PART 9 — HOUSING AND SMALL BUILDINGSUpdated for the 2024 Ontario Building Code
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9.23.4.3.Steel Beams
(1) The spans for steel beams with laterally supported top flanges shall conform to Table 9.23.4.3. for floors and Span
Tables 9.23.4.3.-A to 9.23.4.3.-J for roofs and floors. (See Note A-9.23.4.3.(1))
(2) Beams described in Sentence (1) shall at least meet the requirements for Grade 350 W steel in CSA G40.21,
“Structural quality steel.”
(3) A beam may be considered to be laterally supported if
(a) the wood joists bear on its top flange at intervals of 600 mm or less over its entire length,
(b) the load being applied to this beam is transmitted through the joists, and
(c) 19 mm by 38 mm wood strips in contact with the top flange are nailed on both sides of the beam to the bottom of the
joist supported.
Table 9.23.4.3.
Maximum Spans for Steel Beams Supporting Floors in Dwelling Units(1)
Forming Part of Sentence 9.23.4.3.(1)
Supported Joist Length, m (Half the sum of joist spans on both sides of the beam)
Section 2.4 3.0 3.6 4.2 4.8 5.4 6.0
One Storey Supported
W150 × 22 5.5 5.2 4.9 4.8 4.6 4.5 4.3
W200 × 21 6.5 6.2 5.9 5.7 5.4 5.1 4.9
W200 × 27 7.3 6.9 6.6 6.3 6.1 5.9 5.8
W200 × 31 7.8 7.4 7.1 6.8 6.6 6.4 6.2
W250 × 24 8.1 7.6 7.3 7.0 6.6 6.2 5.9
W250 × 33 9.2 8.7 8.3 8.0 7.7 7.5 7.3
W250 × 39 10.0 9.4 9.0 8.6 8.4 8.1 7.9
W310 × 31 10.4 9.8 9.4 8.9 8.4 8.0 7.6
W310 × 39 11.4 10.7 10.2 9.8 9.5 9.2 9.0
Section Two Storeys Supported
W150 × 22 4.9 4.4 4.1 3.8 3.5 3.4 3.2
W200 × 21 5.6 5.1 4.6 4.3 4.1 3.8 3.7
W200 × 27 6.4 6.1 5.6 5.3 4.9 4.7 4.4
W200 × 31 6.9 6.5 6.2 5.8 5.4 5.1 4.9
W250 × 24 6.8 6.1 5.6 5.2 4.9 4.6 4.4
W250 × 33 8.2 7.7 7.0 6.5 6.1 5.8 5.5
W250 × 39 8.8 8.3 7.8 7.2 6.8 6.4 6.1
W310 × 31 8.7 7.8 7.2 6.7 6.2 5.9 5.6
W310 × 39 10.0 9.3 8.5 7.9 7.4 7.0 6.7
Notes to Table 9.23.4.3.:
(1) See Note A-Table 9.23.4.3.
This provision includes a table — formatting is preserved from the source; refer to the official code for the authoritative layout.
← Previous9.23.4.2. Spans for Joists, Rafters and Beams (See Note A-Next →9.23.4.4. Concrete Topping (See Note A-9.23.4.4.)
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Code text is reproduced for reference from the Ontario Building Code (O. Reg. 163/24, 2024 Building Code Compendium). This page is provided for general information and is not an official copy. Always verify requirements against the official Ontario Building Code and confirm with your local building department.