Uneven, creased paint surface.
Causes:
The paint has been laid on too thick (more likely when using alkyd or oil paint);
Painting a surface that has been heated up by the sun, or painting in direct sunlight.
Impact of humidity on paint that is still wet (rain, dew, fog);
The new layer of paint has been applied on a layer of paint that is still wet.
Solution:
Remove the creased layer of paint with a scraper or by polishing. Then paint the surface again using a high-quality outdoor paint. Let the first layer of paint dry before applying a new layer. Comply with the manufacturer’s recommendations regarding the amount of paint to be used. Optimally painting should be done during cloudy, cool weather with no wind. Do not paint late in the evening or if rain is likely, since the paint might not be dry before the rain or dew.