Feedback on DWV redesign (double vanity and washer) - code compliance

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Mikieboyblue

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Hello folks!

I would like feedback on a DWV redesign with a focus on code compliance and "do-ablity."

I feel like I will have trouble keeping the sink drain below 24" on the washer side. I wish the main stack drain was lower. It would be a good amount of work to pull that all, cut new holes in the studs and sister over the original holes.

Of note, all copper in this diagram will be repiped with PEX (probably B because that is what I have).

Later I will have an inquiry on dealing with a removal of a valve on the water main coming up from the slab.

Thank you in advance!
Mike

Large version: https://i.ibb.co/Fh29JyZ/DWV-20210829.png

 
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Mikieboyblue

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Did some more reading, made some revisions based on other feedback, clarified diagram. This revision is because of the NC amended IPC:

406.2 Waste Connection (Automatic Clothes Washer)

The waste from an automatic clothes washer shall connect to a vertical drain of not less than 2 inches (51 mm) in diameter, or a horizontal drain of not less than 3 inches (76 mm) in diameter. The 2-inch (51 mm) trap in the waste connection may be used as a cleanout for both the 2-inch (51 mm) and the 3-inch (76 mm) drains. In retrofit or remodel work, automatic domestic clothes washers shall be permitted to drain to a laundry sink. Automatic clothes washers that discharge by gravity shall be permitted to drain to a waste receptor or an approved trench drain.


Large version: https://i.ibb.co/mBXVvCs/DWV-20210830.png

[IMG]
 
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Zanne

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I'm hoping one of the pros will weigh in. My brain is not working today. Are you only moving the washing machine over and not having a sink? Or will there be a sink? I'm trying to visualize this. Since I'm a bit braindead right now let me make sure I understand what you're doing. You want to move your washing to the left of the main stack. Will you be keeping a sink to the right side? So, other than moving the washing machine to the left, you want to cut out that section of pipe where stuff currently attaches and connect the replacement section with fernco fittings. Looks like you want to tie in something on both sides (sink on the left?)

I don't think the wye is the right fitting for a vent, but I could be wrong. I generally see it with some sort of tee instead. I think a backwards sanitary tee (one of the few times they are allowed on their backs is to act as vents).

The pipe above the trap weir needs to be between 18" and 30" above the trap weir under UPC and 18" to 42" under IPC. Looks like you do have the 18" from the floor for trap weir down. How high does the pipe go above the trap weir for the laundry box? Are you under UPC or IPC?

IPC 802.4.3 Standpipes.
Standpipes shall be individually trapped.
Standpipes shall extend a minimum of 18 inches (457 mm) and a maximum of 42 inches (1066 mm) above the trap weir.
Access shall be provided to all standpipes and drains for rodding.
-
UPC 804.1 Standpipe Receptors.
Plumbing fixtures or other receptors receiving the discharge of indirect waste pipes shall be approved for the use proposed and shall be of such shape and capacity as to prevent splashing or flooding and shall be located where they are readily accessible for inspection and cleaning. No standpipe receptor for a clothes washer shall extend more than 30 inches (762 mm), or not less than 18 inches (457 mm) above its trap. No trap for a clothes washer standpipe receptor shall be installed below the floor, but shall be roughed in not less than 6 inches (152 mm) and not more than 18 inches (457 mm) above the floor. No indirect waste receptor shall be installed in a toilet room, closet, cupboard, or storeroom, or in a portion of a building not in general use by the occupants thereof; except standpipes for clothes washers shall be permitted to be installed in toilet and bathroom areas where the clothes washer is installed in the same room.

I think the vent pipe for the washing machine or that main pipe will need a cleanout somewhere.

I hope I'm making sense. Foggy this morning.
 

Mikieboyblue

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Hello @Zanne - Thanks for the feedback.

Lay of the land:
  • The photo is taken from the side door in a kitchen toward the kitchen wall opposite the full bath wall
  • The other side of the 2x6 stud wall is the bathroom wall where the vanity, toilet, tub will be (in that order and as see on the existing positioning).
  • Single floor, nothing above the the vent stack.
Originally:
  • The washer was located in the kitchen where the existing box is.
  • The bathroom had a single single vanity all the way to the left stud bay
Remodel:
  • Building a laundry room at the corner of the hall and kitchen for stackable washer dryer; moving the washer box to the first or second stud bay on the left
  • Installing a double sink vanity in the bathroom replacing the prior single sink vanity
New lay of the land:
  • Washer on photo side of the wall
  • Double sink vanity on the opposite side (the blue circles will be into the bathroom (toward the wall with the load center; inside the bathroom)
Are you under UPC or IPC?
NC is IPC (amended)

How high does the pipe go above the trap weir for the laundry box?
I'll stay within 18-42"

...and connect the replacement section with fernco fittings
I was planning to use all the existing ABS, but (since you can't use transition cement for PVC to ABS), maybe replacing that entire section with PVC is best and connect it with the ferncos. In that case, I think I want to use a double fixture fitting for the left and right sink branches.
 
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Mikieboyblue

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In the first drawing, I was trying to reuse as much as possible. The interpretation of the NC amended code may be incorrect and first drawing actually works.
 

Zanne

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Ah. So you're doing a laundry area and a bathroom. Ok. I wish I could get my brain in gear. I'll come back and look at it and read again to see if anything useful pops in to my head. Still hoping a pro will weigh in.
@Twowaxhack any suggestions?
 

Mikieboyblue

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I am debating cutting the stack about two feet below the ceiling plate and 6 inches above the slab and then replacing the entire section with PVC. Use a Fernco to rejoin the top and bottom PVC to ABS. I can use the kind with a separator on the bottom of needed since I'll build up.

From the bottom a combo wye to the washer with a Santee curve up and towards the washer for a vent. Above that on the stack a double fixture fitting for each sink at 18" off slab. No vent needed for those as they use the stack.

Alternatively I could vent the right sink in the same bay as the stack and remove the washer vent as it would use the stack as a common vent with the left sink (I think that is legal).
 

GReynolds929

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Why go through the trouble of PVC to ABS when ABS is already there?
 

Mikieboyblue

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None other than availability of material and fittings, and I have yet to look up if new ABS is allowed in NC.
It appears ABS is allowed by NC (IPC):


Does the last statement mean you cannot use street fittings on interior DWV?

702.1 Above-Ground Sanitary Drainage and Vent Pipe

Above-ground soil, waste and vent pipe shall conform to one of the standards listed in Table 702.1. Pipe fittings shall not be solvent-cemented inside of plastic pipe.
 

Mikieboyblue

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@Twowaxhack - Any thoughts? I have always valued your opinion on past posts.

My only modification to the second drawing at this point is I need a long sweep 90 coming out the wall for the lavs instead of a hard 90 I believe. I am open to better designs.
 

Zanne

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Hmm.. I honestly can't interpret that one. Maybe it means you can't put plastic pipe around it? I dunno. Someone who knows the code would have to weigh in.
Normally Frodo knows about the codes but he just got hit by Ida so he doesn't have electricity.
I wish I could help but it's beyond my knowledge level.
 

Twowaxhack

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I don’t think you need the revent on the washing machine. It appears it’s within 5’ of the vent. The two lavatories above it shouldn’t be a problem. I don’t put long sweep 90’s for turning out of a wall for a lavatory because the 90’s stick out of the wall too far.

All that said it may not meet your code.
 

Mikieboyblue

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All you’re doing is adding a lavatory and moving the washing machine down the wall some. You’re not changing much.
I have a bad habit of over analyzing things and I truly apologize for that. I guess that comes from my propensity to want do something once and not do it over again -- so I research to death (literally).

That is exactly what I am doing.
  1. A lav being added to the right side where the washer is now.
  2. Washer moved to the far left where the existing lav used to be.
  3. Existing lav moved to the right.
I just read the entire venting section of the NC 2018 Amended IPC (2015). I know the two lavs will be fine and I can even leave the double san tee as I am not messing with it (even though it should be double fixture). It is now to plumb the washer into this that has me stuck. The IPC regarding common venting seems to imply one fixture (not a clothes washer) can be on the same floor level above another. This would be the left or right lav and new washer drain branch (not needing a revent). The second lav needs a revent. So basically. one of these three fixtures needs a vent added as I do not believe I have tie all three to the common vent stack without [a code] issue. :)
 

Mikieboyblue

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Hmm.. I honestly can't interpret that one. Maybe it means you can't put plastic pipe around it? I dunno. Someone who knows the code would have to weigh in.
Normally Frodo knows about the codes but he just got hit by Ida so he doesn't have electricity.
I wish I could help but it's beyond my knowledge level.
Yeah, the language in the codes sucks. Very interruptive and I can see why it is a hit or miss depending on what inspector you get. I am making this statement as someone who spent the first 10 years of their professional career writing technical documentation.

@frodo - I hope all is ok buddy!
 

Twowaxhack

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I’d pipe it without a revent. I’d bet $1,00000000000 it would work perfect to any and all takers.
 

Twowaxhack

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How’s your tub and toilet vented ? Through that same 3” ?

If so it would’ve never passed inspection here originally.
 

GReynolds929

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It appears ABS is allowed by NC (IPC):


Does the last statement mean you cannot use street fittings on interior DWV?

702.1 Above-Ground Sanitary Drainage and Vent Pipe

Above-ground soil, waste and vent pipe shall conform to one of the standards listed in Table 702.1. Pipe fittings shall not be solvent-cemented inside of plastic pipe.
My interpretation is that it is basically an over complicated way of saying you can't restrict or reduce the ID of the pipe by installing a fitting that fits inside of the pipe.
 
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