Tiny sink, tiny bathroom. 2" cast iron right there. Any reason not to use rubber T?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by CanOfWorms, Feb 25, 2013.

  1. CanOfWorms

    CanOfWorms Member

    Messages:
    178
    Location:
    New Jersey
    I have a very small powder room that I want to put an even smaller sink into. There is a 2.5" outside diameter cast iron pipe right there running floor to cieling.
    My first thought was to cut and put in a pvc drain T using no hubs. But that is 1 foot from the toilet at eye level. It would be unsightly and big.

    Is there any reason I cannot use a rubber T like the one pictured below. I know it will also be ugly, but it will be smaller and I could probably get away with painting it white like the pipes.
    I also put a little sketch of the corner.

    fernco_rubber.jpg

    Here is a sketch.
    sink.png
    Last edited: Feb 25, 2013
  2. CanOfWorms

    CanOfWorms Member

    Messages:
    178
    Location:
    New Jersey
  3. jimbo

    jimbo Plumber

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    8,997
    Location:
    San Diego
    Do you know if that cast iron pipe is a waste pipe? If it is a vent coming from the lower floors, you cannot put waste into it
  4. CanOfWorms

    CanOfWorms Member

    Messages:
    178
    Location:
    New Jersey
    Its not a vent pipe. It is on the bottom floor. I emailed Fernco they said the QT-200 will fit.

    Any reason not to use the rubber T?

    Last edited by a moderator: Mar 3, 2013
  5. asktom

    asktom Member

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    578
    Location:
    Victor, MT
    It won't support the cast iron above it.
  6. CanOfWorms

    CanOfWorms Member

    Messages:
    178
    Location:
    New Jersey
    It looks like the pipe runs against the wall about as far away as the elbows protrude. It then does a 90 degree turn right above the sheet rock. The wall is a solid concrete wall.
    I suppose a few U braces screwed into the wall would support it as long as they were very snug. I should also shim behind the pipe so it does not pinch in where I put the rubber T.
    What do you think?
  7. hj

    hj Moderator & Master Plumber Staff Member

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    "I" think it's a dumb idea, but I suppose you intend to use it anyway, so telling you that it is NOT the proper way to do it is useless. A PVC tee and No-Hub couplings will be EXACTLY the same size, look better, but would still NOT be proper since it appears this is a waste line, not a vent. If it is a waste line, you could be creating problems for yourself, since the new sink will NOT be vented.
  8. CanOfWorms

    CanOfWorms Member

    Messages:
    178
    Location:
    New Jersey
    I'm here for advice and value your expertise. If you say the rubber T is a bad idea I would not argue with you.

    Venting: On the second floor there is a sink that feeds into a 1 and 1/2 that goes out the roof from there as a vent. That line comes down and becomes this line, so isn't it vented up there? It seems like most of the sinks connect to 2" iron pipes that vent out on roof and toilets connect to a different line. I've lived in the house for 7 years with constant high use and have never smelled sewer gas.
    Also does it need to be vented if the sink is only is 12" from the waste line?
    My slop sink isn't vented immediately.
    Do they make PVC T street?
  9. asktom

    asktom Member

    Messages:
    578
    Location:
    Victor, MT
    The venting situation is what HJ stated above may well cause you problems. You are wet venting between floors. The top floor sink will be fine but not the lower. When water comes down from above it will be pushing air. This may cause the water in the downstairs trap to slosh around, possibly enough to send some down the drain breaking the trap seal. If that happens there is nothing between your nose and your sewer. To do it right is a larger project than you envisioned.

    They make street san tees, but they are only street on the bottom, you would still need a short hunk of pipe for the top.
  10. CanOfWorms

    CanOfWorms Member

    Messages:
    178
    Location:
    New Jersey
    OK. Got it venting ok for up top but two floors down it would create problems. I can imagine old pipes that may be slow to drain will make it even worse in that small sink two floors down
    Taking that into consideration.
    I have three thoughts: 1. Back flow valve?
    2. More downward slope from sink rather than a horizontal run.
    3. Using a 45 degree Tee instead of a rounded entry Tee
    See the pic:
    sink.png
  11. jimbo

    jimbo Plumber

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    8,997
    Location:
    San Diego
    1) wrong
    2) wrong creates S-trap code violation
    3) wrong code violation....must be sanitary Tee

    Still violated wet vent codes
  12. CanOfWorms

    CanOfWorms Member

    Messages:
    178
    Location:
    New Jersey
    My first instinct is to say code shmode. : )>
    But if I did not have to worry about code, would a horizontal run with a back flow preventer before the sanitary trap to the trick?
  13. asktom

    asktom Member

    Messages:
    578
    Location:
    Victor, MT
    A check valve won't work and the other two approaches will just compound the problem, the trap could syphon. Code and physics require a vent before you tie into the waste line. The vent would need to either go through the roof or tie into another vent above the fixture that vent serves. Sorry, but that is the deal. Is there an existing toilet in this room? If it is plumbed correctly you may be able to tie into the toilet vent.
  14. CanOfWorms

    CanOfWorms Member

    Messages:
    178
    Location:
    New Jersey
    There is a toilet in the room. It is on the caddy corner from this. The waste line runs floor to cieling and goes up to the third floor where it connects to that toilet.
    There is a squirrels nest of drains and such behind the washer, I suppose I could tie into that.

    On another note, can I connect a shower waste drain to the 4 inch toilet line I mentioned? I have a clawfoot tub in the room behind this with no drain pipe. I want to connect to this 4" waste line.
  15. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,183
    Location:
    New England
    EACH and EVERY fixture drain needs a vent. Once a pipe is used as a vent (or waste) its function CANNOT CHANGE! IOW, you can't make a drain a vent, and you can't make a vent a drain - they cannot be dual purpose (with very few exceptions, and then, only within the same bathroom). Sometimes, it's not easy, and you have to tear up more than you want to make it all work right. When your house was built, it may or may not have passed today's codes. Generally, if you do not touch it, it's grandfathered. But, as soon as you touch it, the part you touch must be brought up to today's codes. Over the years, materials and knowledge has increased, and what may have worked in some circumstances way back when, was found to be faulty thinking, and there were situations where it would fail to provide a safe environment. The codes are designed to keep you safe, and have things work...whether you get it inspected or not, the physics and realities still apply and you should make it pass.
  16. CanOfWorms

    CanOfWorms Member

    Messages:
    178
    Location:
    New Jersey
    There are 6 sinks, two tubs, three toilets in this house that's 110 years old with only one vent pipe sticking out the roof... no sewer gas problems so far. I think I'll just hook it up to the same lines that the washer drain is hooked up to and see what happens.
    Last edited: Feb 27, 2013
  17. mtcummins

    mtcummins In the Trades

    Messages:
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    Location:
    Pittsburgh PA
    Jim is a respected member here. He is trying to explain to you why your idea won't work. You clearly don't want to listen, just want someone to tell you to do what you already intend to do. That's not the point of this forum. We're here to tell you how to do it right, and tell you when your idea is wrong.

    You're backcheck/extra pitch/etc ideas will make your problems 10x worse. You're going against not just code, but basic fluid dynamics.

    You need to get a vent into this setup. Use an Air Admittance Valve if you absolutely have to, but don't just skip the vent. We're not talking about "code scmode" here, we're talking about serious health risks. Just b/c something you do seems to work (which just tying into that line very well may appear to be "working fine," doesn't mean that its working safely.

    Ultimately, the advice I would give, and this is also coming from someone who doesn't hold the code in particularly high regard but cares about doing things at least as close to "right" as possible, is that you either need to learn a LOT more about plumbing before taking on this project, or call a plumber.
  18. CanOfWorms

    CanOfWorms Member

    Messages:
    178
    Location:
    New Jersey
    I got it. I was actually changing my reply to something a little less heated as you posted this.

    About 6 feet away there is a slop sink and washer drain hook up. Tapping into that seems to be a better option
  19. mtcummins

    mtcummins In the Trades

    Messages:
    380
    Location:
    Pittsburgh PA
    is this setup vented? If so, you can tie in your drain line to the line you wanted to before (don't do the pitch thing, come over and tie in with a PVC SanTee, not the fernco thingy), and then bring up a vent line to at least 6" above the flood rim of the highest fixture in the room (typically 42" works) and tie the vent into the existing vent using an upside-down santee.
  20. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,183
    Location:
    New England
    110-years ago, they used S-traps and relied on a single, often quite large, drain to act as the vent. They were still doing this in the 1950's, as my mother's house is built like that. 110-years ago, the only plumbing in the house was maybe one bathroom and a kitchen sink. It worked. Today, after modifications, adding yet another bathroom is just not going to work well.

    A single vent pipe through the roof does not imply that what's there couldn't be vented properly...there are many code-compliant ways to combine vents, but as I said, you cannot combine FUNCTIONS of the piping if you want it to work. Getting things to drain often isn't the issue, it's that they drain too well and siphon other traps dry, or, you end up with backups.

    Code assigns each type of drain a certain fixture unit...the amount of fixture units determines the size of the vent(s) and the drain line(s).

    You need to figure out which pipes are drains and which are vents...it may be that everything is wet vented except maybe the top floor.
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