I have a similar waterfall setup on my pond. I have 3 large pieces of flagstone that the water runs down. It is surrounded by smooth river rocks.

I didn't use any sealent, but when I lined the pond, I extended the liner out 3' in the area I was going to put the falls. So any water that gets on the rocks simply runs back into the pond.

I think the plastic sheeting you have gotten should do the trick.

There always needs to be a liner underneath all of the rockwork. You will never be able to seal rock completely..

OK, this is very interesting (especially about NOT needing sealers, which are a pain in the neck). So when you are building your "steps" are you putting them on a slope? in other words, currently my steps are level with the ground, therefore any liner I put under them would be flat too (like you'd spread a blanket on the ground for a picnic), and therefore the water would not be compelled to run back down into the pond. Are you angling your steps and your waterfall downward?

I am also interested in how you did the sides, because I find that even when the front didn't leak (in a previous incarnation of the pond), the water tended to run to one side or another (or both), simply from sheer force of the pump. In other words, it spilled nicely off the "lip" of the preform waterfall, but then, when it hit the steps it fanned out toward the sides and out the edges, hitting the soil!

I'm wondering if your waterfall "lips" (plural as in, there are two of you responding)are positioned actually over the pond so that the water simply HAS to fall into the pond with no lateral spill. My "lip" is somewhat away (back) from the actual pond, so that I have room for my two additional steps. However, this gives the water all that time and space in which to flow to the sides (and onto the ground, before the pond even "appears")

So --- how do you build sides without sealants?

Does this make sense at all? Hard for me to describe without pictures.

Again, I really appreciate your comments! thank you

Liz

Slopping of the rocks downward toward the pond is obviously good advice. So is putting a liner under your falls so any leaking water gets directed back into the pond.
My personal preference is not to rely on greatstuff foam or related foaming products. I use them for filling holes but not if I want a water tight seal. In my experience, after several years water will find a way around or through the foam. Plus, they are hard to work with because they are so messy.

I would consider two alternatives for waterproofing between rock. First, you can use hydraulic cement. It cures within minutes of being made (so you cannot make a large quantity at one time or it will be wasted) and if done right it providces a waterproof seal that last for years.

The other alternative is liquid epdm in black color. Google "liquid roof" or "liquid rubber" and it will pull up the website for the product. They used to sell this stuff in only 1 and 5 gallon containers. Now, however, you can purchase it in smaller quantities (1 quart) for relatively cheap prices (something like 18 dollars a quart). This stuff takes about 3 days to cure but it will create an absolute waterproof seal and its easy to apply with a paintbrush -- far easier to apply than the foam. I used it between rocks and on the sides of my walls to resolve an ongoing leak and I used it six years ago to resolve a ripe in my liner.

I was lead to beleive that the foam actually does not seal per sec but directs water to flow. A liner under the falls is the best way to go. Make sure none of the rocks even think of sloping away from the direction you want it to go also make sure the lip of the falls allows the water to flow other then some to trickle under the lip. I goofed and used very porous rocks (DG) and they absorb water and allow whicking to the soil but the plants sure do love it an automatic watering systm

Thanks, everyone I have ordered a quart of Liquid Rubber, which comes in GRAY as well as black and white!

I will be constructing the new waterfall set-up with plastic underneath and covering the side rocks with plastic too. Then I'll epoxy rocks to everything.

Sounds as if it has a much better chance of success than what Ive been doing. Thanks ---

What kind of "plastic" are you talking about. "plastic" probably won't work.

I think she meant liner, although in a post she had mentioned a very thick plastic sheet for painting. As it won't take direct sunlight, that shouldn't be a problem.

Actually I looked at the plastic I bought and decided it's not sturdy enough so I just ordered a 5' x 5' piece of pond liner. My Labor Day weekend this year will have an emphasis on Labor.

"Yes, it's an obsession -- but it's a MAGNIFICENT obsession."

-- Jane Wyman in Magnificent Obsession,
dir. by Douglas Sirk

In process, and flummoxed!

I now have extra liner I bought. We have wrapped it around some cutting boards (plastic) as sides. But I don't seem to understand: Do you put the (14") wide waterfall INSIDE the liner or on TOP of it?

In other words: the waterfall has a deep cylindrical reservoir, right? Are you sitting that on TOP of the "chute" you have made with the liner? Or are you attaching the edge of the liner to the lip of the waterfall? (where the water falls down initially)

And: I understand that you are extending the sides, where the slate steps are, by wrapping the liner around rocks, but how are you dealing with the *space* between those sides you have formed and the waterfall itself? have you extended those sides to form additional sides along the edges of the waterfall too?

I know this is very very hard to explain (not to mention to ask) without PICTURES. If anybody has any urls to recommend with construction advice, I'd be most grateful.

Thank you. (my entire area here is about four feet back. TINY waterfall, can't believe it's so hard to get this right!)

Liz

Liz, I see the postign appers to have stopped on this topic back in August. I admit I don;t understand your question in teh lat post but am wondering if you made it thru your project and how you addressed your queries? Also I would love to see pics aside from the ones I have seen on the web which have been many, but would like pics from people in MA who have done this. msassisi@comcast.net
Thanks cherbirdwise