DWV help please

BimmerRacer · Feb 15, 2009

Can I do this?

The pipe to the left is the 1 1/2" vent which used to have a lavy hooked up to it. The one with the rubber cap is the tub drain. Can I add double vanity in the manner depicted?

Thanks

trip-l-jax · Feb 15, 2009

From what I see your double vanity is not vented.
Second, your DWV appears not to code as there is no indication of purple primer in areas.

Sponsor · 2022-01-29T12:20:58-0800

BimmerRacer · Feb 15, 2009

Is connecting it to the 2" vent not making it vented due to the length of the run? I have another vent stack which is closer, but it has a shower connected to it and its only 1 1/2".... Any other options?

Thats an interesting point about the primer. The shower drain did just fall out of that T. Was the primer purple 25 years ago? I will likely have to redo join anyway as I need to put in a header for windows on that wall.

This is the shower drain I am talking about.

Terry · Feb 15, 2009

Your drawing should have the waste from the lavs below the tee for the tub.

The double lav would use a fixture cross like the drawing below with the vent in the center.
A 2" waste line would be needed for two lavs,
You can then use a 2.0 'x1.5 'x1.5 'x1.5 ' fixture cross.

BimmerRacer · Feb 15, 2009

So, like this? The old 1.5" vent is pretty useless, eh?

Is there any flexibility? I have three skylights right above the vanity, is it possible to move the vent?

trip-l-jax · Feb 15, 2009

How was the original sink vented?
Your vent should tie into the other vent above waste flow,unless you plan on a vent going through the roof.
i.e. at the location above the tub drain if possible.
I would install a cleanout, being you have a double vanity, cheap insurance.
I know the purple primer has been out 23 years ago at a minimum.

BimmerRacer · Feb 16, 2009

Terry said:
Your drawing should have the waste from the lavs below the tee for the tub.

trip-l-jax said:
How was the original sink vented?
Your vent should tie into the other vent above waste flow,unless you plan on a vent going through the roof.
i.e. at the location above the tub drain if possible.

trip-l-jax said:
How was the original sink vented?

I know the purple primer has been out 23 years ago at a minimum.

Original sink was not a double...they were at two corners of the room. One of them was on the 1.5" vent you see in the diagram.

House was built in 1982

NHmaster · Feb 16, 2009

Your second drawing is correct, cut out and cap off the old 1 1/2" lav connection.

BimmerRacer · Feb 16, 2009

Can I just leave it there? I can't just cut it at the connection, I'd have to cap it at the roof as well. This is, by the way, after I moved that thing once already as we moved the wall it was in

hj · Feb 16, 2009

drain

You can do almost anything you wish to with the vent, except run it downhill. I do not know what the pipe to the left is for, or what its purpose is, but it can stay there if it is not in your way.

trip-l-jax · Feb 16, 2009

BimmerRacer said:
:Is there any flexibility? I have three skylights right above the vanity, is it possible to move the vent?

BimmerRacer said:

Original sink was not a double...they were at two corners of the room. One of them was on the 1.5" vent you see in the diagram.

House was built in 1982

Click to expand...

Your second drawing was a little confusing as it did not show where you were venting directly to. Whether it was to the original vent for the single sink or not, with the mention of moving the vent due to skylights above.

What Terry and I were getting at was to ensure the vent was installed above the level of where waste will travel, avoiding a wet vent. Your first drawing would make the tub wet vented.

BimmerRacer · Feb 16, 2009

Sorry, still confused.

What I think you guys are saying is

- add its own vent to the double lavs
- run the 2" combined drain from the double lavs to below the 1.5" tub drain
- the existing 1.5" vent is not serving any purpose

Are there other options? This is the layout. The tub DWV is right between the two windows above the tub and the other 1.5" vent is in the wall between closet/tub. I am going to build out the exterior wall that the vanity is going on as I discussed in this thread https://terrylove.com/forums/showthread.php?t=26676 another 4" so I have room for plumbing after I added 4" of rigid foam insulation.

Thanks again!

BimmerRacer · Feb 16, 2009

Exterior view, don't mind the plywood "window", courtesy of a fallen tree

You can see the two vents there.

And the old layout

trip-l-jax · Feb 16, 2009

Yes run the 2" combined drain from the double lavs to below the 1.5" tub drain.
The new lavs do need to have a vent that is represented in your second drawing tied into another vent if you can.
Is there any way to take your new double lav vent over and away from the skylights and tie in to another existing plumbing vent (maybe the existing 1.5" vent that is not serving any purpose) from above the ceiling or in the attic area ?

BimmerRacer · Feb 16, 2009

Well, there's really no attic...how far over can I run the vent? Can I go up from the lavs, back toward the entrance to the room and over into the vent that is in the closet wall? I would disconnect it from the 2" drain it's connected to.

trip-l-jax · Feb 16, 2009

BimmerRacer said:
Well, there's really no attic...how far over can I run the vent? Can I go up from the lavs, back toward the entrance to the room and over into the vent that is in the closet wall? I would disconnect it from the 2" drain it's connected to.

You can go as far as it takes. Yes you can do it as you describe.

BimmerRacer · Feb 16, 2009

Not quite...can't go straight up from there and into the joist bay. You guessed it, the skylights.

Can I go up, over, up, over, up?

There's got to be some sort of max lengths clause to prevent me from doing this. I just know it would be my luck!

trip-l-jax · Feb 16, 2009

BimmerRacer said:
Not quite...can't go straight up from there and into the joist bay. You guessed it, the skylights.

Can I go up, over, up, over, up?

There's got to be some sort of max lengths clause to prevent me from doing this. I just know it would be my luck!

You can do what it takes to vent the sink. Do not be concerned with length of run. Look up a revent, it is similar to what you are doing.

BimmerRacer · Feb 16, 2009

Cool, thanks. And as far as the drain length as long as it's pitched properly at 1/4" per foot I should be OK?

trip-l-jax · Feb 16, 2009

Yes that is correct. I'd slope the vent at 1/4" per foot horizontally (the above portion) so rain water will not set dormant in the pipe.

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