The Ontario Building Code | Holes Drilled in Framing Members
9.23.5.1. Holes Drilled in Framing Members
(1) Holes drilled in roof, floor or ceiling framing members shall be not larger than one-quarter the depth of the member and shall be located not less than 50 mm from the edges, unless the depth of the member is increased by the size of the hole.
In Plain Language
Holes drilled in framing members are limited in size and location as set out in this article, since an improperly placed hole can significantly weaken a joist or beam.
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.