Plumbing Through Wall Question

Discussion in 'DIY' started by bee505, Mar 20, 2015.

  1. bee505

    bee505 Supporting Member

    In the next couple of weeks, I will be plumbing PVC from the dining room through to the garage. The kitchen to the garage will have a 3-4 foot drop. With the tank elevated in the Garage, the high of the sump will be about a foot lower than the dining room. My goal is to keep the plumbing as simple as possible, 1 up 1 down plus and emergency drain. There will be two 1.5" drain pipe and one 1" return.

    Here are some of my questions:
    <li>If I run horizontal pvc through the wall, what are my options to fill the wall gaps and the holes? Do I use spray foam or are there fittings available?
    <li>Rather than using horizontal pvc through the wall (been reading that using 90 elbows and horizontals are not the best solutions), should I use spa flex?
    <li>If I use flex spa, should I make a big square cut out and stuff all the pipes through? Are the boxes available for this type of projects?

    If anyone has any experience or suggestions, please let me know. Thanks in advance.
  2. rygh

    rygh Supporting Member

    I did the same thing.

    Key #1 : There are fire codes for that.
    The garage wall, and anything though it, needs to be fire rated.
    They sell special fittings that go around the outside of your pipe. There is a metal pipe, with a special expanding foam inside.
    You can just use the foam as well, but not sure if that is entirely to code.
    (I used foam and some sheet metal ... ehh...)

    Key #2: Avoid accidentally transferring pump vibration into the wall.
    The wall will amplify it, and make your whole house noisy. Trust me on that one!!!
    So you need to dampen the vibration from return pump, and have a thin bit of light foam between pipe
    and any solid part of the wall.

    My advice:
    1) Use standard PVC through the wall, to keep it from flexing your sealant.
    Spa-flex will move and it is never quite straight.
    But otherwise, not all that important.

    2) Super-size it.
    Going through the wall is not something you can do-over easily. Best to be VERY conservative.
    Plus, drag is based on velocity squared, velocity is based on cross sectional area, and area of a pipe is radius squared.
    Put simply, a 2" pipe has 1/16" the resistance of a 1" pipe.
    And, it makes those 90-deg/45/flex issues rather moot.
  3. bee505

    bee505 Supporting Member

    Great information rygh. I knew I was playing with fire.

    3M makes a firestop collar for through wall pvc pipes. Interesting product. I will head to OSH to see what is available tomorrow. It seems like even if you use the firestop collar, you will still need a steel pipe wrapping the pvc (i think).

    The plumbing from the garage wall to the return pump will not be plumbed with pvc. I am hoping the noise from the return pump will be dampen using a vinyl tube leading to the 1 inch pvc on the garage wall. This will probably eliminate the vibration from the pump.

    If the project becomes too difficult, plan B is to hire a plumber.
  4. gimmito

    gimmito Guest

    +1 what Mark said. I also used uniseals to dampen the sound and cover up the hole made through the wall.

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