How long to let liner sit before cutting Bottom Drain?

Discussion in 'Pond Archive' started by Bill Stock, Sep 3, 2007.

  1. Bill Stock

    Bill Stock Guest

    I ask because I took out the old PVC liner today and I discovered that it no
    loner touched the bottom of the pond when empty. It was in decent shape
    after six years although perhaps a little brittle.

    I was going to let the new liner settle (with water) about 24 hours before
    cutting the hole for the bottom drain, but if the old liner is still
    settling after six years!

    The other bad news is that the weight of the water has turned the clay into
    one large brick bowl, even the Mattock has a hard time breaking it up. I was
    hoping that all the moisture around the pond would make the clay soft, but
    that is not the case.
    Bill Stock, Sep 3, 2007
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  2. Bill Stock

    RichToyBox Guest

    "Bill Stock" wrote in message
    I don't think that the bottom was still settling, the vinyl shrank when
    allowed to dry. My daughter pumped her swimming pool dry and allowed it to
    be dry for a few days to do some major cleaning after not using it one year.
    The sides shrunk enough that the bottom was pulled up the sides some. She
    had to replace the liner due to shrinkage.

    When you install the bottom drain, concrete around it to prevent it from
    twisting or shifting. Pull the liner into roughly the final position,
    making sure that there is liner enough to go around. The hole for the
    bottom drain can be cut into the liner and the bolts attached as the first
    thing done. Start filling with water and pull the wrinkles out, working
    outward from the bottom drain. Wait until the water level is up to the
    skimmer opening before cutting for the skimmer. The weight of the water
    will be pulling down on the liner from the top as it conforms to the exact
    shape of the pond and could pull away from the skimmer.
    RichToyBox, Sep 3, 2007
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  3. Bill Stock

    ~ jan Guest

    IIRC, we installed the under-the-liner part of the bottom drain (with
    concrete as RTB mentioned), and the little stub of the skimmer poking up.
    Laid the liner and filled. This made the liner tight over those areas, so
    the next day when we emptied, we knew where we'd be cutting... granted,
    because of the skimmer pipe in the bottom, we had to lift the liner, glue
    the small extension piece, wait to dry, and then wiggle the Greg Bickle
    pipe boot over it. Can't remember if guys marked the liner... but I think
    the markings, the bottom drain hole (which we had plastic wrap over to keep
    dirt out) and screw holes remained indented in the liner. Kind of like
    pillow marks on your face when you get up. ;-) ~ jan
    ~ jan, Sep 3, 2007
  4. Bill Stock

    Reel McKoi Guest

    "Bill Stock" wrote in message
    Clay soil is the pits. Rock hard when dry and like mustard when wet. After
    about 8 years we had to drain both ponds and make cement berms. The clay
    sank over the years, some washed away, the sides, sloped, still started to
    collapse.... the rocks were falling in, runoff was entering one pond. I
    would make the cement berm before adding the liner rather than have to go
    back years later when the problems start.

    My Pond & Aquarium Pages:
    Zone 6. Middle TN USA
    ~~~~ } ~~~ }
    Reel McKoi, Sep 3, 2007
  5. Bill Stock

    Gill Passman Guest soil is also clay and although some of the sides of
    the construction have held up well with the variations in weather some
    bits will need more stability (this is the bit I've got left to do). We
    were going to go with building/using wooden (untreated) planters which
    will then be filled with bog irises (the liner will go up the outside)
    and eventually use the same to create a veggie filter that will sit on
    the deck.

    Gill Passman, Sep 3, 2007
  6. Bill Stock

    Bill Stock Guest

    "RichToyBox" wrote in message
    Thanks, the plan is to put a patio slab under the drain and then cement the
    drain on top of it. The skimmer will attach with a bulkhead opposite the

    How much below the pond bottom should the drain opening sit? 3/4"?

    I more or less have the shape dug now (taking a break from the chiseling),
    but I really won't know what I want until I see it. I still have to get the
    depth I want (probably another 2') in order to break into the drain line. I
    will soak the clay with water overnight so I can scoop out the bottom.

    Then comes the hard part, digging the remaining plumbing channels.
    Bill Stock, Sep 3, 2007
  7. Bill Stock

    RichToyBox Guest

    The bottom of the pond should be graded to be smooth with the top of the
    bottom drain with the clamping ring on. It does not need to go any deeper.
    If it is set too low, there won't be room between the cover and liner for
    water and debris. It is always good to bowl the bottom to make it easier
    for the debris at the wall to find its way to the bottom drain easier, but
    if it is bowled much, it makes it difficult to walk to the edge to get out
    if you get in for any maintenance.
    RichToyBox, Sep 4, 2007
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