Sealant or other fix for leaking waterfall?


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I have lined, concrete ponds with stainless-steel and stone waterfalls. The concrete stays dark right under the falls, some more than others. The edges of the falls next to the concrete feel a little wet. I think water is leaking, running down the walls, and going behind the liners into the ground. (See photos below.)

The upper, all-concrete fall has a problem with water wicking back under the fall, dripping on the wall, and then running behind the liner into the ground. My plan here is to face the vertical part of the fall with tile that extend a half-inch below the concrete, to stop the wicking.

The person who built the pond tried everything he could think of to fix this, but maybe more experienced Garden Pond Forum members can suggest solutions, or tell me to focus on the lotus and forget the leaks. I was thinking about getting foam sealant, turning off the pump, waiting for the trouble spots to dry out some, and applying pond-sealant foam.

I’m running a hose full tilt for about seven minutes a day to keep the pond topped up, unless It rains. It’s a little more in hot weather and a little less when it’s cold, but necessary year round to keep the pump under water. Is this normal? I have a 2,000 gph pump with approximately 170 square feet of surface area. The pond gets lots of water from the roof when it rains, so I had anticipated this.

Thanks for any help. I’m learning so much from this forum! I’m adding plants and studying up on improving my bog.

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brokensword

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I have lined, concrete ponds with stainless-steel and stone waterfalls. The concrete stays dark right under the falls, some more than others. The edges of the falls next to the concrete feel a little wet. I think water is leaking, running down the walls, and going behind the liners into the ground. (See photos below.)

The upper, all-concrete fall has a problem with water wicking back under the fall, dripping on the wall, and then running behind the liner into the ground. My plan here is to face the vertical part of the fall with tile that extend a half-inch below the concrete, to stop the wicking.

The person who built the pond tried everything he could think of to fix this, but maybe more experienced Garden Pond Forum members can suggest solutions, or tell me to focus on the lotus and forget the leaks. I was thinking about getting foam sealant, turning off the pump, waiting for the trouble spots to dry out some, and applying pond-sealant foam.

I’m running a hose full tilt for about seven minutes a day to keep the pond topped up, unless It rains. It’s a little more in hot weather and a little less when it’s cold, but necessary year round to keep the pump under water. Is this normal? I have a 2,000 gph pump with approximately 170 square feet of surface area. The pond gets lots of water from the roof when it rains, so I had anticipated this.

Thanks for any help. I’m learning so much from this forum! I’m adding plants and studying up on improving my bog.

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first off, wonderful pictures; seldom have I seen a poster with a problem give such well done visual data!

Now, my first thought is; you don't have a 'lip' on the stainless steel weir and I can easily see why the concrete one is wet. I'd first try taking some silicone caulk (pure, not some percentage) and with the falls off, clean the stainless with a bit of sandpaper (on the bottom of the weir edge) and apply a bead all the way across, sometihing in the 1/4" avenue. This will make the water drip off that edge and not run back toward the wall.

For the concrete weir; you need to create a similar 'lip'. You can try taking a stainless angle and siliconing it to the front face of the weir, making sure it extends down past the face, giving you the drip edge I'm talking aboout. That's one way. Or, you can get some aluminum drip edge like they use for roofs and silicone that to the top edge of your weir. Either way, the water should now hit the edge and while most goes over and down, any residual leakage down should drip off this new edge.

The darkness is algae and you can (with the falls off) spray it down with hydrogen peroxide, wait 30 minutes, and hose it down. Whatever doesn't come off can be scrubbed with a wire brush. I'm not sure the H2O2 will get any deep set stain out but it'll kill the growing algae. Some muriatic acid will but you'll have to monitor the effects on the pond water as you'll no doubt get some in the water which might affect your pH. If you're thrifty with it, shouldn't do any harm. Just don't wash it down or flood it. The acid is used to clean mortar off brick. Use gloves if you go this route.

If you see improvement by using the H2O2, keep hitting the stain with that first as it's harmless to the pond water.

btw, the waterfall foam is not waterproof and is not intended to seal anything; it's used to 'direct' water flow. Silicone, however, is waterproof once cured.
 
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What is the construction detail on the stainless weir? Kind of looks like a small amount of water could be sneaking behind it rather than going over it.

How does the liner interface w/ the weir? I would inspect the pond side of the weir for any possible seepage.

Cool house and cool pond, by the way!
 
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What is the construction detail on the stainless weir?

Thanks! I think that’s at least part of the problem. The liner runs under the weirs and up to the top of their sides. Three screws hold each of the metal weirs in place, pressing them down onto the liner. I don’t know if he used any silicone caulking.
 
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first off, wonderful pictures; seldom have I seen a poster with a problem give such well done visual data!

Now, my first thought is; you don't have a 'lip' on the stainless steel weir and I can easily see why the concrete one is wet. I'd first try taking some silicone caulk (pure, not some percentage) and with the falls off, clean the stainless with a bit of sandpaper (on the bottom of the weir edge) and apply a bead all the way across, sometihing in the 1/4" avenue. This will make the water drip off that edge and not run back toward the wall.

For the concrete weir; you need to create a similar 'lip'. You can try taking a stainless angle and siliconing it to the front face of the weir, making sure it extends down past the face, giving you the drip edge I'm talking aboout. That's one way. Or, you can get some aluminum drip edge like they use for roofs and silicone that to the top edge of your weir. Either way, the water should now hit the edge and while most goes over and down, any residual leakage down should drip off this new edge.

The darkness is algae and you can (with the falls off) spray it down with hydrogen peroxide, wait 30 minutes, and hose it down. Whatever doesn't come off can be scrubbed with a wire brush. I'm not sure the H2O2 will get any deep set stain out but it'll kill the growing algae. Some muriatic acid will but you'll have to monitor the effects on the pond water as you'll no doubt get some in the water which might affect your pH. If you're thrifty with it, shouldn't do any harm. Just don't wash it down or flood it. The acid is used to clean mortar off brick. Use gloves if you go this route.

If you see improvement by using the H2O2, keep hitting the stain with that first as it's harmless to the pond water.

btw, the waterfall foam is not waterproof and is not intended to seal anything; it's used to 'direct' water flow. Silicone, however, is waterproof once cured.
first off, wonderful pictures; seldom have I seen a poster with a problem give such well done visual data!

Now, my first thought is; you don't have a 'lip' on the stainless steel weir and I can easily see why the concrete one is wet. I'd first try taking some silicone caulk (pure, not some percentage) and with the falls off, clean the stainless with a bit of sandpaper (on the bottom of the weir edge) and apply a bead all the way across, sometihing in the 1/4" avenue. This will make the water drip off that edge and not run back toward the wall.

For the concrete weir; you need to create a similar 'lip'. You can try taking a stainless angle and siliconing it to the front face of the weir, making sure it extends down past the face, giving you the drip edge I'm talking aboout. That's one way. Or, you can get some aluminum drip edge like they use for roofs and silicone that to the top edge of your weir. Either way, the water should now hit the edge and while most goes over and down, any residual leakage down should drip off this new edge.

The darkness is algae and you can (with the falls off) spray it down with hydrogen peroxide, wait 30 minutes, and hose it down. Whatever doesn't come off can be scrubbed with a wire brush. I'm not sure the H2O2 will get any deep set stain out but it'll kill the growing algae. Some muriatic acid will but you'll have to monitor the effects on the pond water as you'll no doubt get some in the water which might affect your pH. If you're thrifty with it, shouldn't do any harm. Just don't wash it down or flood it. The acid is used to clean mortar off brick. Use gloves if you go this route.

If you see improvement by using the H2O2, keep hitting the stain with that first as it's harmless to the pond water.

btw, the waterfall foam is not waterproof and is not intended to seal anything; it's used to 'direct' water flow. Silicone, however, is waterproof once cured.
 
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Thanks! I think that’s at least part of the problem. The liner runs under the weirs and up to the top of their sides. Three screws hold each of the metal weirs in place, pressing them down onto the liner. I don’t know if he used any silicone caulking.

I would check that. If your contractor has been out lots of times and tried to remedy, I imagine that's something they checked. But who knows!

I don't know what NC's winter climate is like, but if you get big temperature swings, then I could see needing to fix the waterproofing between the liner and the weir on a regular basis.
 
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What a lovely feature! Concrete was a challenging choice though... hopefully you can find your weak spots and, like @combatwombat suggested, deal with them on a maintenance basis so they don't plague you with water loss!
 
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I don't know what NC's winter climate is like, but if you get big temperature swings, then I could see needing to fix the waterproofing between the liner and the weir on a regular basis.
Thanks! We’re in USDA zone 8a, heading for 8b. The annual range last year was -20 to 96F, but some years we get several days over 100. The daily swings are moderate compared to many places.
 
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LOVE your pond water feature, absolute perfect design for your gorgeous house. I agree with adding drip edges and the silicone caulking any- and every-where that any two materials come together - liner meets metal, metal meets concrete, each screw, and so on. If the concrete is not sealed (?), splashing would add to water loss, and over time, the concrete will start to break down, and in freezing weather, water in any concrete crack will freeze, and as the ice expands, it will chip away parts of the concrete over time. (You're missing a screw near the amazingly neat grasshopper.) Let me/ us know how this goes.
 

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