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jrterry1976 · 01-21-2009, 01:43 PM

I want to add a pedestal sink and toilet in my garage against a studded wall (no drywall) which currently contains a 3” PVC waste line vertical in the studded wall and ½” PVC water line capped beside the 3” waste line. The floor is concrete, so I am going to build a platform (floor) to set the sink and toilet on so I do no have to dig.. I am new to plumbing rough in, so my questions are:

What is the best combo of flange/joints /3” pipe so that my flooring height will be as short as possible and I have good drainage?
The plumbing above the 3” waste line in the house is vented. Do I need to vent these new fixtures. If so, I will need to use a AAV. Where does it need to connect.
What type of wye(s) should I use to make the connection to the current 3” line. Do they make a wye with both a 3” and 1.5” connection?

See attached diagram. Thanks for the feedback.

USP45 · 01-21-2009, 02:53 PM

In a vetical application a sanitary tee will do fine and give you more room to work your pipe in.

Best way to do it for a DIY'er is:
Install the sink top to the base. Next install the P-Trap. Make sure that the P-Trap is centered on the tail piece of the sink. Not all the way up, and not at the bottom, somwhere in the middle. This will allow for adjustments if needed. Now measure from your finished floor up to the center of the trap outlet. You need to have 1/4" per foot fall to the wey. So calculate the approx distance the pipe will travel through the wall to the 3" pipe. There is no need to be specific or exact to the inch. Closest foot will do. Now figure how many inches of fall you need. (Feet of run x .25) Now subtract this number from what you got to center of P-Trap. Now center a 3x1-1/2" sanitary tee against the 3" pipe in the wall. Move it up or down untill the center of the inlet of the tee is at the desired height. Mark where you need to cut out. Install tee, and run line.

Now that you are done, turn on sink, and wash your hands, they probably will be dirty by then!

zosoplumber · 01-21-2009, 08:25 PM

Yeah, 3" sanitary tee is whats used, if you cut your 3" stack 2" above floor and install a tee at that height you will be about 5-6" above the concrete to the top of the inlet of the tee, so thats How high you are at the start of the run, (not sure how far the run is to toilet)at end of run and adding in the toilet 90 w/ flanges height is how high the deck will be. Using a 3" street 90 with flange glued directly on it will save you about 1"1/2 in height. you should put your AAV on your run to the sink, to prevent the toilet from sucking your lav's p-trap dry. but it needs to be accessible.

jrterry1976 · 01-22-2009, 09:03 AM

Very helpful. Thanks for the responses. One question, so I will have to have one 3" T for the toilet aand then another 1.5" T above that for the sink? Do they make a combo T where the 3" toilet and 1.5" sink can connect?

md2lgyk · 01-22-2009, 11:00 AM

Yes, I believe they do. I've seen combos that will take the toilet, sink, and tub as well.

zosoplumber · 01-22-2009, 05:07 PM

it depends, how far will the toilet line extend from the 3" stack? Or are you building the platform directly behind the stack?

jrterry1976 · 01-22-2009, 07:40 PM

The stack will be directly behind the toilet so I guess only 12-18" or so. I guess I will stack a 3x1.5 on top of the 3x3 and go that route. I could not find a combo. Here is a question that has been bothering me. If I have 3" sanitary tee that comes out at a 90 degree angle and the pipe under the flange makes a 90degree turn to go to the t, how is this going to have a 1/4"drop / foot. I can't understand this. Is there enough play for the toilet to be slightly higher?

rick42wood · 01-22-2009, 07:56 PM

I have just torn my bathroom apart for a remodel project. The previous owner had built the toilet up on a platform as you are planning to do. It turned out that the toilet flange had been leaking very slowly and it was a mess under there. The wall framing has started to rot and there is mold. If I had not torn it up it would have been years before the leaking was detected. So.. I would advise you to construct the platform so that the underneath can be inspected occasionally. Or line it with plastic so that any leaking will be directed to somewhere where it will be noticed. The platform I tore out was covered in ceramic tile.

zosoplumber · 01-22-2009, 08:24 PM

Are you talking about the run of pipe coming out of the t in the stack to the toilet? If so yes, there is enough play in the line, you said the stack will be behind the toilet, so if you do the math, and place your toilet at 12"-12"1/2 from the face of your wall, that leaves you with around a 1/4" diffrence from center of the t's inlet to center of the toilet 90.

drunknmaster · 01-22-2009, 09:12 PM

any one ever hear that wet venting is not code?

**thekctermite** · 01-22-2009, 11:52 PM

Quote:

Originally Posted by drunknmaster_4u@yahoo.com

any one ever hear that wet venting is not code?

I havent'...

Either help or don't post...Antagonizing those that have assisted is pointless and unproductive.

drunknmaster · 01-23-2009, 12:12 AM

so is the wrong answer

**thekctermite** · 01-23-2009, 12:30 AM

Quote:

Originally Posted by drunknmaster_4u@yahoo.com

so is the wrong answer

If someone is wrong or if you feel someone is wrong, by all means feel free to make the necessary corrections. But back up your statements. In this case, a code section qualifying your statement would be appropriate. Since this is a DIY-oriented site, a coherent explanation of your logic would help people understand what you mean.

jrterry1976 · 01-23-2009, 09:30 AM

Good point on the raised platform. This project is going into my garage, so the floor is concrete. The back side of the platform will be towards the garage, so I should be able to check it.

As for venting, My only option is to use a AAV. Based on the advice, I was going to vent the drain pipe b/t the sink trap and the waste pipe. If someone has a suggestion, please share. Most of the diagrams I have looked at show through ceiling vents, which is not an option for me.

Since the plumbing above the stack is vented, do you think I could get away without venting for this section?