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§ 1575.14
<br />DWELLING HOUSE CODE
<br />(b) Nailing. Boards "less than 8 inches
<br />wide shall be double-nailed with 8d nails at
<br />each bearing. 8 inch boards shall be tripled-
<br />nailed with 8d nails.
<br />(c) Blocking provided for d i a g o n a l
<br />boards, Blocking shall be installed between
<br />the ends of joists at walls and at openings to
<br />provide nailing ends for diagonal subfloor
<br />boards.
<br />(d) Clearance at masonry walls. At least
<br />1/z inch clearance shall be provided between
<br />subfloor and all masonry walls and parti-
<br />tions.
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<br />(e) T&G boards under linoleum or tile.
<br />Wood boards used as a base for linoleum,
<br />composition, rubber or ceramic the shall be
<br />T&G boards with minimum nominal thick-
<br />ness of 1 inch and maximum joist spacing of
<br />16 inches.
<br />1575.13 Plywood subflooring.
<br />(a) Type and thickness. Plywood, when
<br />used as a base for wood finished floors, lino-
<br />leum, composition, rubber or ceramic tile,
<br />shall be not less than 5-ply and shall have
<br />the minimum thickness and the maximum
<br />joist spacing as follows•
<br />
<br />Minimum Thickness Minimum Thickness Maximum Joist Spacing
<br />Subfloor Floor Finish (inches)
<br />r/i" * 25/32" wood strip laid at right angles to joists 24
<br />I/z" * 25/32" wood strip laid parallel to joists 20
<br />~/a" 25/32".wood strip laid at right angles to joists 20 "
<br />1/z" less than 25/32".wood or other finish 16 **
<br />5/s" * less than 25/32" wood or other finish 20 **
<br />s/4"'" less than 25/32" wood or other finish 24 **
<br />* Installed with outer plies of subflooring at right angles to joists.
<br />* * A wood strip flooring, 25/32" thick or less, maybe applied in either direction.
<br />(b) Blocking and nailing. When plywood
<br />is used as a base for block or parquetry,
<br />wood flooring less than actual 25/32 inch
<br />thick, linoleum, compositions, rubber or
<br />ceramic tile, solid wood blocking shall be in-
<br />stalled under all edges of plywood at right
<br />angles to the floor joists and be nailed se-
<br />curely_ to the joist and blocking with 6d
<br />nails, 6 inches o.c, along edges and 10 inches
<br />o.c. along intermediate framing supports.
<br />(c) Clearance at masonry walls. At least
<br />i/z inch clearance shall be provided between
<br />plywood sub-floor and all masonry walls and
<br />partitions.
<br />(d) When used over other subflooring.
<br />Plywood, when used for leveling purposes
<br />over other sub-flooring, may have a mini-
<br />mum thickness of ~4 inch, 3 ply.
<br />1575.14 Concrete floors.
<br />(a) Precautions against moisture penetra-
<br />tion. All ground supported concrete floors
<br />shall be constructed to resist water penetra-
<br />tion and ".to provide a stable construction.
<br />Where water conditions exist, such floors
<br />shall be constructed to safely resist uplift
<br />due to water pressure encountered, unless
<br />pressure is relieved by under-drainage or by
<br />any other method approved by the Building
<br />Official,
<br />(b) Insulation o f ground floors under
<br />habitable rooms. Ground supported concrete
<br />floors of habitable rooms shall be insulated
<br />around the outer perimeter against heat loss.
<br />Concrete floors shall have a minimum thick-
<br />ness of 4 inches and shall be installed over a
<br />porous underbed of gravel, cinders, or
<br />crushed"rock not less than 4 inches thick,
<br />leveled with 1 inch of mortar or cinder con-
<br />crete, and with heavy roofing felt or other
<br />waterproof membrane directly under the 4
<br />inch concrete slab, Waterproofing membrane
<br />shall be turned up to top of slab at edges.
<br />When floor is below grade, waterproofing
<br />membrane shall extend up the enclosing
<br />walls to six inches above grade. A continu-
<br />ous waterproof insulation strip at least ~/z
<br />inch thick shall be installed between the ex-
<br />terior wall and floor slab,
<br />(c) In basements or cellars. Ground sup-
<br />ported floors in basements or cellars shall be
<br />of concrete not less than 3 inches in thick-
<br />ness, or of other construction of equivalent
<br />stability and resistance against water pene-
<br />tration approved by the Board of Building
<br />Code Appeals.
<br />(d) For garages or porches. Concrete
<br />floor slab for garage, terrace, or porch shall
<br />have a minimum thickness of 4 inches. The
<br />4-inch bed of gravel, cinders or crushed rock
<br />under the slab may be omitted if the slab is
<br />reinforced with wire-mesh reinforcing hav-
<br />ing aminimum weight of 40 pounds per 100
<br />square feet,
<br />(e) Quality of concrete. All concrete floor
<br />slabs, described in this Section and not made
<br />with controlled concrete, shall be mixed in
<br />the proportions of 1 volume of portland ce-
<br />~ ~
<br />f •
<br />~ •
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<br />Wood
<br />joists, with hangers of 1 x 4's or 2 x 2's spaced
<br />not more than the allowable span for Ceiling
<br />Joists with "No Attic Storage" in TABLE 45B,
<br />(c) At right angles to roof joists. Hung
<br />ceiling joists, at right angles to flat roof joists,
<br />shall be not less than 2 x 4's spaced not more
<br />than 24 inches o.c, Hangers, not less than
<br />2 x 2's, shall be spaced not more than the
<br />allowable span for Ceiling Joists with "No
<br />Attic Storage" lrl TABLE 45B. Not more
<br />than 3 hangers may be attached to any one
<br />roof joist.
<br />1545.05 Allowable stresses. -
<br />The allowable stresses for the more com-
<br />mon species of yard lumber are listed in
<br />TABLE 45A of this Dwelling House Cade.
<br />Sizes and grades of lumber with allowable
<br />stress in bending" less than 650 psi shall not
<br />be used for frsming members without the
<br />permission of the Building Official.
<br />1545.06 Dimensions.
<br />Unless specifically stated as actual size, all
<br />lumber dimensions are nominal sizes and the
<br />American Lumber Standards for dressed
<br />sizes shall be accepted and used as the cor-
<br />responding net dimensions for all structural
<br />design.
<br />1545.07 Lintels.
<br />Lintels over openings in exterior walls or
<br />bearing partitions, supporting concentrated
<br />loads, shall be designed for the loads and
<br />strength properties of the lumber. For ordi-
<br />nary loading and using the average available
<br />yard lumber, without approved truss con-
<br />struction, the spans of lintels. shall not exceed
<br />the maximum listed as follows:
<br />Size Maximum Span
<br />Two 2 x 4's. on edge 3'-6"
<br />Two 2 x 6's 'on edge 4'-6"
<br />Two 2 x 8's on edge ~ 6'-0"
<br />Two 2 x 10's on edge 7'-6"
<br />Spans over 7'-6" shall be designed to the ap-
<br />proval of the Building Official.
<br />1545.08 Framing and bracing.
<br />Exterior walls and interior partitions of
<br />wood frame structures shall be constructed
<br />so as to develop strength and rigidity in ac-
<br />cordance with the requirements of this
<br />Dwelling House Code and in a manner
<br />satisfactory to the Building Official. The
<br />frame shall be braced or sheathed at all
<br />angles and the floor, attic and roof framing
<br />of wood joists, beams and rafters shall be
<br />secured by nailing or other connecting de-
<br />vices satisfactory to the Building Official.
<br />§ 1545.12
<br />In buildings more than one story in height,
<br />corner posts shall be the equivalent of not
<br />less than three pieces of 2 x 4 studs braced
<br />by not less than 1 piece of 1 x 4 diagonal let
<br />into the studs unless the frame is sheathed
<br />with plywood in panels not less than 4' x 8'
<br />in area, fiberboard or gypsum sheathing in
<br />vertical not less than 4' x 8' in area, diagonal
<br />"wood or other materials aproved by the
<br />Building Official.
<br />1545.09 Floor joists and rafters.
<br />The spans of joists, beams, and rafters
<br />shall be in accord with TABLE 45B except as
<br />provided in subsections 1545.03 (b), (c), and
<br />(e). Beams and joists shall be spaced not
<br />more than 24 inches, except when otherwise
<br />approved. by the Building Official. In can-
<br />tilever construction, where the exterior face
<br />of the second floor extends beyond the sup-
<br />porting wall of the first floor, the overhang
<br />of the second floor joists shall be not more
<br />than 15 inches, unless expressly approved
<br />by the Building Official.
<br />1545.10 Bridging.
<br />In all floor, attic and flat-roof joist fram-
<br />ing, there shall be not less than one line of
<br />bridging for each 8 feet of span and the
<br />bridging shall be of not less than 1 x 3 inch
<br />lumber, double nailed at each end, solid
<br />wood bridging or of equivalent metal lateral
<br />bracing of equal rigidity secured at the in-
<br />tersection. Aline of bridging shall also be
<br />required at supports where lateral stiffness
<br />is not otherwise provided.
<br />1545.11 Cutting and Notching.
<br />In girders, beams, or joists, cuts shall not
<br />be deeper than i/s the beam or girder depth;
<br />bored holes shall be not more than 21/z
<br />inches in diameter, and shall not be closer
<br />than 2 inches to,the top or bottom of the
<br />beam, nor located nearer to the end of the
<br />span than 3 times the beam" depth nor within
<br />the middle half of"th'e span, unless reinforced
<br />to meet stress calculation in a manner ap-
<br />proved by the Building Official. In studs of
<br />bearing walls or partitions, notches made to
<br />receive piping or duct work, or for other
<br />fabrication purposes, shall be cut not more
<br />than ~/s the depth of the stud, or the required
<br />studs shall be doubled or otherwise rein-
<br />forced.
<br />1545.12 Plates and ribbon boards.
<br />Plates which are used in exterior walls to
<br />support joists or rafters shall be doubled,
<br />of the same width as the supporting studs
<br />and each not less than 2 inches thick. In non-
<br />bearing partitions at least one top and bot-
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