How To Make a Faux Rock Cover

It is easy to make fake (faux) rock covers to conceal valves, pipes and drip system distribution heads in your lawn or garden. This faux rock making tutorial shows you how to do it.

The art of making artificial (faux) rocks is easy to learn. Most of the materials are available through your local hardware store, such as Home Depot or Lowes, but you may have to hunt for a few items.

Faux rocks can be used for decorations around your home or yard and do not necessarily have to be used to cover yard objects. Although we did not include this in these instructions, if your finished rock is going to be more than one foot in diameter, it would be a good idea to start with a framework made out of chicken wire for additional strength and reinforcement. Projects for creating very large faux rocks or rock walls, such as those you see in zoos, require specially engineered supports to deal with the weight of the cement. Those projects are beyond the scope of this project.

Material List:

  1. Portland cement or type S or type N mortar cement (masonry cement). Portland is stronger, but mortar mix can be easier to work with.
  2. Sand. A bag of play sand, which can be found in any hardware store, will work great.
  3. Acrylic latex polymer. Males the mix sticky and easier to work with. It also help to create a stronger concrete bond.
  4. Cement dye or colorant. This comes in liquid or powder form and can be found at any major hardware store. Try a tan color.
  5. Concrete reinforcement fibers. We use polypropylene fibers, but any type of concrete reinforcement fiber will work. You can skip this part, but if your fake rock is exposed to extremes of weather it may crack.
  6. Polystyrene (Styrofoam) beads. This is the type of small beads used to insulate block walls. They are also used to fill some types of bean bags. The polystyrene beads component can also be skipped, but if you don’t use it your finished faux rock will be much heavier. Unless you live in a state with cold winters, you may have difficulty locating this product. We bought our polystyrene beads on eBay.
  7. Concrete sealer. Helps protect the faux rock from extremes of weather.
  8. Water.

Base Coat Mixture
Use a 5 gallon bucket and a large cement or plaster mixing paddle on an electric drill to mix the components. First combine 2 parts masonry cement and 6 parts styrene beads with a small quantity of fiber. Mix the dry mixture thoroughly with the mixing paddle and electric drill.

Combine 1 part acrylic latex polymer and 3 parts water in a separate bucket. Add most of liquid mix to the base coat mix and mix thoroughly. The final base coat mix should have the consistency of very thick peanut butter. If it is too dry or clumpy, add some more liquid mix.

Applying the Base Coat
Find a plastic bottle or disposable plant pot that covers the object that you wish to conceal. Trim the top or bottom as necessary. This will be the inside form for your fake rock. Begin working on a table that has been covered with plastic. The plastic surface will make cleanup much easier.

Use a margin trowel to start packing the base coat mix around the plastic form. Do not pack the mix uniformly. Start to form the rough shape of the fake rock that you wish to create. Leave the surface rough so that the finish coat adheres easily to the base coat. The base coat should be a minimum of 1/2 to 3/4 of an inch in thickness.

After the rough shape of the rock has been formed, allow the base coat to dry and cure for 24 hours.

Top Coat Mixture

The top coat is mixed similarly to the base coat, but instead of polystyrene beads we will use sand. Sand will give the faux rock a rough texture.

Combine 3 parts sand and 1 part masonry cement with a small handful of concrete reinforcement fiber. Mix thoroughly. Combine 3 parts water and 1 part acrylic latex polymer in a separate bucket. Add most of the mixture to the top coat mixture. Once again, the final mixture should be very thick, but workable with a margin trowel. Add liquid mixture as needed to achieve this consistency.

Add the colorant that you chose. We find that a tan colorant looks the best. Yo may have to experiment with the proper quantity of the colorant to add. That will vary based on the brand that you chose.

Use the margin trowel to pack the top coat mixture around the base coat. The top coat should have a thickness of at least 1/2 inch. As the top coat just begins to harden, you can texture the surface using a variety of methods, including dabbing the surface with a whisk broom, a rough sponge, crumpled aluminum foil or a crumpled plastic bag. There are lots of household objects that you can experiment with to simulate a natural rock texture.

After the top coat has been shaped and textured, allow it to dry for another 24 hours.

After the faux rock has dried, you can seal the surface using any type of concrete sealer. Be aware that some concrete sealers dry with a glossy finish, while others dry with a semi-gloss. The sealer is not absolutely necessary, will help protect the faux rock from deterioration and cracking due to moisture and freezing temperatures. After the sealer has dried, your faux rock cover is ready to use.