Painting exterior stucco is a good option for some homeowners. Most stucco is made of Portland Cement, sand, and lime. It is said to have a lifespan of 50-80 years which makes it very desirable when looking for a durable finish. However, over time exterior stucco can develop fading, staining, and hairline cracks. If deep cracks are discovered, it’s best to contact a stucco repair company to repair the deep crack and avoid any chance of moisture damage.
Hairline cracks, fading, and staining can be dealt with by painting stucco. Hairline cracks, between 1-5 millimeters, are usually not a concern as they tend to be cracks on the surface, but not in the wall itself. Painting stucco can cover over the hairline cracks and staining at a much lower price point than stucco resurfacing. Therefore, painting exterior stucco tends to be the choice for many.
Stucco is a masonry coating and therefore needs to allow water vapor to escape. After stucco is applied it tends to have a high pH. During the curing process that can take 30-90 days, the pH will drop. Before applying any type of coating it is recommended that you wait until the stucco has fully cured and the pH has dropped between 6-9. Depending on the circumstance, when waiting is not an option, using a pH neutralizer or alkali-resistant primer may be beneficial. Always check and make sure the product you plan to use says it can be applied to stucco.
We recommend to always use a flat sheen on stucco. There are stucco specific products on the market and most of them are only offered in a flat sheen. This is because the stucco surface is naturally inconsistent. A glossy sheen will highlight those inconsistencies, which can give a blotchy undesirable finish. If the application of the stucco is consistent a more glossy sheen can be used, but it is often difficult to tell how consistent the texture of the stucco is until after the product with a sheen is applied. We threfore do not recommend it.
Some of the masonry products available are marketed as an elastomeric coating. Oftentimes these products are thicker than typical paint, and contain not only acrylic but other polymers that are “elastomeric”. There is some debate on what conditions and climates a product with extra elastomeric polymers will have a superior performance to paint. Some will argue that you should avoid these products in drier climates. While we are uncertain on this debate, we feel if you use a high quality product from a reputable source you will have a great result either way. Usually stucco is one of the last places we see paint failures on homes. Oil-based paints should be avoided when it comes to painting stucco as they do not “breathe” like a water-based coating will.
Preparing the stucco for paint, especially if the stucco has been painted before, will require a good power washing. It is critical to clear it from all dirt, loose paint, and efflorescence (which is a crusty white salt deposit that can appear on stucco, concrete, brick, and other masonry surfaces). If not properly removed before repainting, these can cause adhesion problems when painting stucco. For hairline cracks in stucco, if they are small enough for the paint to fill them, that is your best bet for giving a uniform finish. However, if the cracks are too large for paint to fill them, and you are not going to have them repaired with stucco, you will want to fill that void with an appropriate caulking material. These filled cracks will be noticeable after painting because the texture of the filled cracks will be different than the texture of the surrounding stucco. Using a flat sheen product will help hide this inconsistent surface.
Painting exterior stucco is a great choice for those homeowners who are unhappy with the cosmetic issues of hairline cracks, fading, or staining, or who simply want a change of color. Painting stucco is about 1/10th the cost of resurfacing and can achieve the end result many are looking for.