Bathroom Remodel DWV Plan

[RifRaf]

I am in the middle of a complete bathroom remodel and will be removing all of the old copper drain pipes (that hang below the floor joist) and replacing them with PVC DWV pipes and fittings (that will hang within the floor joist). Below is an image of the copper drain pipes I will be removing.

Long story short... the current DWV plumbing for this bathroom exists as shown in the attached plan, but without the vent pipe.
The attached bathroom plan is what I am proposing... with adding a vent pipe to the LAV.
My question is can the WC and Shower be wet vented by the LAV vent as shown?
I am located in Maryland and use the IPC Plumbing Code.

Thank you in advance!
Mike

 

[wwhitney]

Yes, you can wet vent like that. You don't need any 3" drains beyond the WC drain path, everything else can be 2". And the IPC would allow your lav drain and vent to be 1-1/2" rather than 2", if desired.

Just to be clear, the shower trap arm runs from the trap outlet to where the lav drain joins it, and the trap arm is limited to one pipe diameter fall.

Cheers, Wayne

 

[Sponsor]

 

[RifRaf]

Wayne, Thanks for the replay and suggestions!
What I may do is run a 2" drain line for the LAV drain and then 1 1/2" LAV vent pipe.

Is there any benefit to running a larger... or smaller branch drain pipe for the Shower and LAV (3" vs 2")?
I just thought the 3" drain pipe would be less prone to clogging (but I have no experience to back up this thought).

Just to be clear, the shower trap arm runs from the trap outlet to where the lav drain joins it, and the trap arm is limited to one pipe diameter fall.

Yes. The shower trap arm will make a 90° turn and then connect to the LAV drain pipe.
Yes. The trap arm distance for both the shower (6' trap arm) and the WC (4' trap) to the LAV wet vent is within the 8' limit for a 2" drain pipe.

Thanks again for all of your help!
P.S. The link you provided (up.codes) in one of my other posts has been an invaluable source of information!

 

[RifRaf]

I removed all of the copper drain pipes that were servicing this bathroom. I also removed the 3" copper pipe that was going into the cast iron hub leading to the septic tank (drilled out the lead and oakum).

I needed to increase the main drain pipe size from 3” to 4” to handle the DFU’s (drainage fixture units) for a basement bathroom ejector pump that will be installed in the future. Once I had the correct size Fernco donut in place, I hammered the 4” PVC pipe into the rubber donut within the cast iron hub and cemented the 4” PVC Sanitary Tee into place. Once the new SanTee was in place, I was able to reconnect the home's main drain pipe and complete the first section of the bathroom drain (toilet hub).

When I was happy with the placement of the PVC toilet hub, I cemented everything into place and drilled holes for the toilet hub into the last sections of subfloor that needed to be screwed into place.

I just thought I would check to see if everything looked okay.

 

[wwhitney]

A quick, not thorough comment: that unshielded rubber coupling is only for below ground use. Above ground you need a shielded rubber coupling such as Fernco Proflex or Mission Bandseal.

Cheers, Wayne

 

[Reach4]

With your hub to receive the glued closet flange, you will want things right the first time.

It is very hard to drill porcelain for the flange hold-down screws. The flange should have a stainless steel ring for long life. The ring should sit right atop the finished floor, rather than having the finished floor built around it.

 

[John Gayewski]

Why is the ejector tee so big? Also what do you have planned for that?

 

[RifRaf]

A quick, not thorough comment: that unshielded rubber coupling is only for below ground use. Above ground you need a shielded rubber coupling such as Fernco Proflex or Mission Bandseal.

Got it!... The 4" to 3" rubber coupling shown is only temporary since I still have a 3" main drain pipe running thru the house. Once this bathroom is complete, I plan to change this rubber coupling to a shielded 4" when I change over the remaining main drain pipe size from 3" to 4"... but to do so will require me to change some of the existing DWV fittings (other bathroom drain branch) to fit the 4" drain pipe. I did not want to have both bathrooms out of commission at the same time.

It is very hard to drill porcelain for the flange hold-down screws. The flange should have a stainless steel ring for long life. The ring should sit right atop the finished floor, rather than having the finished floor built around it.

Agreed! I plan to use a WC flange with a stainless steel ring. Below is a photo of the "mock-up" (flange is not glued... but temporarily installed within the WC hub to check level). The flange will be installed on top of the finished floor after the tile floor is installed. I will be using ceramic plank floor tiles, so they should be easier to drill than porcelain tiles.

Why is the ejector tee so big? Also what do you have planned for that?

I'm not sure I understand the question.... what "ejector tee" are you referring to?
Is that what the 4" PVC Sanitary Tee (that is now attached to the red cast iron hub) is called?

If so, I plan to install a basement bathroom in the future. A sump pit with an ejector pump that will be needed for this bathroom. The ejector pump I was planning to use flows at about 80 gpm. Based on my understanding of the code, I would need to calculate 2 dfu's for each gpm... so my drain line for the ejector pump would need to be appropriately sized to handle 160+ dfu's.
My existing 3" main drain line would only handle 42 dfu's (1/4" per foot slope)... but the future 4" main drain line that will be connected to the ejector pump discharge pipe will handle 216 dfu's (1/4" per foot slope). Please correct me if I an wrong with my understanding of the code.

 

[John Gayewski]

Got it!... The 4" to 3" rubber coupling shown is only temporary since I still have a 3" main drain pipe running thru the house. Once this bathroom is complete, I plan to change this rubber coupling to a shielded 4" when I change over the remaining main drain pipe size from 3" to 4"... but to do so will require me to change some of the existing DWV fittings (other bathroom drain branch) to fit the 4" drain pipe. I did not want to have both bathrooms out of commission at the same time.

Agreed! I plan to use a WC flange with a stainless steel ring. Below is a photo of the "mock-up" (flange is not glued... but temporarily installed within the WC hub to check level). The flange will be installed on top of the finished floor after the tile floor is installed. I will be using ceramic plank floor tiles, so they should be easier to drill than porcelain tiles.
View attachment 85180

I'm not sure I understand the question.... what "ejector tee" are you referring to?
Is that what the 4" PVC Sanitary Tee (that is now attached to the red cast iron hub) is called?

If so, I plan to install a basement bathroom in the future. A sump pit with an ejector pump that will be needed for this bathroom. The ejector pump I was planning to use flows at about 80 gpm. Based on my understanding of the code, I would need to calculate 2 dfu's for each gpm... so my drain line for the ejector pump would need to be appropriately sized to handle 160+ dfu's.
My existing 3" main drain line would only handle 42 dfu's (1/4" per foot slope)... but the future 4" main drain line that will be connected to the ejector pump discharge pipe will handle 216 dfu's (1/4" per foot slope). Please correct me if I an wrong with my understanding of the code.
View attachment 85181

So then you'd need a 4x2 tee. Not a 4x4.

Also a wye not a tee.

 

[RifRaf]

So then you'd need a 4x2 tee. Not a 4x4.

Also a wye not a tee.

Yes... agreed! The ejector pump discharge pipe will be 2" and run from the pump to a 4 x 2 Wye as shown in 712.3.5 below.

"Pumps connected to the drainage system shall connect to a building sewer, building drain, soil stack, waste stack or horizontal branch drain. Where the discharge line connects into horizontal drainage piping, the connection shall be made through a wye fitting into the top of the drainage piping and such wye fitting shall be located not less than 10 pipe diameters from the base of any soil stack, waste stack or fixture drain."

But the ejector pump and pit do not exist yet... I am just putting the correct pieces in place now for this future upgrade.

 

[John Gayewski]

So your running horizontally to get 10 pipe diameters away from the base of the stack and then entering the top of a 4x2 wye? That sounds good to me. I'd still prefer a wye into the stack vs a tee. Tees positioned like that can tend to draw waste horizontally into the branch from fixtures above. But it is legal.

 

[RifRaf]

I'd still prefer a wye into the stack vs a tee. Tees positioned like that can tend to draw waste horizontally into the branch from fixtures above. But it is legal.

The reason I went with the 4" SanTee vs a 4" Wye at the red cast iron hub is because I have about 30 feet of 4" drain pipe to run horizontally > starting at the red cast iron hub (shown in my photos above) and running along the basement wall over to the laundry room area (that is where the future ejector pump will be located). I have about 7 1/2" from the top of the PVC drain pipe (where it connects to the red cast iron hub) to the bottom of the floor joist. At a slope of 1/4" per foot, I have just enough room between the main drain pipe and the joist to maintain the 1/4" per foot slope for the 30 feet of drain pipe.

If I had used a wye + 45 degree bend at the cast iron hub, it would have positioned the horizontal drain pipe closer to the floor joist above... and I would not have been able to maintain the drain pipe slope of 1/4" per foot for the 30 feet of 4" drain pipe.

 

[John Gayewski]

The reason I went with the 4" SanTee vs a 4" Wye at the red cast iron hub is because I have about 30 feet of 4" drain pipe to run horizontally > starting at the red cast iron hub (shown in my photos above) and running along the basement wall over to the laundry room area (that is where the future ejector pump will be located). I have about 7 1/2" from the top of the PVC drain pipe (where it connects to the red cast iron hub) to the bottom of the floor joist. At a slope of 1/4" per foot, I have just enough room between the main drain pipe and the joist to maintain the 1/4" per foot slope for the 30 feet of drain pipe.

If I had used a wye + 45 degree bend at the cast iron hub, it would have positioned the horizontal drain pipe closer to the floor joist above... and I would not have been able to maintain the drain pipe slope of 1/4" per foot for the 30 feet of 4" drain pipe.

Why that much 4"?

 

[Jeff H Young]

I'd be concerned pumping waste into that santee that the toilet having no vent above may get either positive or negative pressure. either bubbling or sucking water out the bowl

 

[RifRaf]

Why that much 4"?

Because that is how far away the 2" discharge pipe of the ejector pump will be located.

Id be concerned pumping waste into that santee that the toilet having no vent above may get either positive or negative pressure. either bubbling or sucking water out the bowl

Thanks for pointing this out!
I am wet venting the the toilet thru a 2" lav drain pipe (see diagram in post #1). I just haven't completed that section of drain pipe/vent yet. There will also be a couple other vents located within the branch drains that connect to the 4" main drain.

 

[Jeff H Young]

Because that is how far away the 2" discharge pipe of the ejector pump will be located.

Thanks for pointing this out!
I am wet venting the the toilet thru a 2" lav drain pipe (see diagram in post #1). I just haven't completed that section of drain pipe/vent yet. There will also be a couple other vents located within the branch drains that connect to the 4" main drain.

picture in post#4 with PVC pipe going up with 90 and combi at toilet is not what you are doing? that appears to be a possible problem if pumping waste just my gut thinking since the vent is far below the toilet if water blasts into that tee it might be issue . why not put a heel out let 90 and vent off top revent into the lav I recommend the walls are open above?

 

[John Gayewski]

Because that is how far away the 2" discharge pipe of the ejector pump will be located.

Thanks for pointing this out!
I am wet venting the the toilet thru a 2" lav drain pipe (see diagram in post #1). I just haven't completed that section of drain pipe/vent yet. There will also be a couple other vents located within the branch drains that connect to the 4" main drain.

Why not run 2" all the way?

 

[RifRaf]

picture in post#4 with PVC pipe going up with 90 and combi at toilet is not what you are doing? that appears to be a possible problem if pumping waste just my gut thinking since the vent is far below the toilet if water blasts into that tee it might be issue . why not put a heel out let 90 and vent off top revent into the lav I recommend the walls are open above?

It would be very difficult for me to vent off of the 90 degree bend due to other structural obstacles that are present within the walls. I really don't think this is going to be a problem. I am just duplicating the drain pipe arrangement that was previously in place with the copper pipes (just changing over to PVC and increasing the 3" main drain to 4" main drain). When I had the copper drain pipes, we used another ejector pump that discharged into the 3" main drain pipe. The ejector pump never caused any bubbling/sucking water from this bathroom's toilet.

Why not run 2" all the way?

I don't understand the question.
Please remember that I am a DIY'er... and sometimes have trouble understanding common terms/references that may be used by professional plumbers.

As always, I appreciate all of the feedback!

 

[Jeff H Young]

Rifraf, The copper was plumbed much different as you can see it would vent much better , but if you think it will act the same (and it may) then go for it . good luck with project!

 

[John Gayewski]

It would be very difficult for me to vent off of the 90 degree bend due to other structural obstacles that are present within the walls. I really don't think this is going to be a problem. I am just duplicating the drain pipe arrangement that was previously in place with the copper pipes (just changing over to PVC and increasing the 3" main drain to 4" main drain). When I had the copper drain pipes, we used another ejector pump that discharged into the 3" main drain pipe. The ejector pump never caused any bubbling/sucking water from this bathroom's toilet.

I don't understand the question.
Please remember that I am a DIY'er... and sometimes have trouble understanding common terms/references that may be used by professional plumbers.

As always, I appreciate all of the feedback!

Why don't you run 2" pipe from the ejector (I assume it's 2" since that's all it would need to be) into your tee? Not directly into the tee since you need to be 10 pipe diameters away from the base of the stack, but you don't need slope (although it's nice) on a pressurized line. Then your not running all of that 4" over to the pump, but running the pump over to the 4" so to speak.