Advice on Toilet Drain

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Inapickle2

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As discussed in an earlier post, I'm re-modelling our main bathroom.

https://terrylove.com/forums/index....for-replaced-sections-of-osb-sub-floor.96818/

I'm not a pro, so it's quite a challenging project for me. The original shower stall, sunken bathtub and toilet were installed on a raised tiered structure and the wife wants it all on the same level, bless her. I've managed to sort out the drainage for the new shower stall and stand-alone bathtub, but would appreciate some advice on the best toilet drain (3" pipe) configuration.

The toilet was originally raised 7" above floor level and when I dismantled the platform I found that the lead sleeve was set too high to be usable; it was glued into a 45 degree elbow connected to the side arm of the wye hub tilted up 45 degrees. I didn't take a photo with the lead attached, but this was after I cut the 45 degree elbow off.

DSCN2042 resized with text.jpg



I can’t drop the Wye piece any lower without compromising the run off slope to the main drain stack. So I’m weighing up the available options. For now I’ve removed the Wye hub section and replaced it with a length of pipe so that condensate from the vent stack can drain.

If I fit a Wye laid flat with a 90 degree elbow that would give sufficient depth for a new lead sleeve but it would set the flange centre point too far out (14") from the wall (allowing for drywall and tile) and the toilet has a 12” RI.

IMG_4925 resized with text.jpg


IMG_4922 resized with text.jpg



A possible work-around could be fitting two 22.5 degree elbows on both sides of the Wye hub creating a 'chicane' that would bring the flange closer to the wall. Here are the pieces laid loose to show what I mean.

IMG_4926 resized.jpg



My concern there is whether the ‘kink’ would be more prone to blockage, especially if crap got backed up into the short section between the wye and vent. And also whether code allows for this ?

The only other option, I can see, is going back to the original configuration (a 45 deg elbow off the Wye) and fitting ABS flange instead of a lead sleeve. I’m going to be applying Ditra XL on the 3/4” OSB and tiling (3/8” tile) over that. That should give just enough floor depth (around 1-3/4’) for an ABS flange inserted directly into the 45 deg elbow.

Although the cheaper option, I am concerned that an ABS flange would be less robust (more prone to cracking) than a lead sleeve with brass flange.
 

WorthFlorida

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I'm not a plumber but a little change may be better. Hopefully a plumber will agree on my suggestion. Cut the vent pipe at the wall or above the floor level in the wall. Do not use a wye, use a closet bend for the toilet and then install a tee 3x2x3 after the bend. Have the tee 2" above the horizontal plane, pointing up if possible or at least 45 degree and connect that to the vent pipe. The vent pip must be a dry vent with no other fixtures draining into it. The 3" vent pipe is needed to frost proof the vent at the roof level. 2" down below is allowed.

See page 14-15
https://www.co.lincoln.or.us/sites/..._-_helpful_hints_residential_construction.pdf
 

Inapickle2

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Thanks for your reply. I hadn't even considered that as an option. I just assumed the vent pipe is connected that way for a reason and that it should be preserved. No, there are no other fixtures connected to it.
 
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John Gayewski

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Does the straight run after the toilet go to a tee? Meaning the straight run going the stack, does that stack run vertical up the wall as well as down?
 

Inapickle2

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Thanks for your reply. I hadn't even considered that as an option. I just assumed the vent pipe is connected that way for a reason and that it should be preserved. No, there are no other fixtures connected to it.

Actually what you are are suggesting looks like it could be doable. Here's how the 3" vent pipe comes down the wall.

IMG_4929 resized.jpg


As you can see, as it passes through the sub-floor it makes a bend to line up with the existing toilet drain line. So if I were to cut it, it would have to be above floor level. In which case, following your suggestion, a 2" (vent) pipe from a 3-2-3 tee (positioned just after the closet bend) would need to be routed up through the base of the wall frame to connect to it. I don't think there would be enough headroom to set the 2" tee directly facing up, it would have to be tilted around 45 deg to the left side.

Another possibility might be cutting the pipe and re-configuring the vertical bend so that it lines up with the re-positioned Wye. That way there would only need to be one (22.5/22.5) lateral bend after the Wye (as per the 'chicane' arrangement I mocked-up above) to connect to the existing floor drain.
 
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Inapickle2

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Does the straight run after the toilet go to a tee? Meaning the straight run going the stack, does that stack run vertical up the wall as well as down?

No it doesn't go to a tee. At the end of the 10' horizontal run it just bends down vertically and passes down to the basement where there is a clear-out. There is nothing else connecting into the vertical section. Over the horizontal run there are two inflow connections. One, a 2" drain line from the shower unit (which has it's own vent stack behind the shower). A 1-1/2" drain line from the bathtub also joins into that 2" line in the middle of the room. The other inflow is the 1-1/2" drain line from a double vanity which has it's own vent stack. Crudely drawn diagram:

IMG_4931 resized.jpg
 

Inapickle2

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Problem solved.

60 degree elbow. Lip of hub will sit just below top of 3/4" OSB subfloor which will work perfectly with with an ABS flange.

IMG_4932 resized.jpg
 

wwhitney

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The flat vent is still a potential issue, not sure what your plumbing code has to say about that. Neither US code would allow that.

Also, in the second to last picture, looks like you have an unshielded rubber coupling. In the US, those are only for use underground; above ground couplings need to be shielded rubber couplings.

Cheers, Wayne
 

Inapickle2

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The flat vent is still a potential issue, not sure what your plumbing code has to say about that. Neither US code would allow that.

I really don't know. House was built in 1995. We moved in 11 years ago. With the temporary patch in place the pipe slope from the vent at the wall is adequate (1" in 4') and I'll make sure that is maintained when I seat the Wye - so the section between the Wye and Vent is not flat.

Also, in the second to last picture, looks like you have an unshielded rubber coupling. In the US, those are only for use underground; above ground couplings need to be shielded rubber couplings.

Actually, before I removed the old Wye the section between the Wye and vent had two couplings - a shielded one and regular rubber. I have no idea why. Had to destroy the old shielded as I couldn't get at the worm screws positioned underneath. I just got another flexible one for the temporary patch.

DSCN2044 resized.jpg


I'll be gluing the Wye to the drain-side pipe. So you think I should use only a shielded coupling on the vent side then ?

Anyhow, I'm thinking to bring in a plumber to help me with replacing the existing Poly B water lines with Pex (some tricky fishing involved that I'm not experienced with) so I'll ask him to check it at the same time.

Cheers.
 
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Terry

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Normally I would have the wye on it's side with a street 45 into the hub of the wye, and a medium 90 into that. Placing the wye downstream a bit allows you to cut whatever length of pipe you need to center for the toilet. The center to center for a wye with a street 45 is pretty close.
 

wwhitney

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With the temporary patch in place the pipe slope from the vent at the wall is adequate (1" in 4') and I'll make sure that is maintained when I seat the Wye - so the section between the Wye and Vent is not flat.
Flat venting refers to a horizontal dry vent takeoff. The codes I'm familiar with require a minimum slope of 1" in 1" for the dry vent (i.e. 45 degrees) until it reaches 6" above the flood rim of the fixture. With the flat vent, there's nothing to prevent waste from accumulating in the dry vent connection on the wye, and in theory eventually blocking the vent.

I'll be gluing the Wye to the drain-side pipe. So you think I should use only a shielded coupling on the vent side then ?
Assuming things aren't different in Canada, any rubber coupling you use on the DWV that isn't buried in the ground should be a shielded coupling.

Cheers, Wayne
 

WorthFlorida

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The vent pipe as assumed to be used for the toilet vent is a dry vent and in the attic is it connected to the vent stack for the lav. sinks? Can the toilet vent be cut and removed completely and run a vent pipe to the same wall as the lav. sinks and tap into that vent stack for the toilet.

You mentioned that condensate drains from the vent pipe and it is why you temporally connected it to the drain. Is this from an air conditioner or condensation from a cold attic space?

As wwhitney stated, your current thoughts on a flat vent will be an issue if solids get backed top the vent pipe. Obviously should a blockage occur, waste will work back to the vent pipe and not be able to be flushed clean.
 

Inapickle2

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Normally I would have the wye on it's side with a street 45 into the hub of the wye, and a medium 90 into that. Placing the wye downstream a bit allows you to cut whatever length of pipe you need to center for the toilet. The center to center for a wye with a street 45 is pretty close.

Thanks for your suggestion Terry. I might have a look at that configuration also, assuming I can find a medium sweep 90 locally.
 
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Inapickle2

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Assuming things aren't different in Canada, any rubber coupling you use on the DWV that isn't buried in the ground should be a shielded coupling.

Yes, you're right. Those unshielded Fernco couplings are not approved for use within interior framing. Thanks for pointing that out. I'll only use the shielded type.

The vent pipe as assumed to be used for the toilet vent is a dry vent and in the attic is it connected to the vent stack for the lav. sinks?

This is the vent pipe configuration in the attic.

DSCN2060 resized wuth text.jpg


As you can see, the main vent stack going up to the roof vent is merely a continuation of that 3" pipe that comes down through the (exterior facing ) wall and connects to the drain line that the toilet is on. The vents for the other utilities tee into that.

You mentioned that condensate drains from the vent pipe and it is why you temporally connected it to the drain. Is this from an air conditioner or condensation from a cold attic space?

Seems very likely that the drips from the (temporarily) disconnected vent pipe are due to warm air from the room being drawn up the pipe and condensing moist cool air moving in the roof vent. I noticed the dripping got faster on cold, humid/windy nights. I'm sure that's what it is. The roof was redone and the vents replaced just last summer. There's no leakage of any sort up there. The pipes are bone dry to the touch.

Can the toilet vent be cut and removed completely and run a vent pipe to the same wall as the lav. sinks and tap into that vent stack for the toilet.

Given the vent configuration I'm not sure that would be a good idea.

Flat venting refers to a horizontal dry vent takeoff. The codes I'm familiar with require a minimum slope of 1" in 1" for the dry vent (i.e. 45 degrees) until it reaches 6" above the flood rim of the fixture. With the flat vent, there's nothing to prevent waste from accumulating in the dry vent connection on the wye, and in theory eventually blocking the vent.

As wwhitney stated, your current thoughts on a flat vent will be an issue if solids get backed top the vent pipe. Obviously should a blockage occur, waste will work back to the vent pipe and not be able to be flushed clean.

I agree, this is a point of concern. We haven't experienced any blockage in the 10 years we have lived here, but I do wonder why the section of pipe between the vent and toilet originally had two flexible couplings on it. Was it maybe opened up before ? I'm wondering if it might be prudent to fit a clear out (with access panel) in the 'toilet' vent pipe in the wall, just above floor level, so that if that if that section does get blocked it can be cleared. And, at the same time, see if I can lift the pipe a bit as it comes down under the sub-floor to create more slope down to the wye.
 
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