In desperate need of advice!! Venting

[hbillingsley92]

I am trying to install a double sink vanity in our master bath remodel. However, when I exposed the pipes to plan my plumbing I ran into a dilemma. How do I tie double sink plumbing into my current plumbing. The issue I have is trying to properly vent and drain the system. In the second photo the black line represents what extends behind the wall. The current plumbing vents into the attic and drains into the basement. The red boxes represent where my two sinks will sit once the vanity is installed. I tried to put the ruler down to show how high the current drain is (roughly 18” off the subfloor). Any advice would be greatly appreciated! Thank you in advance!

 

[Jeff Handy]

Is that black line the vent and drain line for your old sink?

 

[hbillingsley92]

Is that black line the vent and drain line for your old sink?

Yes it is. I just drew that line to represent what’s behind the wall since it’s not exposed

 

[Copymutt]

Not seeing the issue here. Looks straight forward. Slope each sink drain to the existing connection. ????

 

[hbillingsley92]

Not seeing the issue here. Looks straight forward. Slope each sink drain to the existing connection. ????

I’ve been told that you cannot connect two drains with one vent on the far right because there will be draining issues

 

[Copymutt]

That would be no different than 1 sink w/ an overflow. Anyone think otherwise?

 

[rickwhoo]

Wouldn't it be the same as this?

 

[GReynolds929]

Wouldn't it be the same as this?
View attachment 26695

No, because the toilet is vented off the top of the santee. The trap arm ends at the tee, everything below is drain. OP would be creating a trap arm that is too long unless he upsizes and you cannot have two traps on one trap arm.

 

[hbillingsley92]

No, because the toilet is vented off the top of the santee. The trap arm ends at the tee, everything below is drain. OP would be creating a trap arm that is too long unless he upsizes and you cannot have two traps on one trap arm.

Yeah I’m not sure what I should do. I really just need to know how to properly vent the second sink in the double vanity

 

[GReynolds929]

This is most likely what will be needed. Make sure to use a parts cross, not a double santee or double combo.

 

[rickwhoo]

Can he use AAV's???

 

[hbillingsley92]

This is most likely what will be needed. Make sure to use a parts cross, not a double santee or double combo.

Thank you for this advice! This has helped me tremendously

 

[GReynolds929]

Can he use AAV's???

If his jurisdiction allows them yes.