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Thread: Something to seal grout... help me stop seepage

  1. #1
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    Something to seal grout... help me stop seepage

    I'm sure there is an easy answer to this... but for the life of me I'm not sure what to use.

    I'm trying to prevent the tiny grout cracks along the inside wall of my spillway from letting water through. Picture this:

    I have a flagstone spillway from my spa to the pool. The top of the spillway is 12" wide surface of flat flagstone that is bonded via concrete to the gunite structure underneath. On the inside of the spa is tile and between the top of the tile and the bottom of this flagstone surface is grout. The type of grout used to fill the gaps between flagstone pieces tends to get tiny cracks. These cracks are causing seepage.

    I don't think I can use typical concrete/stone sealer as it probably won't fill the cracks and make the area watertight. I'm thinking that something more sticky and pliable would work... like even silicone, but not sure what to use that'll stand up to pool chemicals. This is a "hard to see" area and any material that is dark grey in color would work great.

    Any suggestions? It's a problem for me because I'm getting calcium buildup from the slow seepage.

    Thanks.
    Shelley
    Denver, CO

  2. #2
    Administrator JasonLion's Avatar
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    Re: Something to seal grout... help me stop seepage

    I don't really understand. Calcium buildup is to be expected in the general area of a spillway, with or without seepage, and is unavoidable (though it can be minimized). Further, the grout should be water tight, even if it has small cracks. And even if the grout does leak, the material behind the grout should be designed with the assumption that there will be seepage and not be damaged.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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  3. #3
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    Re: Something to seal grout... help me stop seepage

    I picture would help, I think.

    In the pic below you can see the calcium buildup just below the top flagstone on top of the dam wall. Water is seeping underneath these pieces. I was thinking I could seal the back side of the dam wall below these stones to eliminate the seepage.

    I keep my PH pretty carefully balanced... 7.4 - 7.8... to help keep calcium at bay. My water hardness is under 300ppm. I do have a SWG, but I'm pretty sure this is calcium and not salt buildup. So...

    Is sealing the back of the dam wall a waste, and any advice for helping keep calcium under control? Thanks!

    [attachment=0:3e7bp3fu]20120701_182456.jpg[/attachment:3e7bp3fu]
    Attached Images Attached Images
    Shelley
    Denver, CO

  4. #4
    Administrator JasonLion's Avatar
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    Re: Something to seal grout... help me stop seepage

    While there could be something more complex going on, that looks fairly normal to me. Some water will always get on the stone and as it evaporates it will leave behind salt, calcium, and whatever other solids are in the water.

    How long did it take to get to it's current appearance?

    Is the grout on the outside of the pool wet when the spillway hasn't been turned on for a while? If water is getting through the wall when the spillway is off you have a more serious problem that requires something more than "sealing".
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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  5. #5
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    Re: Something to seal grout... help me stop seepage

    When the pump isn't running the grout is wet until the water in the spa finds its level. It hits its level just below where the flagstone sits on top of the dam wall. No water is getting through the dam wall. It's actually going over the wall... but under the stone... if that makes sense. I suppose this is about 8 months worth of build-up.
    Shelley
    Denver, CO

  6. #6
    Administrator JasonLion's Avatar
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    Re: Something to seal grout... help me stop seepage

    The top flag stone was not installed properly. It needs to be removed and reset in place properly.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    TFP Admin. Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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