Concrete pond - cleaning, patching, and sealing advice

[dsynadinos]

Hello pond aficionados!

We recently bought a house and inherited a pond. We've never had a pond before, but the previous owner gave us some basics, and I did my fair share of internet searches to keep it in working order. However, things have since gone awry, and I'm now in need of some "professional" advice.

The pond has been working nicely and providing smiles for quite a while. However, last fall, the water level began to drop more than usual. I figured there was a leak. After turning off the pump, the water level dropped to a certain level, then stopped dropping. I figured the leak must be at that level. But, it was getting cold, and we didn't have money to hire a pro. So, I simply pumped the pond as low as it would go with the waterfall pump and let it sit all winter. As you might imagine, this spring, it is a mess.

The pond had a rubber liner, and the previous owner told me there was a concrete basin beneath. After some additional Googling, I found that, rather than try and find the leak and patch the liner (or replace the liner), I could totally remove the liner and seal the concrete instead.

So, I've spent the past few days cutting out the old liner (as close to the bottom of the edge rocks as possible), removing the nasty carpets beneath, and cleaning the concrete basin. I've dry swept, power sprayed, and wet-vac'd the pond several times. However, there is still plenty of fine grit left over that I'm unsure how to remove. I assume that I cannot simply seal/paint over it. How can I really get this "clean"? How clean must it be for concrete/pond sealer to adhere and work?

Additionally, the concrete is "rough". It is more like the floor of a cave, than a smooth surface. And some parts have tiny cracks or crumbles. So, I assume I'll have to patch this somehow.

Also, I was originally thinking of just slathering on several thick coats of Flex Seal. However, after additional research, I'm finding that there are lots (and lots!) of options and debates regarding pond sealing approaches and materials. Before I was ignorant of info. Now I'm overloaded with info. Any advice?

I've included pictures to help give a better idea of my comments above.

Thanks in advance...!

 

[Tula]

Welcome, what a lovely pond

Truthfully, you may find it easier to have a liner pond, then concrete. I'll let others with more expertise on concrete join in.

Again, welcome !

 

[addy1]

Welcome to our group!

I would put padding and a new liner back in, if it was mine.

 

[Meyer Jordan]

Normally I would advise just sealing the concrete, but if I am seeing what I think that I am seeing in a couple of the photos, it appears that this concrete is disintegrating and is rapidly losing its structural integrity. So I will have to agree with the others. Replace the liner.

 

[Mucky_Waters]

Before ripping out the liner you really should have tried to determine exactly where it was leaking and patch the liner. Now I'm afraid to do it right you are going to have to break away and remove all the rocks around the edge and waterfall area covering the liner and then replace the liner and rebuild the rock edging and waterfall.
The concrete basin was likely there just to provide rigid support for the hole and never meant to hold water or be water tight. Any attempt to seal that concrete will likely end in failure and the pond will continue to leak.
Please take note of how the liner extends up under the waterfall area and was one continuous piece. This is very important in preventing leaks since waterfalls are a common area where leaks develop.
I'm a stucco contractor and have successfully sealed many concrete swimming pools with cement coatings but I know when to tell the customers it's not worth trying to cement seal them and to get a liner, this is one of those times.
I know this is not what you want to hear, but it may very well save you a lot of work in the end.

 

[TAHOE]

I would recommend Pond Armor "pond shield epoxy" which is specifically designed for ponds and stays somewhat flexible, but I have to agree with others, your concrete is beyond sealing. Go with another rubber type liner over concrete.

 

[dsynadinos]

Thanks to all for the replies...

"I know this is not what you want to hear, but it may very well save you a lot of work in the end." Indeed. This is going to be a mammoth job, and I'm not sure I have what it takes. *sigh*

 

[sissy]

It is not really as hard as you think .I am 63 and redid my pond a couple of months ago ,again .You pace yourself and it is easy .Clean out the loose stuff and pack wet sand in the broken areas and put in the liner and add a pump and water and leave the waterfall until you can get to it .I manage my liner by myself and it was 25 x 28 ..It was like putting a pie crust in a pie pan set the liner in the middle and pull each side out .When I got the liner I laid it out on the grass and unfolded it and folded it like it was a pie crust .Hardest part was it was heavy

 

[Giovanni]

I applied a 2nd gallon of Herculiner to my concrete rectangular pond over the original mortar finish and an application of Pond Shield Epoxy. Slowed leaking down but still losing water. I'm DONE. Pulled out a pond liner from storage last night. Going to put that sucka in there, sandwich the top edges with silicone between another row of cap stones, reframe the two glass windows, then cut the liner from around the glass. That should do it. Too bad I wasted $400 on concrete/cinder block sealers and epoxy. Built mine myself. Saved some money(?) but not TIME.

 

[Mmathis]

@Giovanni Didn’t you just answer this is in another thread? At least I feel like I just read this same answer somewhere else. This particular thread is almost 4 years old.

 

[mrsclem]

@Giovanni Didn’t you just answer this is in another thread? At least I feel like I just read this same answer somewhere else. This particular thread is almost 4 years old.

You got it this time!