No part of a yard or other open space about any building, structure
or use, required for the purpose of complying with the provisions
of this article, shall be included as a part of a yard or open space
similarly required for another building, except when specifically
authorized.
Where a minimum depth of front yards is specified in Article
500, an open space of at least the specified depth shall be provided
between the street line or lines and the nearest point of any building
or structure, except as shall be permitted hereafter. As provided
in Article 200, street lines are considered to be established by future
rights-of-way when so designated. The purpose of this provision is
to avoid interference with future street widenings and improvements.
If the alignment of existing buildings on either side of a lot,
within a distance of 50 feet of the proposed building and fronting
on the same side of the same street in the same block, is nearer to
the street than the required front-yard depth, the average of such
existing alignment within that distance shall be the required front
yard.
Projections, as defined in Article 200, shall not occur in front
yards.
The provisions of § 212-509 shall not apply to front
fences or walls less than four feet high above the natural grade in
the required front yard nor to terraces, steps, uncovered porches
or unenclosed porches nor to other similar features less than three
feet above the level of the floor of the ground story of the principal
structure.
Bays, balconies, chimney flues and fire escapes may project
into a required side yard not more than 1/3 of the width of the projection,
but no more than four feet in any case. Ground-story bays and porches
which encroach on a side yard shall not exceed half the length of
the side wall and may project into any required side yard 3 1/2
feet. In neither instance shall the projection be within 3 1/2
feet of the lot line of side yards.
The provisions of § 212-513 shall not apply to fences
or walls less than six feet above the natural grade nor to terraces,
steps, uncovered porches or other similar features less than three
feet above the floor of the ground story of the principal structure.
No portion of a principal building or structure shall be built
within the minimum rear yard specified in §§ 212-501
and 212-502, except as permitted in § 212-518.
Such projections into side yards, as permitted by § 212-514,
shall also be permitted into rear yards up to the same number of feet,
but in no case within five feet of an accessory building.
Structures, such as, but not limited to, television and radio
towers, monuments, tanks, water and fire towers, ornamental towers
and spires, chimneys, silos, elevator bulkheads, conveyors and flagpoles,
may exceed the height regulation herein prescribed, provided that
each required front, side and rear yard shall be increased by one
foot for each foot of additional height above 35 feet and that the
height of such structures will not constitute a hazard. The Allegheny
County Airport Zoning Committee shall be consulted and a permit secured,
if applicable.