Keywords: chalky paint, color fading, paint failure, pressure washer, power wash
Paint chalking is the formation of fine powdery substances on the surface of the paint due to exposure to the elements. All paints chalk to some degree from normal aging. However, excessive chalking can cause color fading and is a sign of paint failure.
In dry arid climates where there is little rain, like Phoenix, paint chalking tends to happen more quickly than other parts of the country, so proper paint preparation and maintenance is crucial for a long-lasting paint job. It is more prevalent on stucco, masonry, metal, and masonite siding substrates. But it can affect plywood siding and dimensional lumber as well. It is solely an exterior paint issue. The highly exposed areas facing east, south, and west should be inspected for chalking. Be very mindful of the upper areas where the ultraviolet rays have less obstruction.
Severe chalking fades the original paint color. Severe chalking also makes repainting a problem due to the extreme porosity of the powdery surface. New paint will not adhere properly. Instead, the paint bonds only to the chalky powder and will be a skin of paint not properly attached to the building. Once a little time lapses, even as short as a few months, the results can be large popping of the topcoats in sheets or multiple small areas of peeling. Once major popping occurs, the only fix is to remove all loose coatings down to a sound substrate, usually with a large pressure washer, causing a huge paint chip mess. Of course, the best way to avoid the mess is to prep the surface properly in the first place.
Evaluating Chalking
Wipe the surface with your hand or a dark cloth to determine the extent of the chalking. It can be helpful to obtain ASTM D4214 Standard Test Methods for Evaluating the Degree of Chalking of Exterior Paints.
Causes of Excessive Chalking
Some causes of excessive chalking include extended exposure to the sun’s ultraviolet rays, over thinning or overspreading paint, not using the proper primer, or using a cheap paint.
Excessive Chalking Solution
Power wash all surfaces that need to be painted. We recommend using at least a 2600 PSI pressure washer. You might need to do this twice if heavy chalk remains. Once the surface is completely dry, prime the chalked surface using a special sealer/primer to lock down remaining chalk for proper adhesion. Consult with a paint professional who can recommend a primer suitable for a notoriously chalky wall. After priming, use a high-quality latex paint to repaint.
Taking on a project like this, especially if you own a large home or commercial building, can be a difficult project. Multi-story heights can make it a dangerous task. Don’t take the chance of getting hurt or missing important paint preparation. Call MTS Painting and our expert painters will tackle the project for you.
