Notches and Holes in Joists

Doing a practice exam when I came across two issues I need help with.

The first floor is supported by manufactured I-beams. The joists span the full width of the foundation 24’ and supported in the center by the main steel I-beam which runs the length of the house.

Issue 1
Within the center third of this floor joist span holes were bored to accommodate electrical wires. If this joist spans 24ft but is supported in its middle by the main beam, do I have an issue? The graphic for the course shows only that no “notches” can be made in the center third but is silent on holes in the center third. The accompanying text states "The maximum diameter of a bored hole through a floor joist (that is not in the middle third of the joist) is the actual depth of the joist divided by 3.

So I guess a question is my joist spanning 24ft or only 12 feet because it supported in its middle?

Issue #2
Within the outer third of the joist 2" holes were bored to accommodate plumbing and electrical. The joist is 91/2 inches wide. The 2 inch hole is OK (<1/3 of 91/2 inches).
However on several joists they bored three two-inch holes immediately adjacent to each other in a line. The outside diameter of the circles overlap. so now there is 6 inch wide (by 2 inches tall) roughly oval cut-out in this joist. Is that OK?

Ive got pix but cannot seem to include them…

William, watch this short video. Paige does a good job with explaining the where and how of notches and holes in joists:


Thanks Larry that was a good video. If I understood correctly this is what I came away with… These holes in the center third are ok. (small enough and not within 2 inches of the top or bottom). The holes in the outer third are a defect as they were placed well within 2 inches of each other. (actually intersecting to yield a nearly 6 inch oval).

I’m still curious though if the span is measured between supports or from end to end.

Yes and the middle is between the bearing points, William.

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The wall in-between the spans may not be load bearing. In the photo below, the wall in the middle appears to be load bearing. I would evaluate notches as such from the load point (not the entire span). Just my opinion.

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The span is measured between supports (supports implies load bearing).


TJIs or I-Joists have different engineering than wood joints and allow bored holes and cut-outs differently. Research may be warranted on the I-Joist manufacturers website.