Need help on single to double vanity drains

[Kent H]

Drain pipe out of slab is 2" and vent pipe is 1.5" straight to the roof with nothing above.
With the new double vanity placed where we need it the right sink lines up perfect with the drain. I need to add another for the left sink which would end up between the framing with the metal conduit. Distance from center to center on the two drains is 39" the distance from the left sink to the vent/drain pipe is 48" A plumber came out and told me he would have to run a 2" drain to the sink because of the distance. A 2" pipe would compromise the framing, any advise is appreciated.

 

[Smooky]

Sometimes you have to break some eggs when you make a cake. What you have to do is figure out a way to make what you have, work with what you want to do. You can double up the studs or nail plywood on the sides to give them more strength. You could use metal plates the width of the stud with a hole through the middle to screw onto the studs. You need nail plates on the studs anyway. It is only 3 studs and you will still have ½ inch on either side. Don’t worry, you can make it work.

Here we are required to double the studs for a 2" hole and leave no less than 0.625 inch to the edge of the stud. You may need to build out the wall an inch or so. If it is going to be inspected I would contact them first and find out what they will accept.

 

[Sponsor]

 

[Terry]

It's easy enough to make that a double lav in the wall. I see that you have 2" coming out of the ground, and a 1.5" vent. A double fixture fitting, 2.0 x 1.5 x 1.5 x 1.5

 

[Jadziedzic]

Simpson (and others) sell "stud shoes" (referenced in Smooky's post) that will reinforce the studs where you have to drill them larger for the 2-inch drain. My local plumbing inspector was fine with their use in a similar case.

BTW, I noticed in the picture that the corrugated metal covering on the right-most of the two sections of conduit stops well short of the junction box. That looks suspicious; you should have an electrician check into that.

 

[Kent H]

It's easy enough to make that a double lav in the wall. I see that you have 2" coming out of the ground, and a 1.5" vent. A double fixture fitting, 2.0 x 1.5 x 1.5 x 1.5

I saw this in one of your previous posts. My drain and vent are both on the left side of the basins. Would you come up from the 2" and 90 degree it to the left then up and split the difference between the two? I assume then connecting the vent like you have in the picture.

 

[Kent H]

Simpson (and others) sell "stud shoes" (referenced in Smooky's post) that will reinforce the studs where you have to drill them larger for the 2-inch drain. My local plumbing inspector was fine with their use in a similar case.

BTW, I noticed in the picture that the corrugated metal covering on the right-most of the two sections of conduit stops well short of the junction box. That looks suspicious; you should have an electrician check into that.

I cut the conduit off to see how much room I had for the drain. The conduit no longer needs to be there anyways since the shower is not in that location any more.

 

[Kent H]

Since I have the manifold in the way I don't see getting a 2" drain next to them. I did a test fit and believe it will not line up enough with the drain coming out of the floor. I found this post picture from a forum member and was wondering if this is possible with 1.5" drains. And if so how high do the vent stacks need to be?

 

[Standardairconditioner]

Is this going to be a single cabinet? Then why not just use the existing vented drain as it is, without the need to add a 2nd one?

A lot of kitchen double sinks are like this. The trap and drain doesn't have to be in the middle of the two sinks.

39" is not a lot and would still work even if it wasn't graded downwards. You're not going to be pouring hot chicken fat into this daily to stink things up.

Can you take another version of the first pic, and use Post-Its or tape to show where you want the sinks to be? I can't tell if you want both sinks left of the vertical, or one on each side of the vertical as Terry posted.

 

[Kent H]

Is this going to be a single cabinet? Then why not just use the existing vented drain as it is, without the need to add a 2nd one?

A lot of kitchen double sinks are like this. The trap and drain doesn't have to be in the middle of the two sinks.

39" is not a lot and would still work even if it wasn't graded downwards. You're not going to be pouring hot chicken fat into this daily to stink things up.

Can you take another version of the first pic, and use Post-Its or tape to show where you want the sinks to be? I can't tell if you want both sinks left of the vertical, or one on each side of the vertical as Terry posted.

It's a bathroom vanity with drawers between the two sinks

 

[Standardairconditioner]

Then wet vent 1.5" through some studs, bend the copper out of the way if necessary, and that's all.

Drain that is far far left is going to be like half-inch higher than the existing drain closer to the vertical. You can even do all this with 2" if it puts you to sleep.

Don't believe anyone for a second if they say your farthest sink is going to backflow into the closer sink, never gonna happen.

 

[Terry]

A picture I had.

And one more.

And this one.

 

[Kent H]

Is this going to be a single cabinet? Then why not just use the existing vented drain as it is, without the need to add a 2nd one?

A lot of kitchen double sinks are like this. The trap and drain doesn't have to be in the middle of the two sinks.

39" is not a lot and would still work even if it wasn't graded downwards. You're not going to be pouring hot chicken fat into this daily to stink things up.

Can you take another version of the first pic, and use Post-Its or tape to show where you want the sinks to be? I can't tell if you want both sinks left of the vertical, or one on each side of the vertical as Terry posted.

Second sink will be 3 studs to the left between the metal conduit. I marked an x on the wall in the original pic but you would have to zoom in to see it.
Would the 1.5" drains be adequate? They would dump into the 2" coming out of the floor. Thanks

 

[Standardairconditioner]

Terry's 3rd pic would apply to you.

You can see how the 2nd sink is graded down to make a wet vent.

Except you won't be chopping into your vertical at all. You will be stretching the horizonal longer leftward.

Would the 1.5" drains be adequate?

Yes. But use 2" if it puts you to sleep. There is no rule against using a larger diameter.

 

[Terry]

The second trap arm should be added on the 2" for best results.

 

[Kent H]

It's easy enough to make that a double lav in the wall. I see that you have 2" coming out of the ground, and a 1.5" vent. A double fixture fitting, 2.0 x 1.5 x 1.5 x 1.5

I am going to go this route with 2" from the double fixture fitting to the drain. Couple of questions though:
On the 90 degree elbows for the vent and drain do you use schedule 40 elbows?

And what about the 90 degree elbows where the 1.5" exits the wall, schedule 40?
Vent horizontal 42" from ground?

 

[Kent H]

This is what I ended up with. A friend came over and we spent 13 hours on it.

 

[hj]

THIRTEEN HOURS? That is about 2 hours per fitting. Maybe you should have spent more time plumbing and less with the Miller's.

 

[Terry]

THIRTEEN HOURS? That is about 2 hours per fitting. Maybe you should have spent more time plumbing and less with the Miller's.

hj, It was a long time ago, but remember when we both started out? I know I was a lot slower in the very beginning of my plumbing career.

 

[Standardairconditioner]

This is what I ended up with.

Good job! Thanks for the follow up, it's good to see projects that start and end here.

Don't listen to others that scoff your work. They didn't do it for you, you did it, it is done, and now you can enjoy it.

Your post encourages other new DIY members here to follow.

 

[Kent H]

Thanks for the info guys.