Bathroom Plumbing Layout

[Joey Leavitt]

Through previous help on this forum, I have two proposed options for my new basement bathroom plumbing. Could someone please provide some feedback on a couple items?

• Which option is better, if either?
• For Option 1, there will be about 10" vertically between the closet bend and flange. They only make closet bends in 3->4 from what I see. How would this work? My pipes are 3", so do I use a regular 90? Then 3" stub for a 3" closet flange pipe connection? Or do I use the 3->4 closet bend and stub with 4" pipe to a 4" flange pipe connection (this seems as reducing in the direction of flow technically)?
• For option 2, is it okay to have the toilet draining into the vertical combo as I have shown? This case would also end up being small 3" stub to 3" flange pipe connection.
• For both options, is this the appropriate wet venting layout to an AAV at the Lav? There are no vent stacks in the basement, only waste/soil stacks from upper levels.

Also, I have a proposed idea to move a cleanout from behind the shower wall. Since it is in stack, am I reading correctly that the cleanout can be a size smaller? It is a 2" washer drain that transitions to 3" before the existing cleanout.

 

[wwhitney]

Neither of those work for wet venting the shower and WC.

The washer drain can not be part of the bathroom wet vent. So you need to connect the lav to the shower (or WC) and then connect that to the WC (or shower); only then can the combined lav/shower/WC drain combine with the washer drain.

Cheers, Wayne

 

[Sponsor]

 

[Joey Leavitt]

I guess I'm confused. Aren't all of them connected before being tied into the 3" existing at the wye? As it would flow, shower/Lav merge, then both merge to WC, then combined to main.

 

[wwhitney]

Maybe I'm confused, I took the circle within the wall to be the 2" laundry drain coming down. Or is everything in the diagram completely separate from the laundry drain, and that is an unrelated question?

Cheers, Wayne

 

[Joey Leavitt]

Yes, the laundry drop/cleanout was a separate question. Same area (it drops into the line that I am tying into at the left of the sheets). The line wrapping around with two 90's high and low is the lav drain pipe in the wall (appearing as a circle). I am not certain exactly where I want the lav drain, so that made more sense to me right now as it allows for movement laterally after the fact depending on the exact placement of the vanity.

 

[wwhitney]

Ah, sorry for the misunderstanding. It's more typical for the lav drain to drop directly into the slab, but I see that your layout may reduce the amount of concrete you have to break.

As to the two options, I'm not sure if I have a preference. But your geometry is off, in that the line from the shower elbow to the first wye should be parallel to the existing 3" line under the slab. And it would be nice to eliminate the 45 near the the shower trap and just be able to point the trap outlet directly at a wye, if the geometry allows.

So I suggest figuring out the layout angles a bit more exactly to determine for each of the options whether everything actually fits. And on the cleanout, absent extreme geometric challenges, I would suggest sticking with a 3" cleanout.

Cheers, Wayne

 

[wwhitney]

PS If you place the 3" wye on the existing line so the branch inlet lines up with and points at the closet flange, and then immediately put a 3x3x2 street wye into the 3" wye's branch inlet (the 2" branch inlet would be for the shower/lav), do you room for at least a (possibly street) quarter bend without overshooting your closet flange location?

Cheers, Wayne

 

[Joey Leavitt]

If I switch to a 10" rough in WC it would fit.

 

[wwhitney]

Ah, so that may not be desirable. I see from the catalog the 3 fittings I proposed would be 16-1/16" from center of WC flange to centerline of existing 3" line, along the line at 45 degrees to the existing 3" line. Longer than I first realized.

Cheers, Wayne

 

[James Henry]

Try this.

 

[Joey Leavitt]

Yeah, pretty tight quarters. Less than 1' from center of Closet flange perpendicular to existing. I think I am good with it now. The only other thing I need some clarification on is the distance between my closet bend and flange. It will be about 10" of stub. If I use a 4x3 closet bend, then I will need to insert a 4" pipe stub between the bend and flange. Is this a problem, since technically it is reducing going from the 4" to 3" pipe? I could go with just a 3" quarter bend, but then I have to ensure I wrap the pipe good enough at the slab to be able to fit the flange on the outside of the 3" pipe afterwards.

 

[wwhitney]

Yeah, pretty tight quarters. Less than 1' from center of Closet flange perpendicular to existing.

By that metric the 3 fittings I suggested would require 11-3/8".

On the 4x3 closet bend, it exists because there is an exception allowing the reduction for a closet bend.
https://up.codes/viewer/utah/ipc-2018/chapter/7/sanitary-drainage#704.2

Note the riser pipe will need to be wrapped with a compressible material where it passes up through the slab regardless. If you have a 3" riser and want to be able to add an outside fit closet flange, wrap it, slide a piece of 4" pipe over that, and wrap it again. The 4" pipe will be removable and leave enough room for the outside fit closet flange.

Cheers, Wayne

 

[James Henry]

https://www.lowes.com/pd/Oatey-PVC-...Vem1vBB0oLw-4EAQYBCABEgJUmPD_BwE&gclsrc=aw.ds
https://www.google.com/search?q=4x3...ZWM0KHXxZBRQQ9QF6BAgOEAE#imgrc=o7-bSAXOu2CHWM

install a 4 x 3 closet bend, stub up a 4" pipe above the concrete , cut it off flush with the finish floor, install a " inside 4" outside 3" closet flange and glue it inside the 4" pipe.

 

[James Henry]

Correction: cut the pipe at least a 1/4" below the finish floor. The toilet flange is beveled underneath which keeps it from sitting flush on top of the pipe. Had to fix that many times on other peoples installs.