Exterior Concrete Paint Specifications

• Damaged concrete srufaces should be repaired before applying paint. Jupiterimages/Photos.com/Getty Images

  Exterior concrete is used in a wide variety of ways and each use will require its own type of paint. The paint needed for a porch or sidewalk will be different from the concrete paint needed on the concrete masonry wall of a building or the paint applied to concrete yard decorations. However, there are some specifications that are applicable for every type of concrete paint.

Surface Preparation

• Proper surface preparation is necessary for exterior concrete paints to adhere to the concrete. Previously painted surfaces should be free of peeling paint---gentle removal is advised, concrete can be scratched and damaged by rough scraping. All concrete should be clean from dirt and debris and all holes should be filled before applying the paint. Allow concrete to dry completely before applying the paint. Preparing the concrete surface with a bonding primer may be required---read the manufacturer's instructions to find out whether the primer is needed.

Elasticity

• Exterior concrete paint should have an elastic quality that allows the stretching necessary to accommodate extreme climate changes. Concrete paints without this property can crack and become damaged during seasonal temperature changes. Most exterior acrylic latex paints that are designed for concrete application contain this property. Industrial concrete paints usually used for sidewalks, building exteriors and public spaces are called "elastomeric" paints. Elastomeric paints are an acrylic polymer paint with an extra elastic membrane quality making them very thick.

  Sherwin Williams suggests that exterior concrete paints labeled "elastomeric" are best applied using a rolling method when placed on rough surfaces. Flat surfaces like poured in place concrete can be sprayed but the paint may require a specific spray tip because of the heavy body of the paint. Elastomeric coatings can help bridge small gaps and holes in the concrete and prevent moisture from penetrating the concrete.

Temperature

• Specifications for the concrete paint should be on the paint container and should state the temperature range in which the paint will be its most durable. Both the application of the paint and the durability of the paint once it is applied have temperature ranges that provide the best results. The manufacturer will provide a specific range for both on the container. Most products can be applied in 50 to 90 degree weather but high humidity levels will slow the curing process.

  Temperatures that designate durability in certain types of weather should be followed to prevent cracking, peeling and chipping damage to the paint. Freezing climates may require specialty or industrial concrete paints for better wear.