Advice from Phil
Intercoat PeelingIf you look up at your porch ceiling and see some of that old color you painted over a few years ago peeking out, you probably have a case of intercoat peeling.
What is intercoat peeling? It’s what happens when a coat of paint loses adhesion to a surface (usually one that has been previously painted) and starts to peel. There are some pretty common areas in which this happens. Most often, you’ll see intercoat peeling happening under your porches, on the eaves of a house, or within other protected areas such as a car port.
What causes intercoat peeling? The most likely explanation is when these protected areas gather air pollutants or other types of contaminant because they’re not being washed or weathered naturally. Also, salts can form during the existing coat of paints lifetime. If these salts are not previously removed before a fresh coat of paint, the salts are liable to cause peeling under the surface. The sheen of the paint may be a factor as well. If the new coat is applied to an old, hard, and glossy paint film, be expectant of peeling. The last, but probably more common, cause of peeling is improper surface preparation.
The procedure best used to handle intercoat peeling starts with making sure the surface is scraped and sanded well. This ensures all loose paint flakes will not be painted over. It is ideal to remove as much of the old top coat as possible. Next, make sure you wash the area to rid it of pollutants, salts, etc. At this point, further scraping and sanding may be needed after the washing, since sometimes the cleaning process causes tight edges to loosen and rise. Once cleaned and prepped fully, a coat of primer should be applied, to help the top coat bond well to the prepared surface. Then, finish by putting on your preferred new finish coat. Though these are the best steps to take when handling intercoat peeling, it doesn’t necessarily guarantee that peeling will not occur again if the top coat was not fully removed.