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?
Best Answer
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.