Hi, We didn't put anything hard under the surface when seaming,
however, if you can manage to do so, it couldn't hurt.

We laid the liner completely in place before seaming.
Make sure you clean the liner well before attaching and
wait the recommended time for the silicone to cure
before filling with water.

Don't be so nervous, take your time and you'll be fine.

Good luck...Take pics along the way, someday you'll be helping
someone that wants to expand their pond. :)
Joann

Thanks Joann, You're right I should be an expert when I'm done with this. We plan to do this tomorrow, just hope the hole isn't full of water when I take the tarp and plastic off after the rain from yesterday.

I will post photos.

Joann, I emptied some of the water out so I could start digging down the 8 to 10 inches under the liner where it's going to be seamed. I tried to lower my existing liner to where I have dug down and there isn't enough slack to lower the liner as low as it needs to go for the fish to swim across.

I know you didn't have this problem. I just didn't know if you might have any ideas or suggestions of what I can do. I know cutting the liner is never a good idea, but I wondered if I cut the liner in the middle since I have 25' of tape to work with that might be a solution.

I know there probably isn't alot of people out there who try expanding their ponds this way, but I can't imagine no one else has run into this problem.

I'm in a panic and not sure what to do.

I'm not sure I know what you're talking about? if you are just digging 8"
under the exiting liner -- why is it short?
can you add a piece of liner to the existing line to make it longer? ...

can you post some pics?

Joann, It's very hard to explain but I'll try my best. I dug out the 8" needed to bring down the liner, but it would not drop down far enough because it was pulled so taut when installed. There were no folds in that section to give me extra liner to have enough slack to lower to where I needed to. There was enough liner to overlap and to do a seam, but not to drop down.

I had to cut the liner in two places which ended up making 2 Vs, Then I had to cut an extra piece of liner to put on top. So there was alot more seaming than I had hoped for. Just seaming the patched liner took so much time yesterday that I wasn't able to do the two liners together. I didn't dare do it today because it's suppose to rain the next couple of days.

The unfortunate part is that I had to lower the water more than I wanted when I cut the liner. There's a seam that goes into the existing pond. So the fish aren't in very deep water for the next couple of days. I do have 2 bubblers going, another small pump and we put a filter in there.

Looking at the forecast I might not be able to seam the 2 liners until Wed and then need a couple days for that to cure. I'm worried about the fish. My koi aren't near as big as yours. I only have 2 that are about 10" or so. The rest are smaller. Earlier I heard a loud splash and saw one of the bigger ones jump up about a foot into the air. It did this a few ties. I hope that doesn't mean it's stressed. I do have a leaf net over the top to protect them from any birds since it's so shallow right now.

The red lne is where I am continuing the rock wall around as my little upper pond in, which you cannot see in the back right corner. The elevated area is a stream with water fall that drops into main pond. Also cannot see in this photo. To the left of the red line is where I'm putting a waterfall to drop into the new pond. I will post a couple more.

Here is another angle. This was also taken last week. Should have taken more after I finished the digging. I dug that shelf back further (to the left) and made an alcove to house the mini skimmer and pump. They will be under rocks on the ledge and not visible.

Here is the "bridge" area where the 2 liners will be seamed (again taken last week). The distance marked with the red line measures approximatey 25". I did cut back the new pond side and sloped it down more. I had to make 2 cuts running on either side of that red line so I could get more give in the liner to drop it down. When it dropped down more it ended up being 2 Vs where I did the cuts. I then took a large piece of liner and covered the whole top area, which also went down into the existing pond. Of course I used the double-sided tape, cover tape, epoxy and over and over.

Hope this expains it for you. Sorry so long.

Why can't you just pull the new liner over the old liner and seam it? The
new liner will be over the shelf, and draped over the old liner, inside
the old pond...then it can seam inside the old pond on the side wall.

I hope I'm explaining it clearly. You don't have to have the new liner
and the old liner seamed on the top of the shelf between both ponds.
it can be seamed inside the old pond.

That's pretty much what I did (seamed inside the old pond) except that I couldn't get the old liner to drop down so I had to cut it, which created 2 -Vs where I made the cuts. Maybe because the width of the bridge area that caused the liner to be so tight that I wouldn't drop. I know it seems hard to understand.

I did alot of double sided tape, cover tape and epoxy. I hope it does the job. Now I just have to wait for the rain to stop so I can finish the job.