DWV Layout

[phishfood]

Thanks for all your help Frodo. I really appreciate it. I've attached two pictures of possible layouts. I know they're not the best but hopefully they'll illustrate what I'm trying to say. They used to have the tub wet vented right into that wye that ended in the side outlet off of the closet bent, which I am hearing is a huge no-no. so I wasn't sure if the tub would still be wet vented if I left those two lines together. There's not a ton of play vertically because of where they cut the joists, but if I can run over to where the soffit starts, then I have more room and can fix the cut joists as well. either way, what fitting can I use to start the vent for the tub? It's pretty much touching the underside of the subfloor already, so would a fitting on it's side run over to the wall, then a 90 up to the roof work? Thank you so much for the help.

Your first picture, and you don't need a vent on the shower arm. You really don't even need the 3" vent before the toilet.

 

[bbstnr]

Is 2" necessary and required by code? I jut do t know if I can give up that much more room out of the joists. Would it be terribly awful to make it 1-1/2?

 

[Mr_David]

Is 2" necessary and required by code? I jut do t know if I can give up that much more room out of the joists. Would it be terribly awful to make it 1-1/2?

vent 2" min for toilet .
For sinks, tubs and showers 1-1/2" is okay

 

[Mr_David]

Here's an old thread. with a lot of pictures, tips, suggestions and comments. one in particular but don't think you can apply because you have water lines in the way and you would have to cut out a floor joist. But it involves using a low heel outlet fitting.

Anyway.. here's what it looks like now..

.

 

[bbstnr]

So can I stay with 1-1/2" for the tub and sink drain? I notice some people are responding that the wet vented tub is fine and some are saying I need to vent it individually. What say you Mr. Baggins? Mr. David?

 

[frodo]

where are you located at? what state?
reason i ask.
there are basically 2 codes. depending on your state, as which you need to use
UPC 2" drain is minimum. trap arm is 1 1/2 allowed

 

[bbstnr]

Gladstone, MO. Looks like we're IPC. http://www.gladstone.mo.us/CommunityDev/adoptedcodes.php

 

[frodo]

knocks me out of the box. i know nothing about that code.

 

[phishfood]

Florida, where I am at, uses IPC as well.

One word of caution, different areas can, and do, amend the code as they see fit.

Under FL style IPC, the tub trap arm can be 1 1/2", the lavatory (sink) drain can be 1 1/2", and can be the wet vent for the entire bathroom. The pipe leading to the intersection of the tub and the lavatory needs to be 2".

My personal opinion and preference is to run the lavatory drain in 2" so that the vent won't be choked off if you get some buildup on the pipe walls.

 

[Mr_David]

Could not save pictures from flicker. can only link to them. so I sniped them off my screen.

so the Tub never had a vent? It will drain better with a vent. Change that first 90 from tub to a 45.
can you run the vent through attic or ceiling to vent of toilet or just go right up through roof with it?

 

[Mr_David]

Okay now that that I can see the layout and the 2 pictures I see the difficulty in installing /rolling the tub vent up . I wasn't see it before.

Suggestion flip the tub around and make it a left hand tub. Move the water to the same side as the toilet.

Just a thought

 

[phishfood]

The tub can vent through the lav. Don't need to add an additional vent just for the tub.

 

[Mr_David]

The tub can vent through the lav. Don't need to add an additional vent just for the tub.

Okay. I won't argue with that. seeing is I know nothing of the IPC.
I myself am not an expert on code. My current code book is about 15 yrs old.
Wet venting is not allow here unless specifically approved by the Building dept..

Here's another 2 cents I would like to add. eliminate those 3 90's under the toilet flange with 1 - 45 and 1 - 90

 

[bbstnr]

I had actually already redone that. Yay me! (I think I'm understanding this water flowing thing...) One last question. Will that wye right after the toilet, effectively acting as a wet vent, and the vent after that, effect the flushing strength of the toilet? I had read that you don't want to vent closet branches because you need the suction to pull the water out of the bowl. I'm assuming it's fine since no one has said anything so far.

Ok I lied, one more question. On the tub arm, I'm not creating an S trap am I? I mean there's like 10" of horizontal pipe before it starts to drop to the drain. It then turns through the joist to start the fall. Is that enough to stop a "s trap siphon"?

My new plan is to run 1-1/2 on tub arm to where the tub meets lav. All of lav will be 2" to help with wet vent. tub and lav wye will be 2" down to a 3x3x2 wye connected to the main waste line. All sound good? (in picture it's currently 1-1/2 but I'll up it to 2")

 

[phishfood]

On an 1 1/2" trap arm, which is from the trap to the point where it connects to the vent, it can run no more than 5' and have no more than 1 1/4" inches of total fall.

 

[frodo]

i think he is under the impressinon. that from the wye junction of the lav and tub. he can run 1 1/2

ney ney..it is the trap ARM that can be 1 1/2.
from winced yo put in your vent wye. to the trap.

 

[bbstnr]

As I understand what phishfood has said, here is what I am saying.

from tub:
1-1/2 trap --- 1-1/2 arm to 2x2x1-1/2 wye (meeting the 2" wye acting as wet vent)

from lav:
2" vent up to stack, 2" down to 2x2x1-1/2 wye (acting as wet vent)

from 2x2x1-1/2 wye:
2" pipe to 3x3x2 to main waste stack.

I'm not going to downgrade pipe size at the wye if that's what you were asking.
Hopefully the drawing explains.

 

[frodo]

..........

 

[bbstnr]

The tub arm is right at 5', the sink arm is about 2'