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  1. #1
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    Default Did the plumber compromise my joist with too big of a big hole?

    After such outstanding advise on Earthquake Proofing I'm back for more

    A plumber I'm working with got a little over-zealous when relocated an ABS pipe stack. By cutting too large of a hole in a joist, he's undoubtedly created a code violation, but I'm more concerned that he's compromised the structural integrity of the joists. I'm especially sensitive as my side-door appears to be sticking, when it wasn't before - which is always a bad sign.

    There are two photos of the affected area below. I'll try to describe it as best I can...

    The plumber cut a 4 1/4" sloppy hole in a 9" joist. The hole is cut about 3/4" from the bottom edge of the joist. The joist had a bad notch already to begin with close to where it rests on the sill plate and in addition - it appears to be sharing the load of the joist next to it which has been previously cut short and shored into its neighbouring joists.

    These are old 1914 25 foot long 9" joists.

    So assuming the answer is "Yes". How do I fix it?

    Pictures:




  2. #2
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    Default Re: Did the plumber compromise my joist with too big of a big hole?

    Yep ... there are problems .

    In a survey of building inspectors and private home inspectors .... plumbing ranked number 1 compromising structure with doing things like this .... with electrical being number 2.

    It looks as though the drains were run so as not to be in the way of what looks like a window . It looks as though a misguided attempt to run the piping through the structural members in order to minimize intruding the head room and away from the window .... just a guess.

    However ... the 4 1/4 inch hole has compromised the integrity of the joist.... it seems to be too large and definately too close to the bottom edge of the joist ..... allowable by code.
    Considering there is also a notch which has reduced the depth of the joist at the point load to begin with.

    The PEX run near the end of the shortened joist is also questionable as well as the branch that runs up between the subfloor and the header joist.

    There also seems to be a number of change of directions for that drain pipe in question.

    Here is a link with some information as to holes and notches in joists : http://advice.thisoldhouse.com/showt...t=floor+joists

    As for a fix .... that's going to require removing that drain pipe and re-enforcing that joist .... considering you have earthquake requirments that will determine how it's done by the building inspector.

    Hope this helps.

  3. #3
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    Conway, NH
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    Default Re: Did the plumber compromise my joist with too big of a big hole?

    Quote Originally Posted by asc2078 View Post
    Canuk was correct. It should not have been done that way. I would add one point that at least makes it the best of a bad situation. The area of your joist that has been compromised, appears to be very close to the foundation wall. That is not nearly as bad as if it were out further on the joist were there is a greater load stress.

    In a laymen's example: If you were to take a small slat of wood, hold your hands on both ends and break it over your knee, it will not break where your hands support it. It will break more toward the center where the stress point is the greatest.

    As for how much you should worry about it, that one floor joist is not going to collapse your house. If anything it would most likely, only cause some minor settling in that area. While it should not have been done this way, it is what it is. Were I in your situation, at this point, I would do nothing. I would simply keep an eye on it and see if you notice any deflection in the joist over time. I doubt that you will have a problem, with it being that close to the foundation.
    I agree that it shouldn't have been done that way. The pics aren't the best, but it looks like this joist is serving as a trimmer, that is, taking load from some adjacent joists, although I can't tell why from the pics.

    I disagree with DB, regarding his statement that its not bad if its near the bearing rather than midspan. In a typical simply supported beam the bending moment is worst midspan as DB tried to demonstrate, however near the points of bearing shear is at its highest. Bending moment is carried mostly by the top (compression) and bottom (tension) and therefore wouldn't be affected much by a hole in the center at midspan. However shear is carried throughout the height of the beam and is affected greatly by a hole located near the ends.

    Alright, regarding the notch. per American Wood Council NDS 2005 "4.4.3.2 Interior notches, located in the outer thirds of the span of a single span sawn lumber bending member, shall be permitted, and shall not exceed 1/6 of the depth of the member." It goes on later to say the length of the notch must be < 1/3 of the depth. From the looks of it the notch is indeed reducing the effectiveness of the trimmer.

    Regarding the hole, I can't seem to find anything specific, but the hold you have is too big, obviously. You effectively only have a 9"-0.75"-4.25" = 4" joist left, which is likely inadequate.

    Effectively the joist/trimmer is swiss cheese and probably needs to be replaced, supported, repaired, as determined by a licensed structural engineer. Do not ignore this, especially if the door is sticking and especially since you are in a seismically sensitive area.

    Sorry for going on so long, but this happened to me, something I noticed when inspecting our house before purchasing.

  4. #4
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    Default Re: Did the plumber compromise my joist with too big of a big hole?

    Regarding the hole, I can't seem to find anything specific,
    "The diameter of holes bored or cut into joists, rafters, and beams may not exceed one-third the actual depth of the member. Holes may not be closer than 2 inches to the top or bottom of the member or any other hole located in the member. Where the member is also notched, the hole may be no closer than 2 inches to the notch."

    In other words .... for a 9 inch joist the hole can only be 3 inch diameter and no closer than 2 inches from the top or bottom .
    Last edited by canuk; 05-15-2008 at 06:07 PM.

  5. #5
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    Default Re: Did the plumber compromise my joist with too big of a big hole?

    The only other remedy I can see is to install a support post with a plate big enough to cover both sides of the hole.
    Jack
    Be sure you live your life, because you are a long time dead.-Scottish Proverb

  6. #6
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    Default Re: Did the plumber compromise my joist with too big of a big hole?

    Thanks for the great advice.

    Canuk was right - the hole was made in order to relocate the stack away from the window to accommodate framing.

    On Forsemans recommendation - I contacted the structural engineer that helped me with the seismic work.

    He came up with a few ideas to fix to avoid re-doing the pipe. the one we settled on is to relocate the 2x6 wall we were planning on putting in a few inches. the wall will run parallel to the joist and so we'll locate it to center directly under it. The wall will bear on the slab, which he's fairly happy with given that all the conditions were existing except for the new hole.

    Maybe next time I'll ask Richard Trethewey to do the plumbing instead
    Last edited by brettmarl; 05-16-2008 at 01:17 PM.

  7. #7
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    Default Re: Did the plumber compromise my joist with too big of a big hole?

    Quote Originally Posted by jkirk View Post
    all the advice here is correct, the only thing i would mention is to always make sure you and your plumber go over his plan for where his pipes are going to go. that way you can make any framing mods before hand or . he could have run the drain beneath the joist and it can be closed in by a bulkhead if its a finished room below
    great point. we did discuss the general plan before hand - but as always clear communication is key.

    the plumber said - "i may have to notch that joist a little to get the pipe clear, depending on the bends".

    my interpretation/assumption was that that notching would be done to code and if he needed to violate code, he would have reconfirmed; with something like "hey - i'm going to violate two counts of code here - cut too big of a hole and cut it too close to the edge, are you ok with that?"

    good lesson of not being precise in my communication

  8. #8
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    Default Re: Did the plumber compromise my joist with too big of a big hole?

    Good news ... though I missed the part about a wall going in the area .... that would indeed make the differnce.

    It would seem this work wasn't going to be officially inspected otherwise the plumber certainly would have done things differently once his work would have been seen by an official.

  9. #9
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    Default Re: Did the plumber compromise my joist with too big of a big hole?

    it's permitted and inspections will be done when this stage is complete. we already passed the ground work inspection.

    the plumber seems to think that the inspectors he works with are generally forgiving in an retrofit situation like this and he can get it passed just fine; we shall see...

  10. #10
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    Default Re: Did the plumber compromise my joist with too big of a big hole?

    Really ?!?
    *** ...that should be intersting


    Hope it works out for you.

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