Sealing liner to concrete

[pidluk]

Hi,
I have a dilema, i switched form a lined pond to a full concrete pond and after a year, concrete being porous and all it is slowly leaking. I am now going back to covering the concrete pond with a liner.

So here is the issue and i will try and explain , imagine the number 7 the right side of the 7 is the pond wall and the top of the seven is the lip which is a long stream and acts as a waterfall.
I need to seal the top of the seven only a few inches with the liner so that water doesnt go underneath the liner any suggestions?

I have spoke to a couple of water garden supplers and they said no but i am sure someone has come up with a wonderful idea.

 

[addy1]

Have your top of seven be covered with a piece of liner, have that edge of liner go into the pond I have used pl roof goop to seal wb uses a spacer so it does not wick back. My goop had sealed many a lip without any issues.

Can you draw it up? or do you just want a small piece of liner on the top 7? from the pond. think that is what you are saying. What kind of material is the top of the 7? rock, liner, block?

Can you post a picture of the area

 

[Waterbug]

Normally the liner in the stream overlaps the pond liner. If the stream also doesn't have a liner...it will probably need one someday for the same reason as the pond.

There is no way to glue the liner to the concrete and expect it do work long term. It could work of course, just a matter of how lucky you feel and how much risk you wish to take on. If it does fail It could be a really bad issue.

A mechanical seal would be the only option for sealing. A bar of stainless steel, aluminum, or heavy plastic is used to bolt the liner to the the concrete so the liner is compressed between the concrete and bar. Normally a neoprene gasket (weather stripping) is placed between the concrete and liner. However there can be issues at the edges. Probably not a great method, but it depends on the pond.

An easier method might be to cantilever the stream bed out into the pond. This can be done with a large flat rock or something like Hardie board. It doesn't have to extend very far. A small lip is needed on the underside of the edge to stop water from running back along the underside. If rock is used the lip can be formed by cutting a kerf with a concrete saw. For Hardie board a thin piece of Harie board can be epoxied to the underside. Or for either a bead of caulk can be run along the underside, but this isn't as long lasting.