Toilet Drain/Joist Clearance

Discussion in 'Toilet Forum discussions' started by diydude, Aug 25, 2012.

  1. diydude

    diydude Member

    Messages:
    62
    Location:
    Seattle,WA
    Is there a minimum clearance requirement between a joist and a toilet drain opening? I read something about, I think, 3" from the center of the drain to a joist. I'd like to sister the bad joist in the attached pic. If my calculations are correct, doing this will leave me about 1/2" from the edge of a properly-centered 5" drain hole in the subfloor to the new sister.

    Thanks.

    Attached Files:

  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,154
    Location:
    New England
    From a practical viewpoint, most toilet flanges are a cone, so they flare out from the pipe. Thus, if the joist was right next to the pipe, you may not be able to slide the flange on while gluing it in place - at least you may not be able to slide it all the way in. Now, this is often more of an issue with a 3" pipe than a 4" pipe where you could use an internal flange.

    Don't know if there's an actual code issue here, but more of a practical issue on what will fit.
  3. dlarrivee

    dlarrivee New Member

    Messages:
    1,172
    Location:
    Canada
    I don't see much joist left in that photo, I hope it wasn't you who went crazy with a sawzall.
  4. diydude

    diydude Member

    Messages:
    62
    Location:
    Seattle,WA
    No, it wasn't me who hacked together that mess. I just happen to be the beneficiary :). I've since corrected that issue: Floor 005.jpg
  5. Terry

    Terry Administrator Staff Member

    Messages:
    15,136
    Location:
    Bothell, Washington
    I would pull the shutoffs at this time and stub out copper.

    You should go with a new pressure balance valve for the tub there.
    There is a drain for one in the corner, right?
    You will need space for the waste and overflow that will be lower than the floor there. Looks kind of tight right now. Normally the drain is about 10" from the wall at the end.

    I will say the framing looks new and solid.
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,843
    Location:
    Cave Creek, Arizona
    joists

    I would say that "triple" joists are an "overkill".
  7. jadziedzic

    jadziedzic Member

    Messages:
    92
    Location:
    New Hampshire
    I don't know about your jurisdiction, but here they would require EITHER some of the foam "gasket" material between the new joists and the concrete (or block) wall, OR have the new joists rest on a pressure-treated plate. It's generally frowned upon to have non-pressure treated wood in direct contact with concrete.
  8. diydude

    diydude Member

    Messages:
    62
    Location:
    Seattle,WA
    I have building paper under the joists; it's not easy to see in the picture. I confirmed with the city that this is ok.
  9. diydude

    diydude Member

    Messages:
    62
    Location:
    Seattle,WA
    Thanks :) Seriously, I wanted to flatten the floor from below before I attached the subfloor, so I added a second sister to the second joist from the wall to make the joist heights even across the floor. The first joist nearest the wall was an absolute mess, so I patched it and sistered on both sides.

    I have building paper under the joists now. I confirmed with the city that this is ok. I got a lecture about that when I took some pictures to City Hall to ask about boxing in the drain. Is that a newer code standard? Most or all of the floor joists on the first floor are resting on the foundation. The house was built in 1976.

    Sorry, the picture doesn't show that I'm actually boxing in the tub drain. I'll have to read up on pressure balance valves. Thanks for the suggestion.
    Last edited: May 27, 2013
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,843
    Location:
    Cave Creek, Arizona
    quote; I'll have to read up on pressure balance valves Not really, because that is probably the only thing you will be able to find for your installation.
  11. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,154
    Location:
    New England
    For a number of years, ALL legal shower valves sold in the USA have anti-scald technology. The most common way to do this is with a pressure balance valve although some thermostatically controlled valves are fast reacting enough to qualify without some additional internal controls. Some places still sell valves that do not meet this requirement, but that doesn't mean they are legal to use (seems like they'd be required to only sell legal, code-compliant devices, but that isn't the case). The most common ones are a single handle that does not have a volume control...they're either all on or all off. There are some that still have a volume control, if that is important to you, but none I'm aware of still have separate hot and cold valves you control separately, only temperature control.
  12. diydude

    diydude Member

    Messages:
    62
    Location:
    Seattle,WA
    Ah, those valves. Ok, thanks.
  13. diydude

    diydude Member

    Messages:
    62
    Location:
    Seattle,WA
    When I was looking to remove the subfloor, I took a semi-crude route for removing the outside-fitting flange; used a drill, screwdriver, and mini-hacksaw. This left the collar of the flange still attached to the pipe, and the ABS cement is solid as a rock (the pipe is not damaged). Now that I have the floor open and I have a much better view, I want to clean up the sewer pipe before I reinstall the subfloor. I thought about cutting the pipe after the elbow when I initially looked at removing the flange, but there isn't much pipe after the elbow. Now, I was thinking of replacing the elbow and adding a section of pipe for the new flange if I can't somehow remove the remaining portion of the existing flange. Thoughts?

    Attached Files:

    Last edited: Jul 7, 2013
  14. Terry

    Terry Administrator Staff Member

    Messages:
    15,136
    Location:
    Bothell, Washington
    Quit your thinking so much. :)
    Run down and pick up either a long turn 90, or a medium and a coupling.
    Wack off what you have and start over. (with a saw or cutter)

    You could also drill out the pipe from the fitting, but it's cheaper and quicker to just pick up new fittings.
  15. diydude

    diydude Member

    Messages:
    62
    Location:
    Seattle,WA
    Thanks, Terry - needed that :) Moving on now...
  16. diydude

    diydude Member

    Messages:
    62
    Location:
    Seattle,WA
    Ok, I got the new 90 installed, but it's a little of level and puts the center of the drain at about 12 3/4" from the rough wall. Should I be concerned about this? I was thinking about cutting a slight angle on the end of the pipe that will sit in the top of the 90 to correct it.

    DSC01149.jpg

    DSC01150.jpg
  17. diydude

    diydude Member

    Messages:
    62
    Location:
    Seattle,WA
    Take two - started over: The elbow is now fairly close to plumb, and the center is at 12 1/2" from the rough wall.
    Last edited: Jul 14, 2013
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