Except as provided in § 634.4, no structure, including an accessory building devoted to residential use, shall occupy more than seventy- five percent (75%) of the lot upon which it is located.
For the purposes of this section, the percentage of lot occupancy may be calculated on a horizontal plane located at the lowest level where residential uses begin.
For the purposes of this section, "residential uses" includes dwellings, flats, multiple dwellings, rooming and boarding houses, hospitals, and community-based residential facilities.
No public recreation and community center shall occupy more than twenty percent (20%) of the lot upon which it is located; except that it may occupy up to forty percent (40%) if approved by the Board of Zoning Adjustment pursuant to § 3104.1, provided that the agency shows that the increase is consistent with agency policy of preserving open space.
D.C. Mun. Regs. tit. 11, r. 11-634