| 9.23.9. |
Floor Joists |
| 9.23.9.1. |
End Bearing for Joists
- Except when supported on ribbon boards, floor joists shall have not less than 38 mm length of end bearing.
- Ribbon boards referred to in Sentence (1) shall be not less than 19 mm by 89 mm lumber let into the studs.
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| 9.23.9.2. |
Joists Supported by Beams
- Floor joists may be supported on the tops of beams or may be framed into the sides of beams.
- When framed into the side of a wood beam, joists referred to in Sentence (1) shall be supported on
- joist hangers or other acceptable mechanical connectors, or
- not less than 38 mm by 64 mm ledger strips nailed to the side of the beam, except that 38 mm by 38 mm ledger strips may be used provided each joist is nailed to the beam by not less than four 89 mm nails, in addition to the nailing for the ledger strip required in Table 9.23.3.4.
- When framed into the side of a steel beam, joists referred to in Sentence (1) shall be supported on the bottom flange of the beam or on not less than 38 mm by 38 mm lumber bolted to the web with not less than 6.3 mm diam bolts spaced not more than 600 mm apart.
- Joists referred to in Sentence (3) shall be spliced above the beam with not less than 38 mm by 38 mm lumber at least 600 mm long to support the flooring.
- Not less than a 12 mm space shall be provided between the splice required in Sentence (4) and the beam to allow for shrinkage of the wood joists.
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| 9.23.9.3. |
Restraint of Joist Bottoms
- Except as provided in Sentence 9.23.9.4.(1), bottoms of floor joists shall be restrained from twisting at each end by toe-nailing to the supports, end-nailing to the header joists or by providing continuous strapping, blocking between the joists or cross-bridging near the supports.
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| 9.23.9.4. |
Strapping, Bridging, Furring and Ceilings in Span Tables 9.23.4.2.-A and -B
(See Note A-9.23.4.2.(2).)
- Except as permitted by Sentence (5), where strapping is specified in Span Table 9.23.4.2.-A, it shall be
- not less than 19 mm by 64 mm, nailed to the underside of floor joists,
- located not more than 2 100 mm from each support or other rows of strapping, and
- fastened at each end to a sill or header.
- Where bridging is specified in Span Table 9.23.4.2.-A, it shall consist of not less than 19 mm by 64 mm or 38 mm by 38 mm cross bridging located not more than 2 100 mm from each support or other rows of bridging.
- Where bridging and strapping are specified in Span Table 9.23.4.2.-A,
- bridging shall
- comply with Sentence (2), or
- consist of 38 mm solid blocking located not more than 2 100 mm from each support or other rows of bridging and securely fastened between the joists, and
- except as provided in Sentence (5), strapping shall comply with Sentence (1) and be installed under the bridging.
- Bridging specified in Span Table 9.23.4.2.-B shall consist of
- bridging as described in Sentence (2), or
- 38 mm solid blocking located not more than 2 100 mm from each support or other rows of bridging and securely fastened between the joists.
- Strapping described in Sentence (1) and Clause (3)(b) is not required where
- furring strips complying with Table 9.29.3.1. are fastened directly to the joists, or
- a panel-type ceiling finish complying with Subsection 9.29.5., 9.29.6., 9.29.7., 9.29.8., or 9.29.9. is attached directly to the joists.
- Where a ceiling attached to wood furring is specified in Span Table 9.23.4.2.-B,
- the ceiling finish shall consist of gypsum board, plywood or OSB not less than 12.7 mm thick, and
- the furring shall be
- 19 mm by 89 mm wood furring spaced at not more than 600 mm o.c., or
- 19 mm by 64 mm wood furring spaced at not more than 400 mm o.c.
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| 9.23.9.5. |
Header Joists
- Header joists around floor openings shall be doubled when they exceed 1.2 m in length.
- The size of header joists exceeding 3.2 m in length shall be determined by calculations.
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| 9.23.9.6. |
Trimmer Joists
- Trimmer joists around floor openings shall be doubled when the length of the header joist exceeds 800 mm.
- When the header joist exceeds 2 m in length the size of the trimmer joists shall be determined by calculations.
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| 9.23.9.7. |
Support of Tail and Header Joists
- When tail joists and header joists are supported by the floor framing, they shall be supported by suitable joist hangers or nailing in accordance with Table 9.23.3.4.
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| 9.23.9.8. |
Support of Walls
- Non-loadbearing walls parallel to the floor joists shall be supported by joists beneath the wall or on blocking between the joists.
- Blocking referred to in Sentence (1) for the support of non-loadbearing walls shall be
- not less than 38 mm by 89 mm lumber, and
- except as required for the fastening of walls constructed with required braced wall panels, spaced not more than 1.2 m apart.
- Except as provided in Sentence (6), non-loadbearing interior walls at right angles to the floor joists are not restricted as to location.
- Loadbearing interior walls parallel to floor joists shall be supported by beams or walls of sufficient strength to safely transfer the specified live loads to the vertical supports.
- Unless the joist size is designed to support such loads, loadbearing interior walls at right angles to floor joists shall be located
- not more than 900 mm from the joist support where the wall does not support a floor, and
- not more than 600 mm from the joist support where the wall supports one or more floors.
- Loadbearing and non-loadbearing walls constructed with required braced wall panels shall be continuously supported by floor joists, blocking or rim joists to allow for the required fastening (see Table 9.23.3.4.).
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| 9.23.9.9. |
Cantilevered Floor Joists
- Floor joists supporting roof loads shall not be cantilevered more than 400 mm beyond their supports where 38 mm by 184 mm joists are used and not more than 600 mm beyond their supports where 38 mm by 235 mm or larger joists are used.
- The cantilevered portions referred to in Sentence (1) shall not support floor loads from other storeys unless calculations are provided to show that the design resistances of the cantilevered joists are not exceeded.
- Where cantilevered floor joists described in Sentences (1) and (2) are at right angles to the main floor joists, the tail joists in the cantilevered portion shall extend inward away from the cantilever support a distance equal to not less than 6 times the length of the cantilever, and shall be end nailed to an interior doubled header joist in conformance with Table 9.23.3.4.
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