The regulations set forth in Section 23-461 (Side yards for single- or two- family residences) pertaining to R4A Districts shall apply to detached buildings. The regulations in that Section pertaining to R4-1 Districts shall apply to semi-detached residences.

For an existing single- or two-family residence with a non-complying side yard, an enlargement involving a straight line extension of the existing building walls facing such non-complying side yard is permitted, provided that:

(a)        the portion of the building which is enlarged complies with the height and setback regulations set forth in Section 113-55;

(b)        the minimum distance between such building wall and the nearest building wall, or prolongation thereof, on an adjoining zoning lot across the common side lot line is eight feet;

(c)        the enlarged building does not contain more than two dwelling units;

(d)        there is no encroachment on the existing non-complying side yard, except as set forth in this Section; and

(e)        the enlargement does not otherwise result in the creation of a new non-compliance with the applicable bulk regulations.