Converting Single to Double Vanity

[Clourenco]

Hi everyone,
I was wondering if someone could help me in the correct way to go from a single vanity to double vanity. I want to get rid of the cast iron pipe as show below and go with PVC. Can I have two 2x2x1.5 with a 2" drain to the 3" stack? A drawing of how to do this would be greatly appreciated.

 

[John Gayewski]

Is that a drainage stack or dry vent only stack? In other words does anything drain down that 3 inch pipe from above?

 

[Sponsor]

 

[Clourenco]

Is that a drainage stack or dry vent only stack? In other words does anything drain down that 3 inch pipe from above?

No, Below the T converts to a 4" which goes directly to the septic. Everything above is vent. I wanted to cut below the T and to go to PVC with 3x3x2 and use the 2" for the drain for the vanity.

His is what I was thinking of doing. Though, I feel that isn't correct.

yellow - Cut and replace with PVC.
White - 3" pvc
Blue - 2"
Red - 2x2x1.5

 

[John Gayewski]

Yes 3x3x2 then 2" 90 then 2x1.5x1.5x1.5 double fixture fitting. Not a double santee, a double fixture fitting.

Each one of the two arms can be up to 42" long.

If the bowls are 30 or less inches apart they can both be trapped together like a double bowl kitchen sink. Then you wouldn't need to revent as long as the shared trap is within 5 feet of the stack.

 

[John Gayewski]

 

[Clourenco]

View attachment 81318
Yes 3x3x2 then 2" 90 then 2x1.5x1.5x1.5 double fixture fitting. Not a double santee, a double fixture fitting.

Each one of the two arms can be up to 42" long.

If the bowls are 30 or less inches apart they can both be trapped together like a double bowl kitchen sink. Then you wouldn't need to revent as long as the shared trap is within 5 feet of the stack.

Okay, The vanity is only 60" long so the bowls are less than 30" apart. So, is the following drawing my configuration in order to be correct?

yellow - 3" PVC
Blue - 2" PVC
White - 1 1/2 PVC
Red - 1 1/2
Is that the only option that I have?

 

[John Gayewski]

Okay, The vanity is only 60" long so the bowls are less than 30" apart. So, is the following drawing my configuration in order to be correct?

yellow - 3" PVC
Blue - 2" PVC
White - 1 1/2 PVC
Red - 1 1/2
Is that the only option that I have?
View attachment 81320

My second drawing has both options. The drawing to the right would be if the bowls are in fact 30 or less inches apart.

I'm not seeing how a 60" vanity means the bowls would be 30" from one another. Just check that they are and you can do the drawing on the right.

 

[Clourenco]

Okay, The vanity is only 60" long so the bowls are less than 30" apart. So, is the following drawing my configuration in order to be correct?

yellow - 3" PVC
Blue - 2" PVC
White - 1 1/2 PVC
Red - 1 1/2
Is that the only option that I have?
View attachment 81320

My second drawing has both options. The drawing to the right would be if the bowls are in fact 30 or less inches apart.

I'm not seeing how a 60" vanity means the bowls would be 30" from one another. Just check that they are and you can do the drawing on the right.

I'm sorry, you are correct. They are not less than 30 as there are drawers in the middle. So my only option would be your first drawing.

 

[John Gayewski]

I'm sorry, you are correct. They are not less than 30 as there are drawers in the middle. So my only option would be your first drawing.

Unless your area allows AAV's. Which need to be accessible. Some that allow these, require them to be installed above the flood rim of the fixture and accessible.

 

[Clourenco]

Unless your area allows AAV's. Which need to be accessible. Some that allow these, require them to be installed above the flood rim of the fixture and accessible.

No, i'm all set with those things. One last question. Can i use 2" for drain and vent? is that allowed or not allowed?

 

[John Gayewski]

No, i'm all set with those things. One last question. Can i use 2" for drain and vent? is that allowed or not allowed?

Yes 2" for both is fine. The main vent stack should probably stay 3".

 

[Clourenco]

Yes 2" for both is fine.

Perfect, I'll use 2" all around. Thanks for the help!