Basement Bathroom DWV layout
Hi, can I get some feedback on the following DWV layout ? (sorry for the crude drawing) From top to bottom, there's a 2" horizontal stub in a tub pit (to connect to the 1.5" tub drain kit, followed by a 45 degree upturned wye between the tub and toilet with dedicated 2" vent riser, a 3" wye and a 3" elbow to the toilet flange, then a 3/3/2 wye going up into the wall, connecting to two stacked sanitary tees, one draining the lavatory and one on the back of the wall for a bar sink. The output will wye into the existing in-floor 4" cast iron drain just to the outside of the door. The vents will connect and continue up into the upper floors and eventually join the main vent. BTW, the room is 8'x5' and I'm on 2012 IPC. Do I have all the approximate sizes right? Do I need to transition to 4" after I pick up the two sinks? Other comments/suggestions?
Comments (20)
Bruce in Northern Virginia
8 years agolast modified: 8 years agodgeist thanked Bruce in Northern Virginiadgeist
8 years agoGood stuff, Bruce. What I'm hearing is:
- Give the toilet some "runway" and keep it isolated from other fixtures if possible.
- Keep 3" sections of pipe "rinsed" (I assume this is because low-demand fixtures don't put enough volume in them to keep them clean?).I re-did the layout with some suggestions incorporated. The wye near the tub will be purely for venting and up-turned at 45 degress. The next wye (a 3x3x2 with sweep bend) changes the direction of the "grey water" sources. Does that one need to be up-turned to avoid backup from downstream? The in-framing portions will be two 2" sanitary tees stacked and continuing up and tied to the tub vent and with a 90 sweep elbow at the slab level (not sure if that should be a 2x3 transition fitting to help with venting of the toilet or not). With the toilet on the "straight" leg of the last wye, I think I'm getting a straighter shot for the slug. Wet venting with a lavatory is allowed under my code, so will the dual-lav stack give me the needed venting to avoid trap-suck with the toilet as long as all the buried pipe in that section is 3"?
Dan
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Comments (1)Before we get into your layout there are a few points in your post that require attention. 1.A watercloset MUST BE installed on a closet bend. It may not be installed on a wye & 1/8 bend or combo. When it is necessary to install a watercloset on an existing horizontal line you must first install a Wye, wye & 1/8 bend or combo with the side inlet on the side of the line then use a closet bend to transition from horizontal to vertical. 2.Code prohibits installing a "sanitary Tee" on a horizontal line. You must use a Wye, Wye & 1/8 bend or a combo. 3.The length of a waste arm is measured from the "Trap Weir" to the vent opening. The Trap weir is the point were the U section of the trap transitions to horizontal on the trap tailpiece. (The physical point where the water would spill out of the trap and enter the drain line.). 4. Code prohibits any horizontal venting until the vent reaches an elevation of 6" above the flood level rim of the highest fixture served by that vent therefore you may not connect a vent to the vertical riser under the watercloset. Under the International Residential Code the maximum length of a fixture arm or waste arm can be computed by dividing the diameter by the pitch thus your formula was correct, a 2" line with a " pitch could run a maximum of 2" / .25" = 8Â. The UPC begins with the same basic formula but they then de-rate the overall length by approximately 40% and the results are published in UPC table T-10-1 1-1/4"ÂÂÂÂÂÂÂÂ.2Â6" 1-1/2"ÂÂÂÂÂÂÂÂ.3Â6" 2"ÂÂÂÂÂÂÂÂÂÂ5 3"ÂÂÂÂÂÂÂÂÂÂ6 4" or largerÂÂÂÂÂÂ10 The solution is simple. Code requires the watercloset to have a 3" diameter line and you must have a cleanout on the upstream end of all drain lines. Understanding that a watercloset can be lifted granting unobstructed access to the drain line, the code then allows the watercloset to also be the required upstream cleanout. Begin at the closet flange and install a closet bend which transitions the 3" from vertical under the watercloset to horizontal and continue that 3" line as straight as possible to the point where you intend to tie into the house main drain. The UPC requires a 3" line serving a watercloset to have a 2" diameter vent. You may install a Wye, Wye & 1/8 bend or a combo on the 3" downstream of the closet bend, then run a 2" horizontally to the point where your lavatory riser needs to be. Install a 2" ¼ bend and turn upwards to a vertical riser. At the correct elevation for the lavatory drain you will install a "2x2x1-1/2 Sanitary Tee" with a 1-1/2" waste arm extending out to the lavatory trap. The 2" line is then continued up and out through the roof as an auxiliary vent. In this configuration the line extending upwards from the sanitary Tee is a vent, while the line extending down from the Tee and horizontally to the 3" is a "combined Waste & Vent" to the 3" line. Under the UPC a shower stall is rated at 2DFUÂs (drainage fixture units) and a lavatory is rated at 1DFU while a 2" horizontal line is rated for a maximum of 8 DFUÂs, so you may then connect your shower drain into the 2" line or directly to the 3" line. The 2" line from the shower may run a maximum of 5 from the trap weir to the tie in point without requiring any additional venting. The 3" line downstream from the point where the vent ties in is classified as a vented branch and therefore it may run an indefinite length....See MoreBasement bathroom layout dilemma- cross posted
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Comments (5)Thanks for the response kirkhall! Here is another piece of info that's important: ***Bedroom #3 is actually big enough to be a master bedroom by my neighbourhood standards, and has back deck access. I feel weird giving this bedroom to one of my 2 kids, not only because it has the deck access, but also because it is so much larger than the other child's bedroom. (Currently, both kids are in the tiny bedroom, but this needs to change soon.) Another option would be to give one child the big master bedroom (19x11) and keep Bedroom #3 for myself, but then the issue is that one child gets a HUGE bedroom (bigger than their parents') and the other gets a tiny one. So in short: I would really like a new bedroom layout with roughly equal sized kids' bedrooms AND a bigger bathroom, if possible. I think this would be good for resale too.**** Here are my comments on your ideas: - I really like the idea of stealing room from bed #3 to make the existing bathroom bigger. I'll need to play around with that. It would be less costly, I would imagine. Bed #3 would then become a bit smaller, and would be more in line with the other child's bedroom. The back deck access is still an issue, but maybe it's ok. You can't have everything. - In the existing layout, I really like your idea of stealing space from bed#1 and giving it to bed#2 and then putting a powder room in there, maybe in between them, but HOW? - yes, ceiling downstairs is unfinished, and I have ready access to underside of main floor. Comments on my plan: - bed #2 in the new design DOES meet the code for my province. The code is 6 square metres (64 square feet) if a closet is provided, or 7 square metres (75 sf) where no closet is provided. At 77.64 (with closet), and 86.32 sf (no closet), it seems to pass. - privacy: Where the current bathroom is situated, you can peer into it from the living room. So, even though it's far away from the living space, it is still visible....See MoreBasement Bathroom Layout
Comments (15)@seosmp thank you! I’m pretty sure this is the tile we used. https://www.flooranddecor.com/porcelain-tile/hard-cream-wood-plank-porcelain-tile-100198704.html?rrec=true#q=Rondine&start=1 Vanity is from Costco. It’s sold out but there are 2 nice options for 36” right now. If your local warehouse has it in stock it’s usually at least $100 cheaper. https://www.costco.com/CatalogSearch?dept=All&keyword=36”+vanity...See More
Vith
8 years agolast modified: 8 years agodgeist
8 years agoVith
8 years agolast modified: 8 years agodgeist
8 years agoVith
8 years agolast modified: 8 years agodgeist
8 years agolast modified: 8 years agoVith
8 years agolast modified: 8 years agodgeist
8 years agoVith
8 years agolast modified: 8 years agodgeist
8 years agodgeist
8 years agolast modified: 8 years agoBruce in Northern Virginia
8 years agodgeist
8 years agoThanks, Bruce. I also discovered today that my stack is plenty deep at the "northeast" corner of the eventual room. I believe I can connect there and avoid a lot of digging. Back to the drawing board for routing, hopefully this one will be more straightforward. I should be able to replace some of the old iron stack there as well and get rid of a couple code violations while I'm at it :)
dgeist
8 years agoOkay, here's my new attempt with less exposing of non-construction areas. Let me know what you guys think.
dgeist
8 years agoVith
8 years agolast modified: 8 years ago
ramona1976