True silicone does not do that. You most likely are talking about cheap
acrylic caulking. Caulking also peels because a person did not clean the
surface first. I am going to put epdm behind the rocks just want to keep
most of the water on top. Never thought about gravel on top of the foam will
give that a try.

"Offbreed" wrote in message
...
Mickey wrote:

I see people are using foam to help hold rocks in place and stops leaks.
How
long does the foam last ? I know foam is UV sensitive and breaks down in
sunlight. I was thinking of using tubes of clear silicone.

Take a walk through the poor part of town where the houses are close
to the road or through a trailer park. Lot's of silicon around the
windows. Lots of trouble with it, too. Ends up looking pretty bad.
Among other things, algea grows in the pockets, long strips peel off.
You might be able to apply it so it does not develop problems, but
it'll look horrible if you don't.

White silicon is worse. Tried it on my boat. Nope. Not again.

Maybe something other than foam would work well, but I'd suggest foam
and paint, or that gravel trick mentioned earlier. Find a way to keep
lots of gravel against the foam for a day or so.