The exterior walls are more prone to danger and sunlight and its harmful UV rays. You have to keep in mind that you should take preventive measures so as to take care of the outer walls from the exterior environment.
There are several exterior walls coating that prevent the exterior walls from damage due to the harmful UV rays.
“Andura Classic 21 shall be applied in one coat to all primed surfaces by spray at a uniform minimum application rate of 1.2–1.5 litres per square metre; at a minimum of 1200 microns wet film thickness”.
By this way you can prevent your exterior surface walls from getting damaged due to harmful UV rays present in the sunlight.
The above method is a spray based paint that is up to 20 times the thickness of the normal paint so that the normal sunrays cannot penetrate through the thick layer and so no harm is caused to the paint layer.