Concrete is a durable, versatile, and relatively inexpensive building material. About the only drawback in using concrete is the finished appearance: plain old gray. Fortunately, there are an abundance of recently developed acrylic concrete stains on the market that can give your boring gray concrete an exciting, beautiful look. With faux finishing techniques, you can even make your concrete look like a natural stone patio.
Preparing the Concrete
Before applying an acrylic stain to concrete, make sure the concrete has a rough and absorbent profile. It should have the look and feel of a piece of 120 grit sandpaper. The concrete should also be absorbent. Pour a little water onto the concrete; it should immediately absorb. If the concrete doesn't meet these criteria, you will need to etch it before staining.
Rinse the concrete with a hose, then apply the etching solution. There are a few different etching products on the market; some contain organic salts, and others contain mild acids. Follow the manufacturer's instructions regarding how long to leave the etching solution on the concrete. If you haven't achieved the proper profile after etching the first time, etch again.
Clean the concrete with a concrete cleaning product. This will neutralize the etching solution, and remove any concrete powder that was generated during the etching process. Scrub the concrete with a push broom, then rinse the surface thoroughly with water. Allow the concrete to dry at least 24 hours prior to staining.
Creating your Pattern and Applying Stain
Once the concrete is clean and dry you can lay out your stone pattern. Blue painters' style masking tape works well. If you are trying to emulate a flagstone pattern, make your tape lines varied and organic. Take a look at some natural stone patios to get an idea of the stone shapes. The bare concrete underneath the tape will become the mortar joints between your flagstones.
After you have the joint lines taped off, use your pump-up sprayer to apply a coat of stain. Adjust your sprayer's nozzle to create the widest spray pattern possible.
Work in a sweeping, circular motion to give the spray a natural appearance. With a transparent product, if you work in straight lines, you will see straight lap lines in the finished application. Work steadily, applying the stain just until the concrete begins to wet up before moving along. Concrete stain goes down milky clear; you will not see the color emerge until the stain begins to dry.
Multiple colors will give your finished stones a more realistic look. Natural stone has great color variation. By applying two or three different colors to your concrete, you can create accents and depth in the stones. When choosing your stain colors, select one color for the base, and one or two accent colors.
The Finished Concrete
Give the stain at least 24 hours to dry before removing the tape. At this point, you will see the results of your hard work.
Apply a sealer over the entire product. This will give your stained concrete added protection, and can also enhance the colors.
Let the sealer dry 24 hours before allowing foot traffic, and wait 72 hours before moving furniture back onto it.