Concrete block pond/help!

[Jefina]

Hello,
I’m building a sunken concrete block pond that is connected to a lovely stone wall and I have no idea now what to line it with (among other things). I’ve looked at non toxic pond sealers like pond armor and Hecht, and also at regular pond liners. The liners seem to be more affordable but they would hide the stone of the wall, which I hope will be seen below the water. Any suggestions? Help!

 

[Tula]

Welcome Jefina I think using a EDPM liner is your best option, however you'll not be able to see the stone wall. A monolithic pour of concrete, coated with xpedex ( I think that's the name of the product ) would also hold water, but either way I don't think you'll see the stone wall.

Most pond sides are soon covered with green carpet algae, so you probably wouldn't see the stone wall anyway. Is there a way to use the wall as a garden feature near the pond?

 

[zeuspaul]

I built a concrete block reservoir 12 ft x 9 ft deep and sealed it with troweled on Rapid Set mortar that I got at Home Depot. https://www.homedepot.com/p/Rapid-Set-55-lb-Mortar-Mix-04010055/202188453 It has held up well for over five years. You could leave the rocks exposed by just covering the joints with the mortar. Rapid Set is much more water proof than Portland cement products and doesn't shrink like Portland cement products.

I don't know how fish safe it is. Tadpoles and frogs don't seem to be affected.

 

[Jefina]

I built a concrete block reservoir 12 ft x 9 ft deep and sealed it with troweled on Rapid Set mortar that I got at Home Depot. https://www.homedepot.com/p/Rapid-Set-55-lb-Mortar-Mix-04010055/202188453 It has held up well for over five years. You could leave the rocks exposed by just covering the joints with the mortar. Rapid Set is much more water proof than Portland cement products and doesn't shrink like Portland cement products.

I don't know how fish safe it is. Tadpoles and frogs don't seem to be affected.

Hmm.... that sounds interesting. Will be putting fish in it. Maybe I could use that and then time over it to make it fish safe. What do you think? Thanks!

 

[Jefina]

Welcome Jefina I think using a EDPM liner is your best option, however you'll not be able to see the stone wall. A monolithic pour of concrete, coated with xpedex ( I think that's the name of the product ) would also hold water, but either way I don't think you'll see the stone wall.

Most pond sides are soon covered with green carpet algae, so you probably wouldn't see the stone wall anyway. Is there a way to use the wall as a garden feature near the pond?

Thanks! The pond is already attached to the wall but may I could figure something out.

 

[addy1]

Welcome Jefina, glad you joined.

That is a neat stone wall, which over time will be green and covered with algae.

 

[zeuspaul]

Hmm.... that sounds interesting. Will be putting fish in it. Maybe I could use that and then time over it to make it fish safe. What do you think? Thanks!

My guess is it's fish safe. I don't know what "time over" means? If I were to do it I would add some plants and season for a bit and then add a few small fish first.

The blocks have to be well placed and at least every other cell filled with concrete. Rebar might also be advised. If you paint it with something it would make it more difficult to repair should that ever be necessary.

The stuff has a short working life so you have to work quickly and with small batches.

 

[poconojoe]

Nice idea, but as others have stated, the underwater portion of the stone wall will soon be covered with beneficial algae.

Maybe you can add a few courses of block in front of the stone wall, just up to the level of the water. This will give you a support for an EPDM liner to hang over. Then lay flat stones to match the wall on top of that to hide the liner. That way you will have a nice pond with an awesome stone wall above one side.

 

[Jefina]

Welcome Jefina, glad you joined.

That is a neat stone wall, which over time will be green and covered with algae.

Hi, I’m glad I joined too. I figured that I would be cleaning the wall now and then with a scrub brush. I know it will discolor some. I was planning on using the clear pond armor on it as well.

 

[Jefina]

Nice idea, but as others have stated, the underwater portion of the stone wall will soon be covered with beneficial algae.

Maybe you can add a few courses of block in front of the stone wall, just up to the level of the water. This will give you a support for an EPDM liner to hang over. Then lay flat stones to match the wall on top of that to hide the liner. That way you will have a nice pond with an awesome stone wall above one side.

Thanks. Good idea. Last night after the advice I’ve gotten here, we were discussing this idea. We were thinking that the open part in front of the wall could still have water but be at a lower level and have the smaller fish. One thing that may be a concern is that the additional wall wouldn’t have a footing since we’ve already poured the slab and wouldn't be connected with rebar. Any thought on that?

 

[Jefina]

My guess is it's fish safe. I don't know what "time over" means? If I were to do it I would add some plants and season for a bit and then add a few small fish first.

The blocks have to be well placed and at least every other cell filled with concrete. Rebar might also be advised. If you paint it with something it would make it more difficult to repair should that ever be necessary.

The stuff has a short working life so you have to work quickly and with small batches.

Oh, sorry, typo. It’s supposed to say “Tile over.” Wall has rebar. We will definitely fill all the cells. Not enough cells are filled now. Thanks for the advice on timing of the application. Sounds like a good idea to hire someone to help. Very helpful! Thanks!

 

[zeuspaul]

Oh, sorry, typo. It’s supposed to say “Tile over.” Wall has rebar. We will definitely fill all the cells. Not enough cells are filled now. Thanks for the advice on timing of the application. Sounds like a good idea to hire someone to help. Very helpful! Thanks!

I am not suggesting sealing with Rapid Set mortar, just as an alternative to EPDM. I was impressed with how well it worked for me. For sealing the stone wall joints I would probably chip/grind out some of the existing mortar and replace it with Rapid Set.

I would only "tile over" if you prefer the look.

 

[poconojoe]

Thanks. Good idea. Last night after the advice I’ve gotten here, we were discussing this idea. We were thinking that the open part in front of the wall could still have water but be at a lower level and have the smaller fish. One thing that may be a concern is that the additional wall wouldn’t have a footing since we’ve already poured the slab and wouldn't be connected with rebar. Any thought on that?

Would the additional footing be that hard to do? You can mix that small amount by hand. A few wheel barrows full. Some bags of Quickcrete concrete mix and a few pieces of rebar.

I don't see the need to create separate sections of pond. The bigger the pond, the more room your fish will have to swim around. Maybe I just don't understand what you meant. But if you do that, and one section is higher than the other, you could create a nice waterfall feature to allow the water to flow between the two.

 

[zeuspaul]

I found a picture of my concrete block pond/reservoir that I sealed with Rapid Set mortar. I checked and I built this eleven years ago and still no maintenance.

 

[Jefina]

I found a picture of my concrete block pond/reservoir that I sealed with Rapid Set mortar. I checked and I built this eleven years ago and still no maintenance.

View attachment 124320

Wow! Beautiful!