View Full Version : Newb Needs To Move Drain and Install Vent?

05-07-2011, 10:17 AM

Hi all and thanks in advance for some help...
I am installing a tub/shower combo whare there was just a shower.(center drain PVC)
It needs to be a left hand tub because the toilet is on the right side wall...

I have excavated the drain...trap & lines (exterior house wall side)

Can I vent this thing to the same vent on opposite wall...and how?

Can I cut the lines...and re-route out of the way for the new tub drain & trap?
Need to get this going please help...
Hopefully the pics come up...


05-07-2011, 03:09 PM
What does the location of the toilet have to do with it. There are MILLIONS of homes with the valve on the same end as the toilet, in fact it is the most common installation. VERY few tubs are installed with the valve on the opposite end, mainly because of the trap being too far from the vent, and thus requiring a separate vent system.

05-07-2011, 10:24 PM
The bathroom is small. The tub is an American standard 54" which fits existing opening.
You would have to step beside the toilet to grab it to put the faucet on. And they don't want to do that.

The shower lines were/are on the left already too.That's where the idea comes from having it a left hand opening.
There is a tub shower combo on the other side of the wall where the vent is in the picture.
That tub is LHO and opposite the toilet too.

What is the length allowed anyway from the trap to the vent?

With that said...We already have the LHO tub which was special ordered and isn't going back.

So, might I get some help with the new vent that has to go in and the routing of the lines? Or is 54" within the boundaries that
we don't need another one?

Thanks for responding,

05-08-2011, 01:50 AM
A 2" trap arm can be 60" long
A 1.5" trap arm can be 42" long.

05-08-2011, 07:10 AM
The tub is 4'-6", but you also have to include the distance from the vent to where it turns the corner before heading for the trap, which could be an additional 2'. But since you already have a vent at that end, a plumber could incorporate a vent for the new tub and connect to that one.

05-08-2011, 10:26 AM
Thank you hj and Terry.
1.) Can you tell me what a plumber (me... I am tackling this myself) would have to do to incorporate the tub to the existing vent as you mentioned above?
#2...rerouting the lines out of the way under there...am I ok with going off to the sides? Someone recommended
"silver brazing" under there instead of regular solder???


05-08-2011, 01:32 PM
Underfloor, you can ONLY braze or use flare fittings, NOT regular solder. We do not know how you intend to run the piping so we cannot tell how to connect it to the existing vent.

05-08-2011, 06:41 PM
Ok...this is a crude mock up but I hope this gives you what I had in mind...
the wood plate & cement are gone...12987

05-10-2011, 10:00 PM
I sure don't want to be rude or offend but I was hoping to get more help with this.
I have the project on hold so I don't blow it...if the funds were there to have someone
come in, we surely would have...
Not trying to insult the trade by doing this myself...

05-16-2011, 08:00 AM
So, I've had a licensed plumber come out to the job and he said it is within just within specs to cut exisisting 2" drain
extend it to the left and reduce it to 1 1/2" for the tub.
He said he "probably" wouldn't have to move the copper lines (?)...would NOT need new vent.

**I've already excavated the area and the cost he gave is $600-675...
To include: the 2" to 1 1/2" run to tub and setting the tub...
(We have the tub overflow & drain parts, just not the PVC for the run of pipe & Ptrap...)
Seems high. What do you folks think?