Tub Drain and Floor Joist

Discussion in 'Shower & bathtub Forum & Blog' started by diydude, Jan 8, 2013.

  1. diydude

    diydude New Member

    Messages:
    62
    Location:
    Seattle,WA
    The new tub I'm installing in my bathroom will be perpendicular to floor joists. The original tub was installed in the same location, but the notch that was cut for the drain and overflow in the floor joist was about 1 1/2" deep. My understanding is that I can't notch any deeper than a little less than 1" (1/6 the depth of the 2x6 joist). What's the best way to approach this situation? I read something about heading off the joist, which would be a pain, since I've already sistered the joist. See included pic.

    IMG_3619.jpg
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,023
    Location:
    New England
    FWIW, when you notch a joist, you effectively make the whole joist the equivalent of the thinnest section. The top and bottom are the parts that provide the most strength, either in compression on the top or tension on the bottom. When there's a gap from a notch, the bending moment's location changes and it gets much weaker. That's why there are rules about where it is acceptable to put holes in them (basically, avoid the ends, and limit their diameter). I'd probably box it out, but see what the others have to say.
    Last edited: Jan 8, 2013
  3. dlarrivee

    dlarrivee New Member

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    1,172
    Location:
    Canada
    Sorry that you don't want to do any more work (I know you already did some work on the joists).

    Is that seriously a splice on the right hand joist about 4' from the foundation wall?

    Your best bet is a doubled up 2x(8,10,12) whatever you have there, and some joist hangers.

    You use joist hangers to support the header and you sister the joists that the header attaches to.
  4. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

    Messages:
    4,177
    Location:
    North Vancouver, BC
    The stud wall on the right is that a bearing wall? Any point loads coming down on it?

    2"x4"'s a pretty strong but I'm thinking you should have used something like a 4"x6" or 6"x6" fir post instead.

    Strong tie fasteners, hangers there are many ways to go about it. Do you have an engineer giving recommendations? City inspections?

    Water weights about 8 pounds per gallon. That's a lot of weight.

    I'd get the worked looked at by the city before going to deep and check to see if that wall on the right is a bearing wall.

    Looks like it could be a "Do Over" or some more work done to beef things up proper.

    JW
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
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    Location:
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    Well, the wall on the right cannot be a "bearing wall" because there is nothing underneath it to "bear" on, and since it is on 2x6s it wouldn't support very much anyway. 2x6 s are a very poor floor support unless they are very short. We would have to see a lot more of the structure to determine what is the best route.
  6. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

    Messages:
    4,177
    Location:
    North Vancouver, BC
    HJ your assuming that the wall is not bearing but it is quite common to find a wall like that in a residential home. Often home owners make the mistake of removing structure here. Some builders do as well.

    On our last project downtown a young capenters assistant made this mistake. I called it out right away. The builder thought I was making a big deal of it. Then the structural engineer came in and confirmed my concerns. A simple mistake turned into a full day repair for the contractor.

    The wall to the right could bear the weight of the ceiling studs. Drywall. Above that the roofing truss could be layed over top of that. Not a big deal in the summer but what about a heavy snow year or a re-roof. Stack a wack of shingles in thewrong place and this can affect this framing.

    Looks to me like the subfloor was compromised and the homeowner went in with some 2"x stock and toe screwed them in place. No big deal if there is no weight bearing but if there is then this needs repairing.

    Worth checking into.

    JW
  7. diydude

    diydude New Member

    Messages:
    62
    Location:
    Seattle,WA
    No, I don't believe the wall on the right is load-bearing.

    Joist splice: A previous owner tried to repair the floor joist after a leak rotted part of the floor, and he did a terrible job. So, I had to cut out a section of the joist, attach a full-length sister, splice the joist, then sandwich the joist on the opposite side with a second sister.

    If I'm following what you're saying, it seems like you're advocating heading off the joist and boxing the tub drain.

    Closeup of the drain next to the joist:

    Drain 003.jpg

    Here's a drawing I saw online for heading off joists. It sounds like I'd have to sister the joist under the wall also if I decide to go this route. I have a couple questions:

    - Is there a such thing as a triple joist hanger, or is there another option? Edit: I saw an LUS26-3 hanger at the hardware store.
    - What is the best way to cut the "triple" joist? Edit: I'm going to see if I can fit a circular saw, attaching a straightedge to the joist as a guide on either side of it.

    HEADING OFF THE JOIST.jpg
    Last edited by a moderator: Feb 16, 2014
  8. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    You're really confusing a lot of terms here John.

    There is no such thing as a ceiling "stud", you're talking either a joist or a rafter tie here. If the house is built with trusses for the roof, the bottom chord of the truss is what makes up the ceiling, and unless the house is MASSIVE the trusses will only bear upon the exterior walls.

    Do you honestly work for carpenters that do not carry load down to footings? That is scary.

    I doubt the wall is load bearing but cannot say without more pictures, there are lots of interior 2x6 stud walls because the added depth is great to have for "wet" walls full of plumbing piping.
  9. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

    Messages:
    4,177
    Location:
    North Vancouver, BC
    All point loads are brought down to foundation or beams on all new projects. That said most of our work is reno work and I've seen a lot of scary things.

    Here the owner has hacked out a floor joist and sister on some 2" X stock with what appears to be trim screws. This job has red flags all over it.

    Someone that knows what there doing needs to check that the wall has no loads on it.

    It's so easy to check. You should know and not think you know.

    Anytime structure is changed in a home the city and a structural engineer need to be consulted. Period. Fact.

    If I walked into this job we would walk right back out the door if the changes where not signed off on by an engineer. I'm not a framer. I'm not an engineer. But I do know that the work above looks like a dogs breakfast and they want to put a tub there.

    My structural engineer would charge me about $300.00 for his approval of the plans. Nothing in the big picture.

    JW
  10. diydude

    diydude New Member

    Messages:
    62
    Location:
    Seattle,WA
    Correction: The wall is NOT load-bearing. Sorry, it took me awhile to remember that there's a gap above the top plate of the wall, and there's a beam running next to the top plate.

    All joists needed sisters, because I was told the floor was inadequate for tile with single 2x6's for joists. I sistered full-length and full-height using 3" exterior wood screws, Loctite construction adhesive, Douglas Fir 2x's, and clamps to hold the sisters in place. Three screws were installed every twelve inches. The last joist you see in the pic was hacked by the previous owner, so I spliced it like I mentioned previously and sistered full-length on both sides.

    I'm going to check with a building inspector today regarding heading off the joist to make sure that's an appropriate manner in which to proceed.

    Edit: I checked with one of my city's building inspectors, and heading off the joist is the way to go on this project. I showed him pictures and got info on how to do it correctly using joist hangers.

    Wall.jpg
    Last edited: Jan 10, 2013
  11. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    What is a trim screw John?

    I'm glad you admit that you don't know, because it is blatantly obvious that you'd be in over your head on even a small framing job.

    I'm curious as to your explanation on a load bearing wall being a "point" load... first time I've heard that one.
    Last edited: Jan 10, 2013
  12. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

    Messages:
    4,177
    Location:
    North Vancouver, BC

    I miss your absence from this forum Diarrive. Seems like you are about to lay into me again like you have in the past. I do not wish to read your posts or reply to your comments since it's clear to me you bring nothing to the table and have little to add to this form.

    The trim screws I mention are those hex shaped screws.

    Yes I'm a not a framer. And for the record have never framed a house from the ground up.

    That said for years I've posted and helped people on this forum while you sit back and join the ride. You have offered up nothing but your opinion with in these pages and that in my opinion is of a bitter old man.

    Just saying Diarrive. Get a life.

    You really don't know what a point load is?

    JW
  13. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    You're bringing up point loads when we were looking at a load bearing wall.

    A point load would be a post supporting a beam, not an entire wall with studs every 16".

    John, you know your stuff when it comes to showers, but you're off by a lot when it comes to framing advice.
  14. diydude

    diydude New Member

    Messages:
    62
    Location:
    Seattle,WA
    I finally finished heading off the joist.

    DSC01073.JPG
  15. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,650
    Location:
    Cave Creek, Arizona
    notch

    This discussion is like the Greek philosophers who spent weeks debating how many teeth a horse has. You have a triple joist there, and no real "weight" on it. Notch the joist and install the tub. The house is NOT going to come crashing down.
  16. diydude

    diydude New Member

    Messages:
    62
    Location:
    Seattle,WA
    I already headed off the joist per the attached pic (and per the city), so I don't need to notch anywhere.

    HEADING OFF THE JOIST.jpg
  17. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,023
    Location:
    New England
    That's the strongest way to do it...
  18. diydude

    diydude New Member

    Messages:
    62
    Location:
    Seattle,WA
    The city inspector signed off on the floor structure work today :)
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