D.C. Mun. Regs. tit. 11, r. 11-2001
The restrictions set forth in this section shall apply to a nonconforming structure devoted to a conforming use.
Except as provided in §§ 2001.11 and 2001.12, ordinary repairs, alterations, and modernizations to the structure, including structural alterations, shall be permitted.
Enlargements or additions may be made to the structure; provided:
If a nonconforming structure is destroyed by fire, collapse, explosion, or act of God to an extent of more than seventy-five percent (75%) of the cost of reconstructing the entire structure, the nonconforming structure shall not be restored or reconstructed except in conformity with all provisions of this title, except as provided otherwise in §§ 2001.5 through 2001.10.
If a casualty or act of God results in damage to an extent of more than seventy-five percent (75%), and if the structure is nonconforming only with respect to percentage of lot occupancy, lot area, or width of lot, the structure may be reconstructed or restored to its previous condition or to a more conforming condition, even if that condition does not comply with the applicable percentage of lot occupancy, lot area, or width of lot requirements.
If a casualty or act of God results in damage to an extent of seventy-five percent (75%) or less of the cost of reconstructing the entire structure, the structure may be restored or reconstructed to its previous condition or to a more conforming condition; provided, that the reconstruction or restoration shall be started within twenty-four (24) months of the date of the destruction and continued diligently to completion.
If there is a dispute between the property owner and the Zoning Administrator as to whether the structure has been destroyed to the extent of seventy-five percent (75%) of reconstruction cost, the costs of restoration and of reconstruction shall be determined by the average of the estimates furnished by three (3) independent qualified contractors. One (1) contractor shall be selected by the owner, one (1) by the Zoning Administrator, and one (1) by the first two (2) mentioned contractors.
The estimates required by § 2001.7 shall be prepared and submitted according to a standard procedure and format established by the Zoning Administrator, and the cost of estimates shall be at the expense of the property owner.
Notwithstanding the restrictions of § 2001.4, a nonconforming structure that is a historic landmark or certified by the State Historic Preservation Officer to be a structure that contributes to the character of the historic district within which it is located, may be restored or reconstructed regardless of the extent of destruction of the structure, subject to the provisions of the Historic Landmark and Historic District Protection Act of 1978, effective March 3, 1979, D.C. Law 2-144, as amended; D.C. Official Code §§ 6-1101 to 6-1115 (2001)(formerly codified at D.C. Code §§ 5-1001 to 5-1015 (1994 Repl. & 1999 Supp.))), and all other municipal laws and regulations.
The twenty-four (24) month period provided in § 2001.6 may be extended for as long as it takes to apply for and receive any governmental approvals necessary to accomplish the reconstruction or restoration, including but not limited to, approvals from the Board of Zoning Adjustment, the Historic Preservation Review Board, and the Mayor's agent for the Historic Landmark and Historic District Protection Act.
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If a nonconforming antenna stops functioning, a temporary replacement antenna may be installed, subject to the following conditions:
A public recreation and community center in existence as of November 28, 2003 may enlarge or make an addition that causes the structure to exceed lot occupancy requirements if approved by the Board of Zoning Adjustment in accordance with the provisions of § 3104.1.
D.C. Mun. Regs. tit. 11, r. 11-2001