Relining with minimum disruption

[Bill-t]

I'm not really new to ponds, having built this one about 25 years ago. but am new to the forum. IThe pond is about 5m x 4m and used to be clear and full of life. It sprang a leak about 5 years ago due to damage from bullrush roots and there are two areas of damage. I have twice attempted to repair using proprietry butyl liner repair kits. One repair lasted three years, the second only one and the pond is a shallow green puddle with an unknown number of fish and frogs trying to live in it. I have decided to put a second liner in.
Couple of questions.
Should I puncture the bottom of the old liner to allow drainge so water doesn't build up between the liners up to leak level
Secondly the coping is crazy paving (random shapes) slabbed and I really don't want to redo it all. Do you think the I could finish the liner at the underside of the slabs and use sealant to bond it in place
Any advice welcomed. A job that lasts 10yrs will more than see me put.

 

[j.w]

@Bill-t
Yes you will need to punch holes in the old liner and put the new one right over it. Also try to save as much of the old pond water as possible so as not to shock the fish w/new water. You can store the water in food grade tubs or children's plastic pools. Can't tell you about the coping and sealing tho.

 

[poconojoe]

Yes, it is recommended to puncture the old liner. I'm not totally understanding the coping question, but it's always advisable to have extra liner up and over the sides. It can be hidden by folding it and covering with things like rocks. Attempting to cut the liner short and glue any edge will result in failure.

 

[Mmathis]

Hello and welcome! Yes, put slits in the old liner. Not sure about the other question. Can you post some pictures?

 

[Bill-t]

Sorry, I didn't explain clearly. I'm aiming to avoid the dispruption and cost of tearing up the old paving surround. You can see it in the picture and it has about 2" overhang over the water. Water level is regulated to about 3" below by an overflow pipe. Pond shape is rather like a harp, this is the narrow end.
My thought was that since the new liner edge is above top water level sealing might be a viable solution.

 

[Bonsaijon]

Hi Bill-t (and all on the forum). I just wonder did you ever get an answer to this problem or did you try it, because I have exactly the same issue. My current thinking is to chase out a slot under the coping and seal the liner into this slot with waterfall foam. I don't want to rip up the landscaping over the top of the current liner(s)

 

[JamieB]

Don’t use water fall foam, it’s not water proof. Use a good glue, @addy1 uses pl roofing goop which might work.

 

[addy1]

@addy1 uses pl roofing goop which might work.

The pl goop works great, if you clean the surface well, make sure it is dry, also rough it up a bit with sandpaper. I have some repairs I have made with it that are still doing well 7 some years later. Use a lot! I have also put some on one surface, some on the other surface let it dry just a bit the smush it together.

A lot more expensive, but also works, is the GOOP marine, made to be under water, again clean, dry, rough, put some on both surfaces let it dry and bit and push together. I bought it to fix some stuff on our old boat then used some to fix a hard to seal area on my 300 gallon lotus tank.

Amazon.com : marine goop adhesive/sealant

 

[TheFishGuy]

Hi Bill-t (and all on the forum). I just wonder did you ever get an answer to this problem or did you try it, because I have exactly the same issue. My current thinking is to chase out a slot under the coping and seal the liner into this slot with waterfall foam. I don't want to rip up the landscaping over the top of the current liner(s)

On another note, welcome! We would love it if you were to introduce yourself in the “introduction” section

 

[poconojoe]

I wouldn't chance what you are thinking of doing. You'll end up with a mess with whatever glue you are trying to use and it will leak. Then the liner will be too short to do it over correctly. Liners are expensive and the most basic component of the pond.

Cut your losses... pull all the coping stones and do it right. Really... it can't be that hard. Mortar cement is not as solid as concrete. It's just Portland cement and sand, no aggregates. Sometimes they will add a milky looking latex bonding agent to make the mix stickier to better adhere it to the stones.

Cut a piece of 2x4 the length of the coping stone. Hold it underneath the stone and tap lightly up on that. This will distribute the shock and act as a cushion. You don't want to crack the coping stone, so go easy. You'll be surprised how easily they'll come up.

If you intend on reusing them, write on the underside with a sharpie. Number them and write an arrow for orientation.
Get a couple bags of mortar cement from your favorite home center. They are cheap, like $3-$4 a bag. The liquid latex bonding agent is like $10 a gallon. Mix it in a tub or wheelbarrow. It takes a long time to set-up (harden), so you don't have to rush. Don't mix the whole bag at one time until you get the hang of it. Mix it so it's pretty dry, not soupy, just damp basically.

If this is a no-go for you, maybe you can find a contractor, handyman or neighbor that can do it.

It's all up to you. It's your pond and your money. I have learned that you save work and save money in the long run if you do it right the first time.