New 1500L(ish) goldfish pond build

So this started happening today...


Not sure of the exact amount of water the final pond will hold, but it will be in the region of 1500-2000L.

Outer dimensions of the pond are roughly 3m x 1.2m. It will be built out of double layer brick walls, with concrete foundation, and will again be a raised pond (the foundation will be below ground level but the walls will be above, somewhere between 70cm-1m high, I'm still figuring that out.

We've got a guy building it for us, but we're dictating what gets done (he's a guy with building experience, but has never built a fish pond). I still need to figure out what I'll line it with - pond/aquarium paint vs liner. The whole brickwork will be plastered over.

 

I would be very nervous about damp issues in the house wall with the pond right up against it.... Plaster is like a sponge.

Look into using a product like SikaLite when you do the plastering and make sure you do an outstanding job at making things watertight.

Good luck with the build.

 

Thanks, I'll definitely check out SikaLite. Open to any and all helpful hints and warnings.
The house wall is double layer brick, and then the back wall of the pond will also be double layer brick, so hopefully damp won't go through all of that? But the intention is to still waterproof the pond after building. Maybe a layer of damp proof plastic between the back wall and the house wall would also be a good idea though, just to be sure. But I'll definitely consider SikaLite as well.

So the actual structure will be concrete base, with double layer brick walls, which will be plastered both inside and out.
Then when that is totally finished we will either paint the inside of the pond with special aquarium paint (I don't know what it's called but a previous guy that quoted us for the pond mentioned it, it makes the thing watertight), or I will line the pond with a rubber pond liner. I need to still investigate both those options. For now we're just focusing on the build of the actual structure.

 

Had a look at SikaLite and I think we'll buy a bag to add to the final plaster coat. I don't think it's necessary to mix into all the concrete/cement/dugga. I reckon just the final coat will be enough. (please correct me if I'm wrong and totally naive).
Hmm, thinking about it, we can't plaster the back wall of the pond because it will be against the house wall. I wonder if maybe we can apply a layer of plaster to the house wall (on top of the existing plaster) with this stuff mixed in it. Just as added protection.
I might still also add a layer of dpc plastic bewteen the two walls just for extra protection as well.

I also saw this Duram Durapond which is definitely an option for waterproofing the inside of the pond: https://www.builders.co.za/Paint-&-...enyXukPhHGfXXQC8CepI4XMZILHGN6bhoCBUsQAvD_BwE

I need to read up on it a bit more, but surely if it's sold as a pond paint it would be safe for fish. Will do a bit more research before deciding finally. Will prime with Duram Duraprime first.

 

Hi @HugBug. Once again I'm excited to see this play through and cannot wait for results.

As @DarylA has stated, I also have concerns about the waterproofing and I personally would not trust that at all. You may be activating a dampness issue that would require breaking the pond to resolve in the long run so I would not advise it. I would leave a 1 brick space between the house and pond and fill that gap with expanding foam. It can even be a cheap Chinese brand that's probably half the price of sika.

 

Thanks @Shabir, I'll certainly consider that suggestion.

 

After considering the concerns about damp in the house (which honestly had not even occurred to me until it was mentioned above), we are shifting the pond forward slightly so there will be a small gap between the pond and the house, roughly the width of one brick.
Foundation/base slab will be 15cm thick concrete, and the walls will be double layer brick, reinforced with brickforce between every layer (or maybe every second layer). The first two rows of bricks will be below ground level for added strength where the walls join the base.
We will plaster the outside and inside of the pond, and will apply a coat of masonry waterproofing over the plaster (or maybe it should go under it? I still need to figure that out). It can also be applied to old structures so if the gap is big enough for our guy to reach, I'll suggest he paints that on the outside of the house wall as well, between the back of the pond and the house. Then we'll fill the gap between the house and the pond with expanding foam. I couldn't get SikaLite so will use the masonry waterproofing instead.
Will lay a layer of dpc plastic under the base slab as well. We will have enough left that I can also add a layer between the house and pond for extra extra protection, so will see if we do that as well,
Still deciding on the final finish of the pond to make it fully waterproof and safe for fish (e.g. duram durapond vs a pond liner, or something else entirely).

 

Today's progress

 

Final touches to the foundation/slab. It's now nice and smooth and level. Just got to wait for good weather now to start the brickwork (heavy rains due all next week).
(the bricks in the picture are just lining the border to stop the sand constantly falling in)

 

Awesome project.

Duram Durapond is a good product, I have also used it with my ponds. Just make sure when you apply it to the area when it is bone dry. I was pushing my pond and applied it on a small piece of 10% wet plaster and once the pond was full it peeled off almost immediate. I had to empty it out again and left it for a week. Once it was dry I coated it again. Form my experience I would say a few coats is a must. Mine had 4 coats and is running for 2 years now with no leaks at all. Lastly, I also added another paint that one normally uses for roofs, to protect cement roofs from standing water. I will see about the name and also send it along to you. With the second pond I did 3 coats of Durapond and 2 coats of the other product and the product is also safe for ponds and fish.

What will you use for filtration, algae control and how will you introduce oxygen to the water? This is some few things I learned the hard way.

The base look excellent BTW . I also have a flat bottom pond and with my water flow I do not have any issues in keeping the bottom clean.

Best of luck. Will be following the progress.

 

Thanks so much @Bart. And thanks for the paint tips. Will make sure to wait for it to be totally dry as per your recommendation, and good to know how many coats to aim for. That's interesting a roof paint product is fish safe - I'll definitely be interested to know the name.

Regarding filtration and Air I'll probably do similar to what I have going in my current smaller pond (raised wooden pond, roughly 1m x 1m). It's a submersible pump housed inside a 5L ice cream tub which is filled with filter media (things like lava rock and other similar stuff). That sucks the water in through the top of the tub, through the filter media, then out through some pipes and is returned to the pond via a spray bar.

For the bigger pond I will need to upscale it somewhat (stronger pump, bigger bucket), but the concept has been working well for me so I'll probably stick with something along those lines.

 

And now I understand everyone's concerns about damp entering the house...

I had all these good intentions of how to build the pond in a way to avoid it (after initially being made aware of the potential for damp by you lovely people), but with all the rains that came right after the base slab was thrown, none of the plans had been put in place yet.
Just before all the heavy rains we had joined the top layer of the pond foundation to the foundation of the house. Then it was slightly uneven so after the first major rains the guy helping us build chipped away at the higher corner. Then more rain followed almost immediately.
So we sit with a great almost water tight base slab, that holds all the rains wonderfully up to a height of about 5cm, but nothing containing it past that, so water has been seeping out and around and now there's damp in the bathroom, under the tiles (the bathroom is on the other side of the wall between the drain and the pond)


So i've now asked E (the guy helping us) to open up the side between the edge of the pond and the drain (where the damp appears to be in the wall), to help drain it all and dry it.



I'm going to pick up some waterproof cement additive (either sikalite or some other brand) on my way home today, and I think we can then plaster that whole piece of exposed brick wall with it.
I want to then add another layer of dpc plastic (one large solid piece) over the whole slab, folding up against the house (maybe even extending all the way to the drain), and then put one more thin layer of cement/screed/plaster over the top of that (containing the waterproof additive). I'm not sure if we should maybe first seal up that hacked up corner with it though?
And then hopefully the weather will hold long enough for us to start building the walls so if more rain falls it will be better contained and not seep out.

The plan is to full plaster the whole pond with waterproof cement (so plaster with additive added), but I think I might actually opt for lining the inside of the pond with plastic rather than relying on waterproofed plaster as the only layer. (there will be a brick-length gap between the back wall of the pond and the wall of the house as per suggestion)

 

Ah man I'm terribly sorry to hear this. And shocked that a single rainfall caused it to happen that fast. On the bright side it seems to have opened your mind more to our concerns and make sure this is done properly to avoid any further damages

 

It was about 4 days of heavy rain.
But upon further inspection this afternoon it appears it might actually be a leak in the wall or in the bath cavity inside the bathroom, and not related to the pond.
So maybe the pond build is a blessing in disguise as it caused us to look at the wall closely.
Insurance assessor is coming tomorrow to check it out so we'll see then.