Help with Plumbing Code for Full Bath

[frontporch]

thanks for your response and advice! Attaching to that horizontal stretch of 2” sink drain sure would be easier but I want to make sure I limit how many times I need to cut this plumbing

I could also use advice on venting up in the attic area. I will post a picture for that but I basically have an existing roof penetration that is above the shower drain. It’s a 2” pipe. I would need to have my 2” sink vent, 2” inch toilet vent and 1.5 shower vent meet up there and exit the roof. Will most likely be a maze of pipe but I get the basics of flipping the tees and wyes upside down (if that description works) and never letting the horizontal pitch the wrong way

Not sure if I need anything close to 1/4”/ft on horizontal vent pipe or if runs of diagonal pipe cause issues. By diagonal I mean if there was an inverted wye right below the roof line could I carry that 45 degree pipe for any diatance to avoid having it on the attic floor?

 

[frontporch]

This sketch shows the triangular attic space in a 3d and overhead view. Thee is a window in brown that limits a vent anywhere close. The existing roof penetration isn’t quite 10’ away but it’s on the other side of the roof ridge.

My initial thought was to run vents high to keep them off the attic floor for easier access but it seems wrong so I would try to limit bends and run close to the rafters

 

[MicEd69]

Oops, I answered before I thought in regard to your sketch. And I may have left you with the wrong idea when I said slope at 1/4" per foot. And I don't have a copy of the 2021 national standard plumbing code, so my answers are good for IPC and UPC, and I would expect the NSPC would be close.

For a vent line from a P-trap, it must be vertical or no less than 45 degrees off vertical until it reaches 6" above the flood plain of the fixture it is serving. Your sketch appears to indicate a 90-degree elbow at the top of the vertical, and that won't be per the codes to which I'm familiar. I think I see in the back of your picture the location of the vent line in the subfloor. It looks like you could use 45s to get to it, but that will probably drop your shower P-trap lower than it is now, and possibly lower than you like.

Now once you get above the aforementioned 6" above flood plain, the minimum slope of the dry vent is 1/4" per foot, but it can be at any angle over that. Any vent at a 45-degree slope of greater is consider vertical by the code.

All the vents can be combined into the 2" vent, but there is a provision that in colder climates the vent must be one size larger than the normal vent to prevent frost buildup. I'm not sure if New Jersy falls into that category or not.

 

[MicEd69]

This sketch shows the triangular attic space in a 3d and overhead view. Thee is a window in brown that limits a vent anywhere close. The existing roof penetration isn’t quite 10’ away but it’s on the other side of the roof ridge.

My initial thought was to run vents high to keep them off the attic floor for easier access but it seems wrong so I would try to limit bends and run close to the rafters

I think that looks good, provided the vents are sloped as required. And either way would be fine, off the floor or up higher in the attic.

 

[frontporch]

If I can route the 1.5 vent into my attic I can make the drain work and I appreciate you figuring out the sketches
I can bring the shower drain line further along the basement wall and have it turn down to vertical and meet the 3” sewer later where it is horizontal with the 3” wye with 1.5 1/8 bend In that setup the vent line would be pretty close to where it needs to go through the subfloor and the trap would still be high and provide more than enough headroom

 

[frontporch]

I have a good plan going forward and the advice here was a life saver. Thanks to all

 

[MrInfoPhilly]

I horizontal wet vent for this bathroom group would have eliminated a lot of the problems here

 

[frontporch]

Not sure I follow

 

[MrInfoPhilly]

Not gonna confuse you even more., but a horizontal wet vent., would have 1 main drain line., say the 3 inch from the toilet., upstream the sink and tub/shower tied into it., but one of those fixtures., say your tub has the vent that goes to the roof., so the toilet and the sink would be wet vented with the single vent being the dry vent from the shower...
It eliminates the need for running individual vent tie ins in a Single Bathroom Group.

 

[frontporch]

Ok. Confusing me is not an issue because I can only adjust from where I am now with a fix but there always might be a next time I put together something and understanding what would have been a better way isn’t a bad thing. When I get time I may follow up on your thought and try to draw it out