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Thread: Cracks in concrete cantilever coping

  1. Back To Top    #1

    Join Date
    Jun 2015
    Milford, CT

    Cracks in concrete cantilever coping

    Pool (18x36 vinyl, 3' shallow, 9' deep) was installed last July, concrete decking poured 8 weeks later after backfill allowed to settle.
    Minor initial issues with finish on coping - it was very rough in some patches, odd coloration, some small voids, and several of the form pins were sticking out. We had the concrete contractor out several times to deal with those issues, and while I still don't love the result, it's gotten to a point where I don't hate it. I may have unrealistic expectations, but that's why I'm posting here.

    Upon opening the pool this May, we noticed a crack at nearly every single expansion joint in the coping. Pics attached for reference.

    The concrete contractor came out last night after repeatedly canceling, and told us that happens to every pool with concrete cantilever coping. He said that was, in fact, the way its meant to work - that cracks are supposed to appear at those points based on the presence of the expansion joints. I questioned that.

    Is it true that every concrete cantilever pool deck has cracks all around the pool in the coping? Should he have done something different? Am I being unreasonable in my expectations?

    He offered to come back and make vertical cuts in the coping to help mask the appearance of the cracks. He claims that there is no risk of water getting in, freezing, and further expanding the cracks or weakening and deteriorating the concrete, so there are no structural concerns.

    I'm just looking for some honest points of view. Is this how it is, or did something go wrong here?

    Appreciate any thoughts.


  2. Back To Top    #2
    Mod Squad JVTrain's Avatar
    Join Date
    Feb 2014
    Central Minnesota

    Re: Cracks in concrete cantilever coping

    Open concrete cracks. There's no getting around it. Controlling the cracking during installation is the name of the game. Contractor would have been better off making the vertical cuts to begin with and filling them with an expansion joint material to control the cracks. Now you can see that the cracks have gone diagonal, away from being in line with the joint on the top surface, which may make it difficult to repair aesthetically unless they do really wide cuts. Occasionally, concrete is installed under the perfect weather conditions with a perfect mix of portland cement versus aggregate versus moisture and you get very little cracking after hydration... but that's kind of like winning the lottery.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
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  3. Back To Top    #3

    Join Date
    Jun 2012
    western NY

    Re: Cracks in concrete cantilever coping

    Two things I will guarantee about concrete...One, it will get hard. 2, it will crack. The expansion joints are to control where it happens. As JV said, if he would have scribed the vertical edge the crack would have happened inside the scribe and been harder to see.
    Unknown make 18' above ground (bought used in 1999) Sparco sand filter. Hayward 100,000 BTu heater. 2 speed pump

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