Some previous owner of our house moved the washer/dryer to the second floor, but made some pretty dubious decisions when doing so:

suspicious plumbing and electrical

I'm preparing to patch the paster, skim-coat, and paint, so I need to deal with this mess first. It looks like they ran the pipes up without realizing that there wasn't a full stud bay (the exposed portion is only 6"), and rather than changing anything they decided to run everything outside the wall. The supply lines are coming up through the finished floor(!).

The one thing that has me stymied is moving the drain pipe for the washer. (There is a vent for the p-trap along the left side of the wall). Ideally, I could turn the drain, go straight through the stud, and recess everything in the full-size stud bay to the right. To do that, I would be cutting a hole for a 2" drain pipe into a 2x4, which is >40% (code):

Studs located in exterior walls or bearing partitions drilled over 40 percent and up to 60 percent shall also be doubled with no more than two successive doubled studs bored. Exception: Use of approved stud shoes is permitted when they are installed in accordance with the manufacturer’ s recommendations

Should I take this to mean that I can use something like this stud shoe, and then it's fine to drill a hole that large?

My plan is:

|   6"    |   |    16"           |
|         |   |                  |
|         | o | <- electric      |
|         |   |                  |
|         |o o| <- water supply  |
|         |   |                  |
|  p trap |-O-| <- drain w/ shoe |
|         |   |                  |

This is an exterior wall on the second floor supporting a roof and a finished attic. Is it really necessary to sister a stud, or will a shoe suffice?

  • 1
    Incidentally, while your Q doesn't deal with it, the exposed NM wires are a huge no-no. They should be armored or otherwise in conduit to protect them
    – Machavity
    Jan 27, 2019 at 18:35
  • Absolutely - I’m going to recess all of the wires into the wall. But that’s something I’m comfortable doing so I omitted it from the question. Thanks for the warning! Jan 27, 2019 at 18:49
  • If your room isn't already too small, I'd consider framing a second 2x4 wall inside the first for all this. Could save some serious headache and prevent degradation of the exterior wall's insulation. (I'd only put plumbing supplies in an exterior wall as a last resort.)
    – isherwood
    Jan 30, 2019 at 21:19
  • Unrelated - what is that powered beige box with two coax cables? Very strange item to have in a potentially damp box.
    – Criggie
    Nov 5, 2019 at 3:27

1 Answer 1


Here are load tables. Probably wouldn't hurt to add a sister to be safe unless you also want to pay a bunch of money to a structural engineer

  • You could also look into framing a "wet wall" which is something that is commonly done in this scenario I believe Jan 30, 2019 at 21:39

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