Shower venting help

[AmgAddison]

Hello everyone, trying to figure out the last fixture in new bathroom, the shower. Planning on using 2 inch pipe. Trap arm is only about 4 inches to main drain pipe. Was originally planning to wet vent it with the sink but not enough room for a rolled wye fitting. To run it towards wall to dry vent would require a significant notch on top of a joists. Was looking for insight on how to proceed, or if shower even needs its own vent since there is 2 other vents. Any help is greatly appreciated.

Addison

 

[AmgAddison]

bump

 

[user 32496]

Here's what the IPC's, "Methods of venting plumbing fixtures and traps in the 2021,"says.

Wet venting​

A fixture is said to be wet vented when it serves also to carry the discharge from fixtures connecting into the drainage system at a higher level. The use of wet venting reduces the number of individual vent pipes required by a plumbing drainage system as contrasted with the number required by a conventional system and hence reducing the cost of the venting system. There are many types of venting schemes and methods allowed in the IPC. The Horizontal Wet Venting method located in Section 912.1 of the IPC is one that we will discuss first.


What is a horizontal wet vent? A horizontal wet vent is a horizontal branch drain pipe that has been increased in size larger than what is normally required by Section 710. This increase in pipe size allows for a large air space above the maximum probable waste flow level in the pipe so as to provide for adequate venting airflow in the same pipe as the waste flow. Wet Venting as shown in Figure 8 can be used in both vertical and horizontal applications.





Your drawing doesn't specify the size of the main drain. Can we assume it's a 3" pipe?

Your wye's only need to be rolled to a 45 if they are a dry vent.

Are you IPC or UPC?

 

[AmgAddison]

Here's what the IPC's, "Methods of venting plumbing fixtures and traps in the 2021,"says.

Wet venting​

A fixture is said to be wet vented when it serves also to carry the discharge from fixtures connecting into the drainage system at a higher level. The use of wet venting reduces the number of individual vent pipes required by a plumbing drainage system as contrasted with the number required by a conventional system and hence reducing the cost of the venting system. There are many types of venting schemes and methods allowed in the IPC. The Horizontal Wet Venting method located in Section 912.1 of the IPC is one that we will discuss first.

View attachment 43086
What is a horizontal wet vent? A horizontal wet vent is a horizontal branch drain pipe that has been increased in size larger than what is normally required by Section 710. This increase in pipe size allows for a large air space above the maximum probable waste flow level in the pipe so as to provide for adequate venting airflow in the same pipe as the waste flow. Wet Venting as shown in Figure 8 can be used in both vertical and horizontal applications.



View attachment 43087

Your drawing doesn't specify the size of the main drain. Can we assume it's a 3" pipe?

Your wye's only need to be rolled to a 45 if they are a dry vent.

Are you IPC or UPC?

Thank you for your response, has been difficult getting any insight on here besides from one other person. Have been working on plumbing in this bathroom for 2 months trying to do it properly. Main drain is infact 3 inch. I am located in Pennsylvania. Here is my tub drain wet venting toilet, I need to change vent wye to 2inch and continue in 2 inch and tie into toilet drain with a wye+45 I believe?. I believe I figured out shower situation. Here is rough in on it. Runs over to wall were wye+45 will vent straight up. then tie into main drain with a wye+45. let me know your thoughts.

 

[MicEd69]

 

[AmgAddison]

View attachment 43099

thats not good, as I drilled joist already. I dropped down to get into cent of the joist. not sure what I can do now

 

[AmgAddison]

I can just do away with the 45s but would be quite a slope down and my top of p-trap would not be level

 

[MicEd69]

Can you do this and still hit your hole?

 

[MicEd69]

 

[MicEd69]

There are low profile P-traps that may help you fit your shower drain into your limited space and still maintain the proper 1/4" per foot slope.

 

[AmgAddison]

View attachment 43101

clever idea, I'm heading back there now I will check if this will work

 

[AmgAddison]

There are low profile P-traps that may help you fit your shower drain into your limited space and still maintain the proper 1/4" per foot slope.

San tee is a no go. Just went to grab a low profile trap and couldn't find one so going to have to order it but seems like that may solve the issue. Another question, I'm tieing shower in at end of the waste line, should I use a wye fitting and plug one end of it or should I use 2 90s to go up from waste pipe and toward shower. Thanks

 

[AmgAddison]

Forgot to also add, p trap and shower lines are 2 inch.

 

[AmgAddison]

got it to about half inch slope? is that ok?

 

[MicEd69]

The slope should be 1/4" per foot of length, so I'm not sure what your 1/2" is referring to.

With a low profile 2" P-trap, you may be able to use a wye and 45 for the vent and a 90 to go through your hole in the joist.

 

[Twowaxhack]

The slope should be 1/4" per foot of length, so I'm not sure what your 1/2" is referring to.

With a low profile 2" P-trap, you may be able to use a wye and 45 for the vent and a 90 to go through your hole in the joist.

View attachment 43107

The vertical combination fitting in the illustration shown is backwards

 

[MicEd69]

The vertical combination fitting in the illustration shown is backwards

Oops. I was trying to make his layout workable and meet his existing hole in the joist. I don't even know if those fitting will fit.

But even though that wye is reversed and not per code, would that layout work acceptably in your opinion?

 

[Twowaxhack]

Oops. I was trying to make his layout workable and meet his existing hole in the joist. I don't even know if those fitting will fit.

But even though that wye is reversed and not per code, would that layout work acceptably in your opinion?

It would work but the fitting is backwards. Backwards fittings sometimes make your drain cleaning cable end up in some weird places. Not good

We had one job where we had the cable going down the roof vent. The cable came up through the toilet because of a backwards fitting. Broke the toilet and proceeded to thrash the drywall, vanity, broke the mirror, ruined the door and broke a shower door before we found it.

5k worth of damage in 30 seconds

 

[AmgAddison]

The slope should be 1/4" per foot of length, so I'm not sure what your 1/2" is referring to.

With a low profile 2" P-trap, you may be able to use a wye and 45 for the vent and a 90 to go through your hole in the joist.

View attachment 43107

I cleared out some lathe and plaster under p trap, if I bore hole in joist out toward top of joist a little bit more, I should be able to reduce slope a little more to get 1/4 slope. as it sits now the slope is 1/2

 

[MicEd69]

A 1/2" per foot slope will be fine if you vent the P-trap before you drop the line with those 45s.

As I mentioned above, the wye in my sketch was backwards as I was trying to maintain your layout and the hole in your joist. But as Twowaxhack pointed out, that can cause issues with snaking the line in the event of a blockage.

The following is another approach that will meet IPC code, depending on the inspector's interpretation. But again, I'm not sure the fittings will meet your current dimensional requirements. And using a Sanitary tee on its back is not the choice of many plumbers.