This question have a great answer with all the guidelines for drilling holes in joists.

The question: Are the guidelines the same for band joists?

A bit of context: I'd like to add an exterior outlet for my central vaccuum cleaner and the shortest path is through the band joist. But I'm not sure if I can drill a 2 1/2" hole in a 7" band joist.

If the guidlines applies (and are not more restrictive either), the maximum hole size would be 2 1/3 inches. I can get by with a smaller hole, but I'd have to get another hole drill bit.

  • 2
    Are you going to vacuum your lawn with the central vac?
    – BMitch
    Commented Oct 3, 2012 at 15:41
  • Be sure to protect the outlet well. In my area some homes recently burned down because, during a brushfire, the central-vac outlet melted... causing hot embers to be sucked into the house.
    – Matthew
    Commented Oct 3, 2012 at 15:52
  • 1
    BMitch: Haha! It's only to clean the cars' interiors actually. That brings another question: is this a good idea?
    – Danny T.
    Commented Oct 3, 2012 at 15:58

1 Answer 1


No. Since the band (rim) joist is continuously supported by the foundation wall, the boring and notching rules do not apply. You will, however, want to use common sense. Try not to notch or bore directly under a window or door, especially right where the king/jack studs are. You also don't want to notch or bore the entire width of the joist, in other words don't remove a section of the rim joist.

You'll notice the rim joist is a common place for dryer vents, furnace vents, electrical service cables, and other utility openings. This is due to the lack of notching and boring guidelines, which accommodates the placing of such openings.

  • I agree with this answer. If you want a bit more strength, you could sister (attach a similar piece next to the existing one) a joist piece in the location where you plan on drilling the hole. Commented Aug 1, 2013 at 3:40
  • I agree this is probably the correct answer. However, do you by any chance have a code reference in IRC? I can't find it. Commented Aug 17, 2014 at 13:24

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