How to get water to go OVER instead of UNDER rocks??

[Moombaz]

I'm sorry for the elementary question, but I can't find a dependable answer anywhere. I've used several cans of foam, every kind of clay I can find, and some creative/unorthodox methods with little success. How can you make water in the stream flow (at least mostly) over the flat rocks rather than under? The foam sticks to the rocks, but not the liner... All other options stick to the liner...but not the rocks. Maybe I have a basic mistake in my construction? Is there a miracle product that I can't seem to find online? So frustrated from a seemingly peaceful hobby.

 

[RobAmy]

The foam should work well for that application. Do you have a photo of the stream or area in question? That may help to steer you in the right direction better. Some water may go under it but most should go over once foamed. Make sure the liner is clean and dry and let it cure once applied, just in case you did not.

 

[Moombaz]

Thank you, RobArmy. I must say a photo of my little "water garden" would be shameful to post among the amazing things I've seen on this forum. Do you have a recommended foam? Everything I read online concludes that all expansion foams are the same +/- UV protection. The UV shouldn't matter for mine since they are all meant to be submerged and rock covered. Are they not the same? I've used "great stuff" and "red devil" with the same (almost none) results. Thanks again.

 

[Meyer Jordan]

Use a "Black waterfall foam". It is formulated especially for this type of application and is minimally expanding which does help to control the mess. Keep in mind that any foam is a sealant and not an adhesive. It will likely not block all of the water but will redirect the greater majority. It does not work well if used to plug large voids.

 

[cas]

I read online "Pond installers often recommend silicone caulk for sealing rocks to the pond liner as well as to each other. It is waterproof and non-toxic, but it may not be able to hold large rocks together, and while it has bulk, it can't seal gaps wider than about an inch."

This March I tried using silicone caulk to change the water flow on my waterfall. See the area circled in the picture below. It has worked really well so far. I used clear caulk on both stones on the spillway. Because the caulk was so thick on the left side, it still has a white color instead of clear. I don't think I let it dry long enough so it would dry clear.

I guess it depends on how big of a stream and the size of rocks you have, if this would work for you.

 

[Lisak1]

So maybe I missed something in the question, but you said stream, not waterfall - are you trying to use foam in a stream BED to keep the water flowing on top of the rocks in the actual stream?

 

[addy1]

I used pl roofing goop, to make it a water proof seal. Make sure all is dry the goop it up. Still working 5 years later. I also used the black water fall foam and expanding foam (window) both redirect the flow but not water tight.

So maybe I missed something in the question, but you said stream, not waterfall - are you trying to use foam in a stream BED to keep the water flowing on top of the rocks in the actual stream?

I used the stuff in my stream and waterfalls to get the water to flow nicely. OW it hides under the rocks.

 

[mgmine]

It could be that you just don't have enough water going over the rocks. If so you will not get the effect that you want. There usually is water going under rocks but you can't see it because so much is going over the rocks.

 

[Moombaz]

So maybe I missed something in the question, but you said stream, not waterfall - are you trying to use foam in a stream BED to keep the water flowing on top of the rocks in the actual stream?

That is correct Lisak, the waterfall seams to do fine with the foam, but the stream always seems to flow under the rocks I have in the bed. I've assumed it was because of the higher flow rate of the fall? The stream is on a very slight slope, so I guess it just isn't forced up and over. That's why I wondered if it was a mistake in my original construction. Maybe I need to rebuild the stream with a more drastic slope?

Thanks to everyone for your help!

Use a "Black waterfall foam". It is formulated especially for this type of application and is minimally expanding which does help to control the mess. Keep in mind that any foam is a sealant and not an adhesive. It will likely not block all of the water but will redirect the greater majority. It does not work well if used to plug large voids.

So it sounds like the people saying the regular foam is exactly the same as the black are misleading me then. I never opted for the black after reading so many accounts of it being the same.

I have tried the silicone, but probably not enough of it so I will give that another shot. I will also try the the the goop - that's a new one on me.

Thanks very much guys, I will update after I try these.

 

[TAHOE]

I used pl roofing goop, to make it a water proof seal. Make sure all is dry the goop it up. Still working 5 years later. I also used the black water fall foam and expanding foam (window) both redirect the flow but not water tight.

I used the stuff in my stream and waterfalls to get the water to flow nicely. OW it hides under the rocks.

I use this stuff also in my fish tanks and DIY filter builds. It holds up great and it will stick to materials that silicone won't.

 

[Lisak1]

I can't imagine trying to get the water in a stream to flow over the rocks - you're gonna need a heck of a lot of foam if I'm understanding the issue correctly. Foam in a waterfall keeps water flowing over by blocking any paths behind. But to get water to flow only OVER rocks in a stream? That seems nearly impossible in my small mind!

Pictures if you can - always helpful!

 

[tbendl]

So what was the outcome? Did you use silicone or foam or roofing goo?
I am faced with the same issue of having water going under not over my waterfall rock and am curious. I am leaning toward the PL Roofing but Lowes doesn't carry it. They carry dap. Do you think it will work the same as the PL stuff?
DAP Roof Sealant 10.1-oz Black Paintable Solvent-Based Specialty Caulk

 

[tbendl]

They also carry this which says it works in wet and dry conditions. Has anyone used this?

BLACK JACK 10.1-fl oz Waterproof Cement Roof Sealant
http://www.lowes.com/pd/BLACK-JACK-10-1-fl-oz-Waterproof-Cement-Roof-Sealant/3009268

 

[Meyer Jordan]

Use the Black Waterfall foam. There is a reason that Professional Water Feature contractors unanimously use it over any other product. It just works better.

 

[tbendl]

http://www.lowes.com/pd/smartpond-Pond-Accessory/3066381
This stuff? Does it expand like crazy?