Laundry Room Drain Set-Up - is it okay?

Discussion in 'Remodel Forum & Blog' started by bmb2m9, Feb 2, 2010.

  1. bmb2m9

    bmb2m9 New Member

    Messages:
    22
    Location:
    Jefferson City, MO
    I am replumbing the laundry room in our house. I staged the fittings that I am planning on using to see if it is an okay setup. I am using a 2 inch vent (out the roof) and drain with combination tee wye fittings for the washing machine drain with a separate vent before draining vertically (also a separate sanitary tee for the sink). I am hoping this will provide excellent flow for the washing machine drain. Thanks for any pointers and checking my work/thoughts.

    See attached image/link.

    http://picasaweb.google.com/BriceBernskoetter/DIY?feat=email#5433828355001721874

    -Brick

    Attached Files:

  2. krow

    krow Plumber

    Messages:
    906
    Location:
    Ontario, Canada
    loose the 45 degrees between the trap and the vent, unless its on the same plane. Pipe will slope between the trap and vent , 1/4" per foot or 2% or not exceeding 1 pipe diameter.

    I'm not sure in your state, but some northern states require the vent to penetrate through the roof in 3" minimum (to combat build up of frost from condensation), but inside the house it can be 2"
    Last edited: Feb 2, 2010
  3. bmb2m9

    bmb2m9 New Member

    Messages:
    22
    Location:
    Jefferson City, MO
    I see, so basically just use some gradual slope instead of using the two 22.5s between the trap and vent, which give a steeper slope.

    Just curious, is there a reason the 22.5s would cause a problem in the system or are they just pointless to have.

    I am in Missouri and am only required to have a 1.5 inch roof vent, but am using a 2 inch, so I should be fine on that.

    Thanks much for your help. :)

    -Brick
  4. krow

    krow Plumber

    Messages:
    906
    Location:
    Ontario, Canada
    Aside from being pointless, you would be creating an S-trap, which is against code. The S-trap will have a tendency to syphon the water out of the p-trap, causing sewer gases to come back into your home
  5. bmb2m9

    bmb2m9 New Member

    Messages:
    22
    Location:
    Jefferson City, MO
    Wow, my question seems stupid with your superb explanation. That makes perfect sense, I just never thought of it like that.

    FYI - I have an S-Trap in one bathroom sink because it was done years ago in my 1960s rancher. But you are right, I need to do it right, to code.

    Thanks!
  6. bmb2m9

    bmb2m9 New Member

    Messages:
    22
    Location:
    Jefferson City, MO
    Aside from the 22.5s I assume I am in good shape?!
  7. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,142
    Location:
    South*East
    You are also creating a S trap by using the combo on the washer waste. A san tee is the better choice.

    John
  8. bmb2m9

    bmb2m9 New Member

    Messages:
    22
    Location:
    Jefferson City, MO
    I see... I thought that it would be okay (maybe even better) since it is vented before going into the combo and down the vertical drain?! Am I wrong? Is this idea another pointless part of the setup?

    Thanks for the help and insight.
  9. nukeman

    nukeman Nuclear Engineer

    Messages:
    708
    Location:
    VA
    Do it like this (picture stolen from Terry):

    [​IMG]

    If yours will be at the base of a stack (new stack in basement or bottom floor), add a cleanout like you have at the base of the stack. Are you under UPC or IPC? Under IPC, the stack has to be a minimum of 3" for a washing machine. The standpipe and p-trap are still 2". Under UPC, 2" is fine for all of it. For the standpipe, normally it is between 18" and 30" in height, but IPC allows you to go up to 42", I believe.
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,285
    Location:
    Cave Creek, Arizona
    The combo in the vertical stack for the washer is perfectly okay, but just more costly than a sanitary tee. The vent between it and the trap prevents it from causing a 3/4 "S" trap. The washer vent only has to be 1 1/2" and the upper turn can be a regular 1/4 bend, not the long radius one you show. At the bottom is it connecting to a "floor drain" as it says, or a "drain pipe in the floor"?
  11. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    hj has the best eye of anyone on the forum! Some pointed out, and I was starting to comment, on the vertical combo. Normally, that is not used because it does create an S but taking the vent off BEFORE the combo prevents the S.

    As for the horizontal line, on a branch drain, there is no limit on slope, as long as it is at least 1/4" per foot. But your situation is not the branch, it is the trap arm. Dropping it too much could cause the vent take off to be below the trap seal level. That will cause siphon, and thus is prohibited. Plastic pipe joints have enough "wiggle" that you can achieve the necessary slope without using sixteenth bends.
  12. bmb2m9

    bmb2m9 New Member

    Messages:
    22
    Location:
    Jefferson City, MO
    It connects to a drain pipe that goes into the floor in the basement. I am using 2" PVC with a gasket going into a 2" cast iron hub.

    Would using a combo in the vertical pipe be of any benefit over a sanitary tee? (such as better water downflow)

    How high should the washer vent go before tying back into the main line?

    Thanks for all the responses and help.
  13. bmb2m9

    bmb2m9 New Member

    Messages:
    22
    Location:
    Jefferson City, MO
    I am sure that the stack is only required to only be 2" here in Jefferson City, MO. I think in northern states they require 3" due to ice build up etc., right?!

    Thanks for the help everyone.

    By the way, the picture from Terry looks great, I think I will just mimic it!
  14. nukeman

    nukeman Nuclear Engineer

    Messages:
    708
    Location:
    VA
    I am talking about the drain. This is not an ice issue. The IPC requires a washing machine to connect into a 3" minimum stack or horizontal branch. Most agree this is probably overkill, but the thought is a buildup of lint over time + high pump output of newer machines could lead to backup/flooding if the line is too small.

    I took a quick look online and it looks like MO is based on UPC, so the 2" will be fine in your case. Just wanted to make sure you knew about the 3" thing if you happened to be under IPC. VA is IPC based, so I have to do a 3" stack.
  15. bmb2m9

    bmb2m9 New Member

    Messages:
    22
    Location:
    Jefferson City, MO
    Thanks for all the help guys. One last question and I will be out of your hair, should you just always use a sanitary tee to intersect a vertical drain rather than a combo (even if it is vented before the vertical)?
  16. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,285
    Location:
    Cave Creek, Arizona
    Usually, but only because a sanitary tee is more compact and cheaper.
  17. spetrucco

    spetrucco DIY Junior Member

    Messages:
    22
    Location:
    Southeast PA
    nukeman,

    I am in PA and believe under the IPC.
    If I understand you correctly (under IPC) the verticle line above and below the san-tee must be 3" ?.....I am referencing the pic in your previous post via Terry.
    Question :
    I am planning a 2nd fl washing machine that was going to be vented and drained via 2" until the basement where it will tie in to a horizontal 4inch cast iron line.
    So I need to run a 3" vent as well as a 3" line all the way to the 4inch main drain?
    Thanks
    Shawn
  18. nukeman

    nukeman Nuclear Engineer

    Messages:
    708
    Location:
    VA
    The vent could be 1.5" or 2". The drain would be 3". Here is what I did:

    - 2" riser (~30" tall)
    - 2" p-trap
    - ran 2" horizontally (about 3') and connected into a 3x3x2 santee. I used a bushing on the top to reduce to 2" for vent. I then carried the 3" down until connecting into the 4" horizontal main.

    It hasn't been inspected yet, but will be soon. I am working on getting the test balls and such to perform the pressure test.

    Here is the VA code (not sure if it will help): https://www2.iccsafe.org/states/Virginia/Plumbing/Plumbing_Frameset.html

    See section 406 about the washing machine. You can also try talking to someone in your inspection department about it. They might be under an older version of IPC and may allow the 2" drain. For me, the 3" was just as easy as the washer is in the basement, so I didn't have to run through walls or anything. With your washer being on the 2nd floor, being able to run 2" would make things easier for you. You'll just have to see what is required locally.
Similar Threads: Laundry Room
Forum Title Date
Remodel Forum & Blog Tiny laundry room & useless bathroom: need suggestions Jun 17, 2013
Remodel Forum & Blog What type of insulation under new laundry room "closet?" Feb 23, 2013
Remodel Forum & Blog New Laundry Room Nov 23, 2011
Remodel Forum & Blog Tiling a laundry/furnace room Nov 3, 2011
Remodel Forum & Blog How to prep a laundry room floor with floor drain for tiling? Aug 28, 2010

Share This Page