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I am running some new romex for a couple of electrical outlets. One of the outlets is on one side of a wall in one bedroom and the other outlet is on the other side of the wall in another bedroom. When I went in my crawl space to see what was below the wall cavity, I found two floor joists running right underneath it. Based on my measurements, I'm fairly certain I have no room underneath on either side of the double floor joist to drill up into the cavity. If I were to drill right next to the joists, I'd be going up into my button board rock lath walls.

Do people drill vertically through floor joists? If so and if there are two floor joists together, does one drill the hole in one of the joists or right at the seam between the two? Or do I drill a hole diagonally through one or both? In case it would affect the hole size, I'm using 12-2.

Ryan
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1 Answers1

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Disclaimer: We bring in outside contractors for our electrical installs, so I can give you some general tips, but I'll defer to others that may know more about this specific problem.

In general, joists, and any lumber supporting a load on its side, will lose much of its carrying capacity when it is drilled or cut on the top or bottom. For passing through the joists, you should make the hole in the center (between the top and bottom) of the joist, and make it the smallest hole that allows the wire to pass freely.

Having a double joist running beneath a wall means that the wall and joists are designed to be load bearing. So because of this, unless someone with more structural knowledge says it's ok to drill a hole, I'd avoid it.

While I can't think of a good way to get the wire into the wall, you could install your outlet on an adjacent wall, or you could go for a floor mounted outlet as a last resort:

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Niall C.
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BMitch
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