DWV Venting for new home

[bobdeec2]

I am designing and building a new home. Attached is the underground/ below slab plumbing plan. In the master bath I believe the toilet vent would also work as a wet vent for the remaining fixtures in the bath, but not sure. I am hoping that some of the more experience members here could chime in and let me know if everything below the slab looks ok?

All Tee's to the main line will be combo fittings.

I have been referencing the UPC Tables 702.1 and 703.2 for sizing and vent lengths.

 

[Jeff H Young]

Ill point out a few things but tell you first horrizontal wet venting is my weak point but issues with UPC code starting at end of line w/c in master my concerns are 1 end of line cleanout, 2 what apears to be a flat vent for w/c below slab 3 floor drain venting now moving downstream at laundry and powder room 4 floor drain vent 5 w/c vent (id put a 3x3x2 combi to vent w/c) 5 floor drain in mech room change to 2 inch with 2x2x1 1/2 combi venting in that wall on way to the drain 6 vent and cleanout at kitchen sink

 

[Sponsor]

 

[bobdeec2]

See attached, I believe I addressed most of the issues. I am not sure how to put an end of line cleanout at the toilet since I can not get into the exterior walls because their poured concrete. Will a cleanout on the 2" vent work or upsize it to 3" until the cleanout and vent with 2".

 

[wwhitney]

Comments, starting from the upstream end (primary bathroom):

- Keeping the building drain straight with no bends may look good on paper, but there's not a big upside. You could use a couple 22.5s or 45s to jog as required to make things easier or fix any issues.

- Kentucky has its own plumbing code which I have not perused. So I will give you both IPC and UPC based comments.

- For the primary WC vent take off, "rotated greater than 45 degrees" should be at least 45 degrees above horizontal, which is probably what you mean, it's just not clear.

- Upsizing that vent takeoff to 3" and bring 3" up to a cleanout in the wall would be a good practice at least (maybe required, cleanouts aren't my thing); the vent above the cleanout could 2" for UPC, 1.5" for IPC.

- Under the UPC, the vented WC can't wet vent any downstream fixtures, so you'd need to figure out alternate venting for the tub and the shower. Under the IPC, it's fine to use the vented WC for wet venting.

- The length of the lower lav drain is immaterial, even if you are using it for wet venting. What is limited is the trap arm, the distance from a fixture trap to the wet vent (the drain also serving as a vent), not the length of the wet vent itself.

- Both lavs will need dry vents, or for the IPC, AAVs.

- The shower trap arm needs to fall at most one trap diameter, or at most 2". So where its fixture drain joins the branch drain that is wet venting it, the combo would need to be horizontal, not rotated much at all.

- A wet vent like you plan can't carry the washing machine drainage. If you conceptually deleted the washing machine, then the two sinks could share a single stack that is a vent above, a drain below, and that drain could wet vent the WC. If you want to do that, you'd need to keep the washing machine drain (which requires its own vent, although that vent could join the stack at an elevation at least 6" above all the flood rims) separate and only just the WC drain downstream of where the lav drain stack joins it.

- You should check if your floor drain(s) require trap primers. Venting rules for floor drains are fairly forgiving, so I think what you show is fine.

Cheers, Wayne

 

[Jeff H Young]

t he little powder room and laundry area I mentioned to fix your original drawing to add a 3x3x2 combi to vent the toilet but didnt mention to eliminate the stack you had for the washing machine you need that you could wet vent the lav at the w/c vent or use w/m stack . your code might allow only 1 1/2 inch vents on toilets

 

[bobdeec2]

Comments, starting from the upstream end (primary bathroom):

- Keeping the building drain straight with no bends may look good on paper, but there's not a big upside. You could use a couple 22.5s or 45s to jog as required to make things easier or fix any issues.

- Kentucky has its own plumbing code which I have not perused. So I will give you both IPC and UPC based comments.

- For the primary WC vent take off, "rotated greater than 45 degrees" should be at least 45 degrees above horizontal, which is probably what you mean, it's just not clear.

- Upsizing that vent takeoff to 3" and bring 3" up to a cleanout in the wall would be a good practice at least (maybe required, cleanouts aren't my thing); the vent above the cleanout could 2" for UPC, 1.5" for IPC.

- Under the UPC, the vented WC can't wet vent any downstream fixtures, so you'd need to figure out alternate venting for the tub and the shower. Under the IPC, it's fine to use the vented WC for wet venting.

- The length of the lower lav drain is immaterial, even if you are using it for wet venting. What is limited is the trap arm, the distance from a fixture trap to the wet vent (the drain also serving as a vent), not the length of the wet vent itself.

- Both lavs will need dry vents, or for the IPC, AAVs.

- The shower trap arm needs to fall at most one trap diameter, or at most 2". So where its fixture drain joins the branch drain that is wet venting it, the combo would need to be horizontal, not rotated much at all.

- A wet vent like you plan can't carry the washing machine drainage. If you conceptually deleted the washing machine, then the two sinks could share a single stack that is a vent above, a drain below, and that drain could wet vent the WC. If you want to do that, you'd need to keep the washing machine drain (which requires its own vent, although that vent could join the stack at an elevation at least 6" above all the flood rims) separate and only just the WC drain downstream of where the lav drain stack joins it.

- You should check if your floor drain(s) require trap primers. Venting rules for floor drains are fairly forgiving, so I think what you show is fine.

Cheers, Wayne

Yes, KY does have its own code, but I'm exempt from it. All I really care about its that it all drains out without clogging and without it gargling. If one code or the other allows it, its good enough for me.

45 degrees above horizontal is what I was attempting to state

I really wasn't concerned with an end of line cleanout because in the rare event of needing access, I could just remove the toilet. I will add the cleanout. I will give some more thought on upsizing to 3".

I will plan to wet vent the shower. Isn't the tub vented through its own fixture, or are standalone tubs different?

I was confused on this. If I understand this correctly now, the trap would have to be below the slap for this to work.

Updated to vent through roof

Noted

I updated the drawing. Please take another look at it and see if it will work now.

I don't know anything about trap primers, I will have to look into them more. I planned to add some cooking oil to the trap. Hopefully the floor drain will never be used.

Bobby

 

[bobdeec2]

t he little powder room and laundry area I mentioned to fix your original drawing to add a 3x3x2 combi to vent the toilet but didnt mention to eliminate the stack you had for the washing machine you need that you could wet vent the lav at the w/c vent or use w/m stack . your code might allow only 1 1/2 inch vents on toilets

I think I addressed your concerns in the attachment above. I have already bought most of my supplies in 2", but if something changes, I will keep that in mind.

 

[Jeff H Young]

That looks good I was thinking of the toilet to branch off upstream of the lav but However it lays out in the field . dont forget your vent for the floor drain in the laundry room

 

[wwhitney]

45 degrees above horizontal is what I was attempting to state

OK, but not just the takeoff has to be 45 degrees above horizontal, all of the vent from the takeoff to the wall where it turns vertical needs to be at least 45 degrees above horizontal. Reroute the 3" WC drain if required to achieve this with a reasonable depth.

I will plan to wet vent the shower. Isn't the tub vented through its own fixture, or are standalone tubs different?

No, tub traps are never vented via the tub overflow. A vent for a trap is connected downstream of the trap; the tub overflow is connected upstream of the trap.

Noted

Not noted on your drawing, so let me reiterate: to wet vent the shower and the tub, the total fall from each trap outlet to the combo where the fixture drain connects to the 3" branch drain is limited to one trap diameter. So typically the combo is only rolled up 2% above horizontal, the minimum slope allowed. Rolling it up more just eats into your limited fall allowance of 1-1/2" or 2".

Cheers, Wayne

 

[Jeff H Young]

I never saw where omitting vents on floor drains was a forgiving issue , that might be IPC but as far as I know floor drains in laundry and mechanical rooms would require verticle vents

 

[bobdeec2]

OK, but not just the takeoff has to be 45 degrees above horizontal, all of the vent from the takeoff to the wall where it turns vertical needs to be at least 45 degrees above horizontal. Reroute the 3" WC drain if required to achieve this with a reasonable depth.

I added a note.

Not noted on your drawing, so let me reiterate: to wet vent the shower and the tub, the total fall from each trap outlet to the combo where the fixture drain connects to the 3" branch drain is limited to one trap diameter. So typically the combo is only rolled up 2% above horizontal, the minimum slope allowed. Rolling it up more just eats into your limited fall allowance of 1-1/2" or 2".

It was more of a mental note but added it to the drawing.

 

[bobdeec2]

Thanks for all the help Wayne and Jeff.

 

[Jeff H Young]

Your welcome , glanced back through and see you were looking to basicaly comply to good practices and if it technically didnt meet one code but was clear in another then youll just choose by convieniance. so trap primers and 2 inch vents can probebly be skipped.