Joist Holes

Is there a limit on how many holes you can drill in a joist next to each other?


Engineers in my area would pass that since it sits so close to the support beam.


IRC code 502.8.1 covers notching and according to the IRC they would not pass. However, as Jim stated, an engineer may pass the joist if actual load calculations are performed. The IRC code is ultra conservative and is designed to be applied with out detailed analysis. Most codes are prescriptive and if you follow them to the letter you should be OK, no thinking required. However all houses are unique in geometry and in loads patterns applied. In your example detailed design calculations may determine the first three are fine but the next two could fail because a load bearing wall was near them. Its beyond the scope of our SOP but those joist without the holes could still fail the IRC code if the home owner put a grand piano on the floor above and exceeded the 40 psf the code tables were designed for. I may be rambling here but I thought you should know there are few more factors to consider when looking at structural issues.

Thanks, Ken