If your home’s exterior has been beset by paint problems, it pays to do a little detective work and determine the cause. That can help you avoid the same outcome when you paint again.
According to Debbie Zimmer, paint and color expert for the Paint Quality Institute, the clues can be found in the way your paint is failing. “The evidence is right there, you just need to know how to interpret it,” she says.
Peeling: If your exterior paint is peeling , the culprit is probably moisture. Peeling occurs when wet wood swells underneath the paint, causing the paint film to loosen, crack, and ultimately, peel.
Water can reach the wood through un-caulked joints or a leaky roof. Another possibility: water being forced underneath the roofing shingles because of clogged rain gutters .
Moisture coming from inside the home can also create problems, whether from a leaky pipe or shower, or even excessive humidity caused by an improperly vented clothes dryer.
Blistering: Bubbles or blisters can eventually lead to peeling, so they can’t be ignored. This problem can usually be traced to either heat or moisture.
If your house was originally painted on a very hot day in direct sunshine, for example, blistering can result, especially if a dark color was applied.
Sometimes, moisture is to blame. Excess moisture from within the home can build up behind the paint and cause blisters (this is less likely with latex paint, which is vapor permeable); rain or heavy dew can also produce blisters if the surface preparation wasn’t done properly or if a low quality latex paint was used.
Checking: Horizontal and vertical cracks that create a checkerboard pattern are evidence that the paint has lost its elasticity.
Checking typically occurs on surfaces with several layers of oil-based paint. With age, oil-based paint gets brittle. When temperatures rise or fall dramatically, siding can expand or contract, but the inflexible paint simply cracks and checks.
Chalking: This condition occurs when a fine powder forms on the painted surface. Although light chalking is a desirable way for paint to wear over time, excessive chalking can cause the color to fade very quickly – evidence that the protective paint film is rapidly eroding.
Cases of extreme chalking can usually be traced to the use of a lower quality, highly pigmented paint, or use of an interior paint on an outdoor surface.
Discoloration: Often, discoloration is due to mildew , a fungus resembling dirt that thrives in warm, moist conditions. Thick shrubbery near the home can make the problem worse by shading the siding and restricting the flow of air.
A second type of discoloration is “bleed-through,” which can occur with staining woods like cedar and redwood. Failure to apply a primer before painting can allow tannins within the wood to seep through the paint and mar its appearance.
What to do if your home experiences one of these problems? If you can determine the cause, Zimmer advises that you correct any condition that may have led to the paint failure. If you’re stumped, call in a professional painter to do some sleuthing.
Then, when you repaint, do proper surface preparation  (including the application of a primer when necessary), and use only top quality coatings.