Loop vent for bathroom sink?

[Mcnattyp]

Can I use a loop vent for a bathroom sink? How about if I use 2" drain pipe, not just 1 1/2" ?

This is a total bathroom remodel.

My problem arises because the bathroom sink is on an exterior, load-bearing wall. I would have to drill through 6 or so old 2x4 studs to connect to the new vent I'm installing. I do not want to drill through those studs since the wall is undersized already.

I want to have the right plans drawn up when I go to get permitted. The City of Portland (Oregon) can be a PIA to deal with if you need to revise your plans, at least the people I've dealt with.

I've attached a picture of two scenarios I've drawn to illustrate my plan. The top drawing shows a very simple plumbing design, but I don't want to drill through those studs. And I don't want to sister-in new 2x6s.

The bottom drawing shows a standard loop vent, like how you'd install in a kitchen island with the drain below the floor.

Please let me know if I'll get in trouble if I try to submit the bottom, "Loop Vent" plan.

Thanks!

 

[Mcnattyp]

I should mention that the sink is about a foot or 18" away from a closet wall (to the left, in the drawings). I have also thought about using a studor/aav vent, in the closet. That might be the best option, but I've only read to use AAVs as a "last resort".

 

[Sponsor]

 

[Krow]

I don't think it will pass any inspection. Have you tried taking the vent straight up to the attic space and tying in there

Thats the problems with AVV's. One person posts that you can use them under certain conditions and people are interpreting it as , "its ok to use under all conditions." Folks are using them like they're going out of style.

 

[NHmaster]

A Loop or island vent is only legal for a kitchen sink, not a lav or other fixture.
drilling that many studs on an exterior load bearing wall is also not going to pass code.

 

[Mcnattyp]

Thanks for the quick reply, krow.

I have thought about that (venting straight up, through the top plate, then over to the stack), but there is a second story, so I'd have to drill through those studs at that point. Which isn't a terrible thing, of course, if it's gotta be done. Any opinion on the Studor/AAV vent?

 

[Mcnattyp]

Peter Griffin - so I'm just SOL? No other ideas to help? How about an AAV?

 

[Krow]

Any opinion on the Studor/AAV vent?

I'm not a big fan under any conditions. I know it could be frustrating, but I personally would not do it because i do not want to go back to fix something I should have done in the first place, free of charge

 

[Krow]

This may work better for you if you have the space in the floor joists

 

[Mcnattyp]

Thanks, krow, that's pretty cool looking. I guess that's the winning solution.

I had briefly toyed with that idea, which, if I read it correctly, would mean running the vent up a bit (how much is that bit?), through a single stud, down through the floor (and bottom plate), horizontally in the basement, then up the chase to join into the stack. How far above the Tee-in from the toilet can I join into the stack?

And what's up with that little bit of green connecting the vent to the drain in the lower left? (attached below to highlight my question)

Oh and I have no space in the floor joists since they run the other way. I'll be hanging all this piping below the joists in the unfinished basement space.

 

[Krow]

Run the vent up obove the flood level of the sink or about 42" high, then loop back down into the bottom plate and connect back to the drain line. To be safe, connect the vent at 42" from the floor to the vent part of the stack.

That little bit that connects back to the drain line that you show me, will allow water to go back into the drain so that the looped vent will not fill up with water In all types of venting, you need to make sure water/condensation does not get trapped in the vent pipe. You need to make appropriate slopes for the water to drain out completely out of any vent

Double check for the codes in your juresdiction for allowances

 

[Mcnattyp]

Thanks again, krow. How do I repay you since I don't live in Ontario?

 

[Krow]

Thanks again, krow. How do I repay you since I don't live in Ontario?

A thank you is payment enough. I'm glad to help where I can

 

[Dlarrivee]

What if you just do it properly, and vent straight up through the roof? Why do people always want to half-ass it?

 

[NHmaster]

That is still a loop vent and does not meet code for a lav.
AAV's are what they are. Legal (mostly) and an abomination

Go up through and tie into the vent in the attic.

 

[Mcnattyp]

That is still a loop vent<snip>

Sorry for being an amateur, but I don't see it as a loop vent. I've known loop vents as lacking an independent vent, terminating into the drain. This drawing shows the vent going up, then down, then horizontal, then into the dry vent. It kind of has the look of a loop vent, in that it goes up then down, but it doesn't terminate in the drain.

Does it qualify as a loop vent because of the tie-in to the drain, as I noted in my highlighted section above?

Thanks for the help so far.

 

[Terry]

What state are you doing the work in?

 

[Mcnattyp]

Oregon, Portland specifically. I understand you're up in Washington?

 

[Terry]

Oregon is UPC code, same as in Washington here.

Can the vent for the lav go up, and then be piped in the floor joists to be revented to the dry stack?

Most floor joists are 2x10 which would give you plenty of wood to work with.

Or, you can drop the ceiling if needed.

If it's attic space, then reventing would be easy.

 

[Mcnattyp]

Right, so I assume you concur with Peter Griffin that the picture krow drew isn't up to UPC code? I guess I'll have to open up the second story for the vent.

 

[Terry]

He has the Island vent drawn correctly.
I've done that for kitchen sinks, but most inspectors will only allow that if there is no wall above.
It's for an island.

You may be able to use a Studor vent there.