DWV Layout Problems

I am redoing a bathroom including changing the layout - and at the same time replacing all of the copper DWV that is 50 years old and corroding (with PVC). Additionally the adjacent bathroom has layout issues with a toilet that is not vented before the shower ties in, and as such the shower trap gurgles (ALMOST siphoning). I want to correct this while it is all torn up.


The existing bathroom is a standard 5x8 layout with tub along back wall (left drain) and toilet in the middle of the left wall and lavatory on the end of the left wall.

The new layout is as shown below. The shower is a curbless wal thorugh type with the tub inside. The entire room will be a wet room with Schulter Kerdi on everything.



The excess room is being taken from a linen closet and underutilized master closet.
The bump out being the vanity/sink is for the flue vent and return air plenum (which i will rebuild).




Above is an image of where the new bump out will go, framed with 1 5/8 steel stud due to proximity to the Type B flue pipe.



Above shows where the new closet bend and flange will need to reside. Shown is a heel inlet elbow which I will ask about later (one of my primary concerns).



Above shows the location of where the new shower trap will need to reside, as well as the main vent stack on the left and the horizontal drain/vent that runs down to the main drain on the right (not shown).

Continued from previous post:



Above shows the horizontal drain/vent turning downward and the 2" vent for the adjacent bathroom. This is also where the toilet and shower from the adjacent bathroom tie in incorrectly.



Above shows the location that the new bath trap will need to reside. Directly behind this is where the adjacent bathroom's toilet is.



Above shows an overall shot of the room.







Now for the questions:

I had a master plumber over today for about 90 minutes trying to figure out a new layout. He is a pretty good plumber as far as I know and I felt good when he left - but then I started thinking about it and the layout we came up with has both the new toilet AND the new shower venting horizontally below the floor. I will call him back tomorrow but for now I am looking for other opinions. Below is an isometric drawing showing the layout we came up with for the new bathroom as well as fixing the old adjacent bathroom. The biggest concern I have is the toilet beingvented using a heel outlet elbow below the floor, and the shower being vented from a tee/wye below the floor. We went through so many layouts today I got confused on the rules and didnt think of that when the plumber was here. Like I said I'll call him back tomorrow about this.



for now - I am looking for any suggestions you may have even if it is a completely different layout. Thanks.

The 1 1/2" vent from downstairs and the tub/lavatory at the right side are okay. But I would have to reject almost everything else. The heel 90 is not permissible, nor is the side inlet elbow for the other toilet, ( the reason for this one is that the toilet flow goes past the shower connection which is NOT allowed and you would have exactly the same problem with the shower siphoning as you do now). An inspector might not appreciate the toilet dropping into the equivalent of a sanitary tee either. Where is the drain for the tub inside the shower stall? There are better ways of piping the sink/lavatory drains on the left side. The underfloor horizontal vents are all improper as drawn. I would redraw the entire system, but without being there to see the actual conditions it cannot be done from here.

hj said:

The 1 1/2" vent from downstairs and the tub/lavatory at the right side are okay. But I would have to reject almost everything else. The heel 90 is not permissible, nor is the side inlet elbow for the other toilet, ( the reason for this one is that the toilet flow goes past the shower connection which is NOT allowed and you would have exactly the same problem with the shower siphoning as you do now). An inspector might not appreciate the toilet dropping into the equivalent of a sanitary tee either. Where is the drain for the tub inside the shower stall? There are better ways of piping the sink/lavatory drains on the left side. The underfloor horizontal vents are all improper as drawn. I would redraw the entire system, but without being there to see the actual conditions it cannot be done from here.

Click to expand...

Thanks hj. There is only one tub and that is the one in the new bath. My drawing is crappy and it may look like the tub is in the adjacent bathroom but it isnt. The adjacent bath is a 3/4 bath - shwer, toilet and sink only. So, just the W.C., Lav, and Shower on the right side are from the other bathroom.

Below is another picture as seen from the first floor. The wall in this picture is the right wall of the new bathroom (between the adjacent upstairs bathrooms). The stack seen is the main drain, with the visible plumbing being the problematic adjacent shower/toilet. You can see where the shower enters in via a heel inlet elbow on its side as the toilet rushes past (not to mention the destoyed joist integrity with that 2.5" hole at the bottom) . The plan as shown would have this stack being split in to with a vertical combo wye and upturned 1/8 bend. The slpit would occur to the left so I will have to remove more drywall and move that stud over and cut out more of the top plate.



I understand and agree with all of your concerns, and really appreciate you taking the time to help.

If I can provide any more pictures or diagrams that would help you visualize/verbalize a suggested layout please let me know.

Actually, I would want to see the ENTIRE area, including the downstairs before making an assessment of the best way to do it. As a practical matter, the sink/lavatory drain would function as the toilet's vent, so that horizontal vent would not be necessary. You appear to already have a 3" vent out the roof, so you would NOT need another one from the toilet.

Ok thanks hj. I was thinking that same thing about the toilet being wet vented by the run coming from the lavatory and kitchen sink.


With regards to the entire project I have taken 5 video walkthroughs that hopefully illustrate everything that exists and everything I want to do. They are a little dark but I point out everything as I go and I think you can follow along.


Viideo 1: Existing Layout and Existing Plumbing



Video 2: View from below on first floor in another bathroom (below adjacent upstairs bathroom)



Video 3: New lavatory layout and new toilet layout




Video 4: New Shower Layout

Continued:

Video 5: Rerouting adjacent bathroom layout:





Thank you again for all of your help!