RLrobinhood
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what is a "trap primer"?
DWV, am I creating unnecessary work????
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wwhitney
In the Trades
Not working for me, although maybe you are in the middle of posting them. To test how they will look for others, you can open the thread in a "private browsing" window and take a look.
Cheers, Wayne
Cheers, Wayne
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RLrobinhood
Member
Absolutely, here are those pictures:
RLrobinhood
Member
Basic floor plan with common shared walls in the basement and ground floor (single story house with attic).
wwhitney
In the Trades
So the bathrooms are stacked and have roughly the same floor plan? For completeness, can you draw on the floor plan above the DWV configuration for the upstairs bathroom (not shown in your pictures), to the best of your knowledge?
In particular, the lavatory should have a dry vent, and I'm curious how its drain is routed. E.g. through the wall studs to join the 3" stack?
Cheers, Wayne
In particular, the lavatory should have a dry vent, and I'm curious how its drain is routed. E.g. through the wall studs to join the 3" stack?
Cheers, Wayne
RLrobinhood
Member
RLrobinhood
Member
The ground floor bathroom lavatory sink is vented up in the wall and then over to the 3" stack in the wall. The drain goes down the wall and through the floor to a cavity between the floor joists. Then it runs over to the 3" stack. This is a 4' horizontal run before it goes into the stack.
wwhitney
In the Trades
A photo of the 3" stack just below the floor joists, showing how the lav drain, tub drain, and WC drain all join the stack would be good. Just to be sure that's all compliant.
Cheers, Wayne
RLrobinhood
Member
wwhitney
In the Trades
OK, here's my initial thoughts. Some principles:
- Upstairs fixture all join the 3" stack in or just below the floor joists. So the kitchen drain gets run across to the top of the 3" stack, below the upstairs WC connection. The bathtub drain stays in its current location.
- The bathtub drain needs a dry vent takeoff that complies with the trap weir rule and minimum and maximum trap arm distance rules, 2 slightly different ways to do that were previously discussed. I assume you'll have to open up the drywall in the closet behind the bathtub in order to add the vent pipe.
- The laundry downstairs runs across to the 3" stack as it can't be part of the bathroom group when using wet venting for the bathroom group.
- The floor drain needs to be wet vented as part of the bathroom group, but the WC has to be last on the wet vent. So the WC drain is kept separate from the building drain and from the shower/lav drain until after the shower/lav drain joins the floor drain. Note that the total distance along the pipe from the closet flange to the wye where the shower/lav/floor drain join the WC drain is limited to 6', this needs to be verified.
With those requirements, I see two different options. I've drawn option 1, which is where the lav wet vents the shower. The downsides:
- The lav drain has to cross the washer drain within the wall. That's (2) 2" pipes in a 2x6 wall, so it should fit, or you may need to fur out the wall. That wall is presumably not load bearing give how chopped up some of the studs are, but those studs may still need some repairs.
- The lav drain does an awkward 180 under the slab. This is to comply with the length limit on the shower trap arm; for a 2" trap arm, you are allowed up to 60" from the trap outlet to where the lav drain joins the shower trap arm at a wye (or combo).
Orange is 4" (the circle is a cleanout). Red is 3", Green is 2", and Blue is 1.5"
Cheers, Wayne
- Upstairs fixture all join the 3" stack in or just below the floor joists. So the kitchen drain gets run across to the top of the 3" stack, below the upstairs WC connection. The bathtub drain stays in its current location.
- The bathtub drain needs a dry vent takeoff that complies with the trap weir rule and minimum and maximum trap arm distance rules, 2 slightly different ways to do that were previously discussed. I assume you'll have to open up the drywall in the closet behind the bathtub in order to add the vent pipe.
- The laundry downstairs runs across to the 3" stack as it can't be part of the bathroom group when using wet venting for the bathroom group.
- The floor drain needs to be wet vented as part of the bathroom group, but the WC has to be last on the wet vent. So the WC drain is kept separate from the building drain and from the shower/lav drain until after the shower/lav drain joins the floor drain. Note that the total distance along the pipe from the closet flange to the wye where the shower/lav/floor drain join the WC drain is limited to 6', this needs to be verified.
With those requirements, I see two different options. I've drawn option 1, which is where the lav wet vents the shower. The downsides:
- The lav drain has to cross the washer drain within the wall. That's (2) 2" pipes in a 2x6 wall, so it should fit, or you may need to fur out the wall. That wall is presumably not load bearing give how chopped up some of the studs are, but those studs may still need some repairs.
- The lav drain does an awkward 180 under the slab. This is to comply with the length limit on the shower trap arm; for a 2" trap arm, you are allowed up to 60" from the trap outlet to where the lav drain joins the shower trap arm at a wye (or combo).
Orange is 4" (the circle is a cleanout). Red is 3", Green is 2", and Blue is 1.5"
Cheers, Wayne
wwhitney
In the Trades
Once you've had a chance to digest option 1, here's option 2, which avoids the two negatives of option 1, at the expense of an extra dry vent for the shower. Now the shower can wet vent the WC (so its dry vent needs to be 2") and the floor drain. That means the lav drain and vent only have to be 1-1/2", and the lav drain can just join the washer drain. It also means the combined lav/washer vent only has to be 1-1/2" (not shown).
BTW, what the drawing is attempting to show for the lav drain is the way to get it as low as possible relative to the washer drain: a 2x2x1-1/2" wye with a street 1-1/2" san-tee into the branch opening of the wye, where the barrel of the san-tee is at a 45 degree angle. If you are happy to have the lav drain higher, it would be simpler to use a 2x2x1-1/2" combo with a vertical san-tee on top.
Also, the layout of the shower drain near the wall for the vertical vent takeoff is a bit tricky and may require some trial and error. It's showing a wye with the barrel parallel to the wall plate, rolled 45 degrees off straight up, and then a 60 degree bend under/in the wall plate for the vent to go vertical. The trap hopefully ca be arranged so that you only need a 45 between the trap elbow outlet and the barrel of the wye.
Cheers, Wayne
BTW, what the drawing is attempting to show for the lav drain is the way to get it as low as possible relative to the washer drain: a 2x2x1-1/2" wye with a street 1-1/2" san-tee into the branch opening of the wye, where the barrel of the san-tee is at a 45 degree angle. If you are happy to have the lav drain higher, it would be simpler to use a 2x2x1-1/2" combo with a vertical san-tee on top.
Also, the layout of the shower drain near the wall for the vertical vent takeoff is a bit tricky and may require some trial and error. It's showing a wye with the barrel parallel to the wall plate, rolled 45 degrees off straight up, and then a 60 degree bend under/in the wall plate for the vent to go vertical. The trap hopefully ca be arranged so that you only need a 45 between the trap elbow outlet and the barrel of the wye.
Cheers, Wayne
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wwhitney
In the Trades
OK, on your last picture, of the upstairs bathroom drains nexus, the obvious violation is that the san-tee on its side connected to the inlet of the 3x3x3x1-1/2" san-tee with side inlet should be a combo.
So you should at a minimum replace that with a wye plus 45 (given how the tub drain is approaching, you can avoid the 90 by turning the 45 inlet to be parallel to the wye straight inlet). To do that would probably require a rambit/fitting saver type tool that will let you drill out the hub of the 3x3x3x1-1/2 san-tee with side inlet to reuse the side inlet, since the san-tee on its side is so close.
Given that rework is required there, you have another option for venting the upstairs tub drain, which would be to wet vent it with with the upstairs lav. Namely, if the lav drain comes straight down to join the tub drain before the 90, and you lower the tub trap so its outlet is in line with the current horizontal tub drain, what is the distance from the trap to the joint with the lav drain?
If it's 42" or less (not likely), you could just join them with a combo (could be tricky while also turning the combined drain 90 degrees to head to the stack), and the lav would wet vent the tub drain. If it's between 42" and 60" you could do the same, but you'd need to upsize the tub trap and drain to 2" to get the longer allowance on the tub trap arm. That would mean either replacing the 3x3x3x1-1/2 san-tee with side inlet with a 3x3x3x2. Or since you need to cut in a 3x3x2 wye for the kitchen drain just below there, you could instead cap the 1-1/2" side inlet and make that wye a double wye (3x3x2x2), so that the left side can accept the 2" tub/lav drain.
Just something for you to consider as an alternative to adding a tub dry vent.
Cheers, Wayne
So you should at a minimum replace that with a wye plus 45 (given how the tub drain is approaching, you can avoid the 90 by turning the 45 inlet to be parallel to the wye straight inlet). To do that would probably require a rambit/fitting saver type tool that will let you drill out the hub of the 3x3x3x1-1/2 san-tee with side inlet to reuse the side inlet, since the san-tee on its side is so close.
Given that rework is required there, you have another option for venting the upstairs tub drain, which would be to wet vent it with with the upstairs lav. Namely, if the lav drain comes straight down to join the tub drain before the 90, and you lower the tub trap so its outlet is in line with the current horizontal tub drain, what is the distance from the trap to the joint with the lav drain?
If it's 42" or less (not likely), you could just join them with a combo (could be tricky while also turning the combined drain 90 degrees to head to the stack), and the lav would wet vent the tub drain. If it's between 42" and 60" you could do the same, but you'd need to upsize the tub trap and drain to 2" to get the longer allowance on the tub trap arm. That would mean either replacing the 3x3x3x1-1/2 san-tee with side inlet with a 3x3x3x2. Or since you need to cut in a 3x3x2 wye for the kitchen drain just below there, you could instead cap the 1-1/2" side inlet and make that wye a double wye (3x3x2x2), so that the left side can accept the 2" tub/lav drain.
Just something for you to consider as an alternative to adding a tub dry vent.
Cheers, Wayne
RLrobinhood
Member
Wayne, you are truly amazing! I sent you a PM/Conversation. Let me know if you got it. I've spent some time contemplating and thinking through what you have proposed and have a few questions/comments:
1) Option #2 looks similar to Option #1, but the outside green line that goes down from the basement lavatory sink, into the slab, and the weird 180-degree turn is not used on the laundry wall? And option #2 allows the basement lavatory sink to dump into the horizontal 2" laundry drain?
2) Option #2 also has the dry vent going up the wall for the basement shower. Could I use this same 2" vent and tie into the ground floor bathtub (at least 6" above the bathtub flood/spill plane) for the vent? Then continue to the attic where I would tie it back into the 3" main stack.
3) Option #2 seems to be the smartest. Do you agree?
4) You put a 4" cleanout in the drawing. Should this be pointed out perpendicular to the wall but behind the toilet? I also have a cleanout at my septic that runs into the house. So is this new cleanout needed?
5) For the ground floor kitchen sink, you have me run the kitchen sink/basement lav/laundry stack vent all the way (16') back to my kitchen sink. Could I just run it up the wall (parallel to the 3" main stack) and then tie it into the main stack 6"above the highest flood/spill plane on the ground floor?
Again, many, many, many thanks!
1) Option #2 looks similar to Option #1, but the outside green line that goes down from the basement lavatory sink, into the slab, and the weird 180-degree turn is not used on the laundry wall? And option #2 allows the basement lavatory sink to dump into the horizontal 2" laundry drain?
2) Option #2 also has the dry vent going up the wall for the basement shower. Could I use this same 2" vent and tie into the ground floor bathtub (at least 6" above the bathtub flood/spill plane) for the vent? Then continue to the attic where I would tie it back into the 3" main stack.
3) Option #2 seems to be the smartest. Do you agree?
4) You put a 4" cleanout in the drawing. Should this be pointed out perpendicular to the wall but behind the toilet? I also have a cleanout at my septic that runs into the house. So is this new cleanout needed?
5) For the ground floor kitchen sink, you have me run the kitchen sink/basement lav/laundry stack vent all the way (16') back to my kitchen sink. Could I just run it up the wall (parallel to the 3" main stack) and then tie it into the main stack 6"above the highest flood/spill plane on the ground floor?
Again, many, many, many thanks!
wwhitney
In the Trades
1) Yes
2) Yes, you'd have the 2" shower vent from the basement rise up alongside the 1-1/2" dry vent takeoff for the bathtub, and 6" above the tub flood rim they can combine to a single 2" vent.
3) Assuming you can get the dry vent takeoff from the shower drain correct, I think #2 would be easier.
4) The cleanout should be accessible, it could point either way towards the bath or the laundry, and it could stick out of the wall or be hidden behind an accessible panel in the drywall. For the latter you could consider using a wye instead of a test tee for the cleanout.
As to whether it's needed, read the UPC section on cleanouts. If your exterior cleanout is not a 2-way cleanout, I'm pretty sure it's needed. It may still be needed even with a 2-way cleanout.
https://up.codes/viewer/montana/upc-2018/chapter/7/sanitary-drainage#707.0
5)There's no kitchen sink vent in any of my drawings, as that's on the floor above. The top most horizontal green line on the marked up wall drawing is the kitchen sink drain (which needs to be 2" starting at the san-tee behind the kitchen sink where the vent comes off). The middle horizontal green line is the combined downstairs lav/washer vent (which under option 2 only needs to be 1-1/2"). I showed running that vent back towards the kitchen sink so it wouldn't cross the kitchen sink drain. If you have room to cross them in the wall you can run the vent towards the 3" stack and parallel the 3" until 6" above the flood rim of any fixtures on that stack, then join the vent to the stack.
Also, if you prefer that venting arrangement and don't want crossing lines in the wall, you could run the kitchen sink drain down the wall all the way to the right (as seen from the bathroom) of the laundry box, and then run it through the studs under the laundry/lav drain to join the 3" stack between the 4" cleanout and the laundry/lav drain connection (which is currently a wye but could be a san-tee if needed for space reasons).
BTW, check that your laundry standpipe and trap meet the requirements here:
https://up.codes/viewer/montana/upc-2018/chapter/8/indirect-wastes#804.1
And confirm the height exceeds the minimum for your washer model.
Cheers, Wayne
2) Yes, you'd have the 2" shower vent from the basement rise up alongside the 1-1/2" dry vent takeoff for the bathtub, and 6" above the tub flood rim they can combine to a single 2" vent.
3) Assuming you can get the dry vent takeoff from the shower drain correct, I think #2 would be easier.
4) The cleanout should be accessible, it could point either way towards the bath or the laundry, and it could stick out of the wall or be hidden behind an accessible panel in the drywall. For the latter you could consider using a wye instead of a test tee for the cleanout.
As to whether it's needed, read the UPC section on cleanouts. If your exterior cleanout is not a 2-way cleanout, I'm pretty sure it's needed. It may still be needed even with a 2-way cleanout.
https://up.codes/viewer/montana/upc-2018/chapter/7/sanitary-drainage#707.0
5)There's no kitchen sink vent in any of my drawings, as that's on the floor above. The top most horizontal green line on the marked up wall drawing is the kitchen sink drain (which needs to be 2" starting at the san-tee behind the kitchen sink where the vent comes off). The middle horizontal green line is the combined downstairs lav/washer vent (which under option 2 only needs to be 1-1/2"). I showed running that vent back towards the kitchen sink so it wouldn't cross the kitchen sink drain. If you have room to cross them in the wall you can run the vent towards the 3" stack and parallel the 3" until 6" above the flood rim of any fixtures on that stack, then join the vent to the stack.
Also, if you prefer that venting arrangement and don't want crossing lines in the wall, you could run the kitchen sink drain down the wall all the way to the right (as seen from the bathroom) of the laundry box, and then run it through the studs under the laundry/lav drain to join the 3" stack between the 4" cleanout and the laundry/lav drain connection (which is currently a wye but could be a san-tee if needed for space reasons).
BTW, check that your laundry standpipe and trap meet the requirements here:
https://up.codes/viewer/montana/upc-2018/chapter/8/indirect-wastes#804.1
And confirm the height exceeds the minimum for your washer model.
Cheers, Wayne
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RLrobinhood
Member
Thank you so much! I think I will have enough elevation to do the shower vent up the wall. It will be close...
On the laundry room wall plumbing. I like the idea of not crossing pipes. Could I upsize the horizontal laundry drain to 3" and just bring the ground floor kitchen sink in the end instead of under it? See my drawing below. red is 3", green is 2"
On the laundry room wall plumbing. I like the idea of not crossing pipes. Could I upsize the horizontal laundry drain to 3" and just bring the ground floor kitchen sink in the end instead of under it? See my drawing below. red is 3", green is 2"
Close. Vent the laundry standpipe at least 4 inches after the U of the p-trap but before the pipe turns down. So you will need only two basement vents for these: one for the lavatory, as you drew, and one for the laundry standpipe.
The stuff from ground floor must be vented upstairs, and presumably they are already vented.
90 bend at the lower right corner is long sweep.
wwhitney
In the Trades
Like what Reach4 said, and you don't need to go as big on the pipe sizes. Blue is 1-1/2" (but you can use 2" if you prefer for some reason). The length of the laundry standpipe trap arm can be anywhere from 4" to 60" (from the trap outlet to the san-tee), I'm not trying to show a particular length, just the connectivity.
Cheers, Wayne
RLrobinhood
Member
Thanks Reach4. Am I correct in that the horizontal pipe there HAS to be upgraded to 3" and cannot be 2"?
Jeff H Young
In the Trades
Robinhood, i noticed you said your bath tub had 1 1/2 drain that worked good but if it has a horizontal drain pipe it will require 2 inch other than trap and arm 1 1/2 " is fine
wwhitney
In the Trades
Good point, I forgot that the UPC requires that, any horizontal portion of the tub fixture drain after the vent takeoff has to be 2".
[Which I find a little weird for the case of a vent takeoff from a horizontal drain via an upright wye or combo, suddenly the drain size has to increase. Although the same is true for a kitchen sink or a utility/laundry sink under the UPC, for those fixtures it's just much less likely to not use a san-tee.]
Cheers, Wayne
