Painting an old concrete patio is not the best method to add color to the concrete and requires much prep work. Painting is a process that covers a surface with a thin, colored film. Not only will paint peel and chip over time, but it can be also slippery when it gets wet and dirty.
Your best option for coloring a patio is to use concrete stain. This is available in many colors and tints: Browns, greens, and blues are most popular. Unlike paint, stain actually penetrates the concrete surface so it cannot peel off.
If you apply it correctly, it should last five years or more until you have to reapply it. Also, as the color of the stain fades, it will not be as apparent as when sections of paint peel off. Water vapor, moving up from under the patio, does not affect the stain like it does paint.
There are three basic types of concrete stain. One type uses an acid base that chemically attaches itself and the pigments to the concrete surface. It is a complicated chemical reaction, but the color actually becomes part of the concrete to a shallow depth. This is one of the best staining methods.
Another type of concrete stain uses solvents. The stain soaks into the pores of the concrete surface. The finished color and depth depend on the concrete surface. A smoothly troweled surface will accept less stain and color depth than a broom-finished surface.
The third type of stain is water-based. This type is best for the environment because it basically just gives off water as it dries. It uses acrylic compounds to carry the color and to fix it to the concrete. This produces some very deep, attractive tones.
Whether you do the staining yourself or have a contractor do it, make sure that real stain is used. Some materials are called stains, but they actually produce a film type of surface, like paint.
There are several reputable manufacturers of concrete stain: Bomanite, Bomanite.com; Increte, EuclidChemical.com; and L.M. Scofield, USA.Sika.com.
The Portland Cement Association, Cement.org, also has an excellent publication on staining concrete. It is called “Finishing Concrete Slabs with Color and Texture.”
Although it is often used by professionals, you may consider using acid-based stain if you are an experienced do-it-yourselfer. If you have trouble finding a professional, contact the manufacturers listed above for names of local contractors.
Solvent-based stain is probably the best choice for the average do-it-yourselfer because of the simplicity of application. Water-based stains are also easy to install but are a bit more sensitive to weather conditions at the time of application.
The key to a successful stain job is proper preparation. The concrete surface must be clean and especially free of grease and oil. If you have done much barbecuing, there most likely is grease and oil on the concrete.
Either scrub it with soap and a brush by hand or clean it with a power washer. Let it dry thoroughly before applying the stain, at least a full day. The best application surface temperature is from about 50 to 90 degrees. This is not the air temperature. It is the concrete surface temperature. Apply per the manufacturer’s instructions.
