Certain architectural features may project into required yards or courts as follows:
(a) Front and Side Yards. Into any required front yard, or required side yard adjoining a side street lot line: Cornices, canopies, eaves or other architectural features, may project a distance not exceeding two feet, six inches. Fire escapes may project a distance not exceeding four feet, six inches.
An uncovered stair and necessary landings may project a distance not to exceed six feet, provided such stair and landing shall not extend above the entrance floor of the building except for a railing not exceeding three feet in height.
Bay windows, balconies and chimneys may project a distance not exceeding three feet, provided that such features do not occupy, in the aggregate, more than one- third of the length of the building wall on which they are located.
(b) Interior Side Yards. Subject to the limitations in subsection (a) hereof the features named in such subsection may project into any required side yard adjoining an interior side lot line, a distance not to exceed one-fifth of the required least width of such side yard, but not exceeding three feet in any case.
(c) Rear Yards. Subject to the limitations in subsection (b) hereof, feature. named therein may project into any required rear yards the same distance they are permitted to project into a front yard.