(A) Number of main buildings on tract. No more than one main building shall be located on a tract or lot when used for residential purposes. When a tract or lot is used for commercial purposes, more than one main building may be located on the tract or lot provided such buildings conform to all yard requirements around the lot for the district in which the tract or lot is located.
(B) Adjustments to front yard requirements. Where, on the effective date of these regulations, 40% or more of a frontage was occupied by two or more buildings, then the front yard is established in the following manner:
(1) Where the building furthermost from the street provides a front yard not more than ten feet deeper than the building closest to the street, then the front yard for the frontage is and remains an average of the then existing front yards.
(2) Where division (1) is not the case and a lot is within 100 feet of a building on each side, then the front yard is a line drawn from the closest front corners of these two adjacent buildings.
(3) Where neither division (1) nor (2) is the case, and the lot is within 100 feet of an existing building on one side only, then the front yard is the same as that of the existing adjacent building.
(C) Adjustment to side yard requirements. Buildings with side yard setbacks less than required by this chapter, may have additions erected in line with the existing building and provided further that said addition will be erected no closer to the lot line then the existing building.
(D) Projections from buildings. Every part of any required yard shall be open to the sky and unobstructed except:
(1) Eaves may project into a front or rear yard 36 inches, exclusive of gutters;
(2) Eaves may project into a side yard 24 inches, exclusive of gutters;
(3) Ordinary projection of sills, belt courses, cornices, vertical solar screen, and ornamental features which may project 12 inches;
(4) Air conditioners, not to exceed five ton unit or parts thereof, may project into a required side yard, provided that such projections shall be distant at least three feet from the adjacent lot line and shall not extend more than three feet from the building. Such air conditioners may project into a required front yard, but shall not extend more than three feet from the building, and such air conditioner may extend into one side of a corner lot; or
(5) Solar collectors which are a part of the main building may extend into a required rear yard for a distance not to exceed ten feet.
(E) Porches and terraces in front yards.
(1) An open, unenclosed porch may project into a required front yard for a distance not exceeding ten feet. Balconies and paved terraces may project into a required front yard for a distance not exceeding six feet.
(2) An enclosed vestibule containing not more than 40 square feet may project into a required front yard for a distance not to exceed four feet.
(F) Projection of terraces, porches, platforms, and ornamental features. Terraces, uncovered porches, platforms, and ornamental features which do not extend more than three feet above the floor level of the ground (first) story may project into a required side or rear yard, provided these projections be distanced at least three feet from the adjacent side lot line.