"grubber" wrote in message
...
Thanks for all the replies.

But I'm not trying to seal liner together. I have a very large flat rock
that is mostly buried. The downslope edge hangs out a little over a 6"
drop. I want to dig back further under the rock to form a small pool
under
the drop. The stream would flow over the rock, fall into the pool below
and
then continue on its way. The pool would have a liner bottom.

My basic question is, "Is it possible to make a waterproof join between
the
pool liner and the immovable rock, and if so, how?"

If I understand correctly, you can't move the rock so lifting it and placing
say some sealing tape under it, would not work. What I would do is place a
small strip of liner over the edge of the rock where it meets the liner, and
seal that. Or squirt foam into the crevace, trim and then fill.

BV.