Repair or Replace sewer pipes - best method?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by BrittanyATX, Oct 28, 2019.

  1. BrittanyATX

    BrittanyATX New Member

    Joined:
    Sep 30, 2018
    Location:
    Austin TX
    To start, I will not be DIY'ing this. I'm planning to hire the pros.

    My house is a 1500 sqft house, built in 1960 with original plumbing (copper supply lines throughout, except the kitchen cold which is galvanized, and cast iron drain lines). House is slab on grade, in Texas with heavy clay soil. It just started having cracking in the drywall and slab in some areas so I had a plumber come out to test for leaks, the plumber did a hydrostatic test and the house failed such that with the kitchen sink, hall bath, and hall sink all running the water came up to 6 inches below grade at the toilet and stayed steady for 20 mins straight without ever coming up any higher, with the water being run that whole time.

    The plumber told me without running a camera that I likely had many cracks/leaking areas to have the result I was having. He didn't quote me a camera scoping cost, but said it was likely pointless to do and I should just have a complete repiping done on the sewers based on the result and age of my house. He also recommended I call my insurance and see if they would cover that type of leak/repair work.

    I called. It's covered, but my insurance wants to only cover patch repairing the leaks instead of replacing all the sewer lines. I read online mixed information about this method ranging from it will be fine to now you will have areas at each connection that will likely leak where new PVC was connected to old CI and the rest of the old CI pipe will develop new leaks anyway.

    Here's where my questions start:
    I read about trenchless repairs too - linings and pipe bust outs and HDPE replacement pipes - what are the advantages/disadvantages of these methods vs trench repiping. Also, how long will everything last? I am not planning to move out of this house ever so I ideally want it fixed once, the right way, and have it last 60+ years, 10 years beyond my expected lifetime, lol.

    PRO's: If this were your house, and you were planning on living in it another 50 years, what would you do/have done, and why?
     
    Last edited: Oct 28, 2019
  2. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    Broken pipes don't fix themselves and any kind of lining the pipes to save the day to me is a patch, not a permanent fix. If there is a bad break with tree roots or dirt, they would need to be cleaned out before relining if it is possible to get past a broken section.

    The other issues is slope and settlement. After fifty years the ground moves, either tree roots lift the pipes or the ground settles and there could be dips that would cause slow drainage. Clay soil when wet heaves and expands, when dried out it shrinks and settles.
     
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  4. BrittanyATX

    BrittanyATX New Member

    Joined:
    Sep 30, 2018
    Location:
    Austin TX
    That makes sense on the lining not being a long term fix. I'm definitely going to have pipe replaced then. As for slope issues in the pipes, I'm not having any clogging, but I'm guessing those pipes didn't deteriorate on their own from free flowing water....

    Can anyone weigh in on pros/cons and life expectancy of having sewer pipe replaced with schedule 40 PVC ( would require trenching) vs HDPE pipe (which may or may not be able to be done trenchless)?
     
  5. BrittanyATX

    BrittanyATX New Member

    Joined:
    Sep 30, 2018
    Location:
    Austin TX
    Well now I'm thoroughly confused, after doing more research, the pipe relining technology where they cure the resin in place inside the pipes all comes with 50 year guarantees from plumbing companies that install it, same for the HDPE/pipe bursting methods.
     
  6. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Note that if you contract to have a PVC pipe put in without specifying type, they would probably use D2729 sewer pipe, rather than the heavier schedule 40.

    I don't know about the trenchless methods. Trenchless would be trying to preserve the lawn. I would expect trenchess to cost more. With a trench, normally they will leave the old pipe in the trench on top of the new pipe, instead of hauling it away. I don't know how much different your top soil than your subsoil, but when I had my sewer pipe replace, they left a lot of clay subsoil on top. I later had that removed and replaced with subsoil. If they are careful when they dig, they can keep the topsoil on tarps separate. Then put that back on top. They will need to mound the dirt, because it will settle.
     
  7. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    I've seen on This old House about 25 years ago performing the reline method. It's a fiberglass stocking than gets a layer of resin and it is pushed through with air pressure. It was quite impressive but an old house in Boston to about 25 feet to the sewer main would work for many years. You didn't say how long of a run you have but if you do a reline after you had the old pipe scoped to be sure there is slope, the CI still deteriorates and as it does from tree roots that can still getting inside the pipe before the makeshift pipe, you can end up with the weight of the earth on a resin section.

    If you are looking for longevity, Schedule 40 will out last the life of the house and in 50 years will you still be around to worry about it. Other than a burr inside the PVC pipe to catch anything that might cause a clog, nothing sticks to a PVC pipe. It a very smooth surface where as a relined pipe has a rough surface. CI are in 3-4 foot lengths where roots easily penetrate the connection. PVC pipe are 10 to 20 feet in length and with a glued coupling, nothing penetrates it. If the ground moves or heaves, PVC can flex, Ci will continue to degrade. If $$ is a concern and a reline is affordable for you and a full replacement is not, dollars talk loud.
     
  8. BrittanyATX

    BrittanyATX New Member

    Joined:
    Sep 30, 2018
    Location:
    Austin TX
    Thank you all. I will tell them that if they need to replace pipe that I want a complete repipe using PVC schedule 40 pipe. Is there anything else I should make sure to specify in the scope of the work?
     
  9. Plumbs

    Plumbs In the Trades

    Joined:
    Oct 16, 2019
    Location:
    Virginia
    I wouldn't take the word of the first guy you hired. He's just guessing at what needs to be done. Hire someone to do a proper video inspection of your drain lines. That way they can see the actual condition of the pipes. Once you have that information you'll know what the best way to proceed is.
    Also, if you have a video inspection done make sure they make a recording and mark the location of any problem areas. That way you can get several quotes without needing to pay for additional inspections from each additional plumber. Most will want to do their own inspection to make sure the markings are accurate but they can at least give you a rough idea based on the first inspection.
     
  10. BrittanyATX

    BrittanyATX New Member

    Joined:
    Sep 30, 2018
    Location:
    Austin TX
    It's been a few weeks and I've now gotten multiple quotes for replacing my sewer lines. One thing that differs among the options is that most companies want to tie the new PVC sewer lines into any existing cast iron vent stacks,toilet drains or other existing slab cast iron penetrations by cutting the cast iron right below the slab and attaching a coupling to join the new PVC to existing cast iron right below the slab (some have specified what they plan to use such as clamp all couplings, while others haven't spec'd the coupling they will use).

    One company has said that they would instead chip out a ring of concrete about 1" wide around any existing cast iron vent stacks or toilet drains/other cast iron slab penetrations, so they could replace the cast iron that is running through the slab with PVC as they feel strongly that using a coupling to connect the cast iron to new PVC below grade is just creating a leak/failure point in the system.

    Any professional plumbers have any input on if option 2 is actually the right way, or if it's overkill?
     
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