Replacing section of sewer pipe

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Lakee911, Jun 25, 2008.

  1. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

    Messages:
    1,328
    Location:
    Columbus, OH
    Hi All,
    The past couple of days I've been digging to uncover a problematic area in my sewer line. Approx 30" away from the edge of the house 5-6 feet below grade, I uncovered 6" clay pipe that comes from the house and turns in about a 3 foot radius sweep towards the street. The thing is, they used a 90 degree and a 45 degree fitting to make the 90 degree bend, thus the 90 and 45 do not fit together. It should have been two 45's. There is a 2" diameter root entering the pipe there. I'll take a photo later and post it.

    Inside the house I have coming down the main stack, 4" cast iron, 4" PVC, then 4" cast iron again, then it exits the house and somewhere between there and 30" outside the foundation, it transitions to 6" clay.

    I'd like to replace everything from the PVC coming down the stack to the 6" clay headed towards the street. How and where do you speculate is the existing 4" cast iron transitioned to the 6" clay?

    I'd like to cut out the cast iron and push through a 4" PVC through the foundation in the existing pipe (assuming it is all 6" clay) and through to the thirty inches of pipe entering my hole, make the 90 degree bend and then transition to clay as it heads to the street. I'll add a cleanout there as well.

    What is the best way to make the transition from 4" PVC to 6" clay? When I backfill, should I fill with sand or gravel or dirt?

    Thanks,
    Jason
  2. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    The CI probably transitions to clay a short distance out side of your foundation.

    Lakee, I hate to say this but I'd see about getting a camera over there to have a look see at this line and locate your points of interest as well as inspect the balance of the line.

    It's called working smarter not harder!

    Use a banded coupling that is properly sized for the 4" to 6" transition.

    Also make sure that part of your work is installing an outside cleanout that can run in both directions... essentially opposing wye's and 45's to the surface.
  3. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

    Messages:
    1,328
    Location:
    Columbus, OH

    I've actually had it cameraed twice! There was one other bad spot--offset joint--that has been repaired. See here: http://www.terrylove.com/forums/showthread.php?t=19069 This was the only other bad spot. It's fixed now and working well.

    Seems that there were problems at all the changes of direction from the initial install in 1923. There has to be one other 22degree change in direction somewhere that is likely fine because the rest of the pipe looks ok.

    Do I need to install a cleanout going upstream back in to the house if it's only going to be 30" or so and will all be PVC to the stack?

    Thx
    Jason
  4. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    You should have had them locate the transition for you and mark it...

    I would install the cleanout facing both ways... If you ever do have a problem it could probably be handled from outside... No Mess!

    How much does an extra cleanout plug & adapter, wye, 45 el, and a few feet of pipe cost anyhow? You've got the hole dug!
  5. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

    Messages:
    1,328
    Location:
    Columbus, OH
    That's true ... I guess that I could put two cleanouts ... wouldn't hurt. That is if I have room without digging my hole bigger. It's going to have to wait a bit though because I've got a foot of water in my hole and it's 'posed to rain for the next few days. :(


    Is this the Fernco that I need? Strong Back - RC Series Repair Coupling
    ? Part Number 1002-64RC 6" Clay to 4" Cast Iron or Plastic. It says that an insert bushing included with designated part numbers. Is that some sort of rubber doughnut business? I found a price of $80/ea! Eeeck! :(


    Should I put some sort of backflow preventer in while I'm replacing the bottom of the stack and the pipe immediately outside of the transition? I'm at least 50-60 feet higher than the interceptor/trunk line that my street's sewer drains in to, but there are also houses above me on the hill too.
    Thx
    Jason
    Last edited: Jun 25, 2008
  6. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

    Messages:
    1,328
    Location:
    Columbus, OH
    Anyone? Correct Fernco?
  7. Redwood

    Redwood Master Plumber

    Messages:
    7,450
    Location:
    Connecticut
    That would be appropriate.
    Basically its a 6" Clay Strong Back but there is a thick rubber bushing that makes up the space on the 4" side.
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