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Cracks in shotcrete?

Posted by luvh20 (My Page) on
Mon, Mar 14, 11 at 0:55

Is it o.k to have some long hairline cracks in the shotcrete? Starting in shallow end , and working
it's way down to deep end.

Thank You.

Follow-Up Postings:

RE: Cracks in shotcrete?

Sounds like shrinkage to me. Did you water the shell down at all?


RE: Cracks in shotcrete?

poolguynj: Watered twice a day since it was shot on 3/04.
It's only a hairline crack right now,so I'm watching to see if it gets any wider. I will call the PB today, just to let him know about it, and see what he says.
If it's just a hairline crack, and doesn't get any worst,
will the plaster seal the crack?
Thank you!

RE: Cracks in shotcrete?

Yes. Gunite is porous. The plaster finish makes it water tight.

If it's just a surface issue, they'll go right over it. If it was more, they would likely grind it down and fill it.

From your description, this is not a sign of structural problems and is in fact, a normal occurrence.


RE: Cracks in shotcrete?

I have to disagree. Any crack should be sealed up prior to plaster especially one as described above. Expecting the plaster to seal it without mirroring the crack is risky.

The myth that hosing down a shotcrete/gunite shell several times a day is the proper way to cure concrete is also very questionable.

RE: Cracks in shotcrete?

Two saying no problem , and one saying problem.
My oh my...who to believe??
Well I called the PB today, and was told it's normal to have small shrinkage cracks in shotcrete, or any other
cement jobs. He will come out, and take a look at it.
I trust him because he has been building pools for a very long time, and this is my second pool being built by him.

Not to say I don't believe everyone elses opinion, or suggestions on this site. We got alot of good advice, and recommendations on this site. And not knowing who really are the professionals, and who are the wannabe professionals, I think I will take the advice of my PB.
And for some reason,if I don't get a warm and fuzzy feeling
from his answer, I will seek a second opinion.

Again, I thank you for the responses,and I love this site.

RE: Cracks in shotcrete?

renovxpt, you have forgotten more about this than I would learn in 10 years working with you. I have always and will always hold you in the highest regard. Watering a shell is no myth though many do it for far longer than is needed. Depending on the temps of the environment, watering after a few days is useless. Sometimes when it's hot, I was also taught to water every few hours in heat of the day, starting the next morning.

Not all cracks are equal. Micro cracks where its less than 1/2" deep and still tight aren't going to reveal themselves when plastered over. Cracks that have spread to where you can see inside should be notched, cleaned and filled.

If you experience has shown you no difference, I'd love to try to understand why.


RE: Cracks in shotcrete?

Sorry Scott, I wasn't clear in my post.

Hosing down a new pool shell a couple of times a day is like giving a guy in the desert a few drops of water every couple of hours. We use soaker hoses as soon as we can get them on the shell and leave them running for several days if its not raining.

RE: Cracks in shotcrete?

Thank's guy' helps when the pros on on the same page!

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