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§ 1575.03
<br />DWELLING HOUSE CODE
<br />ner or treated with a preservative,.approved
<br />by the Building Official.
<br />(b) Masonry slabs. Unless heartwood of
<br />a durable species is used, woad floor sleepers
<br />or other wood embedded in or laid on ma-
<br />sonry or concrete slabs that are in direct con-
<br />tact with the ground shall be -protected
<br />against moisture in a manner or treated
<br />with a preservative, approved by the Build-
<br />ing Official. Pieces machined or cut after
<br />treatment, shall be given two brush coats
<br />of a preservative approved by the Build-
<br />ing Official.
<br />1575.03 Wood joists bearing on masonry.
<br />~Uhen supported by masonry, joists shall
<br />have a bearing of not less than 4 inches.
<br />When there is masonry above the bearing;
<br />the joists shall have'a fire cut of ~/z the depth
<br />of the joist or 3", whichever is less.
<br />1575.04 Anchoring of joists and' beams to
<br />masonry walls.
<br />(a) When bearing on walls. Masonry
<br />walls shall be anchored to each tier of wood
<br />joists or wood beams bearing on .them at
<br />maximum intervals of 4 feet. These anchors
<br />shall be metal, having a minimum cross.sec-
<br />tion of 1/4 inch by li/4 inch and.at least 16
<br />innches long, securely fastened to the joists or
<br />beams and provided with split and upset ends
<br />or other means approved by the Building
<br />Official for anchoring into masonry. Girders
<br />shall be similarly anchored at their. bearings.
<br />Anchors shall be attached near the bottom
<br />of the framing members.
<br />(b) When 'parallel to walls. Masonry
<br />walls parallel to wood joists or to wood
<br />beams'shall be provided with anchors of a
<br />type required .by this section and at maxi-
<br />mum intervals of 6 feet engaging not less
<br />than three joists or beams.
<br />(c) Anchor end o f strap. Upset or "T"
<br />ends on anchors shall ,develop the full
<br />strength of the anchor strap and shall be
<br />solidly embedded in the masonry. .
<br />(d) Omission o f anchors. Anchors maybe
<br />omitted at the first floor joists when the sup-
<br />porting walls are laterally braced by earth,
<br />or in any other manner approved by the
<br />Building Official, provided that, the: founda-
<br />tion walls are bonded to masonry above.
<br />1575.05 Fastening of joists and beams to
<br />wood construction:
<br />(a) Joist, beam or girder, to th'e wall.
<br />When enclosing walls are. of wood, each
<br />joist, beam; and girder supported by the wall
<br />shall be securely spiked or anchored to the
<br />wall construction, so ~as to stay in place and
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<br />to resist safely all lifts and lateral pressures
<br />required to be assumed by this Dwelling
<br />House Code.
<br />(b) Girder to girder. Girders shall be
<br />fastened to each other where they intersect
<br />or abut.
<br />(c) Joists into header lieams or girders,
<br />Floor joists framing into the side of wood
<br />girders or headers shall be supported on
<br />metal joist hangers or on a. bearing strip or
<br />ledger board fastened to the side of the
<br />girders or headers. Such strip or board shall
<br />measure at least 2.x 3 inches in section. The
<br />notch in the end of the joist .shall not be
<br />more than ~4 of the joist depth. Joists shall
<br />be spiked to metal joist hangers. When sup-
<br />ported on a bearing strip or ledger board,
<br />joists .shall be spiked. thereto and shall be
<br />further supported by spikes driven through
<br />the supporting member into the joists.
<br />(d) Joists abutting or lapping at a support.
<br />When joists are butted, ties ,shall be of metal
<br />not less-than 1/s inch by 1' inch by 18 inches,
<br />or of wood not less than,I inch by 2 inches
<br />and 2 feet long. When joists are lapped to
<br />provide a tie, they shall lap one another not
<br />less than 4 niches' and shall be securely
<br />spiked together and toe-nailed to support.
<br />When joists abut a girder, metal dog anchors,
<br />trot' less than 1/s inch by 1. inch in section,
<br />shall be driven into the tops of the joists, or
<br />metal•straps not less than ~/s inch by 1 inch
<br />by 18 inches may be used. Ties shall be
<br />spaced not more than 4 feet on centers. In
<br />masonry enclosed buildings, ties shall be
<br />installed on each line of joists tied to en-
<br />closing masonry walls.
<br />(e) Metal hangers. Metal hangers for
<br />joists, headers, and ~ other framed-in wood
<br />members shall be of.a.type approved by the
<br />Building Official, shall. provide adequate and
<br />firm support, and shall be punched to permit
<br />spiking to the supporting and supported
<br />members,
<br />1575:06 Rafters.
<br />' (a) Provision against spreading. Rafters
<br />shall be vertically supported near the ridge
<br />when the.slope is less than.4 inches per foot,
<br />or regardless of slope if they are not held
<br />from spreading. Where rafters are not other-
<br />wise held against spreading, collar ties shall
<br />be provided on every pair of rafters. If the
<br />spread of 'the rafters is .prevented .by ties
<br />not at the plate line, the size of 'the rafters
<br />shall be increased to take care of the addi=
<br />tional bending moments induced by the'ties
<br />when the roof is loaded with the "maximum
<br />vertical load: ~ ~ '
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<br />tom plate shall be provided: of the same
<br />width as the studs and the partitions shall
<br />be fire-stopped. Ribbon boards, which sup-
<br />port floor or roof joists, shall be not less
<br />than 1 x 4 inches in size and shall be nailed
<br />to each stud with two 8d nails. Sills shall be
<br />the equivalent of a 2 x 6 inch stud.
<br />1545.13 Roof rafters.
<br />Roof rafters shall be vertically supported
<br />at the ridge or shall be trussed or tied to-
<br />gether with not less than 1 x 6 inch collar
<br />beams spaced not more than 5 feet on centers
<br />and nailed to each rafter with four lOd nails:
<br />Wood '
<br />Table 45B
<br />'Each rafter shall be fastened to the wall
<br />plates or wall studs with not less than two
<br />16d nails.
<br />1545,14 Multiple joists and rafters.
<br />Floor joists under bearing partitions. shall
<br />be doubled or formed of built-up sections or
<br />may be replaced by a solid section of strength
<br />to support the loads. Dormer windows and
<br />other openings in roofs shall be framed with
<br />double rafters and headers, Valley rafters
<br />on spans over 12 feet, measured horizontally,
<br />shall be doubled,
<br />TABLE 45B ALLOWABLE SPANS OF BEAMS, JOISTS AND RAFTERS$
<br /> JOISTS Supporting Not Supporting
<br />Nom- Spac- Finished Ceilings Finished Ceilings _
<br />final ing FLOORS ~ FLAT . ROOF RAFTERS~k
<br /> FLOORS or FLAT CEILING JOISTS ROOF (Slopes greater
<br />Size in ROOFS JOISTS than 4 in 12)
<br /> Light No (Slopes Light Heavy
<br />Inches Inches .
<br />Attic Attic up to Roaf- Roof-
<br /> Storage Storage 4 in 12) ing ing
<br /> 40#LL 30#LL 20#LL No. LL 30#LL 22,~I:I, 22#LL
<br /> 16-20#DL 16-20#DL 13-18#DL 11-16#DL 6-11#DL 5-11#DL 11-16#DL
<br /> ft: in. ft: in, ft,-in. ft: in. ft: in, ft,-in. ft: m.
<br /> 12 5-10 6-1 7-0 9-6 7-6 8-9 8-0
<br />2x4 16 5-3 5-7 6-4 8-6 6-8 7-7. 6-10.
<br /> 20 4-10 5-2 5-9 7-8 6-0 6-8 6-2 ~,
<br /> 24 4-7 4-10 5-4 7-0 5-6 6-1 5=8
<br /> 12 9-0 9-10 11-0 14-7 11-9 13-3 12,6'
<br /> 2x6 16 8-2 9-0 10-0 13-6 10-3 11-8' 11-0
<br /> 20 7-6 8-2 9-1 12-8 9-2 10-6 9-9
<br /> 24 7-0 7-10 8-4 12-0 8-5 9-8. 8-9"
<br /> 12 12-0 13-0 14-3 19-8 15-3 17-5 16-U
<br /> 2x8 16 11-0 12-0 13-0 18-3 13-6 15-4 14-0
<br /> 20 10-2 11-2 11-10 17-1 12-2 13-9 12-6
<br /> 24 9-6 10-6 11-1 16-4 11-2 12-8 ll-6'
<br /> 12 14-0 15-1 16-6. 22-4 19-0 21-5 19-9
<br /> 3x8 16 12-9 13-10 15-3 20-8 16-10 19-6 17--6
<br /> 20 11-9 12-10 14-3 19-4 15-2 17-2 15-9:,
<br /> 24 . 11-0 12-0 13-6 18-4 14-0 15-10 14-6
<br /> 1& 15-2 16-4 18-0 24-0 19-4 21-9 20-0-
<br />' 2x10' 16 13-10 15=0 16-3 22-4 17-0 19-2 17-8 .,
<br /> 20 12-9 13-8 15-0, 21-0 15-3 17-3 15=10
<br /> 24 12-0 13-1 14=0 20-0 14-1 16-0 `. 14""-7'
<br /> 12 17=9 19-.0 20-6 26-6 23-9 26-7 ~" 24='1"'
<br /> 3x10 16 16-3 17-4 19-0 24-10 21-0 23-7 21-1U='~.
<br /> 20 15-0 ' 16-1 .17-10 . . 23-6 19-0 21-3 ]9=8~•~
<br />' 24 14'-2 15-3 17-0 22-6 17-6 19-8 „18-2 .
<br /> 12 18-6 19-10 _ 21-6 28-0 23-1 26'-0 .23-10
<br /> 2x12 16' 16-9 18-3 19-7 26-6 20-4 23-0 ' " : 21-0
<br /> 20 15-6 16-8 18-2 25-0 18-5 20-8 ~ :.:19-0~1.
<br /> 24 14-6 15-8 17-2 24-0 .17-0 19-2 ~ 17-6
<br /> LL-Live load in psf.
<br /> • DL-Dead load in psf.
<br /> ~` See Chapters 39 and 45.
<br /> 1° Rafter span is the actual length of rafter, between the-plate and ridge dr, intermediate support .
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