Bathroom drain and wet vent.

[ScottGS38098]

Good day.
Attached are 2 drawings of my master bathroom. Originally there was a lavatory, water closet, shower stall and a tub occupying each corner of the space. I decided to enlarge the shower and remove the tub. The drains and vent would basically stay as is with the exception of removing the wye and trap that served the tub and reconnecting the 2" vent. I don't have a warm fuzzy feeling that it is correct though. I'm thinking I just extended the length of the dry vent to the shower drain and it's running horizontal in the floor about 24" thus violating some code article. There will be a new knee wall between the toilet and shower perpendicular to the back wall. I could utilize that to get a vent up for shower and toilet. I could also get a 1-1/2" vent up for the sink. I'm just not sure that I need to if this or a slight alteration to this would work and satisfy code. Thanks in advance for any advice or help.

Scott S.
Collegeville PA

 

[Stuff]

Your lav has an S trap but might be allowed as PA is IPC that allows "combined waste and vent system." Best practice though is to provide a vent for the lav to prevent toilet from siphoning the lav's S trap.

You are right to be concerned about the 24" horizontal dry vent as it is not per code (can get clogged). Taking the shower drain under the new knee wall for a vent would be good.

 

[Sponsor]

 

[ScottGS38098]

Your lav has an S trap but might be allowed as PA is IPC that allows "combined waste and vent system." Best practice though is to provide a vent for the lav to prevent toilet from siphoning the lav's S trap.

You are right to be concerned about the 24" horizontal dry vent as it is not per code (can get clogged). Taking the shower drain under the new knee wall for a vent would be good.

I wasn't aware that was an S trap. The house is 25 years old but I'm finding many bs "shortcuts" in all facets of the builders installation methods. Anyway back to my drains and vents. I planned on moving the waste and cw/hw lines into the wall behind the vanity (currently coming through floor) so running a new dry vent up to the attic and over to existing vent isnt a big deal. The shower drain and vent was removed to rework it for a new base location. I guess my next questions are should I add a vent for the water closet and connect it and the shower vent together and size it for the toilet? And is there any harm or advantage if I leave the existing vent (now in violation) connected under the floor where the shower drain ties in via a wye or just 90 the shower drain and remove vent and use the material elsewhere?

 

[Stuff]

The water lines coming through the floor is done when it is an outside wall that can freeze.
You don't need a separate vent for the water closet as the shower's new vent will suffice (a wet vent).
Remove the old vent.

 

[Reach4]

I wasn't aware that was an S trap.

Any chance you could move the lavatory over to where the tub was? Putting a santee fed by a lavatory would make that 2 inch down and across into an allowed wet vent.

Does the drain from the existing lavatory go into the wall, or does the drain go through the floor. If it goes into the wall, there might be a vent that you just haven't seen yet.

 

[ScottGS38098]

The water lines coming through the floor is done when it is an outside wall that can freeze.
You don't need a separate vent for the water closet as the shower's new vent will suffice (a wet vent).
Remove the old vent.

Thanks! I understand about coming through floor on exterior wall with lines. This wall however is interior partition wall with the door that leads to my bedroom. I assume that there were probably timing issues during rough in that prohibited putting them in the wall. Or laziness.

I'm sure that I have enough knowledge now to make it right thanks to this site.

 

[ScottGS38098]

Any chance you could move the lavatory over to where the tub was? Putting a santee fed by a lavatory would make that 2 inch down and across into an allowed wet vent.

I can and that is one of the things I was considering. I am limited to 30 inches where it is now because of the the door and exterior wall. See pic.

 

[Reach4]

To keep the lav where it is, add an AAV. There are various examples of how to do that under a lavatory.

One thing I would do differently is to use a slip, rather than glued, trap.

Moving the lavatory to where the tub was makes this problem go away. For the shower , you could run the trap arm from the shower to a vent at the wall, and then come back toward the shower. I am thinking you wanted to avoid moving the trap arm of the shower. Moving the lavatory to where the tub was makes this problem go away.

 

[ScottGS38098]

Any chance you could move the lavatory over to where the tub was? Putting a santee fed by a lavatory would make that 2 inch down and across into an allowed wet vent.

Does the drain from the existing lavatory go into the wall, or does the drain go through the floor. If it goes into the wall, there might be a vent that you just haven't seen yet.

Would moving the water closet to where tub was achieve the same outcome? I recall reading that the toilet shall be the furthest downstream fixture on a wet vent. If that's the case than that would put it first. That aside I could still move it and use the vent as a dry and still properly dry vent the other 2 fixtures.

 

[Reach4]

Would moving the water closet to where tub was achieve the same outcome? I recall reading that the toilet shall be the furthest downstream fixture on a wet vent. If that's the case than that would put it first. That aside I could still move it and use the vent as a dry and still properly dry vent the other 2 fixtures.

No help I think. IPC venting of a bathroom group is more flexible than UPC, but you still need something vented with a dry vent. Usually that would be the lavatory, and then that drain becomes a wet vent to vent other stuff in the bathroom group. https://wabo.memberclicks.net/assets/pdfs/Plumbing_Venting_Brochure_2018.pdf

 

[ScottGS38098]

No help I think. IPC venting of a bathroom group is more flexible than UPC, but you still need something vented with a dry vent. Usually that would be the lavatory, and then that drain becomes a wet vent to vent other stuff in the bathroom group. https://wabo.memberclicks.net/assets/pdfs/Plumbing_Venting_Brochure_2018.pdf

I understand. Although I did purchase the vanity and top (before this project expanded to where it is now) to fit the 30 inch space I still may move it to where the tub was. That way I have a proper wet vent for the shower and toilet again and I have more flexibility to purchase a larger vanity at a later date if I choose. The more I think about it the closer I get to convincing myself that's the direction I should go.

 

[Reach4]

Run the lavatory drain all in 2 inch. Use a long sweep elbow where you transition from vertical to horizontal. A 2 inch cleanout over or under the 2 inch santee would be a good idea.