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An electrician ran some new wires and had to bore through the floor joists. In doing so, one came very close to a knot in the wood. The floor above squeaks now as a result, where it didn't before. This is probably just a minor annoyance but I'd like to fix it if possible. What options do I have, given the electrical wire running through it?

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    You would need to sister the joist. The hole for the wiring looks to be well within the limits for drilling joists, so I'd think you could get away with adding a 2xY (where Y is the height from the bottom of the joist to the bottom of the hole), several feet long to span the split in the knot. You would put in a couple of rows of nails, spaced every 6-8" to transfer some of the load to your new piece of lumber. However, I'll leave it to those with more experience/knowledge to give you an answer, because I'm not sure how that split has to be dealt with. – FreeMan Mar 15 at 14:38
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I'm not convinced that this is causing the squeak. The amount of wood that was removed is trivial. I'd investigate further first. Some glue and/or shims or the tightening of a fastener may resolve the issue. Otherwise...

They make steel repair channels for this type of thing, but they're likely not cheap. Your goal is to restore the tension strength of the bottom portion of the joist. Here's what I'd do as a DIY repair, based on decades of home construction and ownership experience:

  1. Determine whether the joist has sagged at all. Run a long level or other reliable straightedge across the bottoms of the joists. If that one's low even 1/16" relative to several in either direction, put a jack and a stud under it and give it a gentle lift. Ideally, shoot for 1/16" above level to account for some settling later.
  2. Prepare 4-6 foot 2x4 gussets for both sides of the lower portion of the joist. These should be ripped or notched to fit under the cable.
  3. Liberally apply heavy duty construction adhesive to the each gusset and fasten them with 2-1/2" gold general purpose screws in pairs every 12" or so. I recommend Torx-drive for easier installation. Keep them at or slightly above flush at the bottom so you don't create a bump in the ceiling.

Be sure that the gussets pull tight with the first few screws. You can't move them with additional screws. If necessary, pilot through the gussets to the size of the screw threads.

Let the assembly dry for 24 hours before removing the temporary post. 48 hours is even better.

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  • Kind of wondering that also. The split knot was probably there before and drilling small hole should not change, unless done with chisel and big hammer. – crip659 Mar 15 at 15:20
  • @crip659 it's very possible that it was already split prior to the new work. All I can say is that the squeak began after the work was done, and is centered directly over that spot in the floor. – Yuck Mar 15 at 15:51
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    Press your fingers into the joint between the joist and subfloor while someone above bounces lightly. See if you can feel movement. – isherwood Mar 15 at 16:20

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