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§ 1543.08
<br />DWELLING HOUSE CODE
<br />48
<br />1543.08 Design of reinforced concrete.
<br />Except as otherwise provided in this
<br />Dwelling House Code; the design and con-
<br />struction of reinforced concrete shall con-
<br />form to ACI 318.
<br />1543.09 Removal of farms,
<br />The vertical or side forms for reinforced
<br />concrete members shall remain in place at
<br />least 24 hours and until the concrete has
<br />hardened. Those parts of the forms or shor-
<br />ing that support structural members shall
<br />not be removed until such members have
<br />acquired sufficient strength to support safely
<br />any such load that may come upon them, but
<br />in no case in less than 3 days for high early-
<br />strength concrete or 7 days for standard
<br />portland cement concrete.
<br />CHAPTER 45. WOOD,
<br />1545.01 General.
<br />All lumber and timber used in load bear-
<br />ing members shall be sound, free from rat
<br />and large or loose knots, and damaging di-
<br />agonal or spiral grain and shall be of the
<br />grade corresponding to the stresses used in
<br />the design. All-structural members shall be
<br />fastened at their junction with connecters,
<br />bolts, lag screws, spikes, nails, straps or other
<br />devices or by specially designed glued joints.
<br />1545.02 Classes.
<br />Two general classes of lumber shall be
<br />recognized, namely "stress-grade lumber"
<br />and "yard lumber."
<br />(a) Stress-grade lumber. Stress-grad e
<br />lumber is nominally two or more inches
<br />thick and four or more inches wide and is
<br />identified by the grade mark of, or certificate
<br />of inspection issued by, a lumber grading or
<br />inspection bureau or agency recognized as
<br />being competent, in accordance with ASTM
<br />D 245.
<br />(b) Yard lumber. Yard lumber is the
<br />normally available stock of the lumber yard,
<br />which has not necessarily been graded for
<br />strength but is suitable for general building
<br />purposes.
<br />1545.03 Structural design.
<br />(a) General. All girders, beams, joists
<br />and rafters shall be adequate to support the
<br />loads prescribed in Chapter 39 without ex-
<br />ceeding the ,allowable stresses. Members
<br />supporting plaster shall be designed so that
<br />the deflection under the assumed live loading
<br />prescribed by this Dwelling House Code
<br />shall not exceed 1/360 of the span,
<br />(b) Stress-grade lumber. The design of
<br />the respective species and grades of stress-
<br />gradelumber shall be in accordance with the
<br />NLMA National Design Specification for
<br />Stress-Grade Lumber and its Fastenings.
<br />(c) Yard lumber. For the various species
<br />and grades of yard lumber, FHA-2550,
<br />Tables of Maximum Allowable Spans for
<br />Wood Floor Joists, Ceiling Joists,.Rafters, in
<br />Residential Construction, shall be recognized
<br />as accepted engineering practice.
<br />(d) Species not known in advance. When
<br />the exact species available or to be delivered
<br />is not definitely known but will have allow-
<br />able fiber stresses in bending of not less than
<br />700 psi for 8" depth, 750 psi for 10" or 12"
<br />depths, TABLE 45B shall be used for allow-
<br />able spans of beams, joists and rafters, and
<br />TABLE 45C far safe axial loads on frame
<br />walls and load-bearing partitions. Wood
<br />frame walls and load-bearing partitions of
<br />construction types other than those included
<br />in TABLE 45C, shall be designed in accordance
<br />with accepted engineering practice,
<br />(e) Species known in advance. When
<br />stress-grade or a species and quality of lum-
<br />berwill definitely be used and properly iden-
<br />tified, the design, may be based on the proper
<br />allowable stresses as approved by the Build-
<br />ing Official.
<br />1545.04 Ceiling joists.
<br />(a) Spans. In determining the span of
<br />ceiling joists by TABLE 45B or tables in FHA-
<br />2550, the following criteria shall be used:
<br />i. When area of access scuttle to attic does
<br />not exceed 400 square inches or ceiling
<br />height is less than 3 feet, columns entitled
<br />"No Attic Storage" shall be used.
<br />ii. When access to attic is not provided by
<br />a stair but area of scuttle exceeds 400 square
<br />inches, columns entitled "Light Attic Stor-
<br />age" in TABLE 45B or "Limited Attic Stor-
<br />age" in FHA-2550 shall be used for areas
<br />where the attic ceiling height is 3 feet or
<br />more.
<br />iii. When access to attic is made by means
<br />of a permanent or disappearing stair, column
<br />entitled "Floors or Flat Roofs" in TABLE
<br />45B or "Flat Roof Joists-Supporting finish-
<br />ed ceiling" in FHA-2550 shall be used for
<br />areas where the attic ceiling height is 3 feet
<br />or more.
<br />(b) Parallel to roof joists. Hung ceiling
<br />joists, parallel to flatroof joists, shall be not
<br />less.than 2 x 4's spaced the same as the roof
<br />
<br />1575.15 Other types of groundfloor con-
<br />struction.
<br />Other methods of floor construction which
<br />will provide stability, resistance to capillary
<br />action, freedom from condensation, and in-
<br />sulating value substantially equivalent to
<br />that specified in Section 1575.14 may be used
<br />when approved by the Board of Building
<br />Code Appeals.
<br />CHAPTER 77, FLOOR SURFACES AND FINISH.
<br />1577.01 Wood strip flooring.
<br />(a) Materials. All strip flooring, either
<br />hardwood or soft wood, shall be kiln-dried.
<br />When laid over subflooring with joists not
<br />more than 16 inches o.c., the minimum thick-
<br />ness shall be 11/32 inch actual. When laid
<br />without subflooring, the minimum thickness
<br />shall be 25/32 inch actual and the joist spac-
<br />ing not greater than 16 inches o.c, Steel cut
<br />nails shall be used with 25/32 inch flooring
<br />and bright wire casing nails for flooring
<br />thicknesses less than 25/32 inch. Building
<br />paper or deadening felt shall be applied un-
<br />der all finished flooring.
<br />(b) Installation. Finished flooring in-
<br />stalled aver wood board subflooring shall be
<br />applied at right angles to the board subfloor-
<br />ing except when subflooring is laid diago-
<br />nally, in which event, the finished flooring
<br />shall be laid perpendicular to the joists.
<br />When applied over plywood, finished floor-
<br />ing shall be installed as required by Section
<br />1575.13. Single flooring shall have end joints
<br />over joists, unless boards are end-matched.
<br />If end-matched, no two adjoining boards
<br />shall break joints over same joist space and
<br />each board shall bear on at least two joists.
<br />Strip flooring installed over concrete shall
<br />not be applied directly to the concrete but
<br />shall be supported approximately 1 inch
<br />therefrom by means of sleepers not less than
<br />2 x 2's imbedded in concrete or secured with
<br />metal clips to the concrete. Sleepers shall
<br />be spaced not greater than 16 inches o.c, and
<br />shall bepressure-treated with wood preserv-
<br />ative as required in Section 1575.02.
<br />1577.02 Concrete.
<br />(a) Installed on wood framing. When in-
<br />stalled on wood framing, concrete floor slabs
<br />shall have a minimum thickness of 4 inches
<br />and shall have reinforcing consisting of wire-
<br />mesh weighing not less than 30 pounds per
<br />100 square feet, or 1/4 inch bars spaced 1
<br />foot o.c, in two directions.
<br />77
<br />Floor Surfaces and Finish
<br />§ 1577.04
<br />ment, 21/4 volumes of sand and 3 volumes of
<br />graded coarse aggregate (1. 21/4: 3). Not
<br />more than 6 gallons of water, including that
<br />contained in the aggregate, shall be used per
<br />sack of portland cement. The maximum size
<br />of coarse aggregate shall be 1 inch. All con-
<br />crete shall be machine mixed for not less
<br />than 11/2 minutes after all materials are in
<br />the mixer, If controlled concrete is used, it
<br />shall have a compressive strength of not less
<br />than 3000 psi at 28 days.
<br />(b) Underlayer. ,Asphalt-saturated felt or
<br />approved water-resisting paper shall be in-
<br />stalled over the subflooring before laying the
<br />concrete, Where there is no subflooring,
<br />sheet metal shall be placed over top of joists
<br />for concrete,form, or 1 inch boards shall be
<br />cut in flush with the top of the joists. The
<br />boards may be removed after the concrete
<br />slab has set.
<br />1577.03 Ceramic tile.
<br />(a) Grade and bed required. Ceramic
<br />tile, vitreous orsemi-vitreous, shall be stand-
<br />ard grade or better. The setting bed shall
<br />consist of a stiff mortar of one part portland
<br />cement to four parts sand or a.stiff concrete
<br />of one part portland cement, two parts sand
<br />and four parts pea size aggregate.
<br />(b) Applied over concrete slab. When ap-
<br />plied over a concrete slab, the thickness of
<br />setting beds shall be not less than 11/4 inches
<br />of mortar or fine concrete, or not less than
<br />1/s inch thickness of bituminous mastic or
<br />mixture of emulsified asphalt and portland
<br />cement.
<br />(c) Applied over wood, subfloor. When
<br />applied over wood subfloor, asphalt-satu-
<br />rated felt or water-resisting paper shall be
<br />installed over subfloor, with a bed of not less
<br />than 3 inches of the mix of mortar or fine
<br />concrete described in (b) of this section.
<br />When reinforced with wire-mesh weighing
<br />not less than 30 pounds per 100 square feet
<br />or with 1/4 inch bar spaced 12 inches o.c.
<br />each way the thickness of the mortar or con-
<br />crete setting bed may be reduced to 11/4
<br />inches.
<br />1577,04 Rubber tile, asphalt file and lino-
<br />leum:
<br />(a) Applied over concrete slab on ground.
<br />Asphalt file maybe applied to concrete slabs
<br />bearing on the ground but rubber. file or
<br />linoleum shall not be used on concrete slabs
<br />resting on the ground unless such slab area
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