D.C. Mun. Regs. tit. 11, § 1518
1518.1 The principal building and any accessory building on the lot shall not exceed total lot occupancy of thirty percent (30%).
1518.2 The maximum impervious surface coverage on a lot shall be fifty percent (50%); provided this subsection shall not:
(a) Preclude enlargement of a principal building in existence as the effective date of the FH/TSP overlay; or
(b) Create nonconformity of a structure as regulated by Chapter 20 of this title.
1518.3 To the extent a side yard is required in the underlying zone district, the minimum side yard requirement for all buildings, accessory buildings, or additions to buildings shall be twenty-four (24) feet in the aggregate, with no single side yard having a width of less than eight (8) feet.
SOURCE: Final Rulemaking published at 54 DCR 4835, 4841 (May 18, 2007).