PART 9 — HOUSING AND SMALL BUILDINGSUpdated for the 2024 Ontario Building Code
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9.4.3.1.Deflections
(1) The maximum deflection of structural members shall conform to Table 9.4.3.1.
(2) Dead loads need not be considered in computing deflections referred to in Sentence (1).
Table 9.4.3.1.
Maximum Deflections
Forming Part of Sentence 9.4.3.1.(1)
Max. Allowable Deflection as an
Structural Members Type of Ceiling Supported
Expressed Ratio of the Clear Span
No ceiling 1/180
Roof rafters, roof joists and roof beams Other than plaster or gypsum board 1/240
Plaster or gypsum board 1/360
Other than plaster or gypsum board 1/240
Ceiling joists
Plaster or gypsum board 1/360
Floor beams, floor joists and floor decking All cases 1/360
Beams, joists and decking for balconies, decks and Serving a single dwelling unit 1/240
other accessible exterior platforms Other 1/360
This provision includes a table — formatting is preserved from the source; refer to the official code for the authoritative layout.
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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.