waterfall leaks, need construction advice!

Liz MargoshesAugust 20, 2008


I've tried to make waterfalls several times and they always leak. My latest attempt: a 12" wide waterfall thing I bought, from a leading supplier. It sits on two thick slate "steps" that we just stacked. Then I sealed everything up with marine epoxy, and put all kinds of rocks on the sides and sealed them. After bolstering this with a ton of that black insulating foam also bought from a supplier (everything bought from justliners.com), it started leaking.

I cannot find the leak but when I reach my hand around the back of the rocks, it is leaking. I seal and seal and seal and foam and foam and foam and still it leaks.

Well last night my husband and I pulled everything apart and we want to start over. Unfortunately I have no extra liner to line everything with, but we might use a very very thick piece of plastic (the thickest dropcloth I could find at the hardware store). But then I want to seal those pieces of slate together like a sandwich, not just stack them and seal the edges, as I did last time.

Basically I would really appreciate any tips on the construction to make this baby WATERTIGHT for the first time in its life.

This waterfall is not even that tall: just two pieces of slate around three inches tall each, with the waterfall sitting on top (there's room for the reservoir because that is sort of sunk below into the ground).

I was thinking about concrete, or some kind of concrete mentioned by a few people at one point (I can't remember the adjective, for concrete or cement that is waterproof) as the "filling" for the slate sandwich. Something like a waterproof mortar?

So ---- VERY much appreciate all advice here.

Thank you for reporting this comment. Undo

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.

    Bookmark   August 20, 2008 at 12:18PM
Thank you for reporting this comment. Undo

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

    Bookmark   August 20, 2008 at 2:46PM
Thank you for reporting this comment. Undo
Liz Margoshes

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


    Bookmark   August 20, 2008 at 3:41PM
Thank you for reporting this comment. Undo

Well, a couple of things. You need to slope the ground under the waterfall area. It doesn't need to be much. Even 2-3% slope is adequate to keep any water spill back into the pond.

As far as the side issue, I used beach sand 1" deep, and then pushed large river rocks into the sand as a base. Then I put the liner over the flat (sloped) area, and over the line of rocks (outside edge). This area is about 4-5" higher than the flat area for the waterfall.

This solved 2 problems for me. One-the water coming off the falls goes back into the pond.

Two-during rain, the raised edge helps prevent runoff from going into the pond. I didn't use rock under the liner all the way around the pond, but I did use a "mound" of sand all the way around. It is about 1" deep or so. This also made a nice surface to place the loose flagstone around the perimiter of the rest of the pond.

I hope that makes sense.

    Bookmark   August 20, 2008 at 4:30PM
Thank you for reporting this comment. Undo

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.

    Bookmark   August 21, 2008 at 8:22AM
Thank you for reporting this comment. Undo

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

    Bookmark   August 21, 2008 at 2:44PM
Thank you for reporting this comment. Undo
Liz Margoshes

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 ---

    Bookmark   August 22, 2008 at 10:44AM
Thank you for reporting this comment. Undo

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

    Bookmark   August 22, 2008 at 1:12PM
Thank you for reporting this comment. Undo

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.

    Bookmark   August 22, 2008 at 3:28PM
Thank you for reporting this comment. Undo
Liz Margoshes

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

    Bookmark   August 23, 2008 at 11:36AM
Thank you for reporting this comment. Undo
Liz Margoshes

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!)


    Bookmark   August 31, 2008 at 5:01PM
Thank you for reporting this comment. Undo

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

    Bookmark   March 5, 2010 at 6:57PM
Sign Up to comment
More Discussions
Floating plants for my hot TX pond (other than lilies)
Any suggesting for good floaters or submerged plants...
Inspiration and help sought - turning a 12,400 gal pool into a pond.
I'm fed up running my pool; expenses plus my wife and...
Pond Heat
What is the best method of heating water to 70 degrees...
Rubbermaid vs Galvanized stock tank pond
I'd like to upgrade from my little whiskey barrel ponds...
I'm a bad steward of my pond. :(
I only have a 300 gallon Rubbermaid stock tank sunk...
Sponsored Products
Vintage Rust Post Mount Adapter
$21.90 | Lamps Plus
Natural Wood Potting Bench
Cost Plus World Market
Polished Chrome S-shaped Shower Arm
Cappucino Fabric Cordless Cellular Shade
Moooi | Paper Cupboard
Cast Iron Privacy Rim Lock
Signature Hardware
Armen Living Barrister Chair - Gray Velvet with Black Piping - LC8441GRAY
$816.00 | Hayneedle
Cristel Casteline 10-qt Stock Pot with Removable Handle
$309.95 | FRONTGATE
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™