Shower drain pipe not plumb- is this a problem?

Discussion in 'Shower & Bathtub Forum & Blog' started by Jppenner, Jul 27, 2021.

  1. Jppenner

    Jppenner New Member

    Joined:
    Jul 27, 2021
    Location:
    Vancouver, BC
    Hello, I am trying to finish the basement bathroom for my inlaws but seem to have encountered a problem. I was going to install a Maxx shower kit and in the instructions it says the shower drain pipe must be plumb. When I look at the rough-in pipe coming out of the concrete it is definitely not plumb. I have attached a photo with a level. I am guessing that the reason it must be plumb is so the drain will seal against the base. I imagine that a gasket can handle some variability but this looks like quite an angle. Is there a solution for this or what would the builders have been expecting somebody to do when they went to finish it? We are not actually fussy about what gets installed (shower, tub) but I figured a shower kit would be easiest. The pipe is centered about 14.5” from each wall and the kit calls for 12” but I figured I could just frame out a bit.

    thank you.

    01D6B12E-2644-4740-8DB7-FC57708BD650.jpeg
     
  2. Jeff H Young

    Jeff H Young In the Trades

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    92346
    not familiar with your kit. I wouldn't want to fur out 2 1/2 inches. but wouldn't want to jack hammer to fix it either. I'd likely jack hammer down put pipe where I wanted it and make it plumb as well just to get it done right
     
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  4. Jppenner

    Jppenner New Member

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    Jul 27, 2021
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    Vancouver, BC
    Oh boy, that is definitely more advanced then anything I have done before. Do you have any tips? I guess I just go slowly to be careful not to damage any pipe below the concrete while I’m jackhammering? I have no idea which direction the piping is coming from. Is there a standard depth that I would likely go down? Will I be removing the entire depth of concrete or just a top couple of inches? Their preference would be for a tub but I didn’t think that was feasible because it looked like tubs want that drain about 8” off the wall and there was no way I could achieve that. I guess the advantage of jackhammering the concrete is that I will be able to adjust the piping for a tub.

    I assume I will be able to just rent a jackhammer at Home Depot.

    thank you very much for the help.
     
  5. Jppenner

    Jppenner New Member

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    Jul 27, 2021
    Location:
    Vancouver, BC
    I just had another idea. Since I have a full 8’ ceiling height in that bathroom maybe I could just raise the subfloor in the shower area and adjust the piping in that raised section? I could cut away a bit of the concrete around the rough in so that I could get a 45 on, couple inches of pipe and another 45 to get it vertical in the location I need it (12” from each wall). Then just finish with a little row of tiles on the front of the raised section of subfloor. Would add a few inches to stepping into the shower but that is probably fine. Does this sound like a viable option or is there something I’m not thinking about?

    I watched some videos on chopping out the slab with a jackhammer and I’m definitely a little nervous because this is a townhouse and it sounds like it would be really bad if I damaged a tension wire.
     
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

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    Retired Systems engineer for defense industry.
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    New England
    I was in an old hotel in London, England one time, and they did a similar thing to retrofit a shower in the room by raising the pan...it was a major safety hazard! Stepping down from a wet shower when it's raised much just begs for your foot in the shower to slide. Almost did a face plant the first time, and it didn't get easier the few days I was there, just elicited more caution!

    There's no standard about how deep the p-trap will be below. A typical slab is 4" or so thick, maybe a little less, but not much.

    Depending on how deep the p-trap is, you may or may not have much room to add couplings to turn that pipe so it's plumb. You won't know for sure until you've exposed things. Worst case, you may need to remove the p-trap to rearrange things enough to get it where you want. You may want to buy or rent a special tool like a RamBit, if the p-trap is fairly close to the top of the slab, as that will allow you to ream out the pipe from the p-trap fitting, so you can glue in a new piece.

    With a shower receptor it sounds like you're talking about, you need the pipe not only plumb to get a good seal, but also, you want the thing to rise up in a very specific location...there's really very little leaway in where it is, otherwise, you'll need to maybe fur out the wall on one side or another.
     
  7. Terry

    Terry Administrator Staff Member

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    Occupation:
    Plumber
    Location:
    Bothell, Washington
    They can X-Ray for wires. They never should have poured up to the pipe like that. Is this a ground floor, or a story above?
    The drain always sits down a bit from the main floor, and like Jim mentioned above, stepping out so high, which I have done is kind of freaky.
    I tell myself to remember how how I'm stepping down from, and then I nearly fall. I don't know how my sister does it at her place.
    The cabin she rents to me is done right.
     
  8. Jppenner

    Jppenner New Member

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    Vancouver, BC
    Hi guys, thank you very much for the great advice. Good point about the danger of stepping out of a raised shower, I had not thought of that. However, I tried dryfitting a couple of 45’s and it does not appear there will be enough flexibility to be able to straighten that pipe in such a short distance. I think my only option is to jackhammer around the pipe and try to fix it. We will call the builders and see if they will come fix it because they are a large development company and still building in the area. It was built about 9 years ago. Not sure how they got away with such a terrible job. How hard would it have been to just make sure it’s plumb before pouring concrete?

    thank you
     
  9. Reach4

    Reach4 Well-Known Member

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    Location:
    IL
    This is a basement. Tensioning cables seem unlikely to me. I am not a pro.

    Is the building a steel framed high-rise, wood frame 2 story, or what?
     
    Last edited: Jul 29, 2021
  10. wwhitney

    wwhitney Well-Known Member

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    Mar 17, 2019
    Location:
    Berkeley, CA
    I agree with the comments that breaking the concrete to rework the shower drain to plumb is the proper approach.

    However, it's definitely the case that you could transition the existing drain to plumb with a pair of bends (at least one street, for maximum compactness), I'll consider 22.5 degree bends for explaining. With both elbow arranged to bend in the same direction, you have a flat (planar) configuration with 45 degrees of bend. Rotate the common joint 180 degrees, and now you have a flat configuration with no net bend, but an offset. In between these extremes, you can get any net bend angle between 0 and 45 degrees, along with an offset (the input axis and output axis are skew, not coplanar).

    So it's a matter of trial and error, start off with the 0 degree bend configuration, then rotate the bend-bend joint a little; rotate the bend-pipe joint to get as close to plumb as possible; repeat. [Or measure the angle the current pipe is off plumb, then do some tricky vector math to figure out how much to rotate the bend-bend joint, and then rotate the bend-pipe joint to get to plumb.]

    Cheers, Wayne
     
  11. Jppenner

    Jppenner New Member

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    Jul 27, 2021
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    Vancouver, BC
    The building is a 3-story wood frame and this is the walk out basement. It is a duplex style townhouse so two units share the building side by side.

    If it is unlikely that I would encounter tension wires then probably best to just cut out the concrete and fix it. I will buy a diamond blade for my circular saw and score the area then use a jackhammer to break it up. I am thinking that once I have it exposed I would lay the shower pan down and insert a pipe through the drain hole to locate where I need to rerun my pipe to. Is that a traditional way to make sure the drain gets located correctly or is there a better way?

    thank you
     
  12. Reach4

    Reach4 Well-Known Member

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    Location:
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    I don't see the need for a saw. I am not a pro.
    I think this describes clever position marking for shower base in concrete.

     
  13. Jppenner

    Jppenner New Member

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    That is a great idea for locating the drain, thank you very much for sharing. I had thought by scoring the concrete before jackhammer it would make a cleaner hole. However, it will probably create a lot of dust so if it isnt going to make the job easier then I am definitely happy not to do it. I am definitely worried about the size of hole I am going to have to make because the current pipe is at around 14” from each wall and they want a tub put in so the new drain will be very close to the wall. Plus, I am guessing the p-trap goes in the opposite direction so I will also have to enlarge the hole in the direction away from the wall.
     
  14. dj2

    dj2 In the Trades

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    Aug 13, 2013
    Location:
    California
    First contact the builder, who may refer you to the plumber who installed this drain.
    We have homes on slabs, not basements. So we leave a 1 foot square hole in the slab, with the drain in it and we fit in the trap and riser later when we install the shower.
    If you don't get a positive response from the builder/plumber, move to plan B (cutting the slab).
     
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