Double vanity rough in

[Alexpeter357]

Hello everyone,
I wanted to get some advice on a rough in I just did for a double vanity sink. This is my first time and so just wanted to get some advice and input of all you guys. I love the knowledge and experience on this page. Thanks in advance

 

[Sylvan]

Looks good

 

[Sponsor]

 

[Terry]

You should have 2" pipe when roughing for two lavs. Each trap arm can be 1.5"
The vent can also be 1.5"

 

[Alexpeter357]

You should have 2" pipe when roughing for two lavs. Each trap arm can be 1.5"
The vent can also be 1.5"

Thanks for the input Terry! I’m really kicking myself now because I glued everything. Rookie mistake. I’ve gotten mixed opinions, but really trust yours. I’ll have to make some cuts and rework it.

 

[wwhitney]

You should have 2" pipe when roughing for two lavs.

2" is probably better, but IPC Table 710.1(2) allows 3 DFUs on a 1-1/2" horizontal branch. [Each lav is 1 DFU.] And Michigan appears to be on the IPC.

https://up.codes/viewer/michigan/mi-plumbing-code-2015/chapter/7/sanitary-drainage#table_710.1

Cheers, Wayne

P.S. UPC Table 703.2 allows only 1 DFU on horizontal 1-1/2" pipe, 2 DFUs on vertical, so quite the difference.

https://up.codes/viewer/california/ca-plumbing-code-2019/chapter/7/sanitary-drainage#table_703.2

 

[Alexpeter357]

2" is probably better, but IPC Table 710.1(2) allows 3 DFUs on a 1-1/2" horizontal branch. [Each lav is 1 DFU.] And Michigan appears to be on the IPC.

https://up.codes/viewer/michigan/mi-plumbing-code-2015/chapter/7/sanitary-drainage#table_710.1

Cheers, Wayne

P.S. UPC Table 703.2 allows only 1 DFU on horizontal 1-1/2" pipe, 2 DFUs on vertical, so quite the difference.

https://up.codes/viewer/california/ca-plumbing-code-2019/chapter/7/sanitary-drainage#table_703.2

Thanks Wayne, just so I understand completely. As I have it technically “meets code” however best practice would be to have a 2” drain coming down

 

[Reach4]

Thanks Wayne, just so I understand completely. As I have it technically “meets code” however best practice would be to have a 2” drain coming down

You could improve that by putting a cleanout above your double santee. That would make for easy rodding down that 1.5 inch if it ever came up.

Depending on how flush with the wall you want, you could use a santee with a cleanout cap. You could use a cleanout fixture, which sticks out less, and there are other choices that stick out under the vanity more.

 

[wwhitney]

Thanks Wayne, just so I understand completely. As I have it technically “meets code” however best practice would be to have a 2” drain coming down

I don't have the experience to say whether the performance improvement from upsizing the common drain to 2" would be worth the rework. I think adding a cleanout would be a good idea, and that would be simpler rework.

I trust you're going to repair the stud with the missing segment? Particularly as that stud appears to support your tub surround on the reverse side.

Cheers, Wayne

 

[Alexpeter357]

I don't have the experience to say whether the performance improvement from upsizing the common drain to 2" would be worth the rework. I think adding a cleanout would be a good idea, and that would be simpler rework.

I trust you're going to repair the stud with the missing segment? Particularly as that stud appears to support your tub surround on the reverse side.

Cheers, Wayne

Ok thanks for the input! I’m not sure yet what I’m going to do! I’m not psyched about reworking the drain to 2” but seems like from what I’ve read it may be the way to go.
Oh yes, I fixed that. Builders ran hvac duct through there for a wall register ‍♂️

 

[Alexpeter357]

You could improve that by putting a cleanout above your double santee. That would make for easy rodding down that 1.5 inch if it ever came up.

Depending on how flush with the wall you want, you could use a santee with a cleanout cap. You could use a cleanout fixture, which sticks out less, and there are other choices that stick out under the vanity more.

Awesome! Thanks for the input! Makes total sense

 

[Reach4]

Ok thanks for the input! I’m not sure yet what I’m going to do! I’m not psyched about reworking the drain to 2” but seems like from what I’ve read it may be the way to go.

I would not. Adding a cleanout, which you might never need, is much easier.

 

[Boldini53]

Terry. I have a double vanity rough in very similar to the top photo.1.5x1.5x1.5x2 The vent pipe will go up to 48 inches then branch right to clear the mirrors. The drain will turn under the floor for 30 inches then tee into the 2 in drain which is shared with the tub. I would like to put an AAV in the wall with a cover plate. My structure is a post and beam with this wall being totally framed by posts and beams. Is this something that will work? Sorry for not starting a new thread but thought it would fit.

 

[Boldini53]

Terry. I have a double vanity rough in very similar to the top photo.1.5x1.5x1.5x2 The vent pipe will go up to 48 inches then branch right to clear the mirrors. The drain will turn under the floor for 30 inches then tee into the 2 in drain which is shared with the tub. I would like to put an AAV in the wall with a cover plate. My structure is a post and beam with this wall being totally framed by posts and beams. Is this something that will work? Sorry for not starting a new thread but thought it would fit.

This is my first time so if I am out of line guys let me know.

 

[John Gayewski]

The double santee isn't great. Better to use a double fixture fitting.