DWV layout new construction- will this work?

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Schibig87

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Hello All,

Please see attached and below explanation as to whether this DWV layout will work or do I need to make changes?

Washing machine would be main vent thru roof for whole house

Soaking tub & shower would wet vent to lav-
lav vents to WC
WC vent runs over to wash machine vent to roof

Kitchen vents to washing machine vent.

I choose to come straight from septic then 90 due to floor joist and supports layout.
Hope this makes sense. if you need distances I can add them as well.
We use UPC in this county
As always thank you for your help :)
 

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wwhitney

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1) The kitchen sink drain needs to be 2" starting at the san-tee.
2) For the kitchen sink san-tee to be under the window, the window has to be high enough so that the vent can rise to 6" above the sink flood rim before it turns horizontal. If the window is too low to allow that, move the sink san-tee just to the side of the window.
3) If this is the only house on the property, then the vent through the roof needs to be 3", or 3 separate penetrations, minimum two 2" and one 1-1/2".
4) If you'd like the lav to wet vent the WC, the lav needs a 2" dry vent.
5) The bathroom wet venting order is not correct. The fixture order starting at the lav has to be lav - 2" drain - wye for fixture 1 only - wye for fixture 2 only - wye for fixture 3 only. As WA has amended the UPC, the tub, shower, and WC can be in any order (in the unamended UPC the WC has to be fixture 3). If the WC is fixture 3, then between wye 2 and wye 3 you need a 3" drain.
6) With wet venting, the trap arm for each of the tub and shower are measured from the trap outlet along the pipe run to the wye where the trap arm joins the lav. If both traps are 2", then they each are limited to 2" of fall and 60" of length.
7) From the WC closet flange, measured along the drain horizontally and vertically, the wye where it connects to the lav drain to be wet vented is limited to 72".
8) If you can't make one of those limits on trap arm / fixture drain length, then you can individually dry vent that fixture, e.g. the way you are showing the WC dry vented. That dry vent takeoff would need to be via a combo with the barrel horizontal.

Cheers, Wayne
 

Jeff H Young

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Id probebly bring a 3 inch stack up at the lav and maybe a seperate vent at kitchen looking at the floor plan . personally like the single stack.
 

Schibig87

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1) The kitchen sink drain needs to be 2" starting at the san-tee.
2) For the kitchen sink san-tee to be under the window, the window has to be high enough so that the vent can rise to 6" above the sink flood rim before it turns horizontal. If the window is too low to allow that, move the sink san-tee just to the side of the window.
3) If this is the only house on the property, then the vent through the roof needs to be 3", or 3 separate penetrations, minimum two 2" and one 1-1/2".
4) If you'd like the lav to wet vent the WC, the lav needs a 2" dry vent.
5) The bathroom wet venting order is not correct. The fixture order starting at the lav has to be lav - 2" drain - wye for fixture 1 only - wye for fixture 2 only - wye for fixture 3 only. As WA has amended the UPC, the tub, shower, and WC can be in any order (in the unamended UPC the WC has to be fixture 3). If the WC is fixture 3, then between wye 2 and wye 3 you need a 3" drain.
6) With wet venting, the trap arm for each of the tub and shower are measured from the trap outlet along the pipe run to the wye where the trap arm joins the lav. If both traps are 2", then they each are limited to 2" of fall and 60" of length.
7) From the WC closet flange, measured along the drain horizontally and vertically, the wye where it connects to the lav drain to be wet vented is limited to 72".
8) If you can't make one of those limits on trap arm / fixture drain length, then you can individually dry vent that fixture, e.g. the way you are showing the WC dry vented. That dry vent takeoff would need to be via a combo with the barrel horizontal.

Cheers, Wayne
Hi - I really appreciate your help-I spent the better part of the week pondering this situation.
I have included a new drawing with distances between fixtures, joist & support direction including depth in hopes of showing my layout a bit more accurate.
The Laundry wall behind washer is 2 x 6. The bath wall behind toilet & lav is 2 x 4.
I plan to run all horizontal vents in the attic to the stack to avoid drilling across studs.
My thoughts are below

) The kitchen sink drain needs to be 2" starting at the san-tee.-Understood
2) For the kitchen sink san-tee to be under the window, the window has to be high enough so that the vent can rise to 6" above the sink flood rim before it turns horizontal. If the window is too low to allow that, move the sink san-tee just to the side of the window. The window is not high enough and the dishwasher will sit directly next to it on the right. The main 3" drain out to septic is directly below the left of window. I would need to go left in order to fit the Dishwasher- Would I need to adjust the main waste stack? Could I still run the vent over to the Laundry stack?
or could I configure it like an island sink?

3) If this is the only house on the property, then the vent through the roof needs to be 3", or 3 separate penetrations, minimum two 2" and one 1-1/2". This is an ADU 3 acres across from main home. I could do 3" for laundry.
4) If you'd like the lav to wet vent the WC, the lav needs a 2" dry vent.
I set to 2' to 6" above FR then back to 1 1/2 for horizontal run to Laundry stack. Should I have left all 2"? Can I run to ;laundry vent- approx 3 1/2 feet over?
5) The bathroom wet venting order is not correct. The fixture order starting at the lav has to be lav - 2" drain - wye for fixture 1 only - wye for fixture 2 only - wye for fixture 3 only. As WA has amended the UPC, the tub, shower, and WC can be in any order (in the unamended UPC the WC has to be fixture 3). If the WC is fixture 3, then between wye 2 and wye 3 you need a 3" drain.
I wet vented Toilet to Lav- rest below in #6 & 8
6) With wet venting, the trap arm for each of the tub and shower are measured from the trap outlet along the pipe run to the wye where the trap arm joins the lav. If both traps are 2", then they each are limited to 2" of fall and 60" of length.
The tub drain would exceed the allowed length by a foot or more.
7) From the WC closet flange, measured along the drain horizontally and vertically, the wye where it connects to the lav drain to be wet vented is limited to 72". I am good here.
8) If you can't make one of those limits on trap arm / fixture drain length, then you can individually dry vent that fixture, e.g. the way you are showing the WC dry vented. That dry vent takeoff would need to be via a combo with the barrel horizontal.
Nixed that and decided to utilize the 2 x 6 back wall to vent the tub and ran the shower vent to it. the shower drain catches the tub drain then to main stack. Would this work since both are vented?
Hoping I didn't overthink/complicate and go the wrong direction from the original layout.
If I did and there is an easier way- bear with me- takes me a few tries to orient. ;):)


Cheers, Wayne
Best, Patty
 

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wwhitney

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2) The usual configuration when the window is too low for the kitchen sink vent to rise up to at least 6" above the flood rim level before turning horizontal is to put the san-tee for the kitchen sink just outside the king stud for the window. Then the drain goes straight down and the vent goes straight up. The kitchen sink trap arm (which is 1-1/2") gets drilled through the studs (behind the dishwasher in your case, if you put it on that side) until it reaches a point where it can emerges into the kitchen sink cabinet, via either a LT90 or a 45. Note that the trap arm, which extends from the trap outlet to the san-tee and includes the pipe in the kitchen sink cabinet, is limited to 42" in length. Use stud shoes to reinforce the drilled studs, e.g. Simpson's HSS2 line, https://www.strongtie.com/miscellaneousconnectors_woodconnectors/hss_studshoe/p/hss

3) I don't follow your description of "3 acres across". The code section in question is UPC 904.1 https://up.codes/viewer/washington/upc-2021/chapter/9/vents#904.1 So you either need a minimum of a 3" vent through the roof (or the equivalent area, (2) 2" plus a 1-1/2"), or you need to use the exception. For that, you need to determine the minimum common building sewer size for both buildings (count DFUs and WCs); if it's 3" and the main house complies with 904.1 by having a 3" vent (or equivalent area), they your ADU satisfies the exception. Likewise if it's 4" and the main house has a 4" vent (or equivalent area).

But if the minimum common building sewer size is 4", and the main house has a 3" vent (or equivalent area), then a single 2" vent through the roof at the ADU will not satisfy the exception. You'd need a 3" vent through the roof, or (2) 2" vents, or a 2" plus (2) 1-1/2" vents. I.e. in this case the exception doesn't buy you very much over just complying with 904.1 directly.

4) The WC needs a vent path from its vent connection (wet vent via the lav drain) to the roof that is 2" minimum throughout.

8) The way you've drawn the tub trap vent takeoff isn't actually possible--you can't replace the elbow portion of the p-trap with a san-tee for the vent-takeoff. The vent takeoff would need to be a horizontal combo (could be 2x2x1-1/2) with at least a short section (could just be an inch or two) of pipe between the p-trap outlet and the horizontal combo.

But if you do that, and if the tub vent rises vertically (which includes up to 45 degrees off plumb) to at least 6" above the tub flood rim before going horizontal (less than 45 degrees off plumb), then the tub is properly dry vented. And if the shower trap arm, from the shower trap outlet to the wye where the tub fixture drain joins it, is under 60" in length and 2" in total fall, then the shower is properly wet vented by the tub.

9) (New) The laundry sink and the washing machine standpipe each need their own dry vent takeoffs. The two dry vents can be 1-1/2" and combine to a single 1-1/2" vent at an elevation at least 6" above both fixture flood rims.

[It is actually possible to vent both fixtures via a single vent takeoff if you use circuit venting; that would require that both trap outlets be at basically the same elevation, and that you have a horizontal drain connecting them at that elevation, with the vent takeoff in between the two fixture connections. That's probably more trouble that it is worth barring some unusual circumstance.]

Cheers, Wayne
 

Schibig87

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Thank you for your reply. I was busy doing my wiring rough and I passed!
So back to plumbing...

1) The usual configuration when the window is too low for the kitchen sink vent to rise up to at least 6" above the flood rim level before turning horizontal is to put the san-tee for the kitchen sink just outside the king stud for the window. Then the drain goes straight down and the vent goes straight up. The kitchen sink trap arm (which is 1-1/2") gets drilled through the studs (behind the dishwasher in your case, if you put it on that side) until it reaches a point where it can emerges into the kitchen sink cabinet, via either a LT90 or a 45. Note that the trap arm, which extends from the trap outlet to the san-tee and includes the pipe in the kitchen sink cabinet, is limited to 42" in length. Use stud shoes to reinforce the drilled studs, e.g. Simpson's HSS2 line, https://www.strongtie.com/miscellaneousconnectors_woodconnectors/hss_studshoe/p/hss
Thank you for this I finally understand what you are saying. Found a couple illustrations to help me as well.
And the stud shoes I really appreciate. Helped remedy some worry


3) I don't follow your description of "3 acres across". The code section in question is UPC 904.1 https://up.codes/viewer/washington/upc-2021/chapter/9/vents#904.1 So you either need a minimum of a 3" vent through the roof (or the equivalent area, (2) 2" plus a 1-1/2"), or you need to use the exception. For that, you need to determine the minimum common building sewer size for both buildings (count DFUs and WCs); if it's 3" and the main house complies with 904.1 by having a 3" vent (or equivalent area), they your ADU satisfies the exception. Likewise if it's 4" and the main house has a 4" vent (or equivalent area).
I went a little too literal here. This is an ADU on the same 10 acre parcel as the main home and on a separate well & septic.
It will require the 3". That said- I am really fixated on tying into the one 3" vent stack. Not sure why, feels easier in my mind
My dilemma is whether to use the laundry wall because it is 2 x 6 or the bath wall which is only 2 x 4.
Can a 3" stack fit in a 2 x 4 wall and meet UPC? or do you go 2" to top of sill plate (attic area) from Lav or toilet and expand to 3" to tie in the rest of the dry vents and then VTR


But if the minimum common building sewer size is 4", and the main house has a 3" vent (or equivalent area), then a single 2" vent through the roof at the ADU will not satisfy the exception. You'd need a 3" vent through the roof, or (2) 2" vents, or a 2" plus (2) 1-1/2" vents. I.e. in this case the exception doesn't buy you very much over just complying with 904.1 directly.

4) The WC needs a vent path from its vent connection (wet vent via the lav drain) to the roof that is 2" minimum throughout.
I think I fixed this in new drawing
8) The way you've drawn the tub trap vent takeoff isn't actually possible--you can't replace the elbow portion of the p-trap with a san-tee for the vent-takeoff. The vent takeoff would need to be a horizontal combo (could be 2x2x1-1/2) with at least a short section (could just be an inch or two) of pipe between the p-trap outlet and the horizontal combo.
Yes I totally botched this one and my drawings aren't exactly easy to read.
I was trying to figure out how to utilize the exterior wall directly behind the tub to run a 1 1/2 vent either VTR or across to the main vent stack when the main drain line is in the opposite direction.

But if you do that, and if the tub vent rises vertically (which includes up to 45 degrees off plumb) to at least 6" above the tub flood rim before going horizontal (less than 45 degrees off plumb), then the tub is properly dry vented. And if the shower trap arm, from the shower trap outlet to the wye where the tub fixture drain joins it, is under 60" in length and 2" in total fall, then the shower is properly wet vented by the tub.

9) (New) The laundry sink and the washing machine standpipe each need their own dry vent takeoffs. The two dry vents can be 1-1/2" and combine to a single 1-1/2" vent at an elevation at least 6" above both fixture flood rims.
I see what you are saying- I didn't draw it correctly and did search for a UPC diagram/example for this one as well. Thanks so much for pointing that out.
[It is actually possible to vent both fixtures via a single vent takeoff if you use circuit venting; that would require that both trap outlets be at basically the same elevation, and that you have a horizontal drain connecting them at that elevation, with the vent takeoff in between the two fixture connections. That's probably more trouble that it is worth barring some unusual circumstance.]

Hopefully I am getting closer
Best,
Patty
 

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wwhitney

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My previous answers aren't fresh in my mind, so here's my somewhat isolated response to the latest diagram only. I skimmed the latest textual comments but nothing jumped out at me as requiring a response:

The basic connectivity pattern is fine.

So you've got 5 dry vented fixtures: the lav, the tub, the kitchen sink, the laundry sink, and the washer standpipe. Each of those requires only a 1-1/2" vent, except the lav requires 2" as it is wet venting the WC. You can combine those all into a single roof penetration, of size 3", the minimum allowed by UPC 904.1. I don't see any particular upside to having a single 3" vent anywhere in the system; it's enough that at every elevation above all the fixtures, the aggregate cross section of the vents is at least that of a 3" vent. Which any 4 vents at least 1-1/2" achieves; you have 5 vents, 1 of which is 2".

On the lav wet venting the WC, the WC fixture drain run, both horizontal and vertical, from the closet flange to the wye with the lav drain is limited to 6'

On the tub wet venting the shower, the tub trap arm, from the trap outlet to the 2" wye where the shower drain joins the tub, is limited to 5' of run and 2" of fall.

Sorry if any of that is repetetive.

Cheers, Wayne
 

Schibig87

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My previous answers aren't fresh in my mind, so here's my somewhat isolated response to the latest diagram only. I skimmed the latest textual comments but nothing jumped out at me as requiring a response:
My apologies! I myself had a hard time coming back to my original plan and thread after two weeks.

The basic connectivity pattern is fine.
What a relief. I think I can find an example of each to follow and have studied the pipe fittings.

So you've got 5 dry vented fixtures: the lav, the tub, the kitchen sink, the laundry sink, and the washer standpipe. Each of those requires only a 1-1/2" vent, except the lav requires 2" as it is wet venting the WC. You can combine those all into a single roof penetration, of size 3", the minimum allowed by UPC 904.1. I don't see any particular upside to having a single 3" vent anywhere in the system; it's enough that at every elevation above all the fixtures, the aggregate cross section of the vents is at least that of a 3" vent. Which any 4 vents at least 1-1/2" achieves; you have 5 vents, 1 of which is 2".
Please see attached snip- am I following this correctly? For some reason I thought the whole main VTR had to be 3"

On the lav wet venting the WC, the WC fixture drain run, both horizontal and vertical, from the closet flange to the wye with the lav drain is limited to 6'
I am good here it's 3'6" from WC center drain to Lave center drain.

On the tub wet venting the shower, the tub trap arm, from the trap outlet to the 2" wye where the shower drain joins the tub, is limited to 5' of run and 2" of fall.
Thank you I reversed this from prior layouts due to tub drain being over 9' from the shower drain. I was able to get that distance under the 5 feet by reversing.

Sorry if any of that is repetetive.
Not repetitive at all- I really appreciate you hopping on her with patience to help me understand this.
Patty
 

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wwhitney

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Please see attached snip- am I following this correctly? For some reason I thought the whole main VTR had to be 3"
There are two separate issues. In a cold climate (where frost can accumulate, not sure if it applies to you), every individual vent through the roof should be 3". This reduces the chance of frost closure blocking the vent. If the vent approaching the roof is smaller, then you expand the vent to 3" just before the vent exits the thermal envelope (before it leaves the warm area). That's what your picture shows.

A separate issue is that the UPC wants the building sewer connected to the roof vents with passage(s) whose total area is at least the minimum size building sewer, which is 3" for a house with only two WCs. No bottlenecks, so a single 2" vent enlarged as in your picture would not suffice.

So if you are in a not-cold climate, and you have two separate 2" vent take offs for two WCS, and one 1.5" vent takeoff for the kitchen sink, and no other dry vents, you could pass them all separately through the roof, 3 penetrations. And that's because 2*2 + 2*2 + 1.5*1.5 > 3*3, and area goes as the square of diameter (the constant factor of pi/4 cancels). Of course, you could have more dry vents, but (1) 3"; or (2) 2" and (1) 1.5"; or (1) 2" and (3) 1.5" are the minimum possible ways to match or exceed a 3" aggregate area.

Or if you were in a cold climate, you could bring all 3 vents together in one warm location and combine them as a single 3" vent through the roof. Or they could pass separately into a cold attic, each as an enlarged 3" vent, and all of them could combine in attic to a single 3" vent through the roof.

Anyway, part of the point of all is this there's no reason to put a 3" vent on the laundry standpipe.

Cheers, Wayne
 

wwhitney

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I am good here it's 3'6" from WC center drain to Lave center drain.
Just to reiterate, the 6' limit is measured as the pipe runs. So you could be 3'6" apart in plan (projected onto the floor), but if the pipe goes down 2', north 2', and west 3' before reaching the wye with the lav drain which will wet vent it, that's too far.

Cheers, Wayne
 

Schibig87

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There are two separate issues. In a cold climate (where frost can accumulate, not sure if it applies to you), every individual vent through the roof should be 3". This reduces the chance of frost closure blocking the vent. If the vent approaching the roof is smaller, then you expand the vent to 3" just before the vent exits the thermal envelope (before it leaves the warm area). That's what your picture shows.
Washington State - not a cold climate.. just wet.

A separate issue is that the UPC wants the building sewer connected to the roof vents with passage(s) whose total area is at least the minimum size building sewer, which is 3" for a house with only two WCs. No bottlenecks, so a single 2" vent enlarged as in your picture would not suffice.
ahhh .... Understood.

So if you are in a not-cold climate, and you have two separate 2" vent take offs for two WCS, and one 1.5" vent takeoff for the kitchen sink, and no other dry vents, you could pass them all separately through the roof, 3 penetrations. And that's because 2*2 + 2*2 + 1.5*1.5 > 3*3, and area goes as the square of diameter (the constant factor of pi/4 cancels). Of course, you could have more dry vents, but (1) 3"; or (2) 2" and (1) 1.5"; or (1) 2" and (3) 1.5" are the minimum possible ways to match or exceed a 3" aggregate area.
5 individual dry vents- Lav, Tub, Laundry Sink, kitchen sink, wash machine.
Or if you were in a cold climate, you could bring all 3 vents together in one warm location and combine them as a single 3" vent through the roof. Or they could pass separately into a cold attic, each as an enlarged 3" vent, and all of them could combine in attic to a single 3" vent through the roof.
so all 4 would be the 1 1/2 inch & the Lav 2" (WC wet vented to lav) until past the top plates (conditioned space) to cold attic (unconditioned space) then need to increase from 1 1/2 to 3" then meet to a 3" pipe through roof?
I keep trying to google an example and come up empty. Sorry! I may be a tad confused, but I will get it!


Anyway, part of the point of all is this there's no reason to put a 3" vent on the laundry standpipe.
Understood. So a lot can go on in the attic to satisfy my single penetration above either the bath or the laundry

ust to reiterate, the 6' limit is measured as the pipe runs. So you could be 3'6" apart in plan (projected onto the floor), but if the pipe goes down 2', north 2', and west 3' before reaching the wye with the lav drain which will wet vent it, that's too far.
Oh! Ok :) I do remember reading that elsewhere in this forum. Thanks for the reminder.

Patty

Cheers, Wayne
 

wwhitney

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so all 4 would be the 1 1/2 inch & the Lav 2" (WC wet vented to lav) until past the top plates (conditioned space) to cold attic (unconditioned space) then need to increase from 1 1/2 to 3" then meet to a 3" pipe through roof?
I don't think you're in a cold climate, so the concern about warm area / cold area and expanding to 3" before you go through the roof would not apply.

No particular need for every one of the 5 vents to rise through the top plate; once a vent is 6" above the flood rim of the fixture served, it can go horizontal and/or connect with other vents that are at least 6" above their flood rims. So it's common to combine nearby vents in the wall, and then if you want to have only one roof penetration, combine what comes into the attic within the attic itself. Note that top plate penetrations in load bearing walls require reinforcement with a metal strap if over 50% of the width of the top plate has been cut; see IRC R602.6.1.

My suggestion would be that if you combine (2) 1-1/2" vents, you make the combination a 2" vent. And then when you combine a 2" vent with anything, make the combination a 3" vent. Except that as you have an extra 5th vent, you could forego the size increase in one junction and still comply with UPC 904.1.

Cheers, Wayne
 

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Hello All,

Please see attached and below explanation as to whether this DWV layout will work or do I need to make changes?

Washing machine would be main vent thru roof for whole house

Soaking tub & shower would wet vent to lav-
lav vents to WC
WC vent runs over to wash machine vent to roof

Kitchen vents to washing machine vent.

I choose to come straight from septic then 90 due to floor joist and supports layout.
Hope this makes sense. if you need distances I can add them as well.
We use UPC in this county find a professional, follow the link and have professionals reach out to quote your for free.
As always thank you for your help :)
Your DWV layout should work if:

  1. The washing machine vent through the roof is appropriately sized.
  2. The wet venting from the soaking tub and shower to the lavatory and the lavatory’s vent to the WC is compliant with UPC.
  3. The WC vent to the washing machine vent and then up to the roof is correctly installed.
  4. The kitchen's venting to the washing machine vent does not cause issues.
  5. The 90-degree turn from the septic is properly supported and aligned.
Ensure everything complies with UPC standards and consult a licensed plumber for confirmation.
 

Schibig87

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Thank you for your suggestions - they are appreciated. Will a licensed plumber confirm for me if not doing actual work?
  1. The washing machine vent through the roof is appropriately sized. I have switched to individual venting most fixtures with exception of show to tub. Plan to vent 2 inch to attic then tie in all at 3" through roof.
  2. The wet venting from the soaking tub and shower to the lavatory and the lavatory’s vent to the WC is compliant with UPC. I will research this a bit more
  3. The WC vent to the washing machine vent and then up to the roof is correctly installed. Do you foresee a problem with this set up?
  4. The kitchen's venting to the washing machine vent does not cause issues. Would it be better as suggested by John to vent individual 1.5 through roof over by sink?
  5. The 90-degree turn from the septic is properly supported and aligned. Supported every 4 feet with 1/4 per foot fall correct? I planned to add additional support at the bend
Best Patty
 

Schibig87

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I am back with what I hope will be my final drawing ask for this layout.
I have redone everything based on input from previous posts and spending time in the crawl space measuring everything.
I have included 2 options
I prefer option 1 - wet venting the whole bath.
My question on the Tub/shower wet vent is the 5' the total distance from the trap arm to 3" main drain or where the 2" intersects the 2' pipe leading to the 3" drain? If it is the 2" to 3" - this will not work.
Option 2 is my back up wet venting the tub to the shower using a dry vent in outside wall then wet venting the WC to the lav.
I also corrected my laundry sink & wash machine DWV and my kitchen set up as well
Both options tie in all fixtures to a single 3" vent in the attic exiting the roof.
That said I am willing to have more than 1 penetration- I think I meet code with the single.
My pipe intersections are wye's and/or why's w 45's & San Tees - Upside down San Tee's in attic to tie in branches.
For option 2, I would need to roll the Wye w 45 to get into the wall.
As always Thank you! and hope this makes sense.
 

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wwhitney

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Option 1 does not work. The way wet venting works is that the the dry vented drain counts as the vent for the other fixtures. That would be the lav. You can't combine 3 unvented fixture drains, the tub, the shower, and the WC, whether you are wet venting or dry venting. If you sent the lav across the room to join the tub drain first, then it would work.

To wet vent an entire bath through the lav, the lav drain needs to be one of the two upstream-most fixtures (branching-wise, not via total distance or anything). So starting at the lav, you do lav -- 2" wet vent -- shower (or tub) joins -- 2" wet vent -- tub (or shower) joins -- 3" wet vent -- WC joins. Or since you are in WA state, you could put the fixtures in any order of joining the lav drain, they just have to join one at a time individually. And the wet vent itself needs to be 3" as soon as it carries a WC or carries both a tub and a shower (or more precisely, if it is carrying more than 4 DFU).

Cheers, Wayne
 

Schibig87

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Option 1 does not work. The way wet venting works is that the the dry vented drain counts as the vent for the other fixtures. That would be the lav. You can't combine 3 unvented fixture drains, the tub, the shower, and the WC, whether you are wet venting or dry venting. If you sent the lav across the room to join the tub drain first, then it would work.

To wet vent an entire bath through the lav, the lav drain needs to be one of the two upstream-most fixtures (branching-wise, not via total distance or anything). So starting at the lav, you do lav -- 2" wet vent -- shower (or tub) joins -- 2" wet vent -- tub (or shower) joins -- 3" wet vent -- WC joins. Or since you are in WA state, you could put the fixtures in any order of joining the lav drain, they just have to join one at a time individually. And the wet vent itself needs to be 3" as soon as it carries a WC or carries both a tub and a shower (or more precisely, if it is carrying more than 4 DFU).

Cheers, Wayne
Thanks Wayne,

I simply cannot for the life of me grasp the wet vent scenario in option 1- so option 2 may be best.
Do you see anything glaring wrong with option 2?
Is it ok to wet vent my Tub and shower as long as the trap distance to the vent is within 5'? The vent will be in the wall behind the shower.
I corrected the kitchen sink and the laundry - Can my laundry sink drain above the standpipe as shown?
Do my individual vents look ok connecting to the Lav vent 3" VTR- My drawing shows them sloped down- I realize they need to slop up from Kitchen sink, Laundry and shower to allow for condensation etc to not pool.

Best,
Patty
 

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Reach4

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On option 2A, the revent would be on the lower trap arm rather than the higher one.
 

Schibig87

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On option 2A, the revent would be on the lower trap arm rather than the higher one.

Hi,
I patterned it off this but flipped my drain assembly, went from 1.5 to 2 at the beginning of the trap and moved it down a ways.
Am I to put the vent with the tub? I wouldn't meet distance requirement? I can just vent the tub too if that is better.
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