Introduction: Homemade Manufactured Stone Veneer
If you have ever decided to renovate, well...anything in your home you know it can be a pretty expensive undertaking. I recently decided to upgrade my front yard and went looking for ways to cut costs but maintain a certain look. Home improvement/decorating projects are great for cutting costs because many of the things you would buy are luxury items which when you stop and really look at them have no earthly business being as expensive as they are. One such thing is manufactured stone veneer.
I wanted to build a garden wall in my front yard so I built a small cinder block wall and decided to face it with river rocks. There are some problems with just using natural river rocks. First, they are heavier then manufactured stone. Second, they are kind of smooth and don't stick well, without using a lot of filler mortar between the joints. Manufactured stone is lightweight, and has a nice flat surface to help stick it to the wall. The downside of manufactured stone is that it is ridiculously expensive. It can range anywhere from $8.00 - $15.00 per square foot depending on where you buy it. My goal is to get that down to just $1.00 per square foot.
Stuff I bought:
Portland Cement: $8.00
Medium Sand: $8.00
Colorant x4: $20.00
Polystyrene x16: $40.00
Stuff I had:
Measuring buckets, Plywood, Playdoh, drill, screws, wooden spoons, patio heater, screen frame, binder clips.
To make DIY stone veneer we are going to use three DIY sub-instructables.
1) Making a quickie vacuum former.
2) Making our own stone forms.
3) Mixing and forming our own stones.
Step 1: Quickie Vacuum Former
There are tons of vacuum former tutorials and instructables to show you step by step how to make one. Here is one i made a couple years ago. My Vacuum Former
This one is going to be quick and dirty though. I whipped this one up from stuff I had in my garage in about 4 hours.
The vacuum table is just a sandwich of plywood. A top layer with holes, a mid layer to create the vacuum chamber, and a bottom layer. There is a small hole cut in the side just the right size for one of my vacuum attachments. Layer the plywood as shown in the drawing and pictures. Make sure you completely seal the inside of the chamber before you secure the top layer. Use a bead of silicone when putting the top layer on since you won't have access to it later. There is a ring of foam tape around the outside to help seal the frame to the table when forming. This seal is critically important to a good form.
The hot box used for heating the plastic will be a 14" x 14" to 8" x 24" transition that is 24" tall. The 8" x 24" side will fit over the top of an infrared patio heater I own. The 14" x 14" side will face up and the plastic will sit on top of it while heating. The whole box is lined with tinfoil and foil tape to help reflect the infrared up towards the plastic.
The heat source is a medium infrared patio heater. I mounted it to a small wood base and just set the hot box on top of that. With the foil liner the wood does not get very hot at all while whatever you put on top get pretty dang hot pretty quick. I should point out that having the heat source underneath the plastic like this can be a little dangerous. If you aren't paying attention and let the plastic over heat it could come lose of the frame and fall onto your heat source most likely destroying it.
Step 2: Creating the Forms
The next step is to pick out some stones that will give a variety of shapes and depth to make the wall interesting. The home builder in my neighborhood chose to give just about every house a faux riverbed in the front yard. Its a pretty common landscaping element here in the desert. Unfortunately my yard got mostly small river rocks about 3" to 4" in diameter. This works for most of the wall but I also wanted some larger 6" - 7" stones. So while i'm out walking my dog in the evening I snagged a few larger stones from my neighbors yards. I'll put them back, I just need to borrow them to make a mold.
After you've got the rocks its time to form the molds. The frame I made is only 12" x 12" made from window screen frame. I lined up the frame and positioned some rocks to try and get a good fit. One thing you want to avoid when molding the plastic is any undercut in your blanks. To avoid this you'll need to put clay or something similar around the rocks to keep the plastic from forming under them and locking them in so you can' get them out. I used playdoh because its easy to mold and reusable.
I used relatively inexpensive polystyrene sheets pre-cut to 12" x 12" from Amazon. I used different thicknesses from 0.030" to 0.060". I used the thicker sheets for the larger stones thinking the plastic would need to be thicker to stretch over the taller stones more effectively. Ultimately I found out that this didn't really matter for such small forms.
You can do a quick google search to find many resources advising you on what temperature to heat the plastic to. This polystyrene sheets has an optimal forming temperature around 240F. You don't want to overheat it and have it melt out of the frame. Also, if it gets too hot it could melt and stick to the frame.
Your exact vacu-sucking procedure will vary depending on your vacu-sucking machine. This one is as simple as heating the plastic and then quickly transferring it over to the suction table and pressing it down over the rocks.
Step 3: Creating the "rocks"
Once your forms are prepared you can begin mixing the concrete. I am using a basic 1-2-3 formula for the concrete. I have to give credit to a Youtuber named the "Craftsman" for teaching me a lot about this process. His videos are pretty entertaining and he gives fairly clear instructions. The formula is 1 part water, 2 parts portland cement, 3 parts sand. You'll mix the sand and cement dry first to make sure they are thoroughly mixed before adding the water. The portland and sand can be purchased at any home improvement store. I used sand because it leaves a much smoother texture as opposed to using other aggregate like rocks. You could also used a lighter aggregate like vermiculite to lower the overall weight of the finished product. After the dry mix is ready you'll add water. Then you'll add some coloring if you desire. The Craftsman's videos show him using some kind of iron-oxide powder that he applies to the form before pouring the concrete. This means that his coloring is really only on the surface. I chose to color the whole mixture so that if there was a chip in the stone it wouldn't be a discolored spot. For the coloring I used bottles of quikrete coloring. Its good stuff and a little bit goes a long way if you're looking for muted colors.
Before mixing I had prepared the molds by coating them with a mold release agent. When I first started i used a Castin Craft brand release agent that I already had and it worked well but was an expensive product. So I went back to the Craftsman and found a recipe for DIY release agents. I used 1 part mineral oil and 8 parts rubbing alcohol in a spray bottle. This works great. In fact when the concrete is cured it will almost slip right out if you aren't careful.
Once the mix is ready I spooned it into the molds. I made sure to give the molds a few seconds of tapping on the ground to get most of the air bubble to rise to the top. If you don't get all the bubbles its not a big deal, they give the finished surface a little texture and make it look more natural.
I created 12 distinct rock shape molds and have 5 colors (4 colorants and then no color), meaning I have 60 different stones I could make right off the bat. I used different amounts of the colorant to create different shades and even mixed some so I could conceivably have thousands of unique stones. Folding in different colorants after the mix is complete helps give striations to make the stone look more natural.
I need about 54 square feet of stones so I figured I'll need about 250 stones. At the time of writing this I am about 1/3 the way there and have only used about 1/3 of an $8.00 bag of portland cement and 1/2 a bag of $8.00 medium sand.
If I make 54 square feet with the material I had to buy the cost to me would be about $1.40 per square foot. The molds are holding up great and could conceivably be used to make hundreds of these stones for my back yard as well which would bring the cost down even further
The stones are about 1/2 the weight of the rocks I made them out of and they are nice and flat on the back side giving a nice surface for sticking them to the wall with mortar.
I hope this was helpful to anyone looking for inexpensive ways to improve their home or yard. I will post udated pictures once my wall is complete.