Trenchless Water Line Replacement - Sleeve to prevent collapse?

Discussion in 'Plumbing Forum, Professional & DIY Advice, Tips & ' started by Markos, May 26, 2014.

  1. Markos

    Markos New Member

    Messages:
    3
    Location:
    WA
    I need to replace my water line. It's about a 230' run. I currently have 3/4" ID poly, which is failing at the seam. I've repaired it myself about 5 times in the last 3 years.

    Due to proximity to the gas line and my neighbors line, the first 150' needs to be hand dug. Alternatively, I can go with a directional bore under my driveway. I've received conflicting info from my bids. Once company said that they can't do directional boring because the 'vibrations on the road will cause the line to fail'. Another company said no problem, and gave me a quote. The last company also recommended trenching. His concerns are the rocky glacial soil. The soil is littered with rocks between the size of a golf ball to a cantaloupe. He states that with a bore, the line is smaller than the hole. The earth will collapse around the line and can cause stress on the pex line. This makes sense to me, but I'm wonder how concerned I should be. I want this to last for at least 15 years, preferably 50 years like the original poly line. The plumber recommended sleeving the line, but warned that it would be expensive. I'm waiting on the bid.

    Any thoughts on the subject?
  2. craigpump

    craigpump Member

    Messages:
    950
    Location:
    ct
    Trench and sleeve the pipe. It will cost more but you will have the security of knowing the job will last.

    IF for some reason that pipe fails, you will the be able to pull it out and replace it with minimal digging if it is in a sleeve.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,689
    Location:
    Cave Creek, Arizona
    You can "directional bore" a larger pipe and then slide your line through it, but it has nothing to do with the pipe being smaller than the bore. It is to prevent the stones and rocks from damaging the pipel
  4. Markos

    Markos New Member

    Messages:
    3
    Location:
    WA
    I was referring to the implications of *not sleeving. If the bore has an ID of 3" and you run 1" pex through it, there will be a void that can/will collapse onto the pipe over time. Installation of a sleeve would prevent this from occurring. With that said, my plumber today said that they inject the void with a slurry to fill the voids and protect the pipe.
  5. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,689
    Location:
    Cave Creek, Arizona
    slurry would "lock" the pipe in place whereas a sleeve would keep it loose, and I would question how they would inject 200' of slurry into the small opening around the pipe.. The "void" collapsing would not be as likely as the pipe rubbing against one of the any rocks that would be in the hole.
  6. craigpump

    craigpump Member

    Messages:
    950
    Location:
    ct
    They may inject the slurry through a tremie line that is shoved in the hole along with the water line. To my way of thinking, this is probably not the best way to go. I would much rather have a nice smooth sleeve that I can get pipe in and out of if need be.
    Last edited: May 28, 2014
  7. Markos

    Markos New Member

    Messages:
    3
    Location:
    WA
    I talked to the drilling company to get direct clarification on the process. The explanation and recommendations of the plumbers varied greatly, but they all subcontract to the only directional drilling company in Seattle (Linescape LLC). The 'slurry' is more of a clay that serves multiple purposes. It serves as a lubricant and coolant for the drill head. It helps to remove the bored earth. It also fills the void and wraps the pipe with a sand-like material. Not as good as sleeving, but better than having a void due to the bore not matching the installed pipe. If you got a sleeve, that would have the slurry on the outside as well.

    Now that most of my estimates are in, I'm comparing them to a total driveway tear out and new blacktop. While the driveway is out, I can ditch witch my own trench, sleeve it, bed it properly in sand, and get a fresh driveway. As it stands, it would be about the same price to replace the driveway and install a new line than it would be to directional drill. That doesn't include the cost of a plumber hooking up the fittings, and the $600 in pipe (pipe + sleeve).

    I also learned from the city inspection office that the gas company laid the gas line too close to the water line, which is causing this dilemma to begin with. I will be speaking with them about offsetting the cost. Seems like a painful process but I do have free legal insurance through my work. We shall see.
  8. craigpump

    craigpump Member

    Messages:
    950
    Location:
    ct
    That slurry is bentonite or drilling mud. Typically in water wells, that slurry won't really do much to grout in pipe, but they may use a different type of drill mud with horizontal drilling than in verticle boreholes.
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