I know this washer/sink rough isn't right...so what's wrong here?

[Debrasville]

Taking a stab at my first DIY plumbing project - converting a small half bath into a laundry room. The room is in no way possible to vent through the roof but I'm in Michigan where AAV can be used so planning to go that route. The prior bathroom wasn't vented at all and didn't seem to have issues but obviously I want add that into the project.

Based on reading a number of other past threads I don't think I can stack the two p-traps as I have laid out in my mock up, but what's the solution with the tight narrow space I'm working with here?

Additional question, I need to bring an AC drain line down the wall too - can that share the same drain box/p-trap as the washer drain line?

 

[wwhitney]

Actually your proposed connectivity is OK. Michigan uses the IRC, so you can put both fixtures on the existing 2" line. And the IRC/IPC allows common venting, where a common vent is good for two fixtures via stacked san-tees. A few further comments:

- If it helped with heights, the cleanout can be above the two san-tees.

- The standpipe needs to be 18" to 42" long.

- The trap arms need to be at least 2 pipe diameters in length. Likely not an issue for the sink, but on the washer standpipe, that translates into about 2" of pipe of pipe visible between the trap outlet hub and the san-tee inlet hub.

- The AAV only needs to be 4" above the upper trap arm, but higher is fine. It will need ventilation and access, so a ventilated box if you are drywalling the studs.

- Check the minimum/maximum height of the top of the standpipe relative to your washer (in the washer manual). It may need to be higher.

Cheers, Wayne

 

[Sponsor]

 

[Debrasville]

Thanks so much, Wayne!

To respond to your additional points:
- If it helped with heights, the cleanout can be above the two san-tees.
I planned to put it as close to that existing pipe as possible for ease of access once I install the sink vanity. That said, is there an advantage to having the clean out be above the tees?

- The standpipe needs to be 18" to 42" long.
I totally missed this being a thing. I think I can sqeeze it in right at around 18-19" and still keep it hidden below the countertop, but if not I'll just live with it being visible.

- Check the minimum/maximum height of the top of the standpipe relative to your washer (in the washer manual). It may need to be higher.

The washer only calls for a 24" high standpipe but I was planning to put it right around 30".

- The trap arms need to be at least 2 pipe diameters in length. Likely not an issue for the sink, but on the washer standpipe, that translates into about 2" of pipe of pipe visible between the trap outlet hub and the san-tee inlet hub.


- The AAV only needs to be 4" above the upper trap arm, but higher is fine. It will need ventilation and access, so a ventilated box if you are drywalling the studs.
Getting good ventilation is why I made it so high so it's not drywalled in behind a cabinet or anything and I can instead just have that top shelf area near the ceiling exposed then hide the front of it with a curtain or similar. That said, is it possible to jog that AAV pipe to the side to where it would be behind the dryer area?
ie:

 

[wwhitney]

1) Not that I'm aware, but it would help you with getting a lower san-tee for the standpipe, which would help you with (2).

2) Or you could have the standpipe trap arm go through the stud, and put the box behind the washer. If it's below the counter, that means behind a cabinet? So you'd have a hole in the side of the cabinet and big hole in the back of the cabinet, and the hose would take up space in the cabinet? Seems awkward.

5) Sure, you could do that. But if it's going to be above a shelf anyway, I don't see the upside. Personally, I don't see the next to hide the hose or the AAV and putting them between the upper and lower cabinets would make them easy to access.

Cheers, Wayne

 

[Debrasville]

2) Or you could have the standpipe trap arm go through the stud, and put the box behind the washer.

Gotcha. I might actually try to do this. Only reason I originally favored the right side of the stud is to help maintain space to get my arm behind the dryer to attach the vent duct.