I am in the process of having my basement finished with a full bath. While we had rough-ins before, they were in the wrong place. So, my contractor today busted up the concrete and laid the rough plumbing.

I am a complete novice when it comes to plumbing, and would like another set of eyes to make sure this is being done right. More importantly, I want to make sure this is going to vent correctly.

Based on the location, I am assuming we are going to need to use an AAV -- which I would assume is OK per code around here, because the rough-in that I did have when the house was built has an AAV siting on top of the drain pipe for the lav.

First, here is a picture of the plumbing layout:

http://www.flickr.com/photos/50001411@N00/308378057/

As you can guess, on the left is the shower drain, that then leads to the 3" toilet drain, and then leads to the lav drain (I am assuming). On the right side, just out of the picture, is where the lav is.

Here is another look at the toilet and lav drain:

http://www.flickr.com/photos/50001411@N00/308378060/


All this 3" pipe then leads down through the floor out to the main sewer drain connection:

http://www.flickr.com/photos/50001411@N00/308378062/

Kind of hard to see, but at the top of the picture is the front-wall of the hosue where the drain pipes leave the house.

First, does this look OK? Second, will an AAV work OK on the lav?

Thanks!

Two additional things.

I talked with my contractor this morning, and explained that I was concerned having the showed drain connect straight to the toilet, and having the vent be downstream of that.

The solution we came up with is to place a 'Y' (is this what you call a wye?) between the connection for the lav drain hole and the toilet drain. The shower will run off this new branch, and the toilet will be separated. So the two will meet at this new connection, then proceed down stream to the lav drain, which will then have the AAV at that top of the T, with the lav drain going to the pedestal sink.

Which leads to me to the second question. Since we are putting in a pedestal sink, there will be cabinet to hide the AAV in. Is it OK to have the AAV be buried in the stud wall, and then drill holes in the top plate to have airflow?

Where the vent would be would have an unobstructed plenum between the joists to get to unfinished space in the basement and the holes in the top plate would allow airflow between the wall cavity, the joists plenum and the unfinished basement (where the furnace is).

Thanks

I'm amazed that your plumber, (is he a licensed plumber) didn't inform you that it's against every code going to discharge a major fixture ,your toilet past a unvented one, your shower. I had hoped he had corrected this in your second post but he simply moved the problem on down the line. If this job will be inspected you're going to get turned down. You now are faced with two options. (1) run a vent on the shower,**or** (2) roll the 3 X 2"lavatory tee over on its side and connect a street tee into it. Connecr the shower drain into the branch of the tee and a street ell turned up to pick up the lavatory. This configuration will wet vent the shower and keep you in code. If you're going with door number two and use a AAV make sure you get one large enough to handle two fixtures. If you bury the AAV in the wall I would suggest you leave a service panel so if it goes bad you can change it. There should be enough air in the wall to keep the AAV happy.
Good luck and let me know. Tom

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Originally Posted by speedball1

I'm amazed that your plumber, (is he a licensed plumber)

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Unfortunetly, no. He is the GC that is doing my basement. And I am really starting to regret having him do the plumbing. I didn't realize how complicated this would be.

At this point, I would like to get it up to code, and have an inspection done. He plans on doing the concrete tomorrow, but at this point I am going to tell him to stop, and let's rework the plan.

Quote:

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(2) roll the 3 X 2"lavatory tee over on its side and connect a street tee into it. Connecr the shower drain into the branch of the tee and a street ell turned up to pick up the lavatory. This configuration will wet vent the shower and keep you in code. If you're going with door number two and use a AAV make sure you get one large enough to handle two fixtures. If you bury the AAV in the wall I would suggest you leave a service panel so if it goes bad you can change it. There should be enough air in the wall to keep the AAV happy.

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Let's make sure I understand this, so I can better relay it.

1) take the 3x2" Lav tee and turn it on it's side, with the 2" branch facing the shower

2) Add a street tee to the 2" branch, which will in essence give be two stubs that are parrallel with the main 3" line.

3) Connect the shower drain to the one stub closest to it

4) Connect a street ell to the other stub, which will then have a stub point straight up.

5) Have the drain line from the lav connect to this pointing-up stub, with part of it going straight up where an appropriate sized AAV is sitting, but below it take a branch off for the lav

I am not quite sure why this is better, other than the shower and lav meet at a common point.

Question: If my contractor has already glued the pieces together, how tough is it going to be for him to redo this?

I feel like a fool, and I appreciate this help. I just want to get this right now.

On (1) through (5) you are correct..

"I am not quite sure why this is better, other than the shower and lav meet at a common point."

The point being that both ways the plumber planned to run the shower it was unvented and being washed by a major fixture. This is against code and may result in the trap seal of the shower being lowered allowing sewer gas to escape. The way I suggested will allow the shower to wet vent through the lavatory vent and the suction from the toilets discharge won't affect the trap seal. It's important that you under stand this so you can explain it to your plumber, because, at this point in time, you know more then he does.
Question: If my contractor has already glued the pieces together, how tough is it going to be for him to redo this?
There are no "do overs" when a PVC joint's been glued. The PVC cement welds the two pieces together. It will have to cut out and rerun.

Quote:

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Originally Posted by speedball1

On (1) through (5) you are correct..

"I am not quite sure why this is better, other than the shower and lav meet at a common point."

The point being that both ways the plumber planned to run the shower it was unvented and being washed by a major fixture. This is against code and may result in the trap seal of the shower being lowered allowing sewer gas to escape. The way I suggested will allow the shower to wet vent through the lavatory vent and the suction from the toilets discharge won't affect the trap seal. It's importent that you under stand this so you can explain it to your plumber, because, at this point in time, you know more then he does.
Question: If my contractor has already glued the pieces together, how tough is it going to be for him to redo this?
There are no "do overs" when a PVC joint's been glued. The PVC cement welds the two pieces together. It will have to cut out and rerun.

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Fantastic! Thank you so much for the help. I had the difficult conversation with him this morning, but based on your information last night, I was able to come to the same conclusion about why it needed to be done as you explained this morning. Given that, I explained to him my concerns, and I believe we are on the same page now -- (there is somewhat of a lanugage barrier -- he not a native english speaker. He is very fluent, but the nuances are not there, so you have to go slow.)

Makes comeplete sense now that the shower has an independent route for drainage and venting to the lav, that is not affected by the toilet.

Hopefully tonight I will come home to it fixed they way we talked about, and I will post a new picture.

Thanks again!