The beginnings of my dream pond

[dakamp84]

Hello all,

I am new to this forum and wanted to say hello!

Intro about me:
I am still a newb by definition. I have had small preformed ponds before (nothing over 500 gallons) with plants and goldfish. So I understand most of the terminology and theories but decided to make my dream pond (6x12x3 with waterfall).

So the question:
I want stack the stone sideways on each other. I have 3-4" thick flat stone and 1-2" also. I noticed that most people who do this method have to mortar the stone like a walkway or patio. I would love to not have to do this to have a more natural look (gapping) of the stone. I have read through the forums about mortar, adhesives, and foam. So I know these will have to be used in some form to keep the rocks from sliding and possibly puncturing the liner. There are shelves at 12" and 22" below water line but the highest point is about 12" above the waterline vertically.

What I want to know is how stable would this be on a 1.5'-2' vertical wall? What would I need to keep the stones there?

I do plan to use the same stone but flat as the coping stones around the pond. So I could possible adhere the wall stone to the large coping stone (not sure how though).

Any direction, links, advice would be greatly appreciated.

I will post pics when I get home to give a clearer idea of what the pond looks like.

Thank you all ahead of time and look forward to becoming a contributing member to this forum.

 

[buckry]

Welcome! It sounds like you are of the same mind as me, I didn't want to have to mortar it so I could change things later without much effort. For my waterfall I found it was really unstable though so when I stacked the rocks I just put great stuff foam on the inside. This expanded and grabbed a hold of the rocks and held them tight. It was super stable and no great stuff was required on the outside, however I did end up trying to make it waterproof so I do have it on the front. It is NOT watertight, so I could have left that off the front, but that is a mistake I will know to avoid next time. The great stuff is super strong and makes things very stable, and as long as you have a side you can't see, you can do it and make it invisible.

For my edging my rocks are just laid flat side my side on top of my liner. I put river stone in all of the gaps that were 1" or so, then I poured pea gravel over it, the combination of these rocks makes it pretty stable, a few of the rocks wobble a tiny bit, but for the most part they are stable and none are held in place by mortar. I did end up putting a tiny bead of waterfall sealant along the rocks that touch the water. It's all under the rocks so it's not visible at all, but I felt like just in case someone stood on a rock and did something stupid that adhesion might help keep the rock from flying into the water.

Bottom line is I don't think too many rocks would truly be stable just stacked, it's a pretty big risk, I would want something there as an insurance policy.

 

[dakamp84]

Thank you for the quick reply.

As far as the waterfall goes, I will be using underlayment, .45 mil EPDM liner, flat stacked stone, foam, etc. This will also be more of a steady stream rather than a little Niagra falls.

For the sides I have attached a drawing of what I want to do. Can this be done safely? If so, what are some ways?

https://www.gardenpondforum.com/gallery/image/2096-po/

 

[addy1]

If you can attach them to the side they might stay. You could use the expanding foam, or even some of the pl roofing goop, it grabs well.

Not sure if you freeze, you would want to make sure water can not get behind the attached stones to freeze and push the stones out. (the stone above water level)

and welcome to our group

 

[dakamp84]

Abby1,

When you say attach them to the side, is this the product I would need to do that? Then use foam/ adhesive for above water level?

http://www.rocktorubber.com/

I am in Knoxville, Tennessee. It does freeze here.

 

[sissy]

Welcome and most foam is not cheap and may cost you a bit and find if it does not work you are left with a mess .The stones even on the side will get covered in gunk and you will not see them anyway .I understand wanted pretty sides and bottom ,I would love them to but if you can't see them after awhile why bother .Spend the money you save on rock and the headache on your filtering and pump as that is whats most important ,healthy living fish to enjoy instead of a headache

 

[sissy]

plus remember with the weight of water your liner will settle some ,mine settled over 6 inches in just a couple of months .Leave plenty of liner on top for this to happen

 

[Waterbug]

Before I started working with mortar I assumed it was difficult to work with, permanent, etc. Once I tried it I found the opposite to be true. Pretty cheap to try it and decide for yourself. Try the other binders too. See which works better for you. For me it's no comparison, I prefer mortar now. Below I'll use the word "mortar" but you can substitute whatever binder you'd like, the concept will be the same.

Grout is optional...
You don't have to grout between the rocks if you don't want to. You can just put mortar behind the rock and press it into place.

The rocks do have to touch each other. The size rocks you're talking about can't be stuck to the liner like tile on a wall can be. Each rock has to set on top of the rock below it. Each rock is the foundation for the rocks above.

Vertical height...
For vertical height I've done exactly what you described in the picture, it's called a rock veneer. The highest I've gone is about 6' vertical. The biggest rocks I've used in this method were a bit over 100 lbs and about 2-3' wide/high, couple of inches thick.

Foundation
The ledge the vertical rocks rest on top of requires a good foundation. This normally means a concrete footer under the liner. Without that the risk is the very heavy vertical face will settle over time and can fail. Sloping the wall can reduce the risk of failure from settling.

Sloped wall...
Sloping the pond wall and liner outward a bit can greatly reduce the risk of failure.

In 'A' you can see you could easily push the top of the vertical veneer over into the pond.

In 'B' the pond wall is sloped back. The gray mortar adheres to the rock and results in a monolithic wedge shape thicker at the top. The wedge wants to fall back against the pond wall. Now if you tried to pushed the vertical wall into the pond it would be difficult because you'd have to overcome the weight of the wedge (center of gravity).

Note also that the result of what is seen is a vertical wall in both cases. With B you could also slant the rock face outward a bit if you like.

The greater the slope the more the veneer presses against the side. Freezing is also less of a problem or no problem at all because the monolithic's center of gravity would have to be moved a long way to fail. If you understand this concept you will realize it's even possible to slant the wall inward, into the pond, which is a cool look.

Cap tie in...
The cap can hold the top of the vertical veneer in place. So the vertical veneer ends up being held in place at the bottom and top. By itself this is not as strong as the wedge concept, but still adds a lot of strength.

Reinforcement...
To improve strength, without adding bulk, you can wrap a stainless steel mesh, or even a plastic mesh, over the liner at the top as shown in blue, figure 'C'. The reinforcement can also be used behind all the veneer to hold everything together in case of cracking.

Gluing rock to liner...
Mortar doesn't stick to liner, which to me is a good thing, but I realize many people like the like idea of glue. You should be aware of an issue with gluing rock to liner in that the back of liner isn't itself glued to anything. So if for example the vertical veneer wanted to bow out in the middle someday the flexible liner would do nothing to stop the bowing.

The bigger issue is once you've glued hundreds of pounds of rock to liner, should the veneer settle the weight of the rocks will pull at the top and can tear the liner over time.

So to me, gluing rock to liner gains you nothing and increases the risk of failure.

Bottomline
There are many ways to install rock veneer. The choices result in longer or shorter lifespans, more or less risk of problems in the future. Ponds don't have to last forever and should be built to what's required or desired.

 

[dakamp84]

Waterbug,

This is very helpful and I think I may follow is idea. I have attached a picture of the pond to help. If you notice the patio, I am basically trying to slightly mimic this idea to allow the design to flow together but not planning to grout in the pond (help keep the more natural look). The narrowest shelf is about 7-9" and goes deeper from there. I measured from the highest shelf to the highest point outside of the pond and it was about 1.5-2'; having about 1-1.5' out of water. The front ledge (closest to patio) will have stone slightly submerged for a kind of low "beached" idea. Between the two bushes is the highest point (which you can see when I filled it with water). As you can see from the dirt pic, the foundation is packed clay at the base and lower shelf. The upper shelf is a mix of topsoil and clay (mostly clay on back wall). The waterfall is going in the corner but is not layed out yet. Let me know what you all suggest after seeing these.


https://www.gardenpondforum.com/gallery/album/253-the-beginnings/

Album: The beginnings
36 images
0 comments

 

[addy1]

Abby1,

When you say attach them to the side, is this the product I would need to do that? Then use foam/ adhesive for above water level?

http://www.rocktorubber.com/

I am in Knoxville, Tennessee. It does freeze here.

Neat looking product, I have never seen that. By their demo looks like it would do the job you want.

 

[Waterbug]

I don't really have anything to add. Like I said, it's really a question of how long you want the pond to last without repair. For example, it could be as simple as just dry stacking some flat rock on the shelf top and laying flat rocks against the wall. Lots of people do this. The rocks fall down from time to time, and you have to set them back up. Save time now, spent time later. One thing you have going for you is the pond isn't some place where you have to worry about people standing on the sides.

The other extreme is how I would build it for myself or if I were charging you. I'd need it to be really solid because I'd want you to be happy and I wouldn't want to have to come back every few months to re-stack loose rocks.

I would get rid of all the shelves and pour a concrete footer around the bottom for the retaining wall and a lip for the veneer. Concrete block retaining wall for all the verticals, stepped back a couple inches half way up on the tall walls so the block lip would be a key. The block is just dry stacked and filled with rebar and concrete. I'd use plastic mesh as reinforcement behind all the veneer. I would also rock veneer the entire bottom just because I don't care for the look of bare liner.

Not saying you should do it the same way, just saying that's how I would. I realize that may all sound like a lot of work and expense but after you go through it a couple of times you see it isn't so bad. Plus it saves you work down the road so to me it's worth it. But most, maybe 90%, of water gardens don't go to that much trouble and people are happy with the results.

There's no right or wrong way. Different ways with different costs and different out comes.

 

[Waterbug]

Scaled back a bit, keeping the shelf.

I'd still want a foundation at the bottom of the veneer, under the liner. Single course of concrete filled block is good enough. Notice the key at the bottom that keeps the bottom of the veneer from kicking out. And in this scaled back version I filled the concrete blocks with soil tamped in, so no rebar or concrete.

Again...just how I would, not saying you should.

 

[dakamp84]

Waterbug,

I am definately taking all this in. Love the knowledge. I will have to walk around the pond and see what option I feel will work the best for my scenario/ budget.

Current Ideas with your advise:

Using the thick rock as the base on the shelves (where applicable) and using the thinner rock as the veneer going up (less vertical weight).

I like using your option "C" (requires less digging lol) but running the mesh/wire all the way down and under the shelf rock. I like the idea of going further down the wall to the base and using that to help anchor the lower veneer. Instead of just starting the veneer at the shelf (continuious from bottom to top).

Questions:

Would the above work (assuming mild maintenance and no traffic around the pond - as you can see)?

Also, is there a mortar of choice for ponds? I searched the forum and google but never got a true answer.

 

[Mucky_Waters]

I've never minded the look of liner under the waterline because you don't really see it after it gets coated with algae, all you see is the algae in the shape of the liner. What I have never cared for is when you see the liner coming up out of the water. This portion of the liner is hard to hide and some people don't even bother, they just lay rocks along the top and call it good enough.
It's really easy to build a small rock ledge just below the water level and stack one or two layers of rocks, fold the exccess liner over the back of that just at, or just above, the water level, then another layer of rocks to hide the edge of the liner. That way you don't see any liner above the water level and the liner below the water level gets coated with algae and dissapears. It kind of looks like that is what you have started to do.

There is certainly something to be said for Waterbugs idea of coating the whole liner with cement to protect the liner, especially if you plan to be walking around in your pond a lot. I once just about got in my pond with some gators on, just as I was climbing in I noticed I had a screw stuck in the side of one of my gators with the pointy end down, had I got in the pond with that I certainly would have poked holes in my liner walking around.

 

[Waterbug]

Using the thick rock as the base on the shelves (where applicable) and using the thinner rock as the veneer going up (less vertical weight).

My guess is this would be fine. You have very wide shelves for the most part, so good base. The horizontal rocks will act as a pretty darn good foundation.

Would the above work (assuming mild maintenance and no traffic around the pond - as you can see)?

I'd assume it would just fine keeping in mind I don't know your plan exactly. Some times it's some small detail that messes things up. But I wouldn't worry, you're verticals are too high and you have good bases. Over time you can expect some issues, but many people rebuild their ponds every few years anyways.

Also, is there a mortar of choice for ponds? I searched the forum and google but never got a true answer.

There isn't a huge difference, but I normally use premixed Type S mortar. I often read people new to masonry work wanting to use the highest PSI because it's the "strongest". Trouble is the highest PSI is only one measure of strength. Glass is higher PSI than wood but you wouldn't want a glass baseball bat. Type S is plenty strong enough, no reason to pick Type M just because it's higher PSI. But if I had some Type M laying around I'd still use it but in less stressful locations like on horizontal surfaces. This is all a bit of hair splitting.

Don't add too much water, should be like mashed potatoes. After you mix it let it set for 10-15 minutes, and then mix once more. If it stiffens up while you're working mix it some more rather than adding more water. Small hoe, not those big hoes will the hole in it. Mix one bag at a time. I like a good wheelbarrow, not the cheap ones. Remember, tools can be sold on Craig's List when the job is done, so good tools don't cost that much.

You can use an acrylic admix instead of some water. It cost a bit, but does make a sticker mortar. And it does reduce leeching which generally is not a problem, but some people worry about it. I normally do not add acrylic.

To set rock make sure the rock is pretty clean by washing it. But the rocks shouldn't be dripping wet. Then smear mortar on its back, like rub it on, like you're cleaning the rock with mortar. That gives you good contact and a good bond when you set the stone. If you just spread the mortar onto the rock there can be then layer of dust between the rock and mortar and a weak bond. Rubbing the mortar onto the rock gets rid of that dust.