Renovation plumbing advice!

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Rod Gilbert, Apr 18, 2009.

  1. Rod Gilbert

    Rod Gilbert New Member

    Apr 18, 2009
    First, I would like to say thank you (as a DYI'er) for such an informative forum and to those who offer their time and expertise. I have spent many countless hours reading various threads about plumbing. Second, I would like to make this clear that I'm no plumber, and don't pretend to be one. In fact if I hadn't purchased a 'money pit' of a home, and if I had the money, I would be hiring a plumber for my renovations. I've purchased books, asked lots of questions and spent countless hours on the Internet. That said, I've run some initial waste and vent pipes (note: Where I live in Canada we must use ABS), and would like some professional advice. I will try to briefly outline what I've done so the attached photos make sense. Rather than ask a number of specifics, I'll wait for you to point out the errors! Sorry, I'm fairly sure of a few no, no's!

    I'm building a full bath and half bath that share a 2x6 wall.
    The first pic shows the crawl space with a supporting pony wall (previous morons cut out floor joists!) for the main floor of a one story home.
    What you see is a branch to the future main bath on the left, and a branch to the future half bath to the right of the supporting wall.
    These 3"pipes meet with a wye and join to the main waste line out to the septic field. On the left run, the far vertical pipe is the 3" vent stack out the roof. I continued beyond this (toward the viewer) to pass under the toilet about 2 feet away. The bathtub will join the 3" waste line about two feet down stream of the vent stack and is this wye is not visible in the photos.
    In the second photo taken from the side, you can see a 3" x3" x 1 1/2" wye to the right(covered in plastic and tape) which will drain the vanity sink about 40" to the left. This wye is between the toilet and the stack. Upstream(left) of the toilet I continued the 3" pipe for a cleanout. Off the top I exit with a 2" pipe as a vent which, although on a slope, I assume is considered 'horizontal' for 16" until I can go vertically up through the floor and 2x6 wall separating the bathrooms. I then use a 90 elbow and tie it into the 3" vent stack about 56" off the floor.

    The last photo shows the right run of 3" pipe for the half bath. In the distance is the toilet drained by a 3" wye and 45 elbow. Next in the foreground (upstream) I come off the top with a 2" vent pipe and run left in a similar manner as before, up through the 2x6 wall and tie into the horizontal 2" vent pipe and then stack as described before. In the immediate foreground (covered in green) is a 1 1/2" tee (should have been a wye?)which is to drain the half bath vanity sink. The blue cap will become a clean out.
    OK, I truly apologize for this 'novel' but I hope I've described my plans clearly enough. Please comment on anything that you see/I've described that can help me do this correctly. I live in an "unorganized" municipality which does not require an inspector; saying that, however, I want this to be done correctly --- even if my ego gets bruised and I have to cut stuff out!!! I would like to think there aren't any mistakes but there's one I think for sure I've made ---- venting behind or upstream of the toilet by running a 'horizontal' vent below flood level of the fixture. I don't think I even needed to do it for the left (main bath) run, but I thought the half bath toilet needed the vent because it's about 2.5 feet from the wye which is about 4.5 feet down stream from the 3" vent stack.
    Thanks in advance for any advice and I do understand that what I've presented here is a huge project!
    Kind regards!

    Attached Files:

    Last edited by a moderator: Apr 18, 2009
  2. Terry

    Terry Administrator Staff Member

    Aug 17, 2004
    Bothell, Washington
    Vents are placed "down stream" of the fixture.

    Each fixture should be vented.

    Vents can be tied back together above the flood level of the fixtures being served.

    If you have a tub downstream of a toilet, there should be a wye, and then a vent, and then the p-trap for the tub.

    Otherwise, when the toilet is flushed, it will siphon the trap dry.
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  4. Rod Gilbert

    Rod Gilbert New Member

    Apr 18, 2009
    Changes to meet your suggestions.

    Hi Terry
    I can't thank you enough for the amazingly prompt reply! Hopefully I'll explain this clearly so you can set me right with only one more response ... others await I know.
    With regard to my present set up and if you're able to refer to it and/or the photos.
    1. Main bath room (left side of pony wall). I'm going to remove the 3"x3" x 2" wye behind(upstream) of the toilet and just end with the clean out. The toilet is slightly less than two feet from the 3" vent stack so I understand it shouldn't require an additional vent.... correct?
    2. Still on the left side ... the 3"x3" x 1 1/2" wye between the vent stack and the toilet that will run to the vanity sink --- It looks like I can put a 1 1/2 sanitee in the 40" long pipe that runs to the sink, and vent straight up into where I presently have a 2" vent pipe. As before this will 90 into the vent stack 56" high in the 2x6 wall.
    3. It will be a tight fit between the studs at the head of the bathtub, but it appears I should be able to fit a 2" vent pipe up here through the floor. This would mean below I could tie the vent pipe into a 2"x2" x2" sanitee just before the wye joins the 3" waste pipe, and in between it and the trap for the bathtub. I believe that is the correct order as you stated.
    4. The last part is the challenging part that I'd greatly appreciate your thoughts on... this refers to the right side of the pony wall, or the half bath.
    a. I think I can fit in a 3"x3"x2" wye downstream of the toilet before it wye's into the main 3" waste line(I only have 2 feet to do this!) At the steepest angle possible off the top, I'd run a 2" vent pipe diagonally back past the toilet to get over to the bottom of the 2x6 wall about three feet away. I can then go vertically up as I previously had. Now I would be venting downstream of the toilet. I'm just not sure if code only allows one to run vent pipes between vertical and a 45 angle from vertical until above the flood rim. The only other possible (?)option is the 2x4 wall behind the toilet but I have almost no room in the attic to tie into the vent stack (it's a crazy 2/12 pitch and I'm near the outside wall.)
    b. Lastly, can the sink in the half bath drain upstream of the toilet? It would drain into the 3" pipe and pass the toilet within a foot and hopefully the vent pipe downstream of the toilet in another foot. I could use an AAV also if necessary. If not, can two sinks be connected to the same 1 1/2 pipe which has a vent, or must two sinks only be shared using a 2" pipe? I could try and tie the two sinks together except the existing wye in place is for a 1 1/2 pipe.
    Again, hopefully I've explained my changes clearly enough, and again, thanking you in advance for all your help!!!
  5. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    One problem is that we are only seeing the main lines under the floor. What happens between the joists and above the floor could be just as important, and could impact the under floor piping. One thing, is the pony wall supported by untreated 2x4's inserted INTO concrete pilings?
  6. Rod Gilbert

    Rod Gilbert New Member

    Apr 18, 2009
    Clarification of structure and intent.

    Hi HJ!
    Really appreciate your response!
    The pony wall, although standard construction wood, is screwed into pressure treated 2x6 'plates' that sit on the concrete piles.
    I'm not sure what you mean by "what happens between the joists" but I'll try to briefly explain. Please let me know any specifics if I'm not clear enough. FYI, you don't see any traps yet because I'm in the early stages and am still waiting for the bathtub and vanities/sinks to arrive.
    1. I will run 2" pipe from the tub& overflow assembly into a trap, then run about 2 feet or so and have a 2" tee with a 2" vent running up vertically through the floor and into the 2x6 wall above. The 2" tub pipe will then drain into the 3" waste line at a wye within a foot of the tub vent tee, and 2 feet down stream of the 3" vent stack.
    2. Assuming both sinks drain independently into the 3" waste pipe, I'll use 1 1/2 pipe and traps below each sink and for the run over to the 3" waste pipe. The main bath sink drain line will run about 40" so I will place a 1 1/2" tee near the centre of the run and vent vertically up through the floor into the 2x6 wall separating the bathrooms.
    3. If I can place a 3"x3" x2" wye downstream of the half bath toilet (last photo in initial post), and if I'm allowed to angle it up (but not vertically), I can go over 3 feet and also vent up into the 2 x6 wall. This would be the 'middle' 2" pipe in the attached photo. My intentions were to have the three vent pipes turn at 90 degrees about 56" off the floor, and join the 3" vent stack which runs up through the 2x6 wall.
    *** The attached photo shows the half bath space in front and the full bath behind the 2x6 wall. The 3" vent stack is on the right and presently I was tying into it with 2" vent pipes. I'm thinking the main bath sink can vent into the left side which is partly done. I'll reduce the 2" to a 1 1/2 pipe. The 2" vent pipe in the middle I'm hoping can be connected below to the vent I'd like to install down stream of the half bath toilet. In the stud space to the right of the vent stack I should be able to come up with the 2" vent pipe from the bath tub run, and tie it into the vent stack with a 90 ell. The vent stack can be cut and redone if necessary, as you can see I haven't tied it in yet with the existing vent stack runs diagonally above in the attic,then up and out the roof. Hope this photo helps!
    4. The half bath sink (right side of pony wall in initial photos) as it is set up now, would drain into the 3" waste pipe about 1 foot upstream of the toilet. If the vent downstream of the toilet as described in #3 exists, would this satisfy as venting for this sink? The sink is about two feet from the 3" waste pipe. I could use an AAV for it, although I've read there are varying opinions on these.
    I realize this is likely difficult for you all to visualize so my apologies. If you have the time I will gladly explain any areas of confusion!!!
    Thank kindly,

    Attached Files:

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