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Thread: Rebar expansion?

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    Rebar expansion?

    Last February, I had a piece of rebar cut out as it was staining the plaster. The plaster company patched it up nicely and I thought this would be the end of it. Yesterday, I noticed a relatively large bulge just below this area...can't be good. Does anybody know what this indicates?

    Thanks!
    10 x 26 IG gunite/plaster
    7300 Gallons
    Hayward Tristar single speed 1 HP
    Hayward CF C4025
    Pool DOB 1/10

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    Charlie_R's Avatar
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    Re: Rebar expansion?

    Best guess from having spent most of my adult life in construction is that your rebar has gotten a steady supply of water to it, and is deteriorating. Some rebar will expand as it rusts, and can break through concrete quite easily.

    Do you remember what the rebar that was removed looked like? I would bet that it was all scale and rust.
    15'x48" 4500 gallon Intex pool, buried 1.5 ft. Pac-Fab Dynamo 3/4 hp pump. Hayward S180T sand filter, bought used. Taylor K-2006 test kit. Rocket mass heater based wood fired pool heater.

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    Re: Rebar expansion?

    Yes, tons of rust, but he cut the rusty part out. No more rust, just this odd expansion.
    10 x 26 IG gunite/plaster
    7300 Gallons
    Hayward Tristar single speed 1 HP
    Hayward CF C4025
    Pool DOB 1/10

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    Charlie_R's Avatar
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    Re: Rebar expansion?

    Can I assume two things from your user name and signature that you are in the inland desert area of CA, and the pool is only 3 years old? The reason I ask about this assumption is the potential high cost to you for another drain, repair and refill.

    It looks to me to be a case of a few small cracks in your gunite allowing water to reach the rebar in that specific location in your pool. If you were inclined and able to poke into that expanded area (I really wouldn't with the water in the pool!!!) if it were dry, you would find the same type of rusty scale that the plasterer removed above it.

    Is there a way you could take a picture of it?

    Another thing short of poking it would be to take something solid and VERY GENTLY tap around the edges of the expanded area and listen for a change in sound from the edge of the area to a known solid part of the pool. This would confirm that you have at least a delamination of the plaster from the gunite. If there is a sound change, it would be time to call the plaster guy back to fix before it flakes off.
    15'x48" 4500 gallon Intex pool, buried 1.5 ft. Pac-Fab Dynamo 3/4 hp pump. Hayward S180T sand filter, bought used. Taylor K-2006 test kit. Rocket mass heater based wood fired pool heater.

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    Re: Rebar expansion?

    Thanks for the reply Charlie. To be able to do any of these things, I will need to do a partial drain.

    New Question: While swimming, I began to feel all of the walls and it appears there are many lumps throughout the deep end. The plaster still looks good, but the walls are far from straight. The lumps are large and appear to be random. Is there anyway that the pool was built like this and I am only now noticing it? I have googled this and am not finding an answer.

    Thanks
    10 x 26 IG gunite/plaster
    7300 Gallons
    Hayward Tristar single speed 1 HP
    Hayward CF C4025
    Pool DOB 1/10

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    Charlie_R's Avatar
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    Re: Rebar expansion?

    You could be right about it being the way the pool was built. Did you have it put in, or did it come with the house?
    15'x48" 4500 gallon Intex pool, buried 1.5 ft. Pac-Fab Dynamo 3/4 hp pump. Hayward S180T sand filter, bought used. Taylor K-2006 test kit. Rocket mass heater based wood fired pool heater.

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    Re: Rebar expansion?

    It came with the house, I'm not finding anything on google about "typical" bumpy gunite/concrete walls. Nor am I finding much about rebar structures disintigrating in a wide spread area. I don't know where to turn at this point. I am hoping there are pool builders here that can deny or confirm
    10 x 26 IG gunite/plaster
    7300 Gallons
    Hayward Tristar single speed 1 HP
    Hayward CF C4025
    Pool DOB 1/10

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    Charlie_R's Avatar
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    Re: Rebar expansion?

    It could very well be that the one piece that you had replaced was the only one that had a problem.

    What you are describing is sounding more like a poor job in finishing the original surface.

    Sorry if I alarmed you.
    15'x48" 4500 gallon Intex pool, buried 1.5 ft. Pac-Fab Dynamo 3/4 hp pump. Hayward S180T sand filter, bought used. Taylor K-2006 test kit. Rocket mass heater based wood fired pool heater.

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    Re: Rebar expansion?

    Thanks Charlie, but I remain alarmed as it looks like the steel is coming through again.....two places where it was patched and a tiny spot in the shallow end. It is something coming from behind the plaster, not on top. I'm having nightmares about this pool!
    10 x 26 IG gunite/plaster
    7300 Gallons
    Hayward Tristar single speed 1 HP
    Hayward CF C4025
    Pool DOB 1/10

  10. Back To Top    #10

    Join Date
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    Re: Rebar expansion?

    Google "pool plaster calcium nodules" and see if that is the problem along with the rebar issue.

  11. Back To Top    #11

    Re: Rebar expansion?

    After spending the last few weeks "feeling up" other plaster pool walls, I am resting easier :P Seems lumps and bumps are part of the original construction in some plaster pools.
    10 x 26 IG gunite/plaster
    7300 Gallons
    Hayward Tristar single speed 1 HP
    Hayward CF C4025
    Pool DOB 1/10

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    Charlie_R's Avatar
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    Re: Rebar expansion?

    Thanks for the update! Glad you've been put more at ease about your pool.
    15'x48" 4500 gallon Intex pool, buried 1.5 ft. Pac-Fab Dynamo 3/4 hp pump. Hayward S180T sand filter, bought used. Taylor K-2006 test kit. Rocket mass heater based wood fired pool heater.

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