Adding a bathroom, is this possible?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Mike Ramsey, Feb 15, 2020.

  1. Mike Ramsey

    Mike Ramsey New Member

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    Feb 15, 2020
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    ohio
    Hey guys long time lurker here but now I have a question on if something is even possible. I don't think it is. First off I will state that I am a carpenter and not a plumber LOL. I have a client that is wanting to do a renovation on their master bath. This is such a strange layout. It almost looks like a jack and jill type bathroom only it leads to another small room that is not a bedroom. Anyway.... my client wants to move the bathroom into the smaller room for a more traditional layout.

    Here is the problem. All of the fixtures would need to move some 12'-18' horizontally from the main stack. The small room to be bath is above a garage so we can't drop a new stack. That lead me into building a chase across the garage ceiling to get under the joists. So the only way I can see this even working is a 4" lateral across the garage ceiling with a vertical drop at the garage wall with a 45 degree through the rim board extending 5' tying into the 4" stack with a wye. My gut tells me there is no way in hell that would fly.

    I know there is a lot more to it than my simplistic explanation but without that bit of tying into the existing stack there is no need for me work up an estimate for the job. Apologies for the crude un-rotated visual.
     

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  2. hj

    hj Moderator & Master Plumber Staff Member

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    This is NOT a job for a carpenter. Call a professional plumber.
     
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  4. Mike Ramsey

    Mike Ramsey New Member

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    No shit LOL That wasn't the point of this, of course I would have a plumber do it. Their whole project hinges on that one thing is even possible. If that can't happen then there is no point to even bidding on the rest. If it is possible I will proceed forward getting bids from plumbers if not I am not going to waste my time and let the client know that it is not feasible.

    Essentially I am looking for confirmation as to whether it is a code legal method for a licensed plumber to take a route like this. I don't think it is. If it is not I will let my client know that its a no go.
     
    Last edited: Feb 15, 2020
  5. Reach4

    Reach4 Well-Known Member

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    You would run 3 inch (3.5 inch OD) rather than 4 inch, because it is easier and just as good. 1/4 inch per foot slope or more should be maintained. You have a lavatory with the toilet, and that would be vented, and the lavatory being vented will provide the venting for the toilet almost automatically. Toilets are a special case. A vent through the roof, or tying in vents through the attic to other vents would be best, but an accessible AAV (air admittance valve) would be allowed to be used in most place.

    I don't know how/ if you have to deal with the fire resistance in the garage. Would PVC pipe have to be in the drywall barrier? I don't know. I am not a plumber.

    I think the thing you worry about is whether the 45s and vertical drops are ok. They are not a problem after the pipe has been vented.
     
    Last edited: Feb 15, 2020
  6. Mike Ramsey

    Mike Ramsey New Member

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    Yes from a fire code standpoint everything would be inside of a fire rated chase. You are correct, my questions were related directly to the overall horizontal run, into a drop and 45s into the existing stack. Venting is a no brainer for the plumber as there is attic access to tie into existing.
     
  7. Terry

    Terry Administrator Staff Member

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    You can add a bathroom using 3" pipe as long as it's plumbed correctly. That means with proper venting. A single 2" vent will handle the bathroom.
    Running under the floor joists is a good idea, so that you can get the 1/4" per foot grade heading over there.
     
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  8. Mike Ramsey

    Mike Ramsey New Member

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    Thanks Terry, This gives me enough info to proceed forward with a design concept for my client.
     
  9. hj

    hj Moderator & Master Plumber Staff Member

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    You show the situation to a competent plumber and HE will tell if it is possible, not US who only have your description to work from. But, as my Dad used to say, "Anything is possible, if you have enough time and money".
     
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  10. Terry

    Terry Administrator Staff Member

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    "Anything is possible, if you have enough time and money".

    hj, that's been my answer for years too. A homeowner asks, "Are you saying it can't be done?"
    And I reply............

    "Anything is possible, if you have enough time and money".

    Then I watch for their reaction. Priceless. :)
     
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  11. Mike Ramsey

    Mike Ramsey New Member

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    Oh I agree with you 100%. I was just looking for a general answer to shifting the existing fixture locations some 18' to the existing stack. Based on the other responses above is that it's not so much the distance as it is proper venting. Well I will take that back distance is ultimately dictated by available space to allow for proper grade. The only real option for the client is below the joists tying into the existing stack. They have a fairly healthy budget and are prepared for some contingencies but breaking concrete and adding another stack would kill it.
     
  12. Mike Ramsey

    Mike Ramsey New Member

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    Indeed that's exactly what I said to them LOL. Then I asked them for their budget.
     
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