Raising the roof.... Eh herm, ceiling. Advice moving plumbing and vents.

[Capnmoench]

Hello, all. Brand spankin' new here. I live in WA. I've been scouring the site for advice, but I can't seem to narrow down particulars for my intended installation. I have a split level with 2 bathrooms, one on top of the other. The downstairs partially below grade with all drains running into a slab. I'm amidst a remodel on the lower bathroom and am not happy with the original hacked build. Hopefully you can help.

The original ceiling was dropped 8" to accommodate plumbing. This created a lot of "stupid" in trimmed moldings / casings and such. The shower head was only 3" from the ceiling. I'm not too sold on this is the way it has to be. Upon removing all of the walls and ceiling, I see it's due to the original install of the upstairs toilet drain, and also a vent line servicing a sink on the opposite side of the bathroom. Less problem with the vent than the toilet. I would like to move the drains to gain some headroom.

My idea after shopping for materials was to use a wye fitting to a vertical run to bring the lead-in from the toilet up higher than original. I have some issues with the way it's been run through the wall and having a floor joist right above where I need to modify everything. I don't want to modify the floor joists and I don't have the access for a double joist and plumber's box without tearing up my remodel in the next room I just finished last year around this time.

Reading the forum, it looks like I can't use the wye for a horizontal to vertical run. Only vertical to horizontal. (Maybe?). Here are photos of the current install.



There is a reducer from 2" to 3" right below the top plate of the framing. This is an interior wall. The photos don't do it justice, but there were 2X6's nailed to the studs below the top plate and still the T was contacting drywall. My original thought was to cut the top plate lower beam to get access to a new section of pipe and install a new reducer. That would be running to a wye as such:


That extra cut in the stub, reduced profile, and rise of the wye would give me way more room. I would then shorten the drain from the upstairs floor and put the 90 elbow up higher. From what I read though, that might be no good. That the wye should only be used from vertical to horizontal. Also, is it ok to shorten the drain below the toilet? It seems excessively long.

My second issue is a vent line. The current install is as such:



There is a sink/vanity over here (removed) below the photo that is services and another drain that goes into the slab.


My plan was the same for this vent to use the lesser profile of the wye to get it above the top plate on the side with the sani-T, notch the top plate on the opposite side, and couple in additional length to raise it, install a new elbow, yet keep it angled towards the drain it services. Hopefully limiting my drop ceiling to 2X4's from the floor beam vs the 2X6 below the header. A gain of 4". The question about the vent is if there is an issue with 2 downward facing 90 degree bends in a vent line.

Thanks in advance to all that can help or suggest anything different and of course, up to code.

 

[Capnmoench]

UPC 706.2 Horizontal drainage lines, connecting with a vertical stack, shall enter through forty- five (45) degree wye branches, sixty (60) degree wye branches, combination wye and 1/8 bend branches, sanitary tee or sanitary tapped tee branches, or other approved fittings of equivalent sweep. No fitting having more than one (1) inlet at the same level shall be used unless such fitting is constructed so that the discharge from one (1) inlet cannot readily enter any other inlet. Double sanitary tees may be used when the barrel of the fitting is at least two (2) pipe sizes larger than the largest inlet. (pipe sizes recognized for this purpose are 2 in, 2-1/2 in., 3 in., 3-1/2 in., 4 in., 4-1/2 in., 5 in., 6 in., etc.)


Does this work for the toilet and approve the wye?

 

[Sponsor]

 

[Terry]

The toilet has different rules.

For the toilet only, you can use a wye or a santee in that location. The wye combo pictured would be fine, or even a simple wye and 45 to get the pipe even higher between the floor joists.

 

[Kreemoweet]

If those walls are just non-structural partitions, you could remove those sections of top plate entirely for an additional inch
or two. There might be fire-blocking considerations if you do that. The 90-deg. bend where your toilet drain goes horizontal
should be a long-sweep fitting, rather than the regular 90 you have now.

 

[Capnmoench]

Thanks, Terry and kreemoweet. I could grab a 45 when I buy some pipe and test fit it. I think it might stick too far out away from the wall though. I do plan on giving the horizontal run a slope due to the toilet usually being a "double flusher" the way it is now. It shoots back up the toilet after a flush. Any advice on venting up, but then down again to the other stack?

 

[Capnmoench]

I originally said the vent was running to a sani-T. Not correct. It is just a regular T. My plan was to raise it above the point it is now. Without completely cutting the top plate, I can notch for the wye and get it so I can frame a ceiling support in with 2X4s with just it. That leaves an upward run from the vanity and instead of a straight shot into the drain system the includes the vent, will actually have have to return down to it. The only thing I've read it a vent has to angle towards the drain it services. Drainage would be correct when I angle it, but the additional 90 turn down on the side of the vent to the existing plumbing has me concerned about trapping. Not of water since everything is going to drain, but is there and concern or code about gas trapping. If sewer gas is heavier than air, it should drain as well. Maybe I'm making an issue of a non-issue.