# Venting a Shower P-Trap



## bkeech (Jun 4, 2008)

Cant you wet vent? I dont think you need a vent for each p-trap.


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## goldenboy (Feb 4, 2010)

Well, after talking to a plumber and explaining my current situation, he thought the distance between the shower and the tub was to much to vent out of the tub vent.


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## bkeech (Jun 4, 2008)

I dont think it would work as the vent pressure needs to be above the p-trap. 

Can you off set the drains in the joist space?


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## goldenboy (Feb 4, 2010)

Depends on what you mean by offset? The problem with the "original plan" is the shower T (the one that goes up to the vent and down to the elow) and the long elbow below it (long because I was told that when you go from horizontal to vertical it must be the "long" elbow) measure 9.5" in height. Being that I only have 10" of space between the floor joists, I can not get the required 2" of slope in that drain.


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## goldenboy (Feb 4, 2010)

bkeech said:


> I dont think it would work as the vent pressure needs to be above the p-trap.
> 
> Can you off set the drains in the joist space?


Also, aren't they venting in the same place on each of the plans (both are above the p-trap)? Not sure I see the difference. Thanks.


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## rudolph58 (Mar 11, 2009)

your original plan is the best.use a double or back to back t if the waste is going vertical and a double or back to back y if going horizontal.
(drain out)


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## goldenboy (Feb 4, 2010)

Can't do the original plan due to not having enough room for the slope. I think I have it figured out. Using the revised plan, instead of using the T after the p-trap, I will use a Y and instead of the 90 degree elbow on the vent I will use a 45 from the Y over to the vertical vent which will be a long 90 elbow.


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## RegeSullivan (Dec 8, 2006)

I think a pro (plumber) would go to 1/8" per foot if they had to to make your first plan work. Maybe a plumbing professional could weigh in on this.

Rege


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## rudolph58 (Mar 11, 2009)

where is your vanity or lavatory sink?


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## rudolph58 (Mar 11, 2009)

and the stool?


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## NHMaster (Dec 21, 2009)

the shower vent, the one on the right side. Where it runs horizontal. You can't do that. Vents must rise vertical until they are 6" above the flood level rim of the highest fixture served. In this case that would be 6" above top of the tub, or 6" above the lave if the drains tie together.


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## goldenboy (Feb 4, 2010)

Sink and stool are on the opposite wall hooked into a different line.

You sure about the venting will not work in the revised plan? Asked a plumber today and he said it would work. If I can't do it this way, what do you suggest?

{EDIT} Saw it in the code...you are right. Sucks that I glued everything together today according to the "revised plan" before I saw your post. Guess I will have to restart it. Let me know if anyone can come up with how to do this right.


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## Alan (Apr 12, 2006)

Cannot use a TEE to tie drains together. Must be a wye or fittings of equivalent sweep.

2" drain coming up ut a 2" wye on the drain and put a 2" street code 90 in the wye branch to keep shower side low. 

Your shower side is going to be similar to your tub side, but slightly different. How many degrees are we allowed on a trap arm? 90* is the correct answer.

When you get to your shower side, instead of using a LT 1/4 bend, put a street 45 in the bottom of a 2x1-1/2x2 sanitary tee, and turn the tee so that it will be perpendicular to your drain line. You will also need a 1-1/2 street 45 in the top outlet to straighten yourself back to level and get up the wall. Now run your trap arm from the sanitary tee to whatever distance your shower drain is, and use a long turn 90* to get back to the drain. I could draw this in a second but I don't have a scanner, so I hope that makes sense. It should fit if you do it that way. You may have to drill a larger hole in the bottom of the wall so that your 1-1/2" 45 will go partially into it. Also to do this you won't want to run your drain straight at center of your shower drain. You will want to be 6" to 12" to either side of it to make room for the 90* offset back to it.


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## Alan (Apr 12, 2006)

Are you familiar with isometric drawings? That would be the easiest to do and i could sketch one out real quick on paint probably. It would be ugly but it might make more sense that way....

I'm also confused to where your drain outlet is coming from. It's just floating in air in your drawing. Do you have a picture to show where this is going? It might make it easier.


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## goldenboy (Feb 4, 2010)

I would love to see a drawing of what you are talking about, even if it is crude. Sorry, just having a hard time picturing what you are saying but thanks in advance for your detailed help. 

The 2" drain goes through the wall to the downstairs. I haven't opened the wall below it but it is a laundry room directly below the master bath. The area I'm working in already had a tub/shower tied into this line but I had to redesign the bath to make more space for a larger shower. Hope this makes sense.


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## rudolph58 (Mar 11, 2009)

u can wet vent with a 2" vent if u wash it with your lav & shower or lav & tub.not over 4 dfu.


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## Alan (Apr 12, 2006)

rudolph58 said:


> u can wet vent with a 2" vent if u wash it with your lav & shower or lav & tub.not over 4 dfu.


The max distance on a 2" trap arm is 5 feet. His is too far.

Goldenboy : I assume your 2" line is coming up in a wall? Is there some reason of not wanting to open up the wall? If you were to do that you could wye off of the existing drain, and run the drain horizontal (on grade) in the wall closer to where the shower is. This requires a lot more drilling however. Let me see if I can throw together a crude drawing for you.


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## Alan (Apr 12, 2006)

Fitting #1 should be a 2" x 1-1/2" x 2" sanitary tee. the 2" obviously points toward the shower and will be the lowest since you have larger fittings and have to travel a longer distance. In the top of the tee, you will want to put in an 1-1/2 code street 90 to shoot back to your tub area. (i think i drew it wrong, not sure why, maybe it just doesn't look right)

Fitting # 2 is a 2" street 45*

Fitting # 3 is a 2" x 1-1/2" x 2" sanitary tee

Fitting # 4 is a 1-1/2" street 45*

Fitting #5 is a 2" Long turn 90*

like i said forgive the drawing, and also it's hard to draw 45*'s in isometric and have them look right so this is really a funky picture.

In case you aren't familiar with isometric, basically everything that is straight up and down is a vertical pipe, everything on the 30* plane is horizontal, and everything on the 60* plane is horizontal also, but perpendicular to the 30* plane.

I hope this makes sense. You can use the same configuration on the tub side if you run out of room using the tee, just use 1-1/2" fittings instead.


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