# Repairing concrete waterfall



## idris (6 Jul 2011)

We have a 70sq ft pond with a small feeder pond about 5f above it and a waterfall inbetween. 
The waterfall is leaking and needs repair work. 

Although I've not investigated fully, I think there is a base layer of matting, then one or two layers of butyl liner and some sort of concrete mix on top. There's then a liberal sprinkling of boulders and "weeds". I know some of the concrete has broken up will need replacing (as opposed to repairing) and I suspect this may be indirectly responsible for the leak. 

I believe some concrete type materials are likely to be toxic to fish, and it is going to be difficult to repair the waterfall without getting some in the lower pond. Any suggestions on what to use?


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## Ed Seeley (9 Jul 2011)

You might be best taking the waterfall apart and lining it with a butyl / greenseal liner and then replacing the rocks and plants on top of that to disguise it.

If you repair it woith concrete then it will raise the pH and you'll need to seal it after it's dried so it'll take a lot longer to do.


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## idris (9 Jul 2011)

Not really bothered how long it takes. It's going to be a right royal PITA at best.

Rebuilding from scratch is not an easy option due to the height, acute slope, and large shrubs surrounding it. And even then, I think some degree of concrete / mortar / etc will be needed. (That's how it was built originally.)


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## martin-green (11 Aug 2011)

I have just recently joined the forum, I wondered how is this going?

Do you have a waterfall or a water course?

I was thinking if you could turn off the water fall / water course  (or by-pass it) if the water level still drops its the pool that has a leak.

If you just want to repair it, then remove anything that is broken or chipped and re cement it. Its the lime in the cement that is harmful. A WORD OF CAUTION. Don't let any cement  fall in the pond, if it does you will have to completely empty it.    Once it has been repaired you should then "paint" the whole area with a pond sealer such as G4 (Other pond sealers are available) You should leave it for at least a week before you seal it, then 36 hours for the sealant to fully cure.

How about a picture?


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