Need some professional plumbing advice - venting

Tim

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Staff member
I'm relocating a bathroom and need to sort out venting.

In an ideal world, I wouldn't put another stack through the roof. It's a vaulted ceiling and the walls don't go all the way up, so if I put in a small 2" vent for the new bath (straight up from the sink in the new bath) a few feet will be visible between the top of the wall and the ceiling. Not ideal.

I could run an AAV vent (cheater vent) but a) that's not kosher to code up here I don't think and b) I'd rather not have the risk of the seal failing.

So - the puzzle is can I somehow use the existing stack as shown in the diagram to vent the new bath which is 15 feet away?

Nothing is really vented well. The bath fixtures all just tie into the drain, and presumably are close enough to the stack to vent reasonably well. All the drains seem to work OK. The kitchen sink is not vented at all, but again it drains (I think being a double bowl sink helps with that).

The cottage is up on piers - 3 to 4 feet over the ground with an enclosed crawlspace where the drains are. It exits the back corner and drops into a septic tank / drain field.

So I have room to play under there. I thought maybe I could run a vent pipe in the crawl space sloped up towards the main stack, come up through the floor in the closet and tie into the stack higher up.

But of course this doesn't put the 'air behind water' very well. Thoughts?
 

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I'd find out for sure whether the Studor vents are code there. They work and for your setup, I think they may be the best option. So, as long you have negative pressure from your current vent and/or Studor vents it seems like you should be good to go. That said, I don't see how running to the existing vent won't work, either. I've seen houses that run only one or two vents. Seems a small cottage like that should be able to run on one.

I say all this as a homeowner and landlord, not as a plumber.
 
cheater vents arent code here
All the old drain lines should double back to the stack for venting and with your new drainage you will need to run a smaller stack out the roof............or just use cheaters and hope for the best. Im not a plumber either just well versed as I just finished doing all the plumbing and drainage in our house because we gutted all the old and renovated it.
Code may be different for your cottage though so best to check locally
 
You know I ran into this in the past and ran a redundant T with two of the cheaters and in 15 years never had trouble, I did put them directly below a medicine cabinet so if I ever needed to access I could. The way you show the vent stack that lav is trouble and won't fly with code.
 
Tim, why can't you run the vent in the exterior wall to the peek behind the sheeting? Or is it open stud walls? Or you don't want to remove the sheeting on the inside? What is the wall covered in on the vaulted portion, if it is painted drywall easy to rip off and re-do, if it is planks or bead board or tongue and groove I could see not wanting to rip that off to run the new vent stack. But I would say if you can run the new stack on the outside wall in front of the insulation all the way to the peek where you won't really see it you can get a good vent without really noticing it outside.
 

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Or you could consider small bulk heads to hide the vent pipe against the exterior wall (interior)
 
Kamn said:
Or you could consider small bulk heads to hide the vent pipe against the exterior wall (interior)

Yep that would work too, need a look at the wall in question in real life to help with that decision. Good venting is important, in my experience a Mickey Mouse solution will cause you grief at the worst possible time, like a family gtg and your toilets all stop flushing LOL
 
vents dont really backfill too badly... so you can actually run a kick up and then take it back down into the floor. Think of how they vent a kitchen sink that is built into an Island... no overhead for a stack... and AAVs are not code everywhere (that seal wont wear out for 15 years... and even then it will just cause a stink that tells you to replace it. As long as the vent comes off the top and is above the max water level for the sink before turning... it should work fine. Notice they still pipe part of the vent into the drain system so that it cant fill up with random junk.

island_sink_bert_polk.jpg
 
Ahhhh - I've looked at that island vent a few times in years past working on different things, but had forgotten about it.

Running a vent up the exterior wall may pose a problem coming up through the top plates of the wall and through what I assume would be a roof truss sitting right on the top of that same wall. That's a lot of structure to punch through. They're 2x4 framed walls, so I'd be chewing out most of it. Not worried about structure failing, but still, a 2 inch hole through 2 top plates and a vertical 2x4 roof truss member is a lot of drilling. Plus the exterior wall is finished above the 8' mark where I took out the drywall. T&G finished pine on the wall which I'd rather not remove just now.

My original plan was to do a typical wet vent, bringing a 2" vent up from the sink in the wall, and then either have a cutout on the opposite side (bedroom) where I could access the studor vent and hang a picture over it, or bring it up just out of the wall at the top. Then if I needed to in the future, I could just extend it through the roof and be done with it. Using a cheater vent (as they're known here) is only a concern to me as this is a seasonal cottage, sitting empty for months. I don't want the entire building to fill up with gasses from my septic tank because the vent has failed.

But, the island vent looks like it should solve the problem. It might not be intended to vent 3 fixtures, but they won't be used simultaneously. I just don't want to flush the toilet and siphon the p-traps of the sink and/or tub dry.

So I run a foot vent in my crawlspace over to the current stack, up through the floor and tie into the 4" stack about 6 feet up in the closet where it is now. Is there any advantage to having as tall a loop vent as possible? I can run it the entire height of the 8 foot wall, if the volume of air in the loop vent is beneficial at all.
 

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Found a u-tube video of exactly my situation - still watching it but it looks feasible.

https://www.youtube.com/watch?v=fxmPwH4dxpk
 
Yup, there is that. If I can swing the island vent I'll do that, as it's never going to fail mechanically. If I could get up into the 'attic' (scissor roof trusses) I might consider going into the ceiling and then running across to tie into the main stack, so at least I don't have to punch through the exterior roof, but that would be a challenge and I'd likely end up falling through the pine ceiling.

I'll do some more reading on the island vent and see if I can make it work. I might do another one at the kitchen sink, as like I say it's not vented either.

I have a studor vent here in my house on a basement sink which is across the finished room from the stack. Was going to be impossible to vent any other way, so I relented and used one. I know they're code in some places, and I bought a proper one (i.e. not a cheapo version from Home Depot). Works just fine, but it's also not like the sink gets used much. I figure a vent is really needed if you're evacuating a large volume of water like when the sink has been filled or flushing a toilet. If I'm running my faucet draining into a 2 inch pipe, I'm pretty sure there's ample air flowing down the drain too.
 
Tune-A-Fish said:
Glue up PVC ball valve, chuter down when you leave and no worries man.
pvc-cbvse-700x700.JPG
This would be good no matter how you vent if you can put them in a easy spot to get at. I had to do something similar to a ruff in for a washer drain that was not being used in a house, trap would dry out and gases would start escaping. It was easier to close a valve and open it when needed vrs remembering to pour water in there once a month.
 
On top of Lazlo's pic, if you put an S-trap in instead of a P-trap, the water that stays in the bottom of the S-trap prevents gases from exiting through the sink drain. In bigger cities, NYC for example, S-traps are code for that reason.
 
Just remember to glue the true north end before you install it or the valve might not actuate too well if some glue drools down, even the cleaner will stick it good! probably know already, but hate to see anyone waste materials.
 
http://www.amazon.com/Leak-Frog-LF001-Water-Alarm/dp/B000WMSTUO

these things have saved my ass a number of times... (flooding in the basement) but I always toss one under a sink after I have been working on anything.
 
LazloH said:
http://www.amazon.com/Leak-Frog-LF001-Water-Alarm/dp/B000WMSTUO

these things have saved my ass a number of times... (flooding in the basement) but I always toss one under a sink after I have been working on anything.
Ha. No confidence in your work?
 
Tim hide the vent line in a false channel that runs above the existing partition walls following the contours of the room shapes. A bit of a snake, but to the unknowing they would never know in was there. And it would comply with the codes!
 
Ha. Deviant... They saved my ass when my sump pump failed... and then after we re-did the whole kitchen... I tossed one under the sink... it went off in the middle of the night because a precarious bottle of cleaner had toppled. It still saved me a lot of pain.... and I have no confidence in my work. hahahaha
 
cqyqte said:
Tim hide the vent line in a false channel that runs above the existing partition walls following the contours of the room shapes. A bit of a snake, but to the unknowing they would never know in was there. And it would comply with the codes!

Well, that would require either rebuilding or adding a good amount of height to the walls. It would be about a 14 foot run or so I think, so would have to rise a few inches for proper vent slope. I'd likely end up with at least 6" added to the tops of the walls, which are finished etc. already.

I'm 90% going to plumb it as a typical wet vent off the sink with a 2" pipe in the wall and an AAV on it, either behind a panel or just above the wall. Then next time I'm bored I'll punch a hole in the ceiling and do it properly.

Reading up on it, I'm not sure an island vent will actually do the trick and it's a lot of extra pipe and work to do something that might not work, and would require a lot of undoing to do a normal vent in the future.
 
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