Liner question

[codasajorusa]

I have a 6ft waterfall. A friend is trying to tell me it is ok to "shingle" the liner horizontally and then add the stream liner on top vertically without doing a seam? He claims the water cannot go underneath if it is shingled. My thought is water can get in anywhere. Thoughts?

 

[Lisak1]

You can indeed overlap liners - the bottom liner needs to come up under the top liner high enough that you are confident it won't slip down. People do it all the time!

 

[codasajorusa]

You can indeed overlap liners - the bottom liner needs to come up under the top liner high enough that you are confident it won't slip down. People do it all the time!

without doing a seam? And what is considered enough?

 

[GBBUDD]

Yes without a seam but look at it this way the liner on the low side has a bend as it comes to the upper layer that is 8 inches tall the water level comes up that edge 6" and the upper liner folds over the lower liner with a 6 inch fold so it's about 2" from the bend of the lower liner . And it leaves the water level down two inches from the top of the lower liner or "LEAK"

 

[Lisak1]

Yup - no seam necessary. How much overlap depends on the exact situation. I've read as little as six inches or as much as two feet. A drop down a straight edge would be different than overlapping a liner in a stream for example. I would bring the pond liner up as high as possible behind the waterfall liner. I mean, there's no concern about having TOO MUCH overlap.

 

[RobAmy]

As already said, no issues overlapping with no seam. Here is my stream as I was just testing it out. I just flipped it back up and then lined the pond going up on top of the stream then dropped the stream liner over the pond liner, no seam.

IMG_2011 by A & R Photography, on Flickr

 

[addy1]

Good picture @RobAmy shows it well.

My stream is around 85 feet long at every turn and where it drops into ponds I just did overlap, no seams no glue, it worked well.

 

[sissy]

but exception to that is plants and algae can grow under the 2 liners and lift them up .I just got done fixing that on my waterfall pond and liner goes up to the top liner by over 4 feet and other liner goes down over that by 3 feet and a sneaky root got under the 2 liners .I thought water lose was from evaporation until I pulled the plant out to trim the roots and the 1 root kept coming out and out and out .I found it last night and lucky it was an easy fix .I also found an elephant ear root that the plant is 4 feet from the pond and the root grew up and into the liner .I moved most of the elephant ear

 

[poconojoe]

I guess it depends on the situation. I would be more Leary if the whole thing was completely flat. I wouldn't worry at all with a downward slope or vertical drop.
If one feels uncomfortable overlapping, why not just run a bead of some type of sealant somewhere underneath as insurance? I don't know what to use. Maybe roofing sealant or waterfall foam?
Bottom line....it's your pond/stream/falls and do what makes you feel comfortable. It's easier to get it right the first time than to go back, tear it all apart and do it over.

 

[GBBUDD]

Bet way I can think of is to use the sealant and roll the edge so that the opening is not facing toward the outside of the stream of falls but faces toward the center so the roots are more apt to grow past the joint and not into it

 

[sissy]

The elephant ear root grew up over a 8 inch high lip where the filter sits .Plants are sneaky