What Causes It?
Dry paint can split through at least one coat, which will lead to complete failure of the paint. Early on, the problem appears as hairline cracks. Later, flaking of paint chips occurs.
A variety of causes exist for cracking or flaking of paint. First, if lower-quality paint has been applied to the surface, it will have inadequate adhesion and flexibility. Another cause is that the paint was spread too thin on the surface.
Poor surface preparation, especially when the paint is applied to bare wood without priming, can also cause this problem. Finally, painting under cool or windy conditions can make latex paint dry too fast, causing it to crack.
How to Solve It
If the cracking does not go down to the substrate, you may be able to correct it by removing the loose or flaking paint with
a scraper or wire brush, sanding the area to feather the edges, priming any bare spots, and repainting it.
If the cracking goes down to the substrate, remove all of the paint by scraping and sanding or use a heat gun. Then prime and repaint with a quality exterior paint.
Note: Images provided by The Rohm & Hass Paint Quality Institute.