In C2 Districts, the street wall location regulations of the underlying district shall apply except as modified in this Section.

(a)        In C2 Districts mapped within R6 and R7-1 Districts, at least 70 percent of the aggregate width of street walls shall be located within eight feet of the street line and shall extend to at least the minimum base height specified in Section 136-222 (Minimum and maximum base height), or the height of the building, whichever is less. Up to 30 percent of the aggregate width of street walls may be recessed beyond eight feet of the street line, provided that any such recesses deeper than 10 feet along a wide street or 15 feet along a narrow street are located within an outer court. For zoning lots bounded by more than one street line, these street wall location requirements shall be mandatory on only one street line.

(b)        In C2 Districts mapped within R5 Districts, at least 70 percent of the aggregate width of street walls shall be located within eight feet of the street line and shall extend to a height of 30 feet, or the height of the building, whichever is less. Up to 30 percent of the aggregate width of street walls may be recessed beyond eight feet of the street line, provided that any such recesses deeper than 10 feet along a wide street or 15 feet along a narrow street are located within an outer court. For zoning lots bounded by more than one street line, these street wall location requirements shall be mandatory on only one street line.

(c)        Below a height of 15 feet or the height of the second story floor, whichever is lower, no recesses shall be permitted within 30 feet of the intersection of two street lines except recesses that do not exceed a depth of 12 inches.

The underlying allowances for street wall articulation, set forth in paragraph (e) of Section 35-651 (Street wall location) shall be permitted to project or recess beyond the street wall locations established in paragraphs (a) and (b) of this Section.

Existing buildings may be vertically enlarged by up to one story or 15 feet, without regard to the street wall location requirements of this Section.