Can you “treat” an old pond liner to re-waterproof? Explained...

[RadarContact1]

Hi guys,

Wondering if there is any excepted practice of putting / spraying / applying something to the pond liner to make it waterproof again. I think mine may be so old it’s become porous, if that’s even possible.

I have a 15 foot diameter by 3 feet deep pond, about 3800 gallons, that loses about 3 inches of water per day. I just spent $175 to have a technician from Hydro Scout come out and search for the leak with their sonic detection equipment. He said it was “quiet as a mouse”, to quote him. In other words, he could not find any leaks.

The pond liner is the old semi-stiff type that you could bend and fold to install; built the pond with it way back in 2003.

To try to narrow down the source of the water loss, I’ve isolated everything individually and the pond will lose water regardless of whether the pump is running or not, etc. So it’s not in my piping, filter, etc. Thinking it’s just letting water pass through the liner due to age?? Idk.

So I was thinking about getting a quote to have Gunite sprayed in it like a swimming pool, or maybe having bedliner material sprayed on it like a truck bed. Are there any other options? Has anyone ever done this or something similar to this before?

As you can tell I’m frustrated and frazzled… This really sucks and my 16 large goldfish are all jammed in a 25 gallon barrel right now. I really don’t wanna put them back until I can figure out what to do. But I’ll have to. I hate to put them back and pull them out again — it’s too much stress on them and they are HARD TO CATCH!

Thanks,
// Radar //

 

[Nevermore44]

Are you saying you have a PVC liner? that's the only material that I heard of getting ridged over time. Regardless... i wouldn't believe Gunite can be sprayed on any substrate that is semi flexible... could be wrong.

3" of water loss at that size of pond is a huge amount of water. You aren't seeing the water daylight out anywhere?

Since you have the fish out... can't you wait till the water stops dropping to see what level the leak is at and repair from their?

Last thought is if you can't find the leak ... to have a new EPDM runner liner replace or overlay you current one.

 

[mrsclem]

Epdm liners don't become porous, they developed leaks. At 16 years old, it may be time to replace!

 

[mgmine]

When you turn everything off and leave the pond alone, how low will the water get before it stops leaking? That is where your leak would be. The cheapest and easiest way to solve your problem would be to drain the pond completely and put a new liner in over your existing one.

 

[Lisak1]

I'm in the "replace the liner" camp. Long term it will give you a pond that will last for many years to come. I've never heard of a "bend and fold" liner - is it EPDM?

 

[RadarContact1]

To all, collectively...

I don’t know what the liner is, EPDM or something else. It was considered the liner of choice back in 2003. It is a round pond so the “bend and fold” just refers to how I had to install it; there are folds and creases to make it fit in the round hole.

I have turned all off and left it and it will get below the lowest pipe and still keep dropping. And the tech said he couldn’t hear anything at all. I don’t see anything. There are no pockets or soft spots on the bottom. That’s why it seems like it is just “passing” water through the liner, but I guess that’s not a reasonable explanation. Had to ask though!

Installing a new liner would really be a huge pita, but may be my only solution. It’s not really the money... I’ll spend the $500 on water bills or a new liner, either way.

 

[RadarContact1]

Here are some pics of the liner, close up. Maybe that helps. Also some of the larger areas where it is really folded over, that may show a better idea of the liners characteristics.
Also, you can see that my liner goes up and under my flagstone which is all cemented together. The new liner would have to go up and under the lip of the rocks, but not completely under them (unlike the current liner which the rocks completely lie on top of). I would have to glue it to the old one at the top, not a great situation. I would also have to redo all of my piping which I just got done doing a few months ago... went from an internal to an external pump setup. (Btw, all that piping will be covered by fabric sleeves, but have left them bare for now while I’m trying to work out my issues.)

// Radar //

 

[RadarContact1]

Are you saying you have a PVC liner? that's the only material that I heard of getting ridged over time. Regardless... i wouldn't believe Gunite can be sprayed on any substrate that is semi flexible... could be wrong.

3" of water loss at that size of pond is a huge amount of water. You aren't seeing the water daylight out anywhere?

Since you have the fish out... can't you wait till the water stops dropping to see what level the leak is at and repair from their?

Last thought is if you can't find the leak ... to have a new EPDM runner liner replace or overlay you current one.

No water draining anywhere.

 

[RadarContact1]

When you turn everything off and leave the pond alone, how low will the water get before it stops leaking? That is where your leak would be. The cheapest and easiest way to solve your problem would be to drain the pond completely and put a new liner in over your existing one.

See explanation above

 

[RadarContact1]

I'm in the "replace the liner" camp. Long term it will give you a pond that will last for many years to come. I've never heard of a "bend and fold" liner - is it EPDM?

See explanation above

 

[Nevermore44]

Looks like the RPE liner... the guy at the pond shop here said a while back that they only use it on really large ponds without too much in regards to curves/bends/etc. Regardless... it's a fine material can can be repaired.

You are saying you had the pipes added a few months ago... but the water continues to drop below them...... so i would just continue down that route without the pumps running to take away all variables in regards to a leak. It might come down so some small fold/crease at the base of the center fountain ... who knows. But at this point you have no other options.

It's a great looking pond.... just keep digging !

 

[poconojoe]

I agree with the consensus here. Leave it alone, let it drain down until it stops. Hopefully you will find the problem somewhere at that level.
If you feel the liner is old and brittle, maybe it's time to bite the bullet and replace it. However, before throwing in a new liner, I would make sure nothing was actually puncturing the old one. A tree root, a sharp rock or whatever could ruin your new liner.
I hear you on those cap stones. Sometimes you just have to do it and not cut corners. I'm thinking you could hopefully tap those stones upward with a rubber mallet or dead blow hammer to release them. If not, a lump hammer with a block of wood to protect the stone.
It sounds like a lot of work, so hopefully you can find and repair the leak instead.
Keep us posted...

 

[mgmine]

No water draining anywhere.

If water isn't draining anywhere then the membrane is porous whatever the cause with a little work it can be fixed. Not that it matters but was it leaking before the new piping was done? Don't try to do the job halfway it will just take longer. It's like remolding a house versus building a new house. Cement doesn't stick to rubber so just take the rocks off the top and clean them up. Remove the piping that is going through the liner, this only increases the chance of something leaking. If the original liner is really folded a lot and uneven then pull it out and line the pond with an old carpet that you can find at the curb on any given day or contact a carpet store and ask them for some used carpet. Put a new liner in and a skimmer. Either reuse your external pump (bad idea water doesn't like to be pulled) or put a new pump in your new skimmer. Reuse the stones for the edge but don't cement them, and enjoy your pond for the next quarter of a century. Total time 2 days three at most. Cost much less than doing the job with gunite or having to do it again after coating it with something else that doesn't work.

 

[poconojoe]

If you remove the cap stones, try to label them so it won't be a hassle knowing where they belong. Mark or tag them somehow underneath. Do it in sequence so you know which goes where and maybe use an arrow to indicate what the orientation was. You can sketch it out or take pictures.
Take the suggestion from mgmine about not piping through the liner. More chance of leakage that way.
I also prefer submerged pumps although some here have external ones. There are pros and cons with both.

 

[Nevermore44]

What is your filter set up ?