Sec. 24. Walls.
For the purpose of determining wall thickness as specified in
this section, basements and sub-basements shall be considered as
stories.
The exterior or division walls of all buildings hereafter erected
within the corporate limits shall be of sufficient thickness to support
the load to be carried; but in no case shall a brick, stone, concrete
or hollow block wall be less than twelve inches thick except
panel walls, non-load bearing and in dwelling house class.
Walls, for warehouse class only (excepting party and fire walls,
for all buildings of other than the dwelling house class) not exceeding
four stories or fifty-five feet in height, shall have the
upper two stories not less than twelve inches thick, increasing four
inches in thickness for each two stories or fraction thereof below.
For all walls of buildings of the dwelling house class the upper
two stories shall be not less than eight inches thick, increasing four
inches in thickness for each two stories or fraction thereof below,
excepting that gable walls shall not necessitate an increase in wall
thickness.
Panel walls in skeleton construction must be of masonry laid in
cement mortar or masonry cement if approved and shall be at
least eight inches thick where the vertical distance between girders
does not exceed ten feet and shall be increased four inches for each
ten feet or fraction thereof that the said vertical distance exceeds
ten feet.
Curtain walls must be of masonry laid in cement mortar or
masonry cement mortar if approved and shall be not less than
twelve inches thick, increased four inches for every additional section
of three stories or forty-five feet. They shall be anchored to
the framing at each floor level, anchors spaced not more than six
feet apart horizontally.
In all buildings except dwellings, frame buildings and skeleton
construction, party walls and fire walls which serve as bearing
walls on both sides shall be not less than sixteen inches thick in
the upper two stories or upper thirty feet, increasing four inches
in thickness for each two stories or fraction thereof below. All
other fire walls shall be not less than twelve inches thick in the
upper four stories for upper fifty feet, increasing four inches in
thickness for each two stories or fraction thereof below. Portland
cement mortar or approved masonry cement mortar only shall be
used in such walls.
Reinforced stone or gravel concrete walls, with the steel reinforcement
running both horizontally and vertically and weighing
not less than one-half pound per square foot of wall, may have a
thickness four inches less than that prescribed for brick walls.
Walls built of rubble stone shall be increased one-third inch in
thickness over that required for brick walls under similar circumstances.
Parapets shall be provided on all fire walls, party walls and exterior
walls of masonry or reinforced concrete, where such walls
connect with roofs other than roofs of fireproof construction; provided,
that a parapet shall not be required for a wall facing on a
street having a width of fifty feet or more, which are finished with
incombustible cornices, gutters or crown mouldings, nor on a wall
of a building the roof of which is ten feet lower than the roof of
a building adjoining or adjacent to such wall, nor on the walls of a
detached dwelling, nor on the walls of a building which is fifty feet
or more distant in all directions from other buildings. A parapet
wall when required shall extend the full thickness of the top story
to at least three feet above the roof at all points and shall in all
cases be properly capped.
Hollow building blocks may be used for masonry walls excepting
party and fire walls and shall be of sufficient strength to safely
carry the loads imposed upon them. The specification and method
of computing this strength of hollow building blocks shall be in
accordance with the requirements established by the National
Board of Fire Underwriters.
All walls and partitions in schools, hospitals and places of public
assemblage, over one story high, and all walls and partitions in
theatres, shall hereafter be built of brick, stone, hollow or solid
blocks, or metal lath and Portland cement plaster on metal studding,
or other equivalent incombustible construction. (Id., §
494(16); Ord. May 20, 1935.)
