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I have a bulkhead or soffit above our kitchen cabinets that is being removed to make way for taller ones that will go all the way to the ceiling. I encountered a vent pipe that will be in the way of the new cabinets:

enter image description here

So here's roughly what it looks like now (this is on an external wall): enter image description here

And here's what I want:enter image description here

Will it be feasible & acceptable to run this 2" pipe through several 2x10 joists in my 2 story home? Or, any other ideas?

kthornbloom
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  • this is an engineering question and has to do with the structural loading of the floor above and the reduced load ratings on those joists. IMO .. you are going to need to add joists to accommodate the load of the second floor. Or find a better way to run that pipe - at 2" diameter that seems to be a venting pipe. – Ken May 10 '17 at 02:23
  • Thanks, I've updated my question to note that it's probably a vent pipe. – kthornbloom May 10 '17 at 02:48
  • https://diy.stackexchange.com/questions/10657/what-are-the-guidelines-for-holes-in-joists – Ken May 10 '17 at 03:04
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    Uh, how are you going to do that? Use a teleportation machine? – Tyler Durden May 10 '17 at 03:07
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    Can you go below that area to where the vent pipe starts and reroute it up another area. If it is for the kitchen sink, can you run the vent pipe horizontally and go up in another area .If the stack is vented you may not need this vent pipe. – d.george May 10 '17 at 09:53
  • @TylerDurden - Yeah... I'm now realizing there's be no way to insert the horizontal pipe through the holes without a ton o' fittings. I guess I need a plan B – kthornbloom May 10 '17 at 11:19
  • @d.george Maybe? 2" pipe seems a little big to run through load bearing wall studs though. I wish it could go straight down into the crawl, over, and up on the left – kthornbloom May 10 '17 at 11:27

3 Answers3

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According to International Residential Code, you can bore a hole with a diameter one-third the depth of the joist. You have to keep the hole 2" from the top or bottom of the joist.

For a 2x10, you can bore a hole up to 3" in diameter.

9.25" / 3 = 3.08333" diameter

However, this is only for sawn lumber. If the floor is made up of engineered joists, you'll have to talk to an engineer.

Tester101
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  • Engineered joists have "installation guides" that show limitations, guides for drilling, etc. – Lee Sam May 10 '17 at 05:40
  • @LeeSam See R502.8.2. You'd have to check with the joist manufacturer, documentation for the specific joist being used, or an engineer. – Tester101 May 10 '17 at 11:36
  • Yes, each manufacturer will have their own requirements / restrictions. – Lee Sam May 10 '17 at 14:00
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https://www.familyhandyman.com/floor/how-to-drill-through-floor-joists/view-all

According to the above you could drill up to 3" diameter holes in the joists if you stay 2" away from the edges. You might or might not have to reroute some other pipes to accomplish this routing. This pipe appears to be ABS plastic drain or vent.

EDIT

Due to the recommendation in the link about staying 6" from any load bearing wall (pointed out in a comment) I withdraw my answer that this link supports the feasibility of rerouting the drain as described by the original poster. (I suppose this means that the 2x10" joist is, or could be, in compression within 6" of a load bearing wall. I was going by the widely noted rule to place penetrations in the outer thirds of the span of a joist.)

Maybe additional support to relieve compression would allow the penetrations as envisioned by the OP, but an engineer should be consulted.

EDIT2

So the rerouted pipe would have to turn laterally away from the load bearing wall so that the 3" holes would be more than 6" away from the wall.

Jim Stewart
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    looking at his diagram and comments the wall is load bearing and according to your web link declares "Just stay 6 in. away from any end or load-bearing wall " this is something that should be made clear. your answer does not specify this piece of critical information. – Ken May 10 '17 at 02:59
  • Even though my problem is unsolved, I think this best answers the actual question I asked here. I may look into an aav valve as an alterative to the pipe... – kthornbloom May 10 '17 at 20:31
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Consider accepting the current location of the drain/vent and cutting the cabinets to fit around it. This would reduce the capacity of the cabinets at the top back, but this might be the best course. The appearance of the cabinets when closed would be unaffected.

Boxing in the piping from inside the cabinets would remove the possibility of damaging the piping by ramming it with heavy objects and improve the appearance when the cabinet was open.

This would avoid any compromising holes in the 2x10" joists.

Jim Stewart
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