(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 11 of 11

Thread: Fixing My Incorrectly Plumbed Bathroom: Isometric

  1. #1
    DIY Junior Member CapstanRec's Avatar
    Join Date
    Sep 2010
    Location
    New Orleans
    Posts
    23

    Default Fixing My Incorrectly Plumbed Bathroom: Isometric

    hi,

    I first want to say that this forum is a great resource. I've been reading the LA plumbing code and this forum off and on for several months.

    I'm planning to fix my incorrectly plumbed half bathroom. The existing vent is upstream from the toilet and I have a sanitary T on its back. I know this cannot be done so I'm going to replace it all.

    Please take at a look at my attached isometric to see if I have my head wrapped around this conceptually. This plumbing is in the crawlspace under my house. I think I'm going to have to relocate a 1/2" water line to keep the 2" vent as a vertical vent (45 degrees).

    Also... one caveat... New Orleans (where I live) has a supplemental code that requires a full size vent. So by code I'm required to have a 3" vent on this toilet. The only way to accomplish this is to run a 3" piece of PVC up the side of my house, which I don't want to do. Louisiana only requires a 2" vent, and this 2" vent is in a 2x6" wall.

    Thanks in advance... if this looks ok I'll get some fittings and pipes and get things roughed in.
    Attached Images Attached Images  

  2. #2
    DIY Junior Member CapstanRec's Avatar
    Join Date
    Sep 2010
    Location
    New Orleans
    Posts
    23

    Default

    Sorry to post again so soon but I went under my girlfriend's house today that was just built in 2009. In the picture attached, it looks like the 3" vent is "horizontal." I thought this was not acceptacle. I know she had a plumbing inspection. But at the same time she had an electrical inspection that passed and some things were missed. The only reason I know is I'm an electrical engineer and am familiar with the NEC.

    Thanks again.
    Attached Images Attached Images  

  3. #3
    DIY Senior Member dlarrivee's Avatar
    Join Date
    Jun 2009
    Location
    Canada
    Posts
    1,172

    Default

    Hope you didn't pay a fortune for that spray foam job.

  4. #4
    DIY Junior Member CapstanRec's Avatar
    Join Date
    Sep 2010
    Location
    New Orleans
    Posts
    23

    Default

    I didn't pay for that spray foam job... it's my girlfriend's house. It's open cell and I sure hope it doesn't trap any moisture and ruin her wood floors.

    I don't have any insulation under my floors. I did get two quotes and I felt the prices were very high... not to mention neither company would give me a floor replacement if it ruined my floors. My house is 75+ years old with the original heart pine flooring. I couldn't risk it.

    Any comment on the plumbing in the picture?

    I already realize my first diagram won't work... I'm going to try and get under my house this weekend and get something roughed in. Post back with an actual picture instead of a diagram.

  5. #5
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,653

    Default

    The only question about the original drawing, other than why you used a black background with red lettering, is what is the purpose of that "dry vent" other than to waste some materials?

  6. #6
    DIY Junior Member CapstanRec's Avatar
    Join Date
    Sep 2010
    Location
    New Orleans
    Posts
    23

    Default

    Good point on the coloring... it's just the way my AutoCAD defaults are set up. I adjusted and reattached the same 1st image.

    As for the dry vent, the lav drain is only 1-1/2" and wyes into the 3" ... From my understanding, that is a wet vent (which is ok) but it is too small to meet my toilet venting requirements. That why I added the 2" vent. But I'm now thinking I should tie the lav in downstream of the toilet.
    Attached Images Attached Images  

  7. #7
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,653

    Default

    And WHAT is wrong with using 2" for the lavatory drain, regardless of where you connect it? I NEVER use 1 1/2" for any drains. And the 2" dry vent is still just cosmetic and serves absolutely NO purpose.

  8. #8
    DIY Junior Member CapstanRec's Avatar
    Join Date
    Sep 2010
    Location
    New Orleans
    Posts
    23

    Thumbs up

    Thanks hj, but the 1-1/2" lav drain and 2" vent are all I have to work with. That's just the way it was plumbed. They stick through my floor. The lav vent ties into the 2" vent somewhere in the wall above the lav flood rim and then the 2" extends through the roof. The bathroom itself is already complete and I'm just trying to make the plumbing under the house correct... if that's even possible.

    So I guess I'm just really stuck on how to properly vent the toilet. I don't think it's ok to vent it from main stack that services my upstairs bathroom. According to LA code it seemed that the lav drain was ok. Maybe not ideal but ok. I'll stew on a new layout but I am a bit stumped.

    On another note, do you have any comments on the photographed I posted? Just curious. How is that horizontal vent ok? If the main sewer starts to back up it seems the 3" vent will fill up because it below the flood rim of the toilet. Thanks again.

  9. #9
    In the Trades Wally Hays's Avatar
    Join Date
    Nov 2009
    Location
    New England
    Posts
    652

    Default

    Toilets don't need to be vented. Tear out the 1 1/2 that goes to the lav, increase it to 2" and get rid of the 2" dry vent.
    Perception is 3/4 of reality

  10. #10
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,653

    Default

    quote; Toilets don't need to be vented.

    That is true, FUNCTIONALLY, but not code wise in most areas. The only time a horizontal vent is appropriate is when it has something, such as a lavatory, connected to it to keep it washed clean, OR which would not drain if the vent were to get obstructed.

  11. #11
    DIY Junior Member CapstanRec's Avatar
    Join Date
    Sep 2010
    Location
    New Orleans
    Posts
    23

    Default

    I think I really do understand what you've been telling me for two days now.

    I went back and re-read section 911 (Wet Venting) in the LA PLumbing Code:

    911.1 Single Bathroom Groups
    A single bathroom group of fixtures may be installed with the drain from a back vented lavatory, kitchen sink or combination fixture serving as a wet vent for a bathtub or - shower stall and for the water closet, provided that the wet vent is one pipe size larger than the upper fixture drain but in no case smaller than the lower fixture drain, whichever is the larger, and that both drains conform to Table 908.1.

    The idea being if my "wet vent" clogs I'll know it because my lav will back up.

    So I need a new 3" drain and from upstream to downstream have a cleanout, 3"x2" combination wye and 1/8" bend to pick up 2" lav drain, then a 3" wye for the toilet tie in and finally a 3" sanitary tee to tie into my main vertical stack. Very simple and straight forward. I also need two 45 degree fittings to offset my lav drain around my 6"x6" sill.

    The concept is shown in the picture below... Not exactly my situation, but similar. I think I'll sketch up my actual situation before I put it together.
    Attached Images Attached Images  
    Last edited by CapstanRec; 10-01-2010 at 08:16 AM.

Similar Threads

  1. Tub incorrectly set in mortar
    By DNP in forum Shower & bathtub Forum & Blog
    Replies: 3
    Last Post: 10-26-2009, 03:23 PM
  2. Isometric Drawings
    By enriquehobart in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 2
    Last Post: 10-21-2007, 02:24 PM
  3. Fixing Basement Bathroom
    By UTChris in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 1
    Last Post: 10-04-2006, 06:47 PM
  4. Is my water heater installed incorrectly?
    By slb in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 5
    Last Post: 10-04-2005, 10:03 AM
  5. New bathroom in un-plumbed basement
    By hannibal in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 13
    Last Post: 01-26-2005, 06:14 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •