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Garden Pond Cement additive

  • 22-09-2023 1:41pm
    #1
    jayo99
    Registered Users, Registered Users 2 Posts: 365 ✭✭


    Hey guys,

    Im in the middle of building a Garden pond. I plan to lay heavy grade plastic and then pour concrete on top of this with some chicken wire for added strength

    Is there any additive (Sika possibly) which I can add to my concrete mix which will make it waterproof?

    I think there are paint on rubber-type sealants which can be applied to the finished concrete but I was looking for something for the concrete mix


    thanks in advance

    jayo



Comments

  • #2
    Croohur1
    Registered Users, Registered Users 2 Posts: 129 ✭✭Croohur1


    I think there is an additive called bentonite that is used to seal ponds. Not sure how readily available it is in Ireland though...



  • #3
    10-10-20
    Registered Users, Registered Users 2 Posts: 8,074 ✭✭✭10-10-20


    https://www.boards.ie/discussion/2058314942/garden-pond-cement-additive

    Yes, some of the plasticiser admixes are also waterproofers.

    https://www.chadwicks.ie/arcplast-waterproofer-plasticiser-5lt-29154.html
    https://irl.sika.com/en/construction/concrete-admixtures/watertight-concrete/sika-1.html

    As for use in fish ponds (if you are adding fish) - not sure - you may need to read the technical documents.



  • #4
    10-10-20
    Registered Users, Registered Users 2 Posts: 8,074 ✭✭✭10-10-20


    https://www.boards.ie/discussion/comment/121143371#Comment_121143371

    Bentonite (cat litter) is used as a admix into clay/soil to seal the base of a pond It becomes a impermeable but flexible base as the bentonite swells up as it takes on water, making a hard sticky pan. It's not a concrete admix that I know of.



  • #5
    Wildly Boaring
    Registered Users, Registered Users 2 Posts: 3,655 ✭✭✭Wildly Boaring


    Concrete is waterproof. For example a brand new reservoir would have no admixture or coatings.


    The main issue is cracking, cracked sizes and location. So the reservoir would be designed to have say minimal cracking.


    Bentonite would generally be in a waterproofing layer, in something like like voltex. Generally used in basements etc. Usually outside the concrete.

    Admixtures will improve concrete quality for water resistance, by spreading any bubbles etc. But only be as good as your cracks. May help with shrinkage cracks?


    What I'm getting at is you'd be better off with doing really good work. Placing in plenty rebar to prevent cracking, but don't overdo it. Max 2 bars lapping with good cover. Also make sure to vibrate every bit of it. Avoid corners. Have a circular, gently sloped design.

    Keep well protected after, for curing again to avoid cracks.

    Then for a pond get a paint on sealer for the underwater bits.



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