Can I run an upstairs vent downstairs, tying into existing vent?

[tbeaulieu]

Yeah, this is kind of crazy I know. I want to move the laundry upstairs. Picture a colonial with a smaller addition on one end (gable, also). The laundry is in that part of the house and there's a vent stack from the basement, through that addition and out the addition's roof. If I could run the laundry vent down into the basement and tap in that vent stack, I could avoid having to run the new vent on the roof, which would require a roofer because I can't get up there. Too high!

Ugh. I just realized that I posted this in the wrong forum and there's no option for deleting it to repost it.

Thank you.

 

[Cacher_Chick]

The path of a vent must go upward from the trap that it serves, it can never go down.

 

[Sponsor]

 

[tbeaulieu]

Excellent. Thanks!

So my kitchen sink is improperly vented. It runs down through the cabinets, through wall and ties into the bathroom stack. Great.

 

[Reach4]

You could probably use an AAV. Search for that term.

 

[Jadnashua]

How far away from where you want to relocate the washer and dryer is the vent stack? Is there an attic above? You don't need to run a new pipe all the way through the roof, you can T into an existing vent in the attic, if possible. Note, though, you need to maintain slope to it so if there's any condensation or precipitation accumulation, it can drain down, and not block the vent pipe.

 

[tbeaulieu]

MA doesn't allow AAVs without an exception permit.

I believe that I could, in theory, join to the bathroom vent in the attic. Alternatively, I have a fortuitous opportunity next week, wherein a roofer will be on premises for another project and could do the flashing for me if, were I to simply go straight up.

In researching this I discovered that my kitchen plumbing is wrong. There's no vent. Or, at least not a correct vent. So, I'd like to correct that while I'm here. My thought now is to extend the kitchen drain up to the second floor and into the attic vent. I'd then add the p trap and stand pipe for the washer along the way. If there's no utility sink in the picture, that's enough, right?

PS: this is quite a challenge in a 280 year old post and beam home! Can't plumb on the outside wall from the basement. Can technically plumb inside the walls above the basement, but again, not into the attic through that wall!

 

[hj]

I am not sure you are thinking correctly, especially when you say you will run the vent through the roof and "add the p trap and stand pipe for the washer along the way" which implies all kinds of errors.

 

[tbeaulieu]

How so?



Not sure this image link is working. Here's what I mean.

https://www.amazon.com/clouddrive/s...OXONKfoTdi7?v=grid&ref_=cd_ph_share_link_copy

 

[Cacher_Chick]

A vent cannot have waste flowing into it at any point. The vent for the first floor can tie into a vent on the second floor, but the connection must be made at least 42" above the upper floor (so that it will be at least 6" above the flood rim of the upper fixture).

 

[tbeaulieu]

I think I know what you mean. I suspect there's also terminology in play here. The main vent stack will, of course, have waste running through it below the highest fixture, right? I suspect you mean the "branch vents" (I made that term up) can't have waste water in them. So this means I need to run two pipes from the kitchen, one to extend the sink drain to the second floor and a second for missing sink vent because that must extend all the way up to 6" above the new flood rim (washer).

Is that correct? Here's the new diagram.



https://www.amazon.com/clouddrive/s...gd0eLDwz1ua?v=grid&ref_=cd_ph_share_link_copy

 

[Cacher_Chick]

Only the section of stack which remains dry is considered the vent stack. At the point which there is a drain connected to it, it is then considered a drain.

The change to your drawing, while not pretty, is showing that you have the right idea.

 

[tbeaulieu]

If you think the drawing isn't pretty, you'd really cringe at how this will need to be implemented. I can't pass pipes between floors inside the wall. Post and beam. So I'll need to either run them up the wall and then jog them out, through the ceiling/floor or just leave them outside the wall the entire way, possibly in the corner where a corner cabinet would waste that space anyway. Those before me created a false wall upstairs in the bathroom to handle this problem, as well as in another downstairs bathroom. This house was built before indoor water was in use.

 

[Jadnashua]

FWIW, post and beam is hard to make concealed plumbing easy, regardless, especially if it is against an exterior wall.