How big a hole can a plumber drill through my Ottawa joists?
How big a hole can a plumber drill through my Ottawa joists?
Plumbing is out of scope here, but the carpentry rule on holes in joists is worth knowing because it is the same rule a carpenter or designer uses when any trade drills through framing.
The 2024 Ontario Building Code (9.23.5.1.) says a hole in a floor, roof or ceiling framing member must be no more than one quarter of the member's depth, and the edge of the hole must be at least 50 mm from the top or bottom edge of the member. Both limits apply at the same time.
A few things matter before anyone drills. First, we found no general limit in 9.23.5. for engineered joists such as I-joists or LVL; ask the designer before anything is cut into those members. Second, the rule allows the member's depth to be increased as an alternative to staying within the limit, but sizing that increase is a design question, not something to decide on site. Third, if a joist has already been cut and you are not sure whether it stays within the rule, have a carpenter or designer look at it before the ceiling goes back up.
Related service: Rot & Framing Repair What it costs: Renovation framing
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Carpentry IQ -- Built from the Ontario Building Code, Ontario regulations and City of Ottawa sources and real construction experience. Answers are for informational purposes only and are not a professional assessment.
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