The Ontario Building Code | Deflections

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)

Item

Column 1

Structural Members

Column 2

Type of ceiling Supported

Column 3

Max. Allowable Deflection as an Expressed Ratio of the Clear Span

1.

Roof rafters, roof joists and roof beams

No ceiling

1/180

Other than plaster or gypsum board

1/240

plaster or gypsum board

1/360

2.

ceiling joists

Other than plaster or gypsum board

1/240

plaster or gypsum board

1/360

3.

floor beams, floor joists and floor decking

All cases

1/360

4.

Beams, joists and decking for balconies, decks and other accessible exterior platforms

Serving a single dwelling unit

1/240

Other

1/360

Note: On July 1, 2017, item 4 of Table 9.4.3.1. of Division B of the Regulation is amended by striking out "single dwelling unit" in Column 2 and substituting "house or an individual dwelling unit". (See: O. Reg. 139/17, s. 71)

9.4.4. foundation Conditions