"Bill Parker" wrote in message
36...
We are putting in a small pond with waterfall/stream. All the literature
that I have read recommends sealing stone in the stream with a foam. Every
foam product that I can find says to not use under water. What kind of
foam
are they talking about.

As CuttySark indicated the "Waterfall foam" is the expanding yellow foam
sold at HD and other big box stores. I bought the yellow foam and covered
the exposed areas with sand/dirt while the foam was still wet. Much cheaper
than buying the black foam.

But in the end, this stuff does not work that well. It's meant to prevent
waterfall leaks by stopping backflow in a loosely constructed (like mine)
waterfall. The only real solution is to put liner under your waterfall. I
dug a small U shaped moat around my waterfall and covered the entire area
with liner. The liner covers the area under the rocks and extends past the
groove (moat) around the waterfall to catch any leaks. I filled the moat
with the same creek stone that covers the liner around my pond. You really
don't know the moat is there, unless you look very closely at the water
flowing into the pond beside the waterfall. Anyone bent over the pond to
look that closely, might just slip. You know, sleepin with the Fishes.
LOL.