D.C. Mun. Regs. tit. 11, r. 11-1502
The DC Overlay District is mapped in combination with the underlying Commercial, Special Purpose, Mixed Use, and Residence Districts and not instead of the underlying zone districts.
Except as specifically provided in § 1502.3 and in other provisions of this chapter, all matter-of-right uses, buildings, and structures permitted in accordance with this chapter and the appropriate regulations of the underlying district with which the mapped DC Overlay District is combined, shall be permitted in the combined district.
Where there is a conflict between this chapter and the underlying zoning, the more restrictive provisions of this title shall govern. Where other chapters provide for additional requirements for planned unit developments, those additional requirements continue to apply.
D.C. Mun. Regs. tit. 11, r. 11-1502