Bathroom DWV Re-Do Help

[Jetboy55]

Hi all, I am replumbing my small main bathroom and replaceing the cast iron and steel DWV pipes. I have been trying to understand wet venting
requirements (among other requirements) to plan this out. But I am somewhat confused, so I thought I would turn to the folks at Terry Love forum for help. I basically want help designing the whole system. 1 Sink, 1 water closet (toilet), 1 tub/shower, 1 laundry drain. My current setup I believe everything is wet vented accept the sink. The laundry setup is wrong, but not sure what to do with that because of the implications for the wet vented tub, if any.
I have complete access below in a full basement. This is 1 story ranch from 1960's. I have included some measurements in the picture.
Also, the sink drain needs to be moved to the left of the vertical branch drain, over to the where the pex is at.
Can you please help me design this so I don't mess it up? Thanks.

Note: I will be putting in a new tub drain/overflow when I do this.

 

[Tuttles Revenge]

A good starting point would be to provide a good plan view of what you want to install and where the point of connection is and what size that is. Joist layout and and idea of the space you have to work with. What plumbing code you fall under and what materials you plan on using. These are the basics that I use to plan a project.

 

[Sponsor]

 

[Jetboy55]

Thanks. I plan to use PVC for all the DWV. Floor joists are 10" installed 16" on center. I probably can't provide a plan drawing as I don't have that kind of skill. I don't understand the term "point of connection". I want to leave most of it as it is with respect to location and routing, only making changes where there is a problem, and to figure out how to trap the laundry drain on the main level and where it can connect without messing up the wet venting of the tub and toilet. I understand there are limits to where and how many fixtures can drain into a wet vent, so that is what I am most concerned about getting right.
Maybe I should plan the system using my own knowledge, draw that up and then post it to see if it is ok, or what to change?

 

[John Gayewski]

From the lowest point to the highest point. Laundry, then toilet, then sink or shower. Those can all drain into the same 3"drain.

The one challenge I see is that the bathroom fixtures need to drain horizontally into the main. You can't drop those in from above (with the exception of the toilet). Your picture looks like you have your main sitting lower than everything else and they connect into the top of it or close to it.

 

[Jetboy55]

The tub drain can connect in side of branch drain, no problem. The first pic below (Plan 1) is how I could make the system, as far as I understand what to do, however, I included the laundry drain as it currently exists. Plan 2 I have tried to trap the laundry drain in the wall and have it co-running with the sink. Plan 3 is to trap the laundry in the wall, but have the sink run seperately, if there is room. If I leave the laundry trapped in the basement, I don't know how I could vent it while keeping the vent nominally vertical. Perhaps it already is wet vented by nature of the main stack being wet vented through the branch drain.

 

[wwhitney]

Your drawings make it look like the 4" stack passes in front the tub drain from the point of view of the drawing, but it would pass behind the tub drain, right?

Take Plan 1, delete the laundry trap and drain. Add the trap above the floor, with the horizontal outlet connecting to the side entry of a san-tee above the floor. The top of the san-tee is a dry vent that needs to rise vertically to 6" above the top of the standpipe and 6" above the flood rim of the sink, then the dry vent can turn horizontal and reconnect to the 3" stack through the roof. That dry vent can be 1.5".

The bottom outlet of the san-tee is the laundry drain, and it needs to run over to the 4" stack and connect below the lav/tub connection to the 4" stack. The laundry drain can't join the lav drain any sooner than that, as the lav drain is wet venting the tub and WC, and horizontal wet vents are restricted to bathroom fixtures.

What's the horizontal distance from the tub trap to the horizontal combo where it joins the horizontal lav drain?

Cheers, Wayne

 

[Jetboy55]

Yes, you are right, the 4" stack is behind the tub drain from pic's point of view. The distance from tub trap to horizontal lav drain is 60 inches. I think 1.5" trap arm can be 6 feet long at 1/4" pitch. Sound right?

 

[wwhitney]

The distance from tub trap to horizontal lav drain is 60 inches. I think 1.5" trap arm can be 6 feet long at 1/4" pitch. Sound right?

Yes for the IPC, or 42" for the UPC.

Wisconsin has its own plumbing code, and it actually has a table that distinguishes based on how the vent connects to the drain, and a slope of 1/4" or 1/2" per foot. For the case of a horizontal drain outlet (like you have), at 1/4" per foot Wisconsin also allows 72".

Note that still requires a perfect pitch of 1/4" per foot. There's also a total limit of fall of one pipe diameter, or 1-1/2". So as your slope increase beyond 1/4" per foot, your allowable length decreases below 72".

Cheers, Wayne

 

[Jetboy55]

yeah, thats how I understood it when I looked at Wisconsin's table. I redid the drawing as you described for the laundry. I numbered a bunch of fittings and was hoping you could name the fittings at those locations. I certainly think I know which to use and where, but I would rather be sure. 9 and 10 are for the connection to the stack, combo's I believe? (wye and 45 together)?
I will try to be precise on my tub slope, I'll use a laser line to set slope exactly, instead of 1/4 bubble on my level.

 

[wwhitney]

1) 2x1.5x2 san-tee (you can use a 2" san-tee with a 2x1.5 bushing on top if you can't find it as one piece)
2) Any 90 (vent 90, quarter bend, or LT90. Quarter bend is cheapest)
3) 3x3x1.5 san-tee, conventionally "upside down" but that's not necessary. Could use 3x3x1.5 straight tee if cheaper, easier to get
4) 3x3x1.5 san-tee
5 and 6) LT90, or if you want a cleanout, a combo with a cleanout fitting in the straight inlet
7) 3x3x1.5 combo required
8) These two are not equal. The upstream one must be a LT90. The downstream one can be a quarter bend or LT90. I assume the jog is for some obstruction? Check if you make the upstream fitting a 45 (higher up), and then omit the downstream elbow 8, with the pipe going directly into 5, which would be rolled 45 degrees.
9) 4x4x3 san-tee or combo, maybe combo is preferred
10 4x4x2 san-tee or combo, maybe combo is preferred

Wayne

 

[Jetboy55]

Thank you so much for your help. Yeah, the fittings at "8" are there to miss some structure (a I-Beam directly under my bathroom wet wall). Again, thanks.

 

[Jetboy55]

Does LT stand for long turn, in other words long sweep? Also, for the laundry trap, I assume I should glue up a trap, and NOT use a slip jointed trap? Is so, what is the combination of pieces to use to build it, that takes up the least amount of space?

 

[Jeff H Young]

You have got some good help so far from guys above often L.T. means Long Turn.
If you choose to come through floor in existing hole for the washing machine with a trap in the stud bay, its often very tight fit in stud bay often go through offseting etc. sometimes I bring my waste line through floor around 4 inches away from the stud in next bay and pop a hole through the stud that way it fits nicely in the bay without offsets or getting fancy with fittings often offseting the stand pipe etc . been there done that too many times. btw use a standard glue p trap

 

[Jetboy55]

Is a standard glue p-trap a specific thing, or just a combination of short sweep 90's put together with short pieces of pipe? I hope that question makes sense

 

[wwhitney]

Yes, LT = long turn or long sweep. Yes, for the laundry trap you want a 2" solvent weld trap, they are a standard part that comes in two pieces, not something you assemble from other pieces.

You can't butt the hub of the trap outlet directly into the hub of the san-tee--there's a minimum distance between trap and vent, which is 2 pipe diameters. Considering the curvature of the trap outlet and the sanitary tee, that works out to IIRC at least 1.5" of visible pipe between the trap outlet and sanitary tee hubs. This assumes the Wisconsin rules don't differ from the IPC or UPC in this regard.

Cheers, Wayne

 

[Jetboy55]

Awesome, thanks for the answer.

 

[Jetboy55]

My tub trap is accessible thru a suspended ceiling in the basement. Does it get a solvent weld trap also, or a slip joint trap?

 

[wwhitney]

That means you could use a slip joint trap. So if you need the flexibility that a slip joint trap provides (as far as what order to hook things up in), that's fine. If you don't, maybe a solvent weld trap is a better long term solution.

Cheers, Wayne

 

[Jetboy55]

Thanks. I forgot to number the 90 behind the sink trap. Does it need to be LT90? Is so, will I have room in the wall for it?

 

[Jeff H Young]

should be long sweep but even better with a 45 if you dont mind moving the copper. solvent weld is more rugged tubular should have access