yard adjacent to the extension or addition shall be a minimum of three feet (3 ft.).
In the case of a lot proposed to be used by a public library or public recreation and community center where a side lot line abuts or adjoins a public open space, recreation area, or reservation, no side yard shall be required.
D.C. Mun. Regs. tit. 11, r. 11-F208