The original Koi pond was built 1990. Since Florida has no rocks, I ordered a 2 ton truckload which I used to border the pond and also build my first low-rise waterfall. The waterfall is circled below and this old shot illustrates that the falls really did show before all the plants took over.
I built the pond with a thick nylon chord reinforced rubber liner called Hypalon ordered from Colorado. I just couldn't see building this with the thin cheap plastic sold at the local home improvement stores. I know that stuff can't last very long. 15 years later the liner is still flexible and withstands my constant floundering around inside the pond.
OK, 1995, 15 years later, this is what the waterfall looks like. Yes, I can cut back the foliage but I need something more dramatic.
I decided a tall rock structure like the ones I have seen at Disney would work great.
Below, I mocked up a bad picture of what I wanted. The wife agreed and I then I started my construction planning.
How do they make these things? I spent quite some time investigating this and at the end of it all came up with my own technique. In the interest of the greater good I'll show you what I came up with here. Please email me with any questions or any success stories.
Some people use iron work frameworks with fiberglass coating. I decided against this since I'm not going to be good at this I don't think. Also, the chemicals involved are pretty nasty and the entire costs would not be any cheaper than other methods. The only plus is that the final product would be pretty darn strong and weather proof.
That leaves concrete which I am familiar with. What framework to use? At first I was going to carve a giant pile of styrofoam and coat with concrete. They use tons of styrofoam on movie sets but of course this is NOT permanent. Then I found out that I could not buy giant blocks of this stuff for any decent price. I spent Winter collecting a giant pile of styrofoam pieces and blocks from dumpsters. Lots of stores throw out their packaging and generate even more waste during the Christmas season.
I ran a little test and tried carving my styrofoam. I became covered with millions of tiny little beady white balls and they were blowing everywhere. My blocks weren't staying very together and my carving experiment was looking very bad. Bad plan.
My better idea was to make my framework from steel garden fencing that has a large 6" x 4" mesh. A 50' x 6' roll only costs $40, it is flexible enough to mold into any shape and it is sturdy enough to support the first layers of concrete. The open meshwork will have to be covered with a fine meshed material before concrete can be applied. I'm using all that styrofoam I collected to stuff the insides of my framework. The non-biodegradeable styrofoam will provide my secondary support should the concrete crack or settle in the future.
Meanwhile, during my investigations and trials I was ripping out the old water feature. I now have 2 tons of rock (that cost me $$ here in rockless Florida) that I can use for other projects.
What kind of concrete to use? I needed something very strong, not permeable to water (don't want the water features sucking up my pond water), and something that would not slump when forming my cliffs, overhangs, etc. Normal cheap handyman concrete has none of the desired properties. The best stuff I found in the local building supply stores is QuikWall. It contains reinforcing fibers and hardeners. It is designed for concrete block wall construction where the blocks are simply stacked without mortar and then faced with this super strong mortar.
I bought some and tried a test project on some narrow mesh window screening. Wow. This stuff hardens within 60 minutes and is super strong. A 1" layer is very difficult to break (handyman concrete almost crumbles in your hand). The slump factor is 0. It has a thick dough like consistency and I found that just taking handfuls of the stuff and plastering upside down framework worked liked a champ. It takes twice a much work to mix QuickWall than normal concrete because of all the fibers it contains. An extra bonus during my concrete investigation was the water factor. I never knew that less water is better for that initial concrete mix. Too much water makes the final set more porous and less strong. So now I spend a little more work and mix my batches as stiff as possible.
Ok, so now I'm working on framework. I've bent the wire fencing to roughly the shape I'm looking for.
Below, I took all the styrofoam are started filling the inside. Near the end of this project I discovered a jackpot of styrofoam that I wish I had found from the beginning. Some local office building construction sites were throwing away giant blocks of this stuff. Seems they use it for roofing work but I can't quite figure how that might be.
Below, I covered the finished framework with cloth soaked in mortar. This makes it stiff for the following coats of Quik Wall that I will be applying. The vertical sides I tried a few different techniques. The best I found was simply a layer of 1/2" hardware cloth bent and wrapped into the fence framework. A meager swipe of Quick Wall to this mesh makes a great base for the following heavier coats of Quick Wall.
Below is a closeup of what the framework and mesh looks like when the QuickWall is being applied.
Below is a great shot from the rear of my mountain showing all the garbage I tried during my attempts at filling this thing. Old shower doors, car tires, propane tanks, etc. Notice the strategic poles I also tried to include for support. Also, some of my handy old roof tiles have come into play again. I used them as a base for my concrete footers that I poured.
I'm now well along in facing my framework with the initial coat of Quick Wall. Trying to keep all my caustic slop out of the pond so I don't kill my fish. I had some aluminum sheeting which I also used behind some of my mesh to help things along.
Now I'm at the point of getting my rock face textures looking right. After lots of trials it was clear my rock carving techniques weren't going to look very nice. I decided to leave the carving for just a few large crevice/crack looking things. My best bet it getting some kind of rock casting working. I came up with the Ekengren Foil Rock Casting methods. Method #1: I dig a shallow bed in the ground making lots of irregular features and adding rock rubble, line it with crumbled aluminum foil that exhibits nice texture, pour the QuikWall in a very thin layer, and next day spray off the aluminum liner. Heck, you end up with some decent looking rock. Also, the aluminum metal interacts with the mortar and creates interesting yellowish coloration patterns in the QuikWall. Below shows a sample shallow bed, a finished casting partially hosed off, and a finished cleaned piece. The aluminum interaction practically melts the original shiny piece of foil. Method #2: Slop some QuikWall onto the rock face and embed wrinkled aluminum foil into the mess. Next day the aluminum can be hosed off. The advantage of this method is that the casting does not need to be cemented on the rock face. However, I found I couldn't create quite as interesting rock patterns as I could get with method #1.
A closeup view
Below shows a picture of the project with some Type #1 and Type #2 castings attached.
Also, at this point I have been trying various coloration tests. I'm definitely going with concrete acid wash which is used in floor coloration projects. You can get a range of browns, yellows, blacks which are perfect for my rock project. This is NOT paint. The acid with trace minerals interacts with the concrete to produce a permanent and non-predicatable coloration effect. I sure don't want to be out here repainting my sun faded rock every year. I had to buy this concrete acid via internet. Couldn't find any local outfits selling the stuff. Home Depot has concrete stain which is NOT concrete stain. Below is a sample coloration test. I used a sprayer. Other spots I tried sponges, splashes, etc.
Below is the final "cast" rock. From here I'm going to start applying color and start planting. Notice on the left on the ground, the aluminum foil carcasses from many Method #2 rock castings.