By Greg Lewis
Stucco is a rough substance, containing cement, sand, water and lime, used for covering the exterior walls of a building and is very common in Southwest states. It is inexpensive to maintain provided it is painted, however problems occur when it is left unpainted. Mildew and moisture can be absorbed into the structure of your home during a sustained rain or by improperly aimed sprinklers. Mold is often the result. Unpainted stucco stains easily during periods of rain, which bring dirt and other pollutants into the stucco. Moisture can also cause stucco to crack and crumble.
Painting: Painting stucco with a high quality water-resistant paint provides a water barrier which helps prevent moisture from penetrating into your home, while at the same time allowing moisture vapor to escape to the outside. This keeps the interior of your home dry. The waterproof “black paper” that was installed when your home was built lasts about 30 years before it begins to degrade and crack, which can allow moisture to get inside your home. To maintain a waterproof barrier, it is therefore especially important to keep a good quality coat of paint on the outside of older stucco structures.
Fog coating: Another option to painting is to “fog-coat” your home. Fog coating is a thin watery coating of colored cement applied to the existing stucco surface. This is usually done with a plastic pump that sprays a mist of color…kind of like a fog.
The benefit of fog-coating is that the surface looks refreshed and it is cheaper than painting. But the drawback to fog-coating is it doesn’t provide a waterproof barrier against mildew, moisture, mold, and staining. You are also not able to change colors, so whatever color was popular back when your home was originally built is what you are stuck with. In addition, it is only an option if the stucco has never been painted.
Power Washing – Power washing unpainted or fog-coated stucco does not usually remove stains and is normally a waste of time and money. However, power-washing painted stucco every few years usually provides much better results, since dirt does not stick to paint nearly as much.
Paint sticks to stucco extremely well and when correctly prepared, does not usually peel. Paint provides better protection than fog-coating, and with a painted surface it is much easier to repair those common cracks that tend to happen around the corners of windows. In addition, it is simple and inexpensive to touch up a painted stucco surface that has been tagged with graffiti. You can’t cover that with fog-coat!
The popularity of colors changes approximately every decade, so painting with a current color palette avoids a “dated” appearance and maximizes homeowner property values!
An easy way to tell if your stucco is painted is to spray some water onto the surface. If the color gets darker, you have unpainted stucco. If the color does not really change, you have painted stucco and are much more protected. You just proved it to yourself!