Putting holes in second story floor joists

Discussion in 'Remodel Forum & Blog' started by red_cabby, Jun 20, 2010.

  1. red_cabby

    red_cabby New Member

    Messages:
    1
    Location:
    London ON
    I've read the building code and realize what I'm about to do won't meet code, but I'm weighing my options and would appreciate any advice you can pass my way. I will be moving a second story toilet across 4 joists, the joists are 10" (9 1/2") on 16" centers. Bathtub and shower will remain on untouched joists.

    The 4" hole will be much bigger than what code allows, so what I'm looking for is:

    1. should I put the holes near the center of the span, or near the ends?
    2. how should I add support to these joists? glue/nail 2x10's on each side and then cut the holes, or fabricate metal panels to attach above and below the holes?

    Any help or advice would be much appreciated. Of course, if your opinion is that I'm an idiot for cutting joists against code, then plse let me know that as well (better to be told I'm an idiot by strangers, than have my wife point it out when the ceiling starts to sag:)

    Many thanks,
    DB
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,117
    Location:
    Bothell, Washington
    3.5" holes, not 4"
    You have to leave 2" at the top, and 2" at the bottom.
    No notching, as this destroys the joists.
  3. nukeman

    nukeman Nuclear Engineer

    Messages:
    711
    Location:
    VA
    Here is a guide that might help some:

    http://www.tileyourworld.com/construction/JoistBoringGuide.pdf

    For 2x10, you should limit the hole size to 3". You'll be a little bigger assuming you are running 3" lines (hopefully you are since the 4" would really be too large to run through the joists).

    If you go 3.5" or so, you may violate code, but it would probably still be okay. Personally, I would probably double up the joists that were bored. It is especially important if you are going with a tile floor (and even more important if the floor was going to use natural stone). If everything is open, I would sister those 4 joists over the full span. If you can't run the full span due to access issues, try to run the sister at least 2'-3' on each side of the hole (more is better). I use construction adhesive (I like PL Premium) and then either use 3" lag bolts or some carriage bolts with nuts/washers to tie the joists together. It might be a little overkill, but would give you a solid floor and would not add a lot of cost/labor assuming you have access.

    In my house, I recently replaced a bathroom fan and replaced the ducting as well since I had access and some of the previous joints in the duct were poor fitting, etc. Well, the people who installed this fan blew through two 2x10 joists (near the center of the span, no less) with this 4" duct. To make matters worse, one hole right at the bottom of the joist (so really became a notch), but atleast they made the hole as small as possible for the duct to fit. On the other joist, they cut a full blown notch that was deeper and much wider than needed. I couldn't easily replace the joists or reroute the vent, so I double them up as best I could. I then installed heavy metal plates across the notches to help prevent them from pulling apart/cracking.
  4. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,811
    Location:
    Cave Creek, Arizona
    How about calling a plumber to see if there is a better option for routing the drain than going through the joists. If you are crossing 4 joists, then you must be moving the toilet about 5 feet, which means the last hole will have to be about 1 1/4" below the first one, which could screw up your spacing, especially once you consider how low the first hole has to be in order to make the toilet's connection at the floor.
  5. Ian Gills

    Ian Gills Senior Robin Hood Guy

    Messages:
    2,777
    Location:
    USA
    You are an idiot for cutting joists against code. Run the pipe beneath the joists and box it in.
  6. Terry

    Terry Administrator Staff Member

    Messages:
    15,117
    Location:
    Bothell, Washington
    Most plumbers would rather leave the integrity of the home in place, and run the pipes either between the joists, or below and box out below by adding more framing.
    Some homes will box out in the corners on four walls to give it a "intentional look". When I was building homes, I could use the soffits to hide heating and plumbing.
    When I crown molded them, they become a "feature" of the home.
  7. GabeS

    GabeS Remodel Contractor

    Messages:
    294
    Location:
    Brooklyn NY
    Isn't there an easier location to place the toilet? Does it have to be in a location where the plumbing is going to be a hell of a job?

    Like the previous poster noted, by the time you account for the slope, the last hole will probably be a notch (which is prohibited in the middle 2/3 span of the joist and limited to 1/3 the joist height if I'm not mistaken).

    The best way to do this would be to build a header to carry the four or five joists that will be cut (such as is done for a stairway) and then run your pipe in the joist bay. However, that would be a much bigger job and should be left to a professional carpenter who is familiar with joist framing and support.

    Do not just wing it and hope for the best. You will be sorry in the end. The joists are sized the way they are for a reason. By reducing the cross sectional area of any part of the joist, you are greatly reducing it's strength.
  8. Terry

    Terry Administrator Staff Member

    Messages:
    15,117
    Location:
    Bothell, Washington
    We did a service call on a plugged toilet on the second floor a couple of months ago on a Friday in Sammamish.
    The lav drained, and the tub drained.
    The toilet was backed up.
    All of this on the second floor.
    The only fixture not working was the second floor Kohler pressure assist toilet.
    So like a smart guy that I am, I send one of my plumbers there to fix the toilet. However, it wasn't the toilet, it was the five feet of pipe that had been changed in the handyman remodel. The lady of the house wanted to move the toilet five feet through the upstairs joists. Now I don't know what the pipes look like, but from talking to her and remembering how money...........yeah money...........did I say money? kept coming up, that I believe I can safely say that no plumber was used to move the toilet plumbing, no permit was purchased and no inspection was ever done. Whatever was done, screwed up five feet of pipe so badly, that not ever a toilet designed to push waste 60 feet could make it past the first five feet.
    Now I know that since money............did I say money? Since money is an issue, the fix isn't going to happen. Instead, the plumbers that will be called over the life of the home will be badgered about how much and how often they have to come out to snake "only" five feet of pipe.
    That won't be me. I don't own main line clearing equipment. I like my fingers where I can see them, on the ends of my hands.
    If a plumbing inspector had looked at the toilet waste before it was covered, it wouldn't need snaking.
    Any problems would have been seen and corrected.
    Last edited: Jun 23, 2010
  9. Esquire

    Esquire Plumber

    Messages:
    65
    Location:
    Newfoundland
    nukeman had a good link there. Does anyone have anything similiar relating to the Canadian Building Code? I imagine it must be close but I would like to have something exact. Thanks
  10. GabeS

    GabeS Remodel Contractor

    Messages:
    294
    Location:
    Brooklyn NY
    ask your local building department.
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