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I have seen some questions that are close, but different, and don't seem to answer my question. I'm in a late 1950s home and the previous owner drilled a bunch of holes in the joists in the basement ceiling for new wiring. The issue is that these holes are not in the correct spot on the joist, they are very close to the rim joist and above the sill plate. I'm this position the joists are subject to compressive force from above and below, unlike when you still the middle of a joist away from the sill plate where the top in under compression and the bottom under expansion. Most of these holes (about a dozen joists) look like 1/2 inch and there are three towards the side of the house where the holes might be about 1 1/4 inch.

My question, is it enough to plug these holes with a dowel to help with the compressive force, or should they just be completely replaced as a precaution?

half inch hole in joist above sill plate

inch and a quarter hole above sill plate

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  • How much is a bunch of holes?
    – JACK
    Jul 29 at 19:32
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    Think your main concern should be those staples on the yellow wires/cables. One staple seems to be too tight, almost cutting into that single cable it is holding.
    – crip659
    Jul 29 at 20:12
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    The two holes shown are not in a bad location, though the 2nd looks a little oversized. Unless the joists show split extended from the back edge of the holes towards the header, I wouldn't touch them, especially you need to cut the cable to do the fix.
    – r13
    Jul 29 at 20:12
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    When that house was built there probably were no specs for joist holes. Folks relied on common sense (for better or worse--one of mine had a 4" duct through it). If those holes were a concern millions of mid-century dwellings would be sagging heaps by now. They aren't.
    – isherwood
    Jul 29 at 21:06
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None of the holes are an issue.

There is some slight compression with the one joist - in your top picture. But it doesn't look to be an issue and it is certainly not caused by that small hole. If you did replace this joist (given the compression) you could introduce flooring issues above.

The second picture... Looks like they drilled it for PVC then didn't use it. Anyways it looks within code plus the section it is on is fully supported so there is absolutely no issue.

My advice is to not worry about these and spend your time on other things you want to do with the house. I won't comment on the electrical, as that is another question.

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    @TrivialCase - you have to pick your battles. This particular "thing" isn't even a battle though as those holes wouldn't matter for the next 200 years. Some of that electric... looks like it may need some tending to - mainly referring to that first picture. Second picture just looks like you need some cleanup. Also on the wiring if everything is in a raceway along the edges... run a few 2x4s parrallel to them to give them support and space.
    – DMoore
    Jul 29 at 21:18
  • thanks! The reason I thought it might be an issue is that we will be putting a considerable library on top of it, and I thought that maybe having increased compression from both directions might be bad. As far as the wiring goes, we've been discussing how to clean it up. When you say to run 2x4s, do you mean perpendicular along the joists? Jul 29 at 21:30
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    @TrivialCase - Yea you can run the perpendicular to joist and maybe a foot out - good method in basement for foregoing the drilling of holes in joists. You could also "cover them with 8" of plywood after putting down a few 2x4s (and they are still accessible). Depends on how you want the room to look. Also the biggest issue I saw in your pics was the lack of insulation.
    – DMoore
    Jul 29 at 21:50
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That orange cable in the first picture is fine.

The large hole in the second picture seems to be less than 1/3 the depth of the joist so it's fine. Those look like 2x10 joists so up to a 3" hole would be permissible.

The only hole that's not to "code" would be the one that is less than 2 inches from the bottom of the joist through which the black electrical cable runs.

Check out this for more info: https://buildingadvisor.com/notching-and-boring-joists/

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  • Each of these joists has oodles of these as well. Apparently no one was too worried about it in decades past. Jul 30 at 20:31
  • Well the house has presumably survived 70 years with those holes so I don't think joist replacement nor sistering is needed at this time. That would probably be overkill. You can get an engineer to assess the situation and they might recommend nothing more than some metal brackets.
    – MonkeyZeus
    Jul 30 at 20:51
  • The holes under discussion (in the pictures) were made in the last three years. The house was continuously owned until 2019 by the same woman, who sold it to a guy who flips houses. Some of these holes were made for the wires that you see in them, the large ones were made but I guess we bought the house before he could make use of them. I know they were made by him because he left the saw dust behind - well, that and he pointed out the new wiring he put in. Jul 31 at 23:21
  • @TrivialCase Yes, the only hole which is not to code is the one which is within 2 inches of the bottom of the joist; the rest of them pose no problems. If you have oodles of holes like that then please take a picture of the situation.
    – MonkeyZeus
    Aug 2 at 12:48

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