In preparing to move our laundry to the basement I am stuck looking for a route out for our dryer vent in our basement.

My initial plan was to run it out a rim joist like all the other posts I found on here, but my house has 2x6 rim joists which obviously are pretty close to 5.5” inches, I am worried about compromising it by drilling in a 4” dryer vent opening.

I understand the rim joist doesn’t do a whole lot of load bearing but a 4” hole in a 5.5” board seems like a lot, am I wrong?

  • Is routing it out the other wall, through the blocking between the joists an option?
    – spuck
    Aug 2, 2022 at 15:01
  • @spuck the other wall would be the end joist I was under the impression going through an end joist (parallel with floor joists) would be worse, this location is basically a corner of the basement.
    – BobDere87
    Aug 2, 2022 at 15:02

1 Answer 1


A rim joist is supported 100% from below by your foundation wall, right?

Unless you have a very heavy downward force directly above the 4" hole there is nothing to worry about.

Large holes are a problem in floor joists and beams since they span a great distance and have minimal/no support from below.

  • Yes, the wall plates and sheathing effectively provide a shear wall above, making such a hole inconsequential.
    – isherwood
    Aug 2, 2022 at 14:51
  • That is correct, the rim joist is sitting on a cinder block foundation wall with a sill plate directly under the joist. All that is above it is the kitchen sink. What about going through an End Joist? Would that be worse?
    – BobDere87
    Aug 2, 2022 at 15:02
  • @BobDere87 If the end joist is supported by the foundation then it's equally inconsequential. The existence of the sink is also inconsequential since that would be resting on a floor joist which rests on the sill plate.
    – MonkeyZeus
    Aug 2, 2022 at 15:06

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