Can I plumb a toilet like this? What toilet?

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by shortcuttomoncton, Dec 4, 2012.

  1. shortcuttomoncton

    shortcuttomoncton New Member

    Messages:
    17
    Location:
    Ontario
    First post, all. A great resource you have here.

    We're in the planning stages of converting a room in the top floor of a 100-year-old house to a bathroom. As seen in the attached picture, what used to be a brick chimney several decades ago is now a large hole running straight down to the basement, and ending almost directly on top of the existing drain pipe in the basement. Our thought was that all plumbing (and even electrical if needed) could be brought up from the basement directly to this bathroom.

    The problem is that the room is a long rectangle, the "hole" is in one corner, and the joists run across the room. We cannot drop the ceiling below, as it is decorative plaster, and we cannot shave or cut the joists (7.5" x 2.5"). So at least one of the toilet/bathtub/shower will have to be raised, as we cannot place exit pipes in the subfloor (except for along the wall on which the drain hole is placed, in between those last two joists).

    The room was a larger room that we're cutting in two; so that wall is framed-out only, and we can drain any plumbing through the back of the wall, on the adjacent side (which will only be a closet). Was wondering about putting a rear-outlet toilet (wall-hung or standing, doesn't matter) near, but not on top of, the drain hole; about 36 inches from centre of the toilet, to the hole. The exit drain for the toilet will have to drain out the back, then down and across ~36 inches before diving below the level of the finished floor and into the stack. The hope is that the toilet would then not have to be raised.

    1. Can this configuration be done without raising the toilet on a platform?
    2. What toilet would work for this configuration? I've looked at the Toto Acquia wall-hung, but the drawings show the elbow joint running straight down into the drainpipe in the subfloor. Is there a reason I could not have it draining off on an angle before it goes below finished-floor level?

    Thanks in advance for any questions/comments and advice!

    Many thanks,
    Greg

    BathroomLayout.jpg
  2. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

    Messages:
    1,328
    Location:
    Columbus, OH
    Am I understanding you that they're laid flat 7-1/4" wide by 2-1/2" high? If that's the case, you cannot even get the pipe in the floor. You'll have to raise the floor.

    If I'm misunderstanding, then how many joists do you have to go through? If only one, maybe two, you could maybe header off the joist and sister up some adjacent ones to make access. What kind of span are you looking at here?

    I know very little about wall mount toilets, but it could be an option. I think you need quite a bit of room in the wall, though, for the hanger and drain assembly.
  3. shortcuttomoncton

    shortcuttomoncton New Member

    Messages:
    17
    Location:
    Ontario
    No, the joists measure 2.5 inches wide by 7.75 inches "deep" (again, 100+ years old) - so I should not cut through them to run any sort of pipe. The joists are spaced 16 inches apart.

    Yes, the idea is that the exit pipe would have to sit on top of the joists (of course at an angle) until it reaches the drain hole. So with a regular toilet, the floor would need to be raised. That's why I'm looking at rear-outlet and/or wall-mounted toilets, where the exit pipe isn't attached at subfloor level.

    Clear as mud? :D

    [​IMG]
    Last edited by a moderator: Dec 4, 2012
  4. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Are you aware that the carrier for a wall hung toilet runs several hundred $$$? In you situation, you could use a floor mount rear discharge, which just uses a standard flange. The height of the flange above the FINISHED floor is critical, so needs very careful planning.
  5. shortcuttomoncton

    shortcuttomoncton New Member

    Messages:
    17
    Location:
    Ontario
    Yes, I've looked at the carrier. The bonus with the wall-hung models is that the wall is only studs and the carrier can easily be framed in, and the toilet itself saves a lot of space by not "projecting" so much into the room (as there is no tank). The bathroom is not overly wide (6'10"), so it would be nice to shave 6 or 7 inches off the depth of the toilet. I've looked at models such as Toto Aquia and some of the Duravit wall-hung models, as well as their rear-outlet floor-standing toilets (there is one called Happy D.).

    I guess my question is, for a wall-hung toilet, is there any reason why the exit drain in the back of the toilet cannot run through the wall, and then sideways for 36 inches before dropping below the floor level?

    Many thanks!
  6. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

    Messages:
    1,328
    Location:
    Columbus, OH
    Ok. That makes more sense. Convention is to list the width first, and the height second (2.5x7.75), unlike your original post.

    If I were you, I'd really hate to bump the floor up the required 3.5" or so. So, maybe the floor mount rear discharge would work for you. Do you have some info on that, Jimbo?

    You'll need to furr out the wall to run the piping within the studs. If it's load bearing, perhaps more than if it's not.
  7. shortcuttomoncton

    shortcuttomoncton New Member

    Messages:
    17
    Location:
    Ontario
    Yes I realized that later - like saying we won 2-5! :D

    The wall is not load bearing (currently it's one large room that we're dividing with this wall).

    Do you see any problems with the pipe running through the wall, and along the back of the studs? As it is a closet on the other side of the wall, it would be easy to box it in from that side.
  8. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

    Messages:
    1,328
    Location:
    Columbus, OH
    I see no issue with it. What are you planning for a floor?
  9. shortcuttomoncton

    shortcuttomoncton New Member

    Messages:
    17
    Location:
    Ontario
    Joists currently have an original rough plank subfloor running diagonally across them. We'll likely add a plywood subfloor and tile over that.

    Rough sketch of view from back:

    Toilet - drain (back).jpg

    When looking at a toilet like this Duravit Starck 2 for example - it sits on the floor, has no tank (I assume there's an in-wall tank system?) and the outlet is horizontal. Without being able to see the toilet itself, I've seen some of these that still have to have an elbow fitted that dives directly into the subfloor. Would it be possible to have it go right out the back and across?

    That is actually the perfect form that I'm looking for - shallow toilet, in-wall tank, rear outlet. Urk. :D

    [​IMG]

    http://www.terrylove.com/forums/showthread.php?34368-Gerberit-Duravit-Install&highlight=gerberit
    Last edited by a moderator: Dec 4, 2012
  10. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    Be aware that a tankless toilet ( i.e. Sloan Flushometer Valve) REQUIRES a 1" water supply line all the way to the toilet. This would be a major project.. There are options like tank hidden in the wall. As with most plumbing problems, ANYTHING can be accomplished using the proper amount of cubic dollars. ( a cubic dollar is the number of carefully stacked one dollar bills in a one cubic foot box, and is equal to about $10,000)
  11. shortcuttomoncton

    shortcuttomoncton New Member

    Messages:
    17
    Location:
    Ontario
    Haha - gotcha. I've asked Duravit about that toilet - they don't give much info on their page, so I'm trying to figure out it there's a flushometer system involved, or if the tank is merely in-wall similar to a wall-mount.

    I've got easy water access straight down to the basement. Having said that, my house intake line is only 3/4 copper....would I need to change that in order to run a 1" supply line upstairs? In which case, the flushometer style is a no-go from the start.
  12. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

    Messages:
    1,328
    Location:
    Columbus, OH
    I would expect the 3/4" incoming to be a deal killer. Essentially it uses the water supply system as the tank.

    Your sketch there will also need a vent too.

    What is the span of your joists (to see if it can handle the tile)?
    Last edited: Dec 4, 2012
  13. shortcuttomoncton

    shortcuttomoncton New Member

    Messages:
    17
    Location:
    Ontario
    That's a great question - I hadn't considered whether the tile weight would be a problem. House is just over 25 feet wide and joists run from the outside wall to the centre load-bearing wall running the length of the house (about 12 foot 7 inches).

    The bathroom is against the outside wall and about 6 feet 10 inches wide, so the tile will be applied to the outermost half of the joists.
  14. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

    Messages:
    1,328
    Location:
    Columbus, OH
    It's not so much the weight, but whether you have deflection that will cause the floor to crack. Best place for tile related stuff is over at the http://www.johnbridge.com forums. They have a nice Deflectolator over there for calculating the deflection--check it out. You're iffy depending on the type of wood and condition of your joists. You might need to take up that floor for to add some reinforcement.
  15. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,932
    Location:
    New England
    You need a toilet with a tank (in-wall works fine, but you'll often need a thicker wall than from a tyical 2x4 studwall), or a storage tank with at least a 1" outlet (sort of like a small well bladder tank) to have the required volume of water available instantly. You should be able to plumb it horizontally as long as you can maintain at least the minimum pitch (verify with the manufacturer). Wall-hung gives you the advantage of easier cleaning underneath, but some do not like the look - depends on the style you're trying to achieve.
  16. shortcuttomoncton

    shortcuttomoncton New Member

    Messages:
    17
    Location:
    Ontario
    Thanks guys. I've spoken to Duravit and their cus. support tells me their wall-hung carriers are available for 2x4 or 2x6 framing, just like Toto.....but their in-wall tanks for the above floor-standing, rear-outlet Starck 2 model is only for a 2x6 wall. Stymied at every turn! :D

    That doesn't make a lot of sense to me, so I've asked them to search for a floor-standing, rear-outlet model that can have a 2x4 in-wall tank....hopefully they find something for me.
  17. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

    Messages:
    1,328
    Location:
    Columbus, OH
    Must need that extra room for the tank.
  18. shortcuttomoncton

    shortcuttomoncton New Member

    Messages:
    17
    Location:
    Ontario
    Yep. It's back to a floor-standing, with-tank, rear-outlet toilet. Hopefully I can drain it the way I want.
  19. kreemoweet

    kreemoweet New Member

    Messages:
    371
    Location:
    Seattle. WA
    I wouldn't take the word of any "customer service" rep on any kind of technical question. Surely they have drawings
    available for you to download? If detailed enough, they will answer all your questions. If the drain pipes can be located
    on the farther side of the wall, one assumes it will be no problem if the tank protrudes likewise into that space? And perhaps
    some frame extensions in the vicinity of the tank? I get the feeling that whoever you've been talking to just cannot visualize
    the "non-standard" setup you're aiming for.

    It might be just the inaccurate scaling of your drawing, but the space you designate as "corner shower" looks extremely cramped
    to me.
    Last edited: Dec 4, 2012
  20. shortcuttomoncton

    shortcuttomoncton New Member

    Messages:
    17
    Location:
    Ontario
    What do you mean "if the tank protrudes likewise into that space"? Do you mean the toilet tank? Why would that have to protrude into the wall?

    Yeah, me too...which makes sense, it's hard to convey verbally.

    Yeah that started out as a different drawing - it's actually a freestanding tub going there. The hole itself is 16 inches wide, plus an additional 36 to the toilet - plenty of space for the size of the bathroom.
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