As a general rule of thumb, an exterior paint job should last 6-8 years without much problem if the surfaces have been properly prepared before painting. There are many variables to consider such as weather, location etc.and some work may in fact last longer, but it has been my experience that a good paint job should be revisited during this time frame.
I drive past a home that I painted in 2001 that still looks good, but I have also seen a couple from that time frame that need a paint job immediately!
It is most important that the surfaces be properly prepared--cleaned,caulked,dry surfaces give the best adhesion. If the paint closest to the substrate is chalky or dirty the new paint will not bond correctly. If the underneath is no good----the most expensive topcoat in the world will have a short life span. The best products last longer. You should insist always on 100% acrylic or
elastomeric paints for exterior. These paints have an elastic quality that allows movement over a wide range of temperature changes.
It is also worth noting that the temp should not exceed 90 in the sun drenched areas or fall under 35 for 12 hrs after application. All paints have to cure and this can take hours beyond the dry to the touch time. Paint that cures incorrectly will have a shorter life span.
It is true that darker colors fade or begin to fail before lighter colors. They absorb more of the u.v from the sun. The sun is always the chief enemy to paint. When choosing a darker color
exterior paint I would suggest a satin sheen as opposed to a flat. This seems to hold up better and stay cleaner. I would also suggest using the top of the line paints for this application. You will notice fading much sooner than the lighter colors, but mostly in the sun drenched areas. I would suggest inspecting these areas each year and repainting when faded. Maybe every 3-5 yrs. depending on color.
Probably the best way to keep your exterior weather resistant is to walk around it every spring and look specifically for these common problems and address them as they appear:
When paint has failed, it will appear faded and feel chalky to the touch. Failed paint allows moisture in and will eventually deteriorate the substrate and possibly let water inside the structure if not addressed.
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