I need to VENT (shower/tub)

16 years ago

Background: Remodel work, bathroom. Double vanity relocated, broke up shower/tub to separate units. Sinks share one dedicated 2" vent to roof. All bath fixtures drain into a common 3", 1/4" per ft sloped horizontal (via long turn 3x3x2 wyes) then vertical 4" main. Large crawlspace where all drains and supplies are located.

My issues:

#1 I want to share one existing 2" vent through roof for both the shower and tub. The shower drain is ~2' from the vent I want to use and 4" from the main 3" horizontal drain. I put a 2" santee under the shower drain to be used as a horizontal vent that would travel 2' to the vent and hooked the p-trap after the santee to a 3x3x2 long turn wye into the horizontal drain. Is the santee/vent arrangement I have ok? If not, what should I do?

#2 I want to vent my tub drain by using the 2" vent shared by the shower. Unfortunately, the tub is about 10' away from the vent (as the crow flies), and the bathrom has finished walls (no putting in a dedicated vent here now). My thought here was to have a 2" p-trap at the tub drain

that is mated to a 2x2x2 long turn wye, head end with a CO, that goes ~6" to a 2x2x2 santee attached @45 degrees with a short arm to a 45 degree short ell that would get 10' of travel vent/pipe to the vertical vent 10' away. Is this ok? If not, what can I do?

I may be able to draw this out if my ramblings aren't mentally cohesive.

Sort by:Oldest

Comments (5)

Ron Natalie
16 years ago
No horizontal vent lines below the flood level of the fixture.
It sounds like you are also venting the shower side of the trap, which won't work either.

I can't even begin to visualize #2. If you did all this remodelling, why don't you open up the walls and run the plumbing and venting correctly rather than the disaster-waiting-to-happen you're working on now.
lazypup
16 years ago
The bad news is that venting a tub or shower in the manner you suggest is prohibited by code. Code prohibits any horizontal venting until the vent reaches an elevation, which is 6" higher than the flood level rim of the highest fixture served by that vent.
The good news is that you may not need additional venting on the tub and shower.

Under the IRC (International Residential Code) all structures are required to have one "main vent" which must run undiminished in size from the house "main drain" through the roof. Once that is achieved any additional auxiliary vents may be reduced to Â½ the diameter of the line they serve, but not less than 1-1/4". Your drain is 3" so you would only need a 1-1/2" vent.

Under the UPC (Uniform Plumbing Code) all vents are sized by the total number of DFUÂs (drainage fixture units) of the fixtures served by that vent. You have one tub (2dfuÂs), one shower (2dfuÂs) and 2 lavatories (1dfu each) and a water closet (3dfuÂs) for a combined total of 9dfuÂs.

The UPC allows a maximum of 24 dfuÂs on a 2" vent. Therefore under either code you would be able to vent the entire bathroom group with one 2" vent. The key then becomes where that vent is located in relation to all the drains.

There is a single pipe, which runs from the fixture trap to the vent or branch drain, which is properly called the "Fixture Arm" or "Waste Arm". By necessity that pipe must serve as both the vent and drain for the trap. Under the IRC the bottom of the fixture arm at the trap weir may not be higher than the top of the fixture arm at the trap, therefore we can mathematically compute the maximum length by dividing the pipe diameter by the pitch. Understanding that all pipes 3" or less are required a Â¼" per foot pitch we can then determine the maximum length by dividing the pipe diameter by .25"

1-1/4" divided by .25" = 5Â
1-1/2" divided by .25" = 6Â
2" divided by .25" = 8Â
3" divided by .25" = 12Â
4" or larger divided by .25" = 16Â
There is an exception in the IRC that states a 3" or 4" that serves only a watercloset may run an indefinite length.

Installers must be very attentive to detail when running the fixture arm. If you inadvertently increase the pitch, it will ultimately shorten the allowable length.

The UPC begins with basically the same formula, but they then de-rate the length by approximately 40% thus we must use the lengths published in the Code Book.
1-1/4" = 2Â6"
1-1/2" = 3Â6"
2" = 5Â
3" = 6Â
4" or larger 10Â

I would need to see a drawing of your proposed layout showing all drains (including diameter and length) and the position of your existing 2" vent in order to determine whether you need any additional venting.

I have not mastered the technique for posting pictures on this forum. If you can post it here that is fine, otherwise you may email it to me direct.
Related Discussions
Tub, shower, tub AND shower, which goes where?
Q
Comments (3)
Do you have grand-kids, or are you expecting any near your guest bedrooms? If so, do consider having tubs (at least a small 5 foot inexpensive one) for baths. You won't regret that, especially for resale. As for your Master Bath, ask a realtor friend and they will likely tell you it's 'best' for re-sale for a 5-piece Master too, but if you'd much rather have the extra-large shower than a smaller shower and tub, then go for the larger shower and forget the tub. We have an oversized shower (dual heads, etc) and absolutely love it. We have a big jacuzzi tub too and it's nice but doesn't get a whole lot of use. Our overall bathroom is quite large, but if I were limited on space, the tub would be the first to go or at least downsize. As you age, you will probably find a better use for a walk-in shower with things you can add in your later remodel (hand-held rails, bench, etc) than a tub that is hard to step into.
...See More
Master bath small shower + tub or no tub?
Q
Comments (27)
Well, phooey. I taped it out in the bathroom with blue tape last night and it looked like it would fit, but with too many nos, I'm back to the drawing board. Interesting thought, Vix. Right now we don't actually have a toilet room, so much as a separate toilet "area" (there's no door, and the closet takes up too much room to add a door), but it's on my agenda to create one. In our house, it's very necessary. I generally use that bathroom to try to FIND privacy, only to have 3 people (and sometimes the dog) follow me into the bathroom. I'm looking forward to having a door that locks and a fan so that I don't have two little people handing me the TP and asking whether I'm doing number 1 or 2 (oh, and the 1 year old likes to flush while I'm ON the pot; so I've got my own special cold water washlet), while DH decides that he absolutely has to shave and brush his teeth at that exact moment. Now if I take a hike to the guest bath on the other side of the house, all three just follow me AGAIN. Sometimes when I have insisted on locking the door in the guest bath (no way to do that with our LOUVERED -- why??? -- pocket door in the master), my one year old plopped down prostrate outside the door and cried until I open the door. For my W/C, I want to put in a LOUD fan; no whisper quiet for me. Maybe I'll even add a radio. :) The way I'm seeing it, I can either get rid of the long vanity altogether and live with a fairly small vanity, plus a tub and shower, I can skip the tub and live with the kids' bathroom on the third level as the only room with a tub, or we can bump out that weird corner jog, which would give us an additional 49'' X 27'' space -- enough to fit a 5X3 tub, 5X3 shower and keep the two vanities. But that sounds very expensive and will require carefully removing and replacing the siding to match the existing. DH's response to all this was "why do we need a tub?"
...See More
bath tub to shower
Q
Comments (3)
Hi there - I remembered reading similar questions earlier today. Here are the links: http://ths.gardenweb.com/forums/load/bath/msg0501465912845.html?24 http://ths.gardenweb.com/forums/load/bath/msg061429391436.html?27
...See More
Need advice with venting/tub trap/shower trap
Q
Comments (1)
The guy at Home Depot just proved to you why he is stocking shelves instead of working in the plumbing trade. Using an 1-1/2" trap as suggest by the Home Depot clerk would be two code violations. 1. A shower is required to have a 2" trap and a 2" drain line & 2. The drain basket in the base of the shower already has a 2" discharge and code strictly prohibits reducing the size of a drain line in the direction of flow. You may need to consult a framer about sistering that joist so you can notch it. The plumbing code prohibits any notches on the top of a floor joist in the center 1/3 of the overall span. On the outer 1/3 of the joist you may notch to a depth not to exceed 1/6 the height of the joist. (a 2x10 could be notched a maximum of 1-1/2").
...See More
tjdabomb70
Original Author
16 years ago
Pup -

I emailed you the drawing about a month ago (this is my second, exact, post) and never heard back from you. Since I didn't hear back from you, I thought you found the edge of the Earth.

Did you never receive my email? Shall I try to send it again?

***Ron, I inherited the work, I got on the job after the walls were sewn up. Regardless, in terms of the tub, it is in a structural push-out which would have made a typical vent (up through the adjacent wall closest to the drain) impossible - the wall is mostly window and the rest stud/jack stud/header.

Thanks -
T
lazypup
16 years ago
i didnt get the email...pls try again...

LazyPup@yahoo.com
tjdabomb70
Original Author
16 years ago
Pup -

I just re-sent the drawing - thanks.

Tjdb

I need to VENT (shower/tub)

Comments (5)

Ron Natalie

lazypup

Related Discussions

tjdabomb70
Original Author

lazypup

tjdabomb70
Original Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

I need to VENT (shower/tub)

Comments (5)

Ron Natalie

lazypup

Related Discussions

tjdabomb70Original Author

lazypup

tjdabomb70Original Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

tjdabomb70
Original Author

tjdabomb70
Original Author