Hi

Want to preface by saying that this is a wonderful forum that I have read and used extensively in past for repairs and replacement of existing plumbing, but never posted a question before. I am NOT a plumber and may not even pretend to be one on this particular project if it gets too complex, but I would like to understand thoughts and learn at very least. I drew a very rough diagram highlighting the general goal, AND I have linked to it below.

In words I want to install one of those shower tub combos in a second floor area. Because of open nature of joists for first floor ceiling I am limited as to where/how I can drain and vent. On the first floor, directly below the space where the shower/tub is to be will be a sink and wash machine. they would drain 2" running into 3" and tying into main drain in a crawl area beneath. I *believe* that independently the sink and washer plumbing and venting I have gotten an understanding of...however the wrinkle comes with the drain from tub. The tub is a 5' tub meaning the distance from trap to san t I believe is around 4'6" or so. Above said T runs vent to roof 1.5"....below is where I would love to drain into same pipe used by washer and sink. If I understand properly I need to revent these up and tie back into vent above tub.

My drawing is bad(sorry) and I didnt go through and identify wyes, Ts combos etc - the drawing is split where I try to show the plumbing on 1st floor on face, while second floor is side view just to show tub. The highlighting shows where the tub/shower drain ties in. I know things get squirrely with washing machine vent/drainage rules and other fixture drains, so before I move forward with planning I want to make sure I haven't stepped in it either in functionality, code or both!

[i1356.photobucket.com]
Thanks, Appreciate those who share their wisdom and experience!

keep the tub drain and vent as you show it upstairs. just drop the tub drain down 10 more feet and tie into the 3 inch below the laundry.
this greatly simplifies the first floor venting..

Thanks for the reply Packy - is that to say do NOT run the tub drain into what currently is slated to be the vent pipe (which would have to be increased in size obviously) for the sink and washer, and instead just run a second 2" drain straight into the crawl?

Is the venting as currently drawn insufficient or just more fittings than a straight shot second drain pipe? Im all for simplicity here!

Thanks!



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tub drain can be 1 1/2 inch...
yes, do not run it into the downstairs vent as shown.
vent the tub as you have it but drop the drain down below the first floor fixtures.
you won't get much simpler than that.
then do away with the additional sink vent.
so the sink and the laundry will both be vented into upright sanitary tees. those vents can be 1 1/2 and tie together at 42 inches above the floor. then run that 1 1/2 vent up an tie into the tub vent at 42 inches above that floor. at that point increase to 2 inch.
put some cleanouts in the crawl space..

Thanks for the analysis. I had mapped it in as 2" for tub drainage due to the distance of trap to vent being around 4.5' and had quick read the UPC which said 3.5' trap to vent, but going to Virgina code it appears up to 5' fixture arm is permissible. Can/should that 1.5" remain drainage size run all the way down to crawl tie-in to 3" main waste line?

yes, 1 1/2 inch all the way.
also, you are correct that 1 1/2 inch trap can be up to 5 feet from its vent.

Thanks once again! Last question for now, and this is more procedural: The wall in question that will contain drains and vents for the 3 fixtures is framed true 2x6 sitting on top of a 6is" by 6"ish hand hewn beam below (old log house, some parts log others framed). In order for my two drains to exit wall cavity and enter crawl I either need a small jog out - maybe with a couple 45s back to back in order to clear the beam before tying into a combo in the 3" line in the crawl. In practice what would be the preferred way to maneuver past impediments while limiting turns/possible points of clogging.

Pls let me know if my description of issue is unclear and I can try to draw it out



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seen this many, many times..
i have used a 2 1/2 inch hole saw to cut a 45deg in the top corner of the 6x6. not too deep but enough to allow the pipe to change direction from vertical to 45 deg. there is always a floor and a sub floor to mess around with so the notch depth is kept to a minimum..
then use another 45 to either change to vertical or horizontal.

Outstanding!Truly appreciate the insight!



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