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  1. #1
    Join Date
    Jul 2009

    Default Main waste line through existing foundation

    Hey all,

    I am installing a new bathroom on a second floor of my house. I need to pass a 4" PVC pipe through the foundation (or wall, depending on what I hear from you) to tie into the existing outside waste line. I had planned on tying in to the interior line, only to discover some real issues with that plan.

    The house is on slab, but I have an area in a utility room (luckily right below the new bathroom) that left the dirt exposed along the foundation, where I can pass through.

    The questions:

    1. Is it better to pass through the exterior siding-above-grade, foundation-above-grade or foundation-below-grade? I was avoiding above grade due to cosmetics and freeze issues and the likelihood that it is against code.

    2. If drilling through the foundation, do I maintain slope or is there some reason to change the angle... level or 45 deg. or some other sneaky tidbit in the code?

    3. If going through foundation above or below grade, am I required to install a 6" sleeve and how do I backfill/seal it?

    4. Any need to flexible boots, as this house is 50+ years old and not likely to settle.

    5. Any other pitfalls I should watch for?

    Thanks for your help!

  2. #2
    Join Date
    Jul 2010

    Default Re: Main waste line through existing foundation

    I would run the new drain down the exterior wall, run it in a trench below grade, and hook it up into the main. Maintain at least a 1/4" per linear foot slope at all time. In my city, exposed pipes must be cast iron, can't be ABS or PVC. Inside walls and in the ground can be ABS.

    I'm sure that you pulled a permit for this job, so it will be inspected and approved.

  3. #3
    Join Date
    Jul 2009

    Default Re: Main waste line through existing foundation

    Thanks for the response, DJ1. I appreciate it.

    I have everything plumbed in PVC to a few feet from where it will exit the house and I hate to have any exposed waste lines outside. I don't mind doing the extra work to go through the cinder block footings, provided it is as cut and dry as "cut a hole, install sleeve/pipe and back fill w/ concrete and other sealants to be sure of water proofing."

    Yep, permit secured for addition of a second story and all that goes with it. I have built it over the last few years and am terribly close and terribly far from finished... at least the upstairs is a livable room!

    Only plumbing, some hvac soffits, drywall for soffits, tile and paint in the bathroom, and trim...and...and...and.
    So close, yet so far!

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