In the case of damage or destruction of less than 75 percent of the total floor area of a non-conforming building containing three or more dwelling units in an M1-1D, M1-2D, M1-3D, M1-4D or M1-5D District, such building may be repaired or reconstructed, and its residential use continued, subject to the following regulations:

(a)        there shall be no increase in the number of dwelling units in the building beyond the lawful number in existence prior to such damage and destruction; and

(b)        there shall be no increase to the pre-existing amount of floor area except as expressly provided in Section 52-46 (Conforming and Non-conforming Residential Uses in M1-1D Through M1-5D Districts).

Enlargements in excess of those permitted, pursuant to paragraph (b) of this Section, may be permitted by authorization of the City Planning Commission pursuant to the regulations of Section 42-311 (Residential uses in M1-1D through M1-5D Districts).