The photos below shows a wood "support block" in my basement, supporting a vertical load bearing beam above.

The second photo shows the support beam in the upper level. The support block is in the middle of the house, on top of a horizontal structural beam.

Question is, is it okay to drill a 1/2" hole through this support block, and the floor joist, in order to bring an electrical cable through? Support block Support beam

1 Answer 1


Yes, you can drill a 1/2" hole through it. Borrowing from the IRC's holes and notches constraints for joists and headers (IRC R502.8 and the text that follows in R502.8.1), I would limit the diameter to less than 1/6 of the joist height. I would feel very comfortable going up to 1/4 of the height based on the end notching constraint.

  • Thanks for the reference. Also, is there a name for a "support block" like this? Feb 21 at 22:28
  • @TotteKarlsson, "blocking" or "solid blocking." Neither term is listed among the code's definitions, where I'm a little mystified by the difference between the two. Whatever the "solid" qualifier means, your giant blob of wood with full bearing top and bottom certainly seems to fit.
    – popham
    Feb 21 at 23:46

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