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  1. #1
    Join Date
    Jun 2014
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    7

    Default Sewer trench mound

    Just had a new sewer line put in which has left me with an abject mound of dirt that is 3 feet high plus a lot of debris and stones:

    1) Can this be leveled out any sooner than the year's time given by my plumber?

    2) Will the broken pipe debris and stones damage the new line?

    3) Why didn't the plumber remove the extra debris?

    Here are photos that look like what I now have:

    http://www.cme-sewer-repair.com/trad...excavation.php

  2. #2
    Join Date
    Jul 2010
    Location
    SoCal
    Posts
    6,736

    Default Re: Sewer trench mound

    Every contractor sets his own rules, as far as the little details, and it's up to the consumer to accept it or reject it. If you object to something in the contract, the contractor can change the wording, terms and conditions, if he wants the job.

    So if your contractor said that he would leave the dirt on your lawn, you could have said: "no, haul it away".

    Now to your mound.

    1. This "Mt Everest" is not going to level itself in a year or in ten years. You can expect some compaction, but if you want it gone, have someone haul it away. You can also put a sign "Free Dirt - Load and Go".

    2. The crushed stones will not damage the new line.

    3. The plumber didn't remove the dirt because you let him get away with it. Next time you hire a contractor, any contractor, put this in writing: "Contractor to completely clean the job site upon completion, haul away all construction trash and leave the place in the same condition as at the start of the job".

  3. #3
    Join Date
    Aug 2007
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    7,191

    Default Re: Sewer trench mound

    What you describe is extremely common. I personally go to the extra effort to remove debris (roots/garbage ), but not stones. IMHO, it isn't all that hard to compact the soil a bit as the trench is backfilled, especially if backfilled with a backhoe or excavator. If filled with a bladed implement, then all you can do is drive over the mound to try to compact it a bit, but still leaving a bit of a mound when finished. Settling of the dirt will depend on how wet it is, and how much rain you get on it now that it's back in place.

    I've done a number of trenches 12" wide and 36" deep, when the dirt is replaced, the mound has always been 6" to 10" in height. Most of the time this will settle to just about flush, though you should expect to need more fill in some areas or level others.
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

  4. #4
    Join Date
    Jan 2008
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    2,203

    Default Re: Sewer trench mound

    The amount of dirt left after installing something in a trench should equal exactly the amount which was displaced by that "something". If there's more than this amount then the soil was not properly compacted as it was filled in and you're going to eventually have a swale there- right where you don't want it. In a worst-case scenario the apparently 'filled' but improperly compacted trench can wash-out from underneath undermining it and collapse all the way to the bottom with no warning in the future. I have a friend who was disabled in that exact manner while simply mowing his lawn

    In general terms, soil should be installed or reinstalled in no more than 6" lifts, then compacted to the same amount as the surrounding soil before another 6" lift is added, repeated until within 4"-6" of the top- that part you fill and walk on till level, giving the proper compaction for rooting the ground cover (grass). For the usual 4" sewer line I find that there's only a few wheelbarrows of dirt left at best when it's done this way and as often as not I end up with nothing left because it's compacted a little better than the surrounding soil. Few people do this because #1- They know nothing of soil engineering standards and #2- Because it's more time and work and nobody makes them do it properly because they don't know #1 either!

    I've never seen anything fix itself properly or get better to the point of being correct over time on it's own (except some alcoholic beverages ). What you see is probably going to be what you get or it will be worse later on so never buy the excuse that it will take care of itself. You're paying to have it taken care of now and you should withhold pay until that happens to your satisfaction. Just tell them that you'll pay them after it fixes itself and see how fast they move to do it right immediately!

    Phil

  5. #5
    Join Date
    Jun 2014
    Posts
    7

    Default Re: Sewer trench mound

    Quote Originally Posted by Mastercarpentry View Post
    I've never seen anything fix itself properly or get better to the point of being correct over time on it's own (except some alcoholic beverages ). What you see is probably going to be what you get or it will be worse later on so never buy the excuse that it will take care of itself. You're paying to have it taken care of now and you should withhold pay until that happens to your satisfaction. Just tell them that you'll pay them after it fixes itself and see how fast they move to do it right immediately!

    Phil
    Hi, Phil:

    Needless to say I am not happy with the mound of dirt and debris I have as the plumber is not going to do anything else as the sewer line and sump pump lines are already installed and have been backfilled without any compaction. I was told to water the mound to get it to settle faster and I don't even own a garden hose!

    Questions:

    1) So, what are my options now to fix the mound of dirt I have, if it's not going to "settle" down on it's own after one year's time, as promised by the plumber?

    2) If I have another contractor (or, landscaper) level and sift out this mound would there be FURTHER settling later on in which I would have to add more TOP SOIL to make up for the sinking (or, sunken) areas?

    3) Or, should I forget about it and just let the **** do whatever it's going to do?

  6. #6
    Join Date
    Aug 2007
    Posts
    7,191

    Default Re: Sewer trench mound

    Quote Originally Posted by homeowner88 View Post
    Hi, Phil:

    Needless to say I am not happy with the mound of dirt and debris I have as the plumber is not going to do anything else as the sewer line and sump pump lines are already installed and have been backfilled without any compaction. I was told to water the mound to get it to settle faster and I don't even own a garden hose!

    Questions:

    1) So, what are my options now to fix the mound of dirt I have, if it's not going to "settle" down on it's own after one year's time, as promised by the plumber?

    2) If I have another contractor (or, landscaper) level and sift out this mound would there be FURTHER settling later on in which I would have to add more TOP SOIL to make up for the sinking (or, sunken) areas?

    3) Or, should I forget about it and just let the **** do whatever it's going to do?
    1 - If you've already paid the plumber, you're screwed for getting any more assistance from them since they don't feel obligated.

    2 - If you level the mound before full compaction has taken place, then you'll have depressions form over the trenches as they compact on their own over time. Watering the mound will help, but only if you water the mound to full depth of the trench. Basically, water will wash out the air and the spaces between the dirt particles, allowing the dirt to compact back to its original state before it was disturbed. How long this takes will depend on the depth and width of the trench (amount of disturbed soil ). another way to settle or compact the dirt will be to drive a vehicle across the top of the mound, while you'll only be compacting the upper most portion, it will help to reduce the mound and to pack the trench, reducing the current mound and the development of a depression later.

    3 - You could remove some of the mound and save it off to the side. As the trench compacts itself, you can then back-fill a little at a time, as needed.
    I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!

  7. #7
    Join Date
    Jul 2010
    Location
    SoCal
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    Default Re: Sewer trench mound

    Watering the covered trench will compact the soil. Don't bring water with buckets, use a garden hose. Don't have one? get one.

    Don't try to compact by driving a car over it.

    Next time you have work done, any work, know what the contractor is going to do BEFORE he starts, have everything in writing and signed.

  8. #8
    Join Date
    Jan 2008
    Posts
    2,203

    Default Re: Sewer trench mound

    Deep watering will speed things up somewhat but it can also over-compact the trench compared to the surrounding soil if that soil is looser. I'm presuming the trench to be narrow and around 2' deep. If you dig halfway down, compact that very well with a hand tamp or 4X4 post, then add a few inches at a time as you walk on it back and forth refilling the trench as you go, you should end up pretty close to even on top. With the soil loose right now it won't be nearly as hard as digging in virgin soil. If you choose this route, do it before watering to keep the work easier.

    Or you can wait it out and hope for the best, helping it stay level when and where needed. It takes 30 years time undisturbed for soil to reach full it's natural compaction. Something tells me that you don't want to wait that long! Look closely at long existing yards and you can often see depressions where trenching occurred. The mounded dirt left behind as much washed away sideways as went downward into the trench leaving it a bit short of full- this is why their method just doesn't work!

    Phil

  9. #9
    Join Date
    Jun 2014
    Posts
    7

    Default Re: Sewer trench mound

    Quote Originally Posted by Mastercarpentry View Post
    Deep watering will speed things up somewhat but it can also over-compact the trench compared to the surrounding soil if that soil is looser. I'm presuming the trench to be narrow and around 2' deep. If you dig halfway down, compact that very well with a hand tamp or 4X4 post, then add a few inches at a time as you walk on it back and forth refilling the trench as you go, you should end up pretty close to even on top. With the soil loose right now it won't be nearly as hard as digging in virgin soil. If you choose this route, do it before watering to keep the work easier.

    Or you can wait it out and hope for the best, helping it stay level when and where needed. It takes 30 years time undisturbed for soil to reach full it's natural compaction. Something tells me that you don't want to wait that long! Look closely at long existing yards and you can often see depressions where trenching occurred. The mounded dirt left behind as much washed away sideways as went downward into the trench leaving it a bit short of full- this is why their method just doesn't work!

    Phil
    Hi, Phil:

    Watering the mound is not an option (other than mother nature doing so)...

    First of all, the dirt that is sitting on top right now is as hard as a ROCK as I have very heavy CLAY dirt that solidifies after getting wet as it isn't loose top soil and I can't even chisel any of it up with a shovel right now as that's how hard this stuff is. So, forget about attempting to get any water from a hose into this mound as it can't be done.

    Secondly, I am considering at having another company (not the original plumber - screw 'em - as they say) come out and for about $450 they will level and sift out the mound with a tractor that has a tiller on it, although I am aware that further settling may occur later that will require and an additional truck load of top soil to fill in the sunken areas where it happens to do so. This will cost at least another $500 so I am looking at another $1K+ at minimum to rectify the current mess.

    Take a look at my current sewer mound in the two (2) photos, below:

    http://imgur.com/rnCcPO2
    Last edited by homeowner88; 06-22-2014 at 05:36 PM.

  10. #10
    Join Date
    Dec 2010
    Location
    Houston Texas
    Posts
    2,969

    Default Re: Sewer trench mound

    That's what I'd do; scr ape it off then fill in as the years go by. It may take quite a while for it to fully settle.

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