Had some 2nd-story plumbing start to fail in my 1950's home, so I had the brilliant idea to re-do a "mud-job" bathroom. It included removing a non-load bearing wall from the adjacent bedroom's closet to add square footage. In spite of how arduous the concrete removal was, everything was going well until I got all of the subfloor up to see there is a support beam standing in the way of where my old plumbing was and where I would like to get to.

Pictured you will see the old plumbing coming up from the stack, my closet flange, air vent, and drain pipes that used to run to the tub + sink. Yes, I am aware that one joist (among others) looks terrible and luckily I am in a position to replace or sister all the joists so that will be happening.

My issue lies in the support beam headers. In the other picture you'll see a red circle which is where I would like the closet flange to go, but I'm not sure any layout would allow for me to actually put one there. According to my county inspector, I can notch those or even bore holes with the same rule of thumb as joists, but I'm not sure I feel comfortable or safe doing so.

I can't go under, as my kitchen ceiling begins. Their cabinets go ceiling high, so a soffit isn't even an option.

The other option I see is where the blue circle is. Basically, still push the closet flange back but up to about where the beam starts and head off that joist where it would be going. I'd end up packing out the wall and building a chase in the room for just the toilet. Maybe even have enough room to keep a small closet on the other side.

Still, that would be disappointing and I'd lose some of the space I was hoping to gain. Are there options for getting me on the other side of those support beams?

Old plumbing

Closet flange options

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    Maybe consider a rear discharge toilet, which would allow you to run the pipe over the beam and to the back of the toilet instead of through the beam.
    – Moshe Katz
    Commented Feb 21, 2021 at 13:40
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    Consider putting one shorter cabinet in the kitchen below, then hiding the difference with some fake door fronts. This would allow your plumbing to go under the beam to alleviate your concerns while still hiding the plumbing from below.
    – FreeMan
    Commented Feb 24, 2021 at 14:23

2 Answers 2


I wanted to follow up on this in case anyone stumbles upon it. I actually ended up using a relatively new solution -- a 2810HR Joist Reinforcer. It's a 14-gauge steel plate which allowed for a larger bore (in my case I made it 4.5") through a 2x10 and I put one on each side of the headers. The IBC/IRC certification they have for the plates passed inspection with no issues.

Only recommendation I would make is to get a better square bit to drive the screws than the one the company provides.

Otherwise, it got my plumbing where it needed to go and it's incredibly sturdy so I'm not worried about the strength of support. Hope this helps someone in the future!

enter image description here

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    This will come in handy as there are many inquiries about brittle joists or beams over-bored/notched or in the way of 3" pipes.
    – P2000
    Commented May 10, 2021 at 14:35

Looks like you have a 4' x 2 x 1 1/2 cast iron specialty fitting -hub and spigot pipe existing. If so, why not cut it back to the stack and reduce it to 3" ty at the top of the stack so you can run the vent straight up the outside wall until you tie it back into the existing vent. This will to allow you drill through the double beam (not sure 2- 2x10s?) to get to your red circle area with only a 3' pipe. Try to put a 3 x2 wye horizontally as close to the first ty to pick up your other fixtures. I would move your red circle 4" or more further from the outside wall so the hole to penetrate the double beam is in the second bay. Still kinda close to the end of the double for the 1/3 rule but better than the first bay. I would have the inspector confirm your plan as acceptable if he is going to inspect the finished work.

  • Thanks for the comment! Yeah, the support beams are 2x10s, as are the joists! I like your idea of moving it further away from the exterior wall, but I think even if I park it right in the middle of the two joists, a 10" rough-in toilet still makes the closet flange have to be almost right against the support beam, so I would probably end up needing more than 3" for the sweep. 3 inches just barely passes inspection and has me concerned I would end up having to bore it out more than that for the flange bend.
    – RCNeil
    Commented Feb 25, 2021 at 15:45
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    Short of a bathroom layout redesign, if you are willing to move the toilet further away from the outside wall you could penetrate the joist on the horizontal with a corner bend or 45 and have a 1/4 bend come up along side the joist. Add an offset flange and you pick up another 2" off the mounting wall for possible a 12" rough. A little tight to assemble and you might need to use a street fitting.
    – Rich
    Commented Feb 25, 2021 at 18:24
  • These are all great ideas. Thanks! I would definitely like to check with the inspector to make sure going 3" in that 2x10 is safe and acceptable, but that's a great suggestion
    – RCNeil
    Commented Feb 25, 2021 at 21:43
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    You are right at the line for hole max for a single 2 x 10 but have a double. As you say it will be at the discretion of the inspector. See chart - imgur.com/pXNmaY1
    – Rich
    Commented Feb 25, 2021 at 23:33

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