Graphic Designer Doing Plumbing Rough In - 2nd Time....

Javelin · January 12

Hi All,

About 2 years ago, I posted a similar thread and you all were of great help… WELL, life got in the way, but am finally getting around to the primary suite… the layout needed to change a bit and I have questions about my layout if you could all weigh in..

Basically this is a bathroom with a laundry room on the other side of it. It's on the 2nd floor of a 3 story single family house and there is a 4" main stack that comes down from the 3rd floor bathroom above. Here are some specific points/considerations/questions for you all:

As shown, there is a finished dining room below half of this bathroom (show in red) which I cannot enter, but there is a green area that will be an eventual soffit below that I can drop into for drains.
The double vanity in the bathroom. Unfortunately where the new wall falls is above a triple joist which obviously I don't want to mess with. As shown, I am planning on dropping through the FLOOR (keeping the plumbing in the cabinet of the vanity. The drain will have to go through the floor to a 90, then through 1 joist, then two other 90s until it's on a strait path to the stack.
I was told somewhere that I can't dump the washing machine standpipe ABOVE the toilet, is that true? THat's why I have it going into the 2" "side drain" near the stack.
Do I need a separate vent for the washing machine since it's so close to the main stack?
Above the sink in the laundry room will be a steam generator that needs a drain. This will be steam feeding the shower on the other side.
Note that all horizontal drains (in dark aqua) shown in my mockup will be sloped at 1/4"/ft. All vents (in light aqua) will be at least 1/8" per foot.
2" PVC will be used away from shower, planning on 1.5" from sinks.

What do you all think? am I on the right track? Please let me know and I can revise and repost.

THANK YOU!!!

Jay

CLamb · January 12

Which computer program are you using for those graphics and how do you like it for that purpose?

Javelin · January 12

CLamb, I'm using a program called Sketchup.. used to be from Google, now it's owned by Trimble? It's meant for 3d modeling, not really plumbing, but it's what I know and is easy to orbit around and get a good sense of spacing.

Intplm. · January 12

The double ty serving the double lav. drains should be in the wall along with their branch drains. The discharge of the double ty should have a 45 deg. ell until it gets to the partition floor and there it should continue the offset out of the wall with another 45 deg. ell.

The discharge serving the washing machine should discharge lower than your drawing. Ideally it should have a dedicated drain passing through the partition and finding the main stack below with a 4 x 2 inch ty into the main stack. This will help prevent the discharge of high volume soap layden drain water from the washing machine, preventing suds backing into other fixtures. The water lines and washing machine box should not be installed on an outside wall to help prevent freezing.

This is my quick take. Plumbing code requirements vary in different areas. Code compliance should be followed in the area that you tend on installing said plumbing systems.

hot_rod · January 12

You have a mixture of a stack vent system and circuit vents.

If the fixtures are clustered, within a certain distance, around that main stack, the 3" VTR can serve multiple fixtures.

The pedestal lav could tie in above the washer, if the washer vent is 2" then the lav is vented through that also. Depends on the distances also.

A double San T is the fitting to use for those lav, not a double Y or combo. My inspectors would want a 2" clean-out under that double san tee.

This fitting for the shower drain needs to be a Y or a combo. You should not tie into a horizontal line with a san t. If that is what you are showing

I would roll a combo up at a 45 and get rid of the 90

Is this the top floor? If so the white circuit venting could tie into that 3" green pipe under the roof so you have just one vent penetration.

If the system has a 3" waste, the VTR through the roof has to equal that. Either a 3" vent or the small vents add up to the same area.

Different codes, different inspectors, different plumbers opinions on what is acceptable. Get an illustrated code book, of the year that your plumbing inspectors use, to be sure you comply with their codebook.

Screenshot 2025-01-12 at 3.06.48 PM.png

Screenshot 2025-01-12 at 3.02.25 PM.png

Intplm. · January 12

@Javelin

It should be noted that "ty" and "san tee" (short for sanitary tee) are synonyms. Both terms are used. Apologies for any confusion.

To be more accurate, "Tee Wye". (ty)

Kaos · January 13

Might be better to put the vanity under the window. You can move that rad, replace it with a toekick heater or converter to floor heat. You can then put the toilet into a small cubby where the shower is and the shower where the toilet. It would leave you the wall where the vanity currently is free so you can build it some storage, or you can put the washer/dryer there.

This would keep the plumbing much closer to the stack, and you would not have to bring any of it bellow the floor.

hot_rod · January 13

https://forum.heatinghelp.com/discussion/comment/1834193#Comment_1834193

Different terms used in different areas I suppose. I was taught that this is a TY, combination of a tee and a Y. When I moved west they call this a double combo, double combination. So..?

Some suggest this fitting

, the Y combo, y combo can siphon a trap, or not allow air flow.

IMG_0948.jpeg

IMG_0952.png

PC7060 · January 13

https://forum.heatinghelp.com/discussion/comment/1834173#Comment_1834173

I had same thought. The layout and routing look impressive. I use Chief Architect (2019) and am unable to get that level of detail.

Alan (California Radiant) Forbes · January 13

Don't drain the steam drain directly into the sanitary. You can combine it with the relief valve and daylight it at the foundation. A rupture pan with drain is usually available from the same company as the steam generator, like Steamist. Edit: You could drain it into the clothes washer standpipe or a lavatory tailpiece.

For any vertical drains that carry through a living space - unless you like frieght trains - use cast iron. Plastic is annoyingly loud.

Out here, the Uniform Plumbing Code allows wet venting of 1 or 2 fixture unit fixtures. A clothes washer is a 3 unit fixture, so no, you wouldn't be able to do it here. But look up your local code. It would save a lot of time if you can and I'm sure it would work perfectly fine, especially on a 3" or 4" vent.

Intplm. · January 13

https://forum.heatinghelp.com/discussion/comment/1834245#Comment_1834245

A very good explanation. Every code book that I have read over the decades have indicated that a horizontal should discharge to a vertical with a (sanitary tee-wye.)

In my first post, I was abbreviating as if I was writing a supply house list of materials. - Whoops -.

Javelin · January 13

Thank you all so much for your expert advice and guidance… Here are some more tidbits I omitted that might help answer some more questions.

More Information:

These joists involved are MEATY.. They actual dimensions of 3" x 10".. while I don't want to drill through that double/triple joist under the double sink, it's effectively at least a 6"x10" double joist. I know nothing in the middle 3rd of the span is a no-no, but literally 2 feet from where I'm thinking, old radiator pipes have been going through a notch for 100 years. (see attached "A").
The 2nd floor of the house exterior wall is 3 courses of brick built on top of the 1st story walls which are stone/masonry and thicker…. there is really no space between the main vertical stack shown and the masonry wall on the floor below.
Main plumbing stack is currently 4" PVC.
@hot_rod - to answer your question, this is a 2nd floor bathroom.. There is a walk-in attic above.. The existing 4" stack goes up in the attic, does a 45 turn to follow the roofline for a bit, then goes through the roof at one point closer to the peak (see attached B). I hope to run my 2" vent up into the attic as well and then tie it into the 4" before it goes out the roof (I did that for the 3rd floor bath venting when I did it years ago)
@Kaos - THank you Kaos for the suggestion.. while I did my best to properly put plumbing runs to scale I didn't really care about the window… it's not accurately represented and in reality is only about 26" from what will be the finished floor, so too low to put a vanity under.. plus we (wife) wants mirrors above sink/etc.
@Alan (California Radiant) Forbes - Alan, Thank you for your steam generator drain advice, but I'm not following, can you please elaborate and/or send a photo (I'm a very visual thinker (obviously)). I'm planning on getting the steam generator sooner than later so I can have in hand for measurements/clearances/etc. Also, you mention verticals in cast iron because of noise.. in the past I've wrapped vertical PVC with insulation to deaden the sound with good results… Any reason I should NOT do that? Seems easy enough and still allows for easy PVC work.
@Intplm. - The washing machine box and some plumbing will be on the outside wall, but I plan on spray foaming and some rockwool behind any possible freezing point. The house is an old house and as much as I try to insulate, I'm SURE there is plenty of heat escaping into that cavity as well, so I'm not too scared about that :)

What I changed - attached in orange pipe to show where I adjusted…

@Intplm. suggested that I rework the plumbing behind the double sink. I changed to double san-ts. I think with the thickness of the floor added in and using 45s instead of 90s I can get the plumbing properly behind the wall. I also changed the standpipe dump to be lower than the laundry room sink discharge.. If I understand correctly, we just want the standpipe to be the lowest of the bunch for suds?
@hot_rod - added a clean out below the double vanity San T.. I guess it will be only accessible through a cut-out on the back side of the future vanity, but I'm sure will be grateful if there is ever a clog.

Still More Questions:

So it DOES sound like i need a separate vent for the washing machine stand pipe right? Or is the close proximity to the 4" stack good enough? It should be noted that the discharge tube from the washing machine always fits loosely into the box (so isn't that a vent in and of itself to the room?)
If I wanted to try to move the double sink plumbing closer to the brick wall, can I do something like the attached in "C"? More of a linear solution than a "cross"? That way I wouldn't have to jog the drain line as much…
Just confirming 1.5" for sink drains and 2" for the shower… vents can all be 1.5".
For the actual toilet flange should I stick to 4" or is 3" find especially since it's so close to stack? Is there a bgi difference in terms of performace?

Again, thank you all so much, sorry if it's too detailed above, but I value your time and input so wanted to try to be as clear as possible!

Javelin · January 13

One more thought.. I took another look.. it looks like I DO have space between the stack and the brick wall to tie in the standpipe with either a 90 or a 45.. Does that make more sense? If so (shown in purple pipe attached) how would I vent it.. like this? THANK YOU!

Kaos · January 14

Washers are drained into a stack above a toilet all the time. Think of a washer above a main floor toilet. I would run the drain right to the stack, since it is close you won't need a vent. Use a reducing sanT for the stack connection and a 45 elbow instead of a 90 there to connect it (ie sanT points 45 to the side, the elbow makes it 90).

For the vanity drain, you can run it along the wall and along the outside wall to the stack. This is too far so it will need a vent as you have shown. It is a good idea to to put some insualtion behind the pipe on the outside wall although tends not to be an issue as water doesn't sit there. You don't want your water supply lines running in the outside wall though. This will keep the drains away from the floor beam and needing to drop bellow the joists.

The pedestal sink can also drain straight into the stack, no need for that branch on the side.

The shower can drain can run along the joist and connected to a reducing Y on the toilet drain, not needed but would also serve as a wet vent for it.

Alan (California Radiant) Forbes · January 14

It sounds as though you're getting a steam generator with an automatic drain. The one Steamist makes opens the drain valve every time the water temperature in the tank drops below 100F. The jury is out on whether this extends the life of the stainless steel tank. But in hard water area, it probably reduces deposits.

To clarify the drain and relief valve piping for the steam generator, the ideal way to terminate the drain is at the foundation where a dripping pipe will be noticed to correct a problem at the steam generator. But in a pinch, I've seen the drain/relief pipes connected to a branch tailpiece at a lavatory and also poking through a washing machine box to drain into the standpipe.

If wrapping the PVC stacks works for you, no problem. We have ABS pipe here and I think it's louder; not as dense as PVC.

Drains and vents below the flood rim + 6" of the plumbing fixture must be drainage fittings. Tees on their backs aren't allowed, short 90's are only allowed when draining vertical to horizontal. So if you're venting a kitchen sink and you want to go horizontal below 42" above the floor (36" + 6"), you have to use a long sweep 90. That tee on it's back for the laundry vent is a no-no.

hot_rod · January 14

is this going to be inspected? If so, get the opinion from your local AHJ as you can see there are a number of way to pipe a DWV system.

I agree with Kaos that the washer could drain into the stack and not need a vent.

We were allowed to put a San tee on its back, but only for venting, not a drain.

What flies in your area is tough to know.

Often you can hide an offset in the kick space of a vanity. So come up through the floor in front of the wall and a 45 and street 45, or two 45’s gets you into the stud bay.

I have also found that a section of cast iron no hub for the drainage section of the vertical stack will make it absolutely quiet. Really no way to insulate PVC or ABS to be quiet.

So where the lav ties into the stack, from there down make cast iron

This section may clear up some questions, if your AHJ uses the ICC. ICC tends to be lest strict than the UPC, but both have been changing with every revision. I’m probably not current with the 2024 edition, if that is what your AHJ adopted?

https://codes.iccsafe.org/s/IPC2015_NY/chapter-7-sanitary-drainage/IPC2015-Ch07-Sec706.3#:~:text=Sanitary%20tees%20may%20be%20used,venting%20applications%20in%20sanitary%20drainage.

Graphic Designer Doing Plumbing Rough In - 2nd Time....

Comments

Categories