It is a situation in which the paint dries up and forms a wrinkled kind of a texture over the wall. This may happen due to the thick layer of paint that has been applied over the wall.
This may happen due to following:
Wrinkling may be caused due to the thick layer of paint applied at a particular place.
Also, painting in too hot or too cold temperature may also be an invitation to wrinkling.
Variations in the environment like dry to humid and humid to dry may result in wrinkling paint.
How to overcome this problem?
Wrinkling can be overcome and solved by following methods:
Scrape off the wrinkled part. Sand it up. Do not forget to clean up the dust with a help of a drop cloth. Prime it well and then paint it with the similar colour. Make sure that you do not apply thick layer of paint this time.
Also, avoid to paint the walls during changing climates and especially during humid climate as it is one of the major reason for wrinkling of the paint on being dried up.