DWV Layout Assistance

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by robh, Jun 25, 2008.

  1. robh

    robh New Member

    Messages:
    13
    Hi folks.

    I have a bathroom remodel project and some rather difficult venting constraints ( two outside walls, shallow ceiling, two tiered floor framing etc ). I made a stab at the venting ( see below ) although I suspect the wet venting of the tub and shower might not be up to code ( Seattle, WA ). The diagrams are color coded for pipe size - Red=3", Green=1.5", Blue=2".

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    I would appreciate any pointers or suggestions.

    -R
  2. robh

    robh New Member

    Messages:
    13
    No feedback? It must be the most amazing layout anyone has ever encountered or it's the worst. :)
  3. sjsmithjr

    sjsmithjr Geologist

    Messages:
    295
    Location:
    Knoxville, Tennessee
    I'm not a professional plumber, but:

    I think the way you've tied in the washing machine drain will give you troubles.

    It would appear to me that your premonition was correct about the tub and shower venting - that's not going to work.

    I'm sure one of the pros will be along shortly.
  4. mnalep

    mnalep New Member

    Messages:
    107
    Location:
    Michigan
    I can't comment on the correctness, but I do wonder what software you used to create this?
  5. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    Okay...
    The tub is not vented with the elbows running down to the drain before hitting the vent you have made an S-Trap.
    The shower is not vented.
    Putting the washer on the toilet has created a venting issue there as well.
    Are those wye's or, sai-tee's bringing in the tub, lav, and shower to the red line?

    Nice drawing by the way!
    Last edited: Jul 2, 2008
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,540
    Location:
    Cave Creek, Arizona
    dwv

    The shower is not vented, and depending on how you actually install the tub trap, it could also have a problem. The washer into the toilet vent could create a problem, I have seen situations where draining the washer aspirated the water out of the toilet bowl.
  7. robh

    robh New Member

    Messages:
    13
    mnalep: I used Google's Sketchup program. It's fantastic for conceptualizing projects.
    Redwood: I used wye's on the mainline drain.

    Thanks for the feedback. Here is my problem with adding vents to the tub/shower. The walls closest to the tub and shower are outside walls ( left of tub and parallel to the final red pipe run ).
    So I can't vent out those walls. Also my ceiling is very very shallow ( above the shower it's a 3" ceiling ). Would you recommend attempting to run a vent up the outside wall across the
    ceiling and connect to the toilet or the sink vent? Where would you bring the washer drain into this system if not in the toilet vent stack?

    Thanks again,

    -R
    Last edited: Jul 10, 2008
  8. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    The washer could drain into the line below the toilet and revent into the toilet vent. The bathtub you show the line curving up and then back down to the drain. If it went in straight without the downward curve it would be vented by what you show. You can run a vent in the outside wall to the attic and tie in above.
  9. robh

    robh New Member

    Messages:
    13
    Redwood: Thanks for the quick reply. I will re-route the washer and fix that problem. The reason for the curve up in the bathtub line was to accomodate the trap. Are you suggesting I remove the trap?

    I will redraw my plan and see if it matches the comments.

    Thanks everyone.

    -R
  10. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    No, you need a trap but if you had a longer tailpiece out of the tub and into the trap then the drain could go straight into the drain, The curve creates an S-Trap effect and makes it unvented.
  11. construct30

    construct30 New Member

    Messages:
    590
    Location:
    NorthWest PA
    The bottom of the pipe where the P-trap starts to drain cannot be higher than the top of the pipe where it goes into the main drain, it does what they said and turns it into an S-trap. That is why there is a limit on the length of an unvented pipe from the vented stack with proper fall.
    Last edited: Jul 11, 2008
  12. mnalep

    mnalep New Member

    Messages:
    107
    Location:
    Michigan
    Robh, Thanks. I will download google SketchUp and try.

    Did you do your drawing with the free version?

    Did you have to draw the individual items in your layout (tub, sinks, pipes, toilets, etc), or was there a library of these things you started building your diagram with?
  13. robh

    robh New Member

    Messages:
    13
    Redwood/Construct30: Thanks for the advice. Now I understand the problem. If I lower the trap to the same level as the red pipe ( pipe vertically down from tub ) and then run a connection over to it with a gradual slope it will be ok.

    mnalep: You can use the free version although printing is a bit restricted. Also I don't know that you can import/export to autocad format in the free version. The sink, tub, toilet, and vanity are all standard objects that come with sketchup. I made the pipe...and the fittings are imported autocad drawings supplied from Thomas Net and the fitting manufacturer.
  14. robh

    robh New Member

    Messages:
    13
    Updated routing

    Here are my updates. Is this closer?

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    Attached Files:

    Last edited: Jul 17, 2008
  15. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    Your shower is now vented on the wrong side of the trap.
    The shower vent also has to go ino the vent higher to prevent the washer from flooding the vent.
  16. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,540
    Location:
    Cave Creek, Arizona
    vent

    Conventional practice would tie the shower vent into the horizontal section of the washer drain where it connects to the toilet vent riser. The shower vent connects AFTER the "P" trap.
  17. robh

    robh New Member

    Messages:
    13
    Oh...I can't believe I placed that above the p-trap. My only excuse is that it was late at night when I was working on these drawings. I will tie the shower vent into the horizontal section of the washer vent. Also I will connect the vent after the trap and upload the drawings. Thanks so much for the help. You guys are great!

    mnalep: Here is a link to the CAD drawings of common DWV PVC fittings:
    http://www.thomasnet.com/cadlibrary...pos=1&cid=10016195&az=26487751&navsec=results
  18. robh

    robh New Member

    Messages:
    13
    Last revision?

    Ok...here are the changes. Look ok?

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    Attached Files:

  19. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    Much much better than before!
  20. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

    Messages:
    2,714
    Location:
    Central Florida
    Why did the washer drain go from 2" to 1 1/2"? I'm not sure that's legal...
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