P-trap for laundry, a little lost

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by syn3rgy, Oct 3, 2013.

  1. syn3rgy

    syn3rgy New Member

    Messages:
    14
    Location:
    Alberta, Canada
    Hey guys, my first post here, but a very important one! haha..

    I bought my first home a little while ago, and I have an issue in my porch area where my laundry is. The drain for the washing machine sticks out about 37" above the floor, and it has no p trap, which I would like to install. However, I am unsure of how much distance I need for pipe to run so that water doesn't back up and shoot out of my drain pipe! I have done a bit of this kinda stuff before but need some help with this one. If you could give me any advice that would be great.
  2. Terry

    Terry Administrator Staff Member

    Messages:
    15,303
    Location:
    Bothell, Washington
    The p-trap will be above the floor, and vented. It should drain fine if it's 2".
    Probably fine if it's 1.5" too, but 2" is in most codes.
  3. syn3rgy

    syn3rgy New Member

    Messages:
    14
    Location:
    Alberta, Canada
    I am wondering how to vent this... the problem right now is that we are getting the smell of sewer every once and a while from there, wouldn't the vent on the p trap cause the same problem?
  4. Terry

    Terry Administrator Staff Member

    Messages:
    15,303
    Location:
    Bothell, Washington
    If you go out and look up at your roof, all those pipes sticking through the roof are vents.
    We normally vent "through" the roof.

    You could use an AAV on the vent.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,056
    Location:
    Cave Creek, Arizona
    IF you sure there is no "P" trap below the floor, then you do need one above the floor, but it has to have a vent run up and through the roof, away from any windows on an upper level.
  6. syn3rgy

    syn3rgy New Member

    Messages:
    14
    Location:
    Alberta, Canada
    I have a question about using an AAV. If I have to use one, does it have to be higher than the highest point in the system? Where my pipe comes out of the wall, like I said, it's 37" or so. So would it have to be higher than that, or can it be less if I run the pipe down a bit, and have the p trap lower? Does that make sense? haha I just done want it to overflow or backup or something.
  7. syn3rgy

    syn3rgy New Member

    Messages:
    14
    Location:
    Alberta, Canada
    Sorry for the questions guys, just trying to plan this out, I am just wondering if I can put an elbow on the pipe coming through the wall, and have it run vertical down for a foot or two, and have it then run horizontal for about two feet, have my p trap and AAV at the end of that run horizontally, and then have a stand pipe coming up behind the washer? Or does the AAV have to be higher than that?
  8. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,260
    Location:
    Land of Cheese
    The p-trap must be at the bottom of the standpipe. The vent must be downstream of the trap. If using an AAV, should be at least 6" higher than the top of he washer to prevent it from becoming damaged by a backup in the line.
  9. syn3rgy

    syn3rgy New Member

    Messages:
    14
    Location:
    Alberta, Canada
    I just did a few quick measurements in the room, if I go too low, there is another pipe there for the outside tap, so I drew this up. Would this work okay? Forgive me if it's a little rough. CAM00235.jpg
  10. Reach4

    Reach4 Well-Known Member

    Messages:
    2,672
    Location:
    IL
    I suggest that you post a photo of the area. Somebody will probably tell you a good way based on that.

    I am pretty sure that your sketch is neither wise nor permitted. I am not a pro, so I am not going to be good to suggest something positive, but I can make negative comments.
  11. syn3rgy

    syn3rgy New Member

    Messages:
    14
    Location:
    Alberta, Canada
    here are a couple of pictures as it stands right now.. sorry they arent the greatest!!

    CAM00236.jpg

    CAM00238.jpg
    Last edited by a moderator: Oct 10, 2013
  12. syn3rgy

    syn3rgy New Member

    Messages:
    14
    Location:
    Alberta, Canada
    I just want to get it at this point so the sewer gas cant come up anymore. Even if it's temporary for winter, I am a student right now, so I can't really gut the thing until I have the cash.
  13. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,260
    Location:
    Land of Cheese
    What you have drawn will be a quick way to flood the room when the washer starts pumping water. The washer standpipe must drain by gravity alone. The trap arm must be vertical off the trap and be pitched to the drain connection. The standpipe, trap, and trap arm must be 2" pipe and the vertical standpipe must be at least 18" tall. The entire standpipe will need to be above the height of the vertical trap arm and it's connection to the drain.

    There are several good photos of laundry plumbing here in the forums. Take some time to look around.
  14. syn3rgy

    syn3rgy New Member

    Messages:
    14
    Location:
    Alberta, Canada
    I will have to look around for some pictures, I am having a tough time understanding what you are saying.
  15. Reach4

    Reach4 Well-Known Member

    Messages:
    2,672
    Location:
    IL
    The biggest problem I see is that your standpipe is barely above the drain output. Even if you cannot do it right, try to make the standpipe input significantly higher. I would see how high you can get that washer output. Maybe you can raise the washing machine a bit by putting it on blocks.

    I am thinking that you are somehow going to connect your drain to that big 3 or 4 inch black pipe in the left of your first photo. I suspect that flex drain is feeding up to a higher point on that pipe, and you did not want to put that into the picture. Good choice. ;-) It would have been entertaining, but I think you would have gotten razzing. So you are looking to make something better than what you have already.

    I am not a pro.
  16. Terry

    Terry Administrator Staff Member

    Messages:
    15,303
    Location:
    Bothell, Washington
    All I see is a wall with a fitting coming out of the wall at the correct height.
    Are you sure there isn't a vent and a p-trap with standpipe behind that wall already?
    That pretty much looks like many other waster installs.
    Are there any pipes and valves that you can see on the other side of that wall?

    [​IMG]
  17. syn3rgy

    syn3rgy New Member

    Messages:
    14
    Location:
    Alberta, Canada
    yes, the pipe goes through the wall, and just drops vertical a bit, then goes into a horizontal pipe that leads to the drain.
  18. cacher_chick

    cacher_chick Test, Don't Guess!

    Messages:
    3,260
    Location:
    Land of Cheese
    It would not be in anyone's interest to suggest how to do it until they could see where the drains and vents are in the wall, and what fittings are already in place. The plumbing codes are quite specific as to what is allowed, but we cannot see what is in your wall, which would determine how best to proceed in your house.
  19. syn3rgy

    syn3rgy New Member

    Messages:
    14
    Location:
    Alberta, Canada
    CAM00244[1].jpg
    this is what the other side of the wall looks like. This pipe runs straight across to the drain, thats all there is.
  20. syn3rgy

    syn3rgy New Member

    Messages:
    14
    Location:
    Alberta, Canada
    Could I possibly put a p trap on the other side of the wall??
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