DWV input for planning new basement bathroom

[Gslenk]

There have been major revisions to the layout. And hopefully this model is easier to read. I am mostly concerned about order of fixtures in branches, and what venting is redundant. I can plan fittings/etc. after I figure out the best routing scenario.

The lav looks awkward. Essentially it would p-trap, then go back into the wall, and 90 to the main stack. 3" stack serves the whole main floor above, so I doubt it counts as a vent.

Looking to tear up as little concrete as possible. The orange line is the existing waste pipe under the slab (located at around 1' 4" according to a camera snake/locator).

 

[Gslenk]

Bumping this since the plan changed, and this should be much easier on the eyes than the original mess of a diagram I posted. Here is a diagram of the existing plumbing. The orange cylinder in the model is the vertical stack seen in the existing diagram. The wye and 90 at the top are not drawn in the model. The cleanout is in the model hiding in the vanity cabinet.

Looks like I have no choice but to break the slab for the wet bar.
Also gotta break the slab for the laundry, toilet etc... Is it possible/recommended to put all of these on one branch?

 

[Sponsor]

 

[Gslenk]

Something like this. Perhaps add a cleanout on the standpipe/laundry sink.

Also could I avoid digging up the slab on the right side, by tying the bar sink to the bathroom lav? Probably needs an extra cleanout under the lav. The previous existing setup was like this, and seemed to work.

 

[Cacher_Chick]

If you can get the drain heights the same, the lav and the bar could both tie into one stack using a double fixture fitting.

Run one primary drain line to the toilet. All of the other fixtures can tie into that line as long as they are each being vented the shower and lav drains can tie together into one line.
The washer connection should be downstream of the other fixtures on the line.

 

[Gslenk]

The stack is cast iron and seems to be supported adequately from above. From there I see two realistic options, and possibly a cheater option, listed in order of perceived difficulty. I think I'd rather do #2 than #3, but if I can somehow legitimately get away with #1...

1) Cheater idea (attached pic): Orange is the stack with a single 3"x1.5" santee center is 13" off the floor. Blue is the lav, green is the bar. This looks to violate the 135 degree/cleanout rule, and makes (at least) the bar sink unvented. Is there any situation where something like this could be midified to function properly, and meet code? Add more vents and a cleanout? On the plus side, the cast iron fitting is threaded, so in the event of an unclearable clog, the entire assembly can be removed and rebuilt relatively easily.

2) Remove some cast iron from the stack, the cleanout wye female end terminates at 10" above concrete, use a rubber doughnut to transition to pvc, use a double fixture, reconnect to CI using stainless shielded fernco.
***In this case, does the stack count as a vent? The stack drains 2 "full" bathroom groups, plus a kitchen sink/DW/disposal. It goes horizontal for about 6 ft (catching one bath group and kitchen) before returning vertical for the roof termination. 3" throughout.

3) Use existing santee in stack for lav, break concrete for bar sink, run a vent for bar sink. I assume the answer in #2 remains the same for this situation on whether the lav needs its own vent or not.

 

[Gslenk]

Run one primary drain line to the toilet. All of the other fixtures can tie into that line as long as they are each being vented the shower and lav drains can tie together into one line.
The washer connection should be downstream of the other fixtures on the line.

Not too sure about the laundry sink (green path) would it tie into. It will be easy to vent everything except the toilet. Toilet drain does not pass under any walls. Would the shower vent count as a toilet wet vent?

Attached is a blank version in case you want to mark that up

 

[Cacher_Chick]

This isn't bad, you can eliminate the separate vent for the water closet because it is vented by the shower vent.
Every stack going into the floor needs a cleanout above the floor.
If you use all the correct pipe sizes, fittings, and put everything in the right place, you should be golden.

 

[Gslenk]

It looks like a crap ton of concrete is going to come up . In light of that, I am really leaning towards the double fixture fitting on the main stack for the bathroom lav and wet bar sink. Attached are some more accurate models.
1) If I put a double fixture on the main stack for the bathroom lav, and wet bar sink, will I need to run vents for each of them? If so, as long as I stay vertical or 45 degrees from vertical (to clear obstructions/framing etc.) can I do as many bends as necessary until 6" above the floor's highest flood rim, then go horizontal.

2) Awesome, I can use the tub/shower for a vent. I was dreading the water closet vent in a very bad way.

3) Can I tie the laundry sink into the clothes washer standpipe's stack, above the slab? This would save a cleanout, and some piping, and hopefully some concrete. I hacked up something in paint, and could be designed better, but is the idea ok?

4) thanks for the tip on cleanouts. I assume those can be hidden in the wall with access panels in front?

5) Anything else that seems redundant, or could be changed to simplify, or reduce concrete demo?

The attached model drains/vents are color coded as:
Turquoise - Lavatory 1.5"
Orange - Main stack/drain (existing) 3", might, doubtfully be 4" under slab.
Red - Water Closet 3"
Green - Tub/Shower 2"
pink/purple - Laundry sink 1.5" (must be 2" if under ground?)
Blue - Clothes washer stand pipe 2"

 

[Cacher_Chick]

You can't vent using the existing stack must draining fixtures on the floor above. A double fixture fitting only fits on a 2" drain stack. You can tie the laundry sink and washer drains together- each needs to be trapped separately & properly vented. All the drain lines should be 2", but the sink traps and sink trap arms can be 1-1/2.

 

[Gslenk]

A double fixture fitting only fits on a 2" drain stack.

Did not know that . Since I am removing the cast iron, maybe use a 2" single fitting and tie lav and bar sink into that? Lav p-traps, then shoots straight back to the orange stack. Wet bar Tee's into that pipe. venting will be interesting in that area (I see 3 possible locations, green brown purple). Take off at a 45 degree angle to get into the cavity and go up from there. Or would the purple line (which would shoot straight up) be adequate as a vent, then the wet bar wet vents the lavatory?

I think I have a plan for the laundry sink and washer pipe. But still a few more questions...
1) I read that once a stand pipe connects to other fixtures, and goes horizontal, it is a branch, and a stand pipe must tie into a 3" branch (unless I screwed up my definition/scenario).
2) Since I am adding a cleanout at the base of the standpipe/laundry sink stack anyway, I feel a lot better about tying into the water closet branch. Could I do that, as long as this connection is the last in the branch? That would save a ton of concrete demo.

 

[Gslenk]

Can I combine the laundry sink and stand pipe like this? And this is what I mean by running it to the water closet branch, or is this a step backwards?

 

[Cacher_Chick]

Terry's photosmight help you-

You can also do something similar to this on the stack for your sinks, but instead of the combo and standpipe, install a sanitary tee on the re-vent to drain the fixture on the right.

 

[Gslenk]

Terry's photosmight help you-

I got the idea from this thread:
https://terrylove.com/forums/index.php?threads/laundry-room-sink-and-washer-dwv-question.61647/

I think I have seen every picture on this site or tried to (including the one you posted). I have read posts saying one cannot vent the other, and vice versa, but my diagram has both individually dry vented. It seems to be preferable that the sink enters the stack below the standpipe, but I have read arguments going the other way. I want to keep the stack as close to the shower plumbing as possible (to the left), to minimize concrete break-up, this means all the fixtures would be to the right of the stack. The only part of my layout that I am unsure of is the 3" requirement for a stand pipe on a horizontal branch or a vertical stack with another fixture. Unless there is something blatantly wrong about the diagram I posted?

 

[Gslenk]

Honestly, I am kind of dreading knocking out some cast iron pipe... I had an idea, I use the existing 1.5" threaded fitting to make a mini stack. Bar sink shoots straight back, and 45's over to the mini-stack. Lavatory shoots straight back to the mini stack. Vent ties into the rest of the bathroom.

I suspect there might need to be a cleanout, unless the lavatory p-trap (with removable fittings) counts as the clean-out.

The bar sink trap arm would be just under 40" total length, I could run a vent in the wall, but at 1.5" pipe, I think I am good. The path of waste/drain seems to be very similar to if the mini-stack/revent was on the right side for the bar sink.

Is it a slick/valid idea, or a silly hack? If so, I was thinking long sweep for the vertical to horizontal (to the main stack) and two fitting tee's for the trap arms to meet the mini stack. If a long 45 exists, I have space to use it.