"stricks760" wrote in message
hlink.net...
I wouldn't count on just the foam. It's supposedly something like 95%
water-blocking. My experience on a waterfall that cascades through three
pools with about 8' of drop substantiates this. In my case, the foam
directs
MOST of the water over the falls, but not all of it.

As far as what WILL work, I have no experience with this, but they make
those fake-rock waterfalls waterproof using concrete (textured with a
rock-like pad), then painted with waterproofing, then painted. Maybe you
could bridge the gap that way. You'd still have a joint between concrete
and rock though.You can't jack the flat rock up, and slip liner
underneath?


I'll probably go with the concrete. There was some white fiberous
waterproof concrete that I'd used before that would probably work. As for
jacking up the rock, the exposed part is 5 foot in diameter , although only
a few inches thick. If that's all, then I could probably jack it up, but I
have a feeling that's just the tip of the iceberg. We've got lots of rocks.
There used to be a quarry about a mile from here. When I dug my 20'x30'
pond, I could only go down 20" because it was one single rock for the entire
area. I had to raise the edge another 15" with the excavated dirt.