What's the difference between these two overhead sewer setups

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by houndzilla, Dec 7, 2016.

  1. houndzilla

    houndzilla Member

    Joined:
    Oct 18, 2016
    Location:
    Illinois
    I'm going a basement renovation as part of the work I am converting to overhead sewers.

    Some relevant information:
    -Basement floor is ~5' below grade
    -Existing sanitary line is ~7'-6" below grade
    -Existing sanitary line exits the building footprint, then runs along side the building (within 24") towards city sewer
    -Driveway runs alongside house with 24" dirt area where new sanitary line could be hand dug, several feet in elevation above the old line
    -Existing sanitary line is cast iron, home built in 1957. Line appears to be in good condition with exception for dip somewhere close to street. Confirmed via camera.
    -North suburb of Chicago​

    Option 1:
    This is what I provided in my permit drawings to the city:
    -Existing underground sanitary is abandoned.
    -First floor gravity drains in basement reworked to exit foundation walls ~18" below grade
    -New high sewer line then pitches towards front yard, once clear of the house excavate for new vertical drop to connect to existing sewer lateral. This happens in the 24" dirt area between house and driveway, and is hand dug.
    -New grinder ejector pit serving basement connects to reworked gravity drain.
    Option 2:
    Several plumbers who have walked the job have recommend this for cost and labor savings:
    -Keep existing sanitary line to remain up to where it enters the building footprint
    -Rework first floor gravity stack to accommodate connecting the basement pit discharge at the top of the stack in the basement.
    -New PVC to connect to existing line outside building footprint (no-hub fitting) all the way up to where the ejector pit connects
    -I would revise my drawings and provide the city with the updates
    Option 3:
    Similar to option 1, but run high gravity drain pipe inside along foundation wall. I'd rather not do this as I lose 5"-6" precious inches of livable area from my basement remodel, and would require I dig up a well groomed juniper bush I have spent years nursing back to health.


    So, in my mind option 1 is the 100% correct way to do this. It's more effort and cost, and I don't mind that. But every plumber I've solicited bids from says they done dozens of overhead conversions like option 2 and claim they've never had issues with water back up getting into the basement.

    What are the downsides of Option 2's design that a lay person may not be aware of? Functionally it's the same, but instead of poop water backing up outside the footprint of my home, it backs up inside but is contained by the sealed PVC sanitary stack.

    If option 2 is acceptable to you all, would it be reasonable to request that the new sanitary stack be pressure tested?
     
  2. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Have you checked for a rebate program for your town? They may have their own rules.

    I think understand #1. Classic overhead sewer, if I understand

    #2 is not clear. Are you saying everything would go through the pit?

    #3 are you saying first floor would go through a line in the basement like #1 but out of the basement through a different wall?

    There are some drawings on https://terrylove.com/forums/index.php?threads/converting-gravity-sewer-to-overhead.67979/ do any of those apply?
     
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  4. houndzilla

    houndzilla Member

    Joined:
    Oct 18, 2016
    Location:
    Illinois
    Yes, there is a rebate program. Minimum three bids are required, each bid has option 1 and option 2 priced. I'm going to present everything to them in a matrix listing out scope and associated cost, and let them tell me what they will fund.

    Your understanding is correct, classic overhead sewer.

    No, if so I would get a duplex grinder. What is happening is the existing sanitary route would be converted to PVC within the footprint of the building. Ejector would tie at the top of the stack in the basement. I hope that clarifies it enough.

    Correct. House is a rectangle with short end facing the street/city sewer. Option 3 has the pipe exiting the short wall, Option 1 has the pipe exiting the middle of the long wall, turning 90 degrees and running parallel to the foundation.


    The first image is what Option #2 in my post is describing.
     
  5. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I think any of the 3 should work well. Some rebate programs don't cover #2 . It sounds like yours does. Good.

    Also consider http://www.floodexperts.com/services/flood-control-systems/ There are others with similar systems, but there is a big advantage to the normally-open valve.

    It does not have unlimited upstairs use with the power off, there is some buffering for a temporary power outage. It does need an annual check (under $100/year). It costs around 1/2 as much before rebates. If the rebate paid half of the first 8000 dollars, it would be attractive. If the rebate only applied to overhead sewer, that changes things.
     
  6. houndzilla

    houndzilla Member

    Joined:
    Oct 18, 2016
    Location:
    Illinois
    I'm in Morton grove, and their documentation isn't really clear on if they would cover option #2. Isn't it technically an interior lift station?

    My neighbor has flood control. I see him messing with it during heavy storms, not sure I want that. I currently (via previous owner) have janky setup where my basement utility tub fills up if the sewer backs up. If it goes beyond the lip he has pipe on the vent that dumps it through the floor to the sump pit, which is a big no-no.

    In advance of my basement reno I have added an electric panel upgrade with a small generator subpanel and my grinder pit has (liberty provore 380) has the nighteye system so I would get email updates of it losing power, my wifi is on a small battery backup so it should be able to push the message out.
     
  7. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I see http://www.mortongroveil.org/govern...d-sewer-and-flood-control-assistance-program/ has poor pictures to illustrate their terms.

    You might benefit from a chat with somebody at the village to see how they subsidize each type. If they are only offering loans, that is not very helpful unless cash flow is a problem. Often programs offer grants.

    Chat with him. I suspect his problem system is substantially different from the one I linked to. But I don't know. Flapper valves are notorious leakers. He can tell you some useful info, even if it is what not to do.
     
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