The Ontario Building Code | Header Joists
9.23.9.5. Header joists
(1) Header joists around floor openings="http://thehandyforce.com/windows/" title ="Window installer in Toronto">openings shall be doubled when they exceed 1.2 m in length.
(2) The size of header joists exceeding 3.2 m in length shall be determined by calculations.
In Plain Language
Header joists, which frame the ends of a floor opening, must meet the sizing and construction requirements set out in this article.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.