Enlarging a pond

Discussion in 'Water Features' started by Niagara Falls, Aug 26, 2010.

  1. Will P.C.

    Will P.C. LawnSite Senior Member
    Posts: 966

    Def just get a new liner. Much easier and will probably be cheaper in the long run
     
  2. CJF

    CJF LawnSite Member
    Posts: 67

    My suggestion was to leave what he has and just put a seperate
    pond up to the existing pond.
    His existing pond looks to be shallow with a nice stream, nobody
    sees the potential to just leaving it as is with a seperate pond up to
    it -- perhaps where that dirt bed is up on the right?

    Tadpole, I think it's more than luck that our seam has lasted 12 years
    without a leak. Even if it did spring a leak, the water level in the pond
    could only drop down one foot. the pond is 3 1/2 deep.
    the pond and fish could stay in tact whilst the leak was being repaired.

    You guys are all pros, if someone wants to add to a pond, you tell
    them to start from square one and start over?
     
  3. tadpole

    tadpole LawnSite Bronze Member
    Posts: 1,216

    It depends on what you mean by "add on". If a customer has an existing Pond that measures, say, 10' x 16' x 3' and they want to increase the size to, say, 10' x 25' while maintaining the current 3' depth, then the answer is , YES, I would recommend installing a new appropriate sized liner. If they are , however, considering connecting the old Pond to a new, separate Pond, then seaming would be a consideration provided that the width of the connecting channel was not over a total of 5' (my own working number).

    The biggest obstacle to seaming is that the liner MUST be on a relatively hard, flat and stable surface when the seaming process is done in order to achieve maximum integrity. This obstacle can be overcome if the seaming is done pre-installation. Attempting to seam post-installation liner, with all of it's curves and wrinkles, is inviting disaster and I don't believe that even a factory rep would attempt such a project.
     
  4. CJF

    CJF LawnSite Member
    Posts: 67

    The biggest obstacle to seaming is that the liner MUST be on a relatively hard, flat and stable surface when the seaming process is done in order to achieve maximum integrity. This obstacle can be overcome if the seaming is done pre-installation. Attempting to seam post-installation liner, with all of it's curves and wrinkles, is inviting disaster and I don't believe that even a factory rep would attempt such a project.

    That is the ideal senero tadpole, however, not always doable with an existing pond.
    At the point where our pond is connected it is only about 2 ft wide(on the bottom).
    it's hardto explain how we did it, but I'll try.

    we took the rocks away (keep in mind we have a rocked-up shelf all around
    that is about 12" wide by 16" deep, so we had to remove a lot of rocks.
    then we dropped the water level down about 1 1/2 feet to be able to work.

    ***we dug down about 1 foot...more about that later.



    after cleaning the liner we put the two pieces together with the liner tape.
    then we folded both sides of the liner in a zig zag fashion using a lot of
    silicone in between the silicone...the taped seam is siliconed between
    the two zig zags.

    then we cut two wide strips of liner and siliconed them to the top and
    bottom of the liner.

    we waited the recommended time for curing the silicone -- I think it was
    5 days

    we then put back the rocks, filled the pond, and did a Hail Mary...:laugh:

    several days later we placed rocks on top of the seam to hide the globs
    of white silicone.

    the seam is only about one foot down where is it seamed...
    to the right of the dock -- the new section it is 2 foot deep...to the left the old section, it's
    3 1/2 feet deep.

    ***if this ever sprung a leak, the water can only drop down one foot to where
    the seam is.

    the fish stayed in the pond the entire time we did the addition.
     
    Last edited: Aug 30, 2010
  5. tadpole

    tadpole LawnSite Bronze Member
    Posts: 1,216

    You have not stated exactly what was the total length of the seam.

    I do congratulate you on applying a successful seam, however, your method would never fly in a contracted project. The customer would run me off their property if I had gobs of silicone showing and multiple folds in the liner at the seam. Silicone, BTW, is not usually recommended as a seaming cement because it is, well, not a cement but a filler or gasket material, if you will. A seam done with silicone can very easily be pulled apart; a properly applied seam cannot.

    When you say "zig-Zag", i am assuming that you mean accordion pleats or folds. This also would never pass the visual test in a bare liner bottomed Koi Pond.
     
    Last edited: Aug 30, 2010
  6. CJF

    CJF LawnSite Member
    Posts: 67

    You're a tough one tadpole...I guess I'll have to provide proof that
    our 12 year old seams looks good.
    btw, have you ever seemed a previously installed pond?
    We did two, after we did our pond, we did our friends pond.
    Our addition is only 13 foot long. Our friends addition is 30+ foot
    long. We helped him do his pond the next spring, so far he hasn't
    had a problem.

    to answer your question... the seam is 2 foot across and 1 foot high
    on each side for a total of 4 foot of seaming.

    one more thing --we called both Dupont and GE and spoke to their
    reps, although they were non-committal in the beginning, they
    said the silicone was ok to use for our purpose as opposed to the small
    aquarium tubes of sealer. I think he used GE silicone over dupont.
    It did take a few days to install and we used at least two tubes, perhaps
    three (it was 12 years ago, can't remember)
     
  7. tadpole

    tadpole LawnSite Bronze Member
    Posts: 1,216

    Go back and read post #13. The 4' length of your seam is within the 5' range that I feel comfortable with.

    I would expect GE and Dupont to waffle on their response. If any semi-liquid product is to be used in seaming EPDM, one should use Firestone Lap Cement, which is formulated specifically for seaming, but even
    Firestone recommends the use of the double-sided tape and the cover tape for a sturdy lasting seam.

    BTW, aquarium sealer is made for use on glass and metal, both non-flexible materials and both possessing a smooth rigid surface. This may account for the response you received from GE and Dupont.

    I am not trying to take anything away from your methods used, but to point out the tried and true industry standards for how and when to seam EPDM. These standards especially hold true if the seam is located in an area of moving water (Stream) as opposed to still water (Pond basin).
     
    Last edited: Aug 30, 2010
  8. CJF

    CJF LawnSite Member
    Posts: 67

    Tadpole, not sure what your last sentence means?

    I asked the head guy to read this thread to make sure i didn't
    give out ant misinformation., he said just say, "Bottom Line
    It Doesn't Leak!"
    :laugh::laugh::laugh:

    i took this today, late in the day....the siliconed seam is covered
    in flat rocks so that it is not visable.

    The head guy around here asked me if you ever seamed a new addition
    to an existing pond with water and fish in the pond?

    pond 8-30-2010


    http://www.youtube.com/watch?v=wC5ZsUamHgE&feature=channel
     
  9. tadpole

    tadpole LawnSite Bronze Member
    Posts: 1,216

    What the last sentence in my post means is that if a seam is not properly done and it is in a stream, the force of the moving water will eventually work it's way into and contaminate the seam and weaken it, resulting in loss of water.In a still or slow moving water scenario this is not as much of a problem and in some cases the weight of the water itself will aid in preventing leakage.

    Evidently, after no leaks in 12 years, your seam has maintained it's integrity even though it was not done according to industry standards. You must remember, as a DIY, you can use any method you choose on your own Pond. This is not the case with me and my fellow contractors. We are not at liberty to experiment on other peoples' property because of liability issues and must rely on accepted industry standards to ensure proper construction of a particular project. We have to be able to guarantee our work.

    I don't know who the "head guy" is, but the answer is Yes. I have connected separate Pond basins with a seam. The seam(s) was(were) done to industry standards using double side tape and cover tape, but in no case was the total seam length over 5 feet.
     
  10. Niagara Falls

    Niagara Falls LawnSite Member
    Posts: 149

    I am working on talking my wife out of expanding the existing pond and trying to lean her to building a separate pond but with some type of connection.
    And I have no idea at this time how I would do that, but I'm sure it could be done.

    Yes, maybe the ornaments are tacky, but we love them. He should come by and look at the gardens, there are all kinds of things in amongst the plants.
     

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