# Added an upstairs washer, how to pipe into existing plumbing without having a shower s-trap?

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#### Amateur 60 Minutes

##### New Member
OK, I suggest you look at a solution like that depicted by the red line below. That just shows the floor plan path, it doesn't consider the elevation aspects. If everything were in one plane, you'd use an upright combo (barrel horizontal) for your tub vent takeoff, which vertical vent is depicted by the red circle.

The question then is whether you have enough space left right in the picture to fit in that joist bay, from left to right (a) the LT 90 of the tub trap arm (b) the vent takeoff (c) whatever fittings you need to change elevation and (d) the combo for the tub drain to join the drain running perpendicular to the joists.

If you provide the left-right distance between the center line of the the tub trap arm where it comes through the joist and the center line of the drain where it goes back through the joist, as well as the elevation difference between those, I could puzzle out if you can make it fit. And just to confirm, the tub trap arm is 1-1/2" trade size, while everything else in the picture is 2"?

Cheers, Wayne

View attachment 92718

I missed your post before posting something pretty similar. These beige images with wiring and abs pipe all camouflaged into one.

I haven't glued everything up just yet, but this all looks correct and functional?

#### wwhitney

I haven't glued everything up just yet, but this all looks correct and functional?
Yes, assuming proper slopes, and with 3 caveats:

(1) When you dry fit plastic DWV pipe, you can't fully seat the joint. So where your spacing between fittings is critical, you should measure the distance between the hubs, add the socket depths to that, and cut a new longer piece of pipe. You may want to do a couple test glue-ups to determine the exact relationship between pipe length and glued-up distance between sockets.

(2) Look like you enlarged the hole in the joist to move the tub drain down? The Canadian Building Code limits prescriptive holes in joists to 1/4 the joist depth. So if you've exceeded that (measuring the largest distance between two edges of your irregular hole), you should do a repair on the joist. Probably as simple as attaching a length of 2x4 to the side of the joist above your pipe, with an appropriate number of fasteners on each side of the hole. The difficulty is figuring out the repair details, since there is no prescriptive guidance available.

(3) What is the material and size of the tub waste and over and how did you adapt it to ABS? If it's a tubular size, then you should have a trap adapter on the left to adapt to ABS Schedule 40. Which is fine, but I just can't tell from the picture. A trap adapter (slip joint connection) needs to be accessible, so if you were to drywall the ceiling you should put in an access panel there.

Cheers, Wayne

#### Amateur 60 Minutes

##### New Member
Yes, assuming proper slopes, and with 3 caveats:

(1) When you dry fit plastic DWV pipe, you can't fully seat the joint. So where your spacing between fittings is critical, you should measure the distance between the hubs, add the socket depths to that, and cut a new longer piece of pipe. You may want to do a couple test glue-ups to determine the exact relationship between pipe length and glued-up distance between sockets.

(2) Look like you enlarged the hole in the joist to move the tub drain down? The Canadian Building Code limits prescriptive holes in joists to 1/4 the joist depth. So if you've exceeded that (measuring the largest distance between two edges of your irregular hole), you should do a repair on the joist. Probably as simple as attaching a length of 2x4 to the side of the joist above your pipe, with an appropriate number of fasteners on each side of the hole. The difficulty is figuring out the repair details, since there is no prescriptive guidance available.

(3) What is the material and size of the tub waste and over and how did you adapt it to ABS? If it's a tubular size, then you should have a trap adapter on the left to adapt to ABS Schedule 40. Which is fine, but I just can't tell from the picture. A trap adapter (slip joint connection) needs to be accessible, so if you were to drywall the ceiling you should put in an access panel there.

Cheers, Wayne

Thanks again for the advice, Wayne. Yeah, I enlarged it to 4" diagonally in a 9.5" nominal size. I'll wood glue the plug into the old hole to reinforce the joist, and add some scrap metal or 2x4s to keep it sturdy. That joist is supported at several intervals, so I'm not concerned about it.

The tub plumbing is just a brass pipe. I'll be replacing the tub in the near future, but for now I sanded down the grit and oxidation on it. The new trap adapter fits nice and snug.

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Hey, wait a minute.

This is awkward, but...

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