# concrete pool repair



## Billy_1948 (Feb 9, 2007)

Hello all, I have a serious problem that I sure could use some help with. My wife and I built a pond in the back yard several years ago. It's a huge koi pond with large water falls. About 3 months ago, we started noticing the water level dropping pretty rapid. We would fill her back up and by the next day we would loose several inches of water. We built this pond out of concrete instead of a liner. I drained the pond and found a crack in the bottom about 3 feet long. This is got to be were the water is leaking out as there is no other cracks in the pond. The pond holds about 6 or 7,000 gallons of water. 
Can anyone tell me what's the best way to repair this crack. I thouht of digging out all loose material and pouring hot tar in there but wanted to ask you guys before I did anything I would have to redo or do something that's not going to solve my problem.
Thanks in advance.
Billy


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## Tscarborough (Mar 31, 2006)

Since the crack is under the normal waterline, that indicates that there is a structural failure. Your options are to figure out and repair the failure, or to line the pond. There is no easy fix.


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## Billy_1948 (Feb 9, 2007)

I think what happened was, we had a huge gum tree cut down about a month or so before building the pond. I had a guy come in and grind the strump, but I think maybe the trunk and roots that were left under ground, rotted and made that area weak. The tree wasn't but about 2 feet from the edge of the pond. It has settled in that area. It could be that a large root rooted under the concrete to cause it to settle.
Thanks for answering 
Billy


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## Tscarborough (Mar 31, 2006)

If it were me (and I have built a lot of ponds), I would do this:

I would buy a bucket of "hydraulic cement" (all cement is hydraulic, but that is what they call it), and grind out the crack to a size that is equal to the depth. That is to say, if the crack was 1/2" wide, I would grind out a joint 1/2" deep. The sides of the crack must be vertical. I would then fill the crack with the hydraulic cement and hope for the best. If the pond shell continues to move, this is a temporary fix. If it leaked after this makeshift repair, I would use a liner.


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## Billy_1948 (Feb 9, 2007)

Thanks, I'll give that a try before I go with the liner. If it doesn't work, I'll have to go with a liner. 
Thanks again


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## POOLMANinCT (Nov 29, 2006)

funny bumping into u here tscar...lol

the hydro mud patch concerns...

where is the lateral support for the "patch"?

a pic would be helpful. if you are confident that the failure is result of decomposed root..

generally to fix a cracked shell I cut out the crack... 
about about a foot along its length.. dig oout a "mushroom" expose bottom of shell, this helps 
w the mechanical bond.

tie new steel into the cut out and repour from there....

did you use steel in construction? I only ask bc I'm surprised a root wood cause this??

so throw up some pix.. I'm curious about this one

ray in connecticut


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## handy man88 (Jan 23, 2007)

Yes, a big question since you and your wife built the pond is whether you used rebar and enough of it to first build the skeleton/structure of your pond. Without this rebar support, your pond will continue to crack. Another important thing is that the ground that you put your pond on must be tamped down and a layer of crushed limestone or gravel is usually applied and tamped down before rebar, and then concrete pour. Your 7000 gallon pond is equivalent to roughly 56,000 lbs, or 28 tons of water. Also, how thick did you pour the base of the concrete?


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## Billy_1948 (Feb 9, 2007)

Guys, I really feel like a dummy. I saw a crack in the bottom of the pond and assumed it was were the pond was leaking. I shut down everything and was prepared to get an idea from you folks on what I need to do. The response has been great. After I shut down the water falls, I noticed there was no more drop in the water level of the pond. I filled the pond back up, and without the water falls running, I have lost no water in the last 3 days. My wife,( who is in charge of the water falls), started removing rocks and found our problem. I couldn't believe that much water was going into the ground and not having a serious wet spot outside of the rocks. We do have a large water fall, and the rocks extend out several feet from the fall runners.
Yes, when we built the pond, we dug it and it was very solid ground. I did use 1/4" rebar in the bottom as well as the sides. I did not use lime stone because the ground was so hard and solid. I just thought maybe a root from the tree we had cut out, might have been a little deeper and I didn't know it was there. The crack I found, is not very deep. The pond botton is 3 inches thick, and the crack does not go that deep. 
So as it turned out, instead of me checking everything before I got on here and bothered you guys, I assumed something that was not correct. I can't tell you guys how much it means to those of us who want to do it our self, to have a group like this to go to and get some professional oppinions.
Thanks again guys, The responses were great.
Billy


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## handy man88 (Jan 23, 2007)

It's definitely worthwhile to seal that crack though, whether with hydraulic cement or a waterproof epoxy sealant. As how cracks are, they will get worse over time and creep. The best way may be to chisel out the crack and repatch the entire area.


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## Billy_1948 (Feb 9, 2007)

Thanks handy man88, 
I think I'll try the waterproof epoxy first. But if I see any further movement with the crack, I might go ahead and chisel out that crack and repair like you said.
Thanks again for everyone who replied to my request for help.
Billy


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