Bathroom sink drain configuration?

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LLPA

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Hello!
This is all just dry-fit so far.
I have a tee coming out from pipe in wall...going up to a Studor vent/AAV. Then a trap adaptor.
I still have to cut down the extension pipe coming down from sink, but how do you suggest I finish this? Unfortunately, they are about an inch apart and I don't have an inch to play with at the wall.
I also bought a street 90 and street 45.
Photos attached.
Thanks!
2024-12-21 12.14.49.jpg
2024-12-21 12.15.06.jpg
2024-12-21 12.14.41.jpg
 

wwhitney

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A couple options if the san-tee location is fixed, i.e. if it's already glued to the pipe in the wall:

Option 1 (simplest): flip the u-bend around so that it runs away from the wall rather than towards the wall. Pull the trap arm bend out of the trap adapter to reach the new joint location. If your existing tubular trap arm is too short, better to get a new one that is long enough, rather than having an extra slip joint on the trap arm, although that would be allowed. Note that the tubular pipe needs to go in the trap adapter at least an inch or two, but it should not go in so far as to obstruct the side inlet on the san-tee, which is your vent connection.

Option 2: get two tubular 45s, each one end slip joint female, the other end straight tubular. They make a tubular offset that you could cut in the middle that would give you those two pieces. Use those two 45s on the sink tail piece, in lieu of your straight extension, to move the trap left/right and/or front/back the right amount to allow the joint to line up.

If the san-tee can be changed/adjusted, a few possible options:

Option 3: put the trap adapter at the wall, and switch to a tubular tee made for accepting an AAV. That might require switching to a 1-1/2" trap, not sure, but that's easily done with a reducing slip joint washer on the trap inlet. Pretty sure, although not certain, that would take up less horizontal run on the trap arm, so you could get tubular trap arm piece to go a bit further back as required with the current u-bend location.

Option 4: not sure this one would work, but you could try putting the street 45 in between the wall and the san-tee. I think if you 45 to the left, though, you may end up with the trap arm tubular piece too far away from the sink tailpiece (in plan). Going 45 to the right would be less likely to have that problem, but then you might have a conflict with the AAV location. Although the AAV only needs to be 4" above the trap arm, so you could shorten the vertical schedule 40 pipe if necessary.

Cheers, Wayne
 

wwhitney

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One more possibility if the san-tee can be changed/adjusted:

Option 5: after the AAV, it's OK for the fixture drain to turn downward. So you could put a street LT90 on the pipe in the wall (actually the IPC would allow a street quarter bend), with the (street) inlet facing up, and put your san-tee on top of that in the usual orientation (side inlet horizontal). That will actually put the trap adapter a bit farther from the wall if you point the san-tee inlet away from the wall, but you can rotate the san-tee so the trap adapter comes off at an angle. That should let you move the inlet end of the tubular trap arm piece to the left, letting you rotate the u-bend to the left, to get them to line up.

Cheers, Wayne
 

Reach4

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I like option #1.

I assume you know you need to use the nuts and washers.

One washer probably needs to be a reducing washer to reduce from the 1-1/2 adapter to 1-1/4. I am not sure if that transition is at the trap adapter or at the tailpiece.
 

LLPA

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A couple options if the san-tee location is fixed, i.e. if it's already glued to the pipe in the wall:

Option 1 (simplest): flip the u-bend around so that it runs away from the wall rather than towards the wall. Pull the trap arm bend out of the trap adapter to reach the new joint location. If your existing tubular trap arm is too short, better to get a new one that is long enough, rather than having an extra slip joint on the trap arm, although that would be allowed. Note that the tubular pipe needs to go in the trap adapter at least an inch or two, but it should not go in so far as to obstruct the side inlet on the san-tee, which is your vent connection.

Option 2: get two tubular 45s, each one end slip joint female, the other end straight tubular. They make a tubular offset that you could cut in the middle that would give you those two pieces. Use those two 45s on the sink tail piece, in lieu of your straight extension, to move the trap left/right and/or front/back the right amount to allow the joint to line up.

If the san-tee can be changed/adjusted, a few possible options:

Option 3: put the trap adapter at the wall, and switch to a tubular tee made for accepting an AAV. That might require switching to a 1-1/2" trap, not sure, but that's easily done with a reducing slip joint washer on the trap inlet. Pretty sure, although not certain, that would take up less horizontal run on the trap arm, so you could get tubular trap arm piece to go a bit further back as required with the current u-bend location.

Option 4: not sure this one would work, but you could try putting the street 45 in between the wall and the san-tee. I think if you 45 to the left, though, you may end up with the trap arm tubular piece too far away from the sink tailpiece (in plan). Going 45 to the right would be less likely to have that problem, but then you might have a conflict with the AAV location. Although the AAV only needs to be 4" above the trap arm, so you could shorten the vertical schedule 40 pipe if necessary.

Cheers, Wayne
Thanks Wayne. Nothing is glued in (not even the san-tee at wall)...this is all a dry fit...and why no washers are there yet. Knowing that, which is your best option (least amount of space taken/least joints needed)? Option 3?
For option 1, when you say 'flip' the u-bend...do you just mean to spin it around to the front?
 

LLPA

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I like option #1.

I assume you know you need to use the nuts and washers.

One washer probably needs to be a reducing washer to reduce from the 1-1/2 adapter to 1-1/4. I am not sure if that transition is at the trap adapter or at the tailpiece.
Yes, this is just dry fit...nothing is glued and no washers on yet. The adapter I have there goes from 1-1/2 to 1-1/4. It came with a screw on nut that's not on there right now.
 

Reach4

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You might want to shorten the riser under the AAV to make changing the AAV easier some day. 4-inch minimum
 

LLPA

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You might want to shorten the riser under the AAV to make changing the AAV easier some day. 4-inch minimum
Thank you. I will do that. I had thought more distance was better so was just trying to use all the space I had.
 

LLPA

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A couple options if the san-tee location is fixed, i.e. if it's already glued to the pipe in the wall:

Option 1 (simplest): flip the u-bend around so that it runs away from the wall rather than towards the wall. Pull the trap arm bend out of the trap adapter to reach the new joint location. If your existing tubular trap arm is too short, better to get a new one that is long enough, rather than having an extra slip joint on the trap arm, although that would be allowed. Note that the tubular pipe needs to go in the trap adapter at least an inch or two, but it should not go in so far as to obstruct the side inlet on the san-tee, which is your vent connection.

Option 2: get two tubular 45s, each one end slip joint female, the other end straight tubular. They make a tubular offset that you could cut in the middle that would give you those two pieces. Use those two 45s on the sink tail piece, in lieu of your straight extension, to move the trap left/right and/or front/back the right amount to allow the joint to line up.

If the san-tee can be changed/adjusted, a few possible options:

Option 3: put the trap adapter at the wall, and switch to a tubular tee made for accepting an AAV. That might require switching to a 1-1/2" trap, not sure, but that's easily done with a reducing slip joint washer on the trap inlet. Pretty sure, although not certain, that would take up less horizontal run on the trap arm, so you could get tubular trap arm piece to go a bit further back as required with the current u-bend location.

Option 4: not sure this one would work, but you could try putting the street 45 in between the wall and the san-tee. I think if you 45 to the left, though, you may end up with the trap arm tubular piece too far away from the sink tailpiece (in plan). Going 45 to the right would be less likely to have that problem, but then you might have a conflict with the AAV location. Although the AAV only needs to be 4" above the trap arm, so you could shorten the vertical schedule 40 pipe if necessary.

Cheers, Wayne
@wwhitney - Thank you.
Nothing is cemented yet at wall.
For option 3, is this the tubular tee and AAV you are referring to? https://www.amazon.com/gp/product/B00FQEX7FK/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1

For option 5: Is something like this what you mean (added 90 at wall). Is this to code? I'm in PA.
See photo:

Thanks!
 

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wwhitney

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For option 3, is this the tubular tee and AAV you are referring to? https://www.amazon.com/gp/product/B00FQEX7FK/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1

For option 5: Is something like this what you mean (added 90 at wall). Is this to code? I'm in PA.
Yes, yes, and yes.

Your pictures of option 5 also include the u-bend configuration I suggested for option 1. The only real advantage of option 5, as far as getting your trap to meet up, is that you can rotate the san-tee left or right, in addition to rotating the trap u-bend left or right. Option 1 is maybe simpler, but if you prefer option 5, it's fine.

Cheers, Wayne
 

LLPA

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Yes, yes, and yes.

Your pictures of option 5 also include the u-bend configuration I suggested for option 1. The only real advantage of option 5, as far as getting your trap to meet up, is that you can rotate the san-tee left or right, in addition to rotating the trap u-bend left or right. Option 1 is maybe simpler, but if you prefer option 5, it's fine.

Cheers, Wayne
@wwhitney - I was thinking option 3 might be preferred, that if that takes up less space, so there's more room under vanity? Would you think this will be a shorter distance from tee to the u-bend (but still double pipe dia)? And be least intrusive as far as space?
For option 5 - I would have to cut down the downspout pipe that came w faucet. i did also try turning u-bend the other way (and rotating san-tee). So this would be okay too? See pics:
In the wall...it meets another 90 and goes down and then another one at floor level to go horizontal across floor joists toward stack. Is that all okay, to code?
 

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wwhitney

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@wwhitney - I was thinking option 3 might be preferred, that if that takes up less space, so there's more room under vanity?
That's entirely up to your preference. I'm not certain that the tubular AAV would actually allow you to use the configuration shown in the OP, I'm guessing that it would be more compact and give you the inch you are missing in that photo.

For option 5 - I would have to cut down the downspout pipe that came w faucet. i did also try turning u-bend the other way (and rotating san-tee). So this would be okay too? See pics:
Yes, that's fine. And if your goals are about space in the vanity, that gets the trap up higher (more space below) while not extending in front of the sink tailpiece (more space in front).

In the wall...it meets another 90 and goes down and then another one at floor level to go horizontal across floor joists toward stack. Is that all okay, to code?
The amount of fall of the trap arm is regulated, but after the vent comes off, those 90s and changes from horizontal to vertical are all fine. No opinion on whether there could be a performance issue, meaning fewer 90s would be less likely to clog, but I would think that would be more of a concern on a kitchen sink than on a lavatory.

Cheers, Wayne
 

LLPA

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That's entirely up to your preference. I'm not certain that the tubular AAV would actually allow you to use the configuration shown in the OP, I'm guessing that it would be more compact and give you the inch you are missing in that photo.


Yes, that's fine. And if your goals are about space in the vanity, that gets the trap up higher (more space below) while not extending in front of the sink tailpiece (more space in front).


The amount of fall of the trap arm is regulated, but after the vent comes off, those 90s and changes from horizontal to vertical are all fine. No opinion on whether there could be a performance issue, meaning fewer 90s would be less likely to clog, but I would think that would be more of a concern on a kitchen sink than on a lavatory.

Cheers, Wayne
@wwhitney - I really appreciate your assistance. One more question I'm pondering...
In order to try to do as my OP, and make up that one-inch...Am I able to use this? A 1 1/2 p-trap (vs the 1-1/4 that i hve now).
Would this eliminate the trap adaptor/reducer coming out of the sani-tee and lessen the distance? Or no, because that's a 'hub' end? Is there any other kind of adaptor from the sani-tee to the trap arm that takes less space? Thanks again!
 

wwhitney

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@wwhitney - I really appreciate your assistance. One more question I'm pondering...
In order to try to do as my OP, and make up that one-inch...Am I able to use this? A 1 1/2 p-trap (vs the 1-1/4 that i hve now).
Would this eliminate the trap adaptor/reducer coming out of the sani-tee and lessen the distance?
No, you'd still need a trap adaptor on the san-tee, and a 1-1/2" p-trap would just make your offset worse, as its u-bend would be wider.

The only way I see to make the configuration shown in the OP work would be to change what's downstream of the san-tee. If the current configuration is san-tee on its back - short pipe segment - quarter bend inside the wall, you could replace that with street san-tee on its back - quarter bend. That would move the san-tee closer to the wall (hopefully not too close so that the AAV would bump into the drywall). But if the short pipe segment is already glued to the quarter bend inside the wall, doing that would be harder than any of the options we've discussed so far.

Cheers, Wayne

P.S. I've been assuming that you've already considered and discarded the idea that you could get your 1" by just shortening the pipe sticking out the wall, and enlarging the hole in the drywall if necessary to accommodate the san-tee outlet hub. I assume that's not possible and the san-tee hub would hit the quarter bend hub.
 

Reach4

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That bend in your newest picture, where you transition from vertical to horizontal into the wall, should be a long sweep.

A 1-1/2 in. PVC DWV 22-1/2-Degree Hub x Spigot Street Elbow could be useful in your original plan.
https://www.homedepot.com/p/NIBCO-1...b-x-Spigot-Street-Elbow-C48082HD112/205799554

I also suspect that the pipe thru the wall is already vented within the wall. Do you have reason to think there is no vent in the wall?
 

wwhitney

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LLPA

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No, you'd still need a trap adaptor on the san-tee, and a 1-1/2" p-trap would just make your offset worse, as its u-bend would be wider.

The only way I see to make the configuration shown in the OP work would be to change what's downstream of the san-tee. If the current configuration is san-tee on its back - short pipe segment - quarter bend inside the wall, you could replace that with street san-tee on its back - quarter bend. That would move the san-tee closer to the wall (hopefully not too close so that the AAV would bump into the drywall). But if the short pipe segment is already glued to the quarter bend inside the wall, doing that would be harder than any of the options we've discussed so far.

Cheers, Wayne

P.S. I've been assuming that you've already considered and discarded the idea that you could get your 1" by just shortening the pipe sticking out the wall, and enlarging the hole in the drywall if necessary to accommodate the san-tee outlet hub. I assume that's not possible and the san-tee hub would hit the quarter bend hub.
@wwhitney - The quarter bend inside the wall is flush with drywall and glued. And I don't think I have enough to cut off and still fit the san-tee and it makes me nervous to cut any more of this pipe. (see photo 1)
2024-12-23 13.24.25-1.jpg
I'm not sure why i'm overthinking this!
You're right..option 1 is the best. I suppose I didn't want u-bend towards front of vanity.
Here's a dry fit of Option 1 (photos 2&3). I just have to cut the extension tube. The trap arm is inserted into adapter and san-tee nearly 2" and NOT blocking the vent up to AAV.
2024-12-23 13.34.39.jpg 2024-12-23 13.34.46.jpg


Here are nuts...the one that came with the trap adapter..that I will screw onto the trap adapter...do I need also a washer in there? Or is this sort of built into plastic? (photos 3&4)
2024-12-23 13.38.57.jpg 2024-12-23 13.56.24.jpg
This has been super helpful...and educational. Thanks so much!
 

wwhitney

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That photo with the pipe sticking out of the hub by 1", if the short pipe segment is not glued into the quarter bend, then you can remove it and use a street san-tee. If it is glued, there are mechanical methods of removing it, but it's not worth it.

Otherwise, yes, you are overthinking it. : - ) You have several solutions now, go ahead and pick one.

As for the nuts, you need to use a washer unless (a) the pipe piece has a built-in bevel on it already, like you an see on the end of the trap arm bend that mates with the u-bend or (b) the nut has a built-in attached extra washer profile, which I think may be true in your very last photo, I can't quite tell; this often (but not always) applies to nuts that come with trap adapters.

On (b) if you compare such a nut with a nut that definitely doesn't have a built-in washer, like the nut that came with the p-trap to join the trap arm bend with the u-bend, you should be able to tell the difference. A nut with a built-in washer should have an inner edge that is slightly deformable, and it will fit quite snuggly just sliding it onto a tubular pipe, while a nut that requires a separate washer will have a non-deformable inner edge and will usually fit sloppily over the tubular pipe if you omit the washer.

Cheers, Wayne
 
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