It is a common phenomenon that over time that the original factory applied primer coat can lose its adhesion at the interface of the galvanized substrate and the bare metal substrate is exposed.
If the” perceived paint failure” reveals the bare substrate exposed this is not a warranted item. When previous coat(s) of paint (not only the newly applied paint) loses adhesion (intercoat adhesion failure) it is a “unforeseen" condition.
Most times paint is the visual effect of an underlying problem, not the cause.
CAUTION:
When dark colors are used in direct sun areas contractor MUST exercise extreme care to not paint when doors are hot or will become hot until the paint film is completely dry. Darker colors will fade faster and may need to be re-paint with (3) three years.
Dark colors on exterior metal will absorption heat and the UV may cause inter adhesion failures, blistering, film surface cracking, failure of underlying paints and other phenomena that is beyond the control of the coating system.
The peeling of exterior doors is not predictable. If one or more areas of peeling is existing prior to painting the door paint will continue to peel. Spot priming the bare areas and repainting will NOT stop the continued peeling.
To remedy the problem the entire door must be completely stripped down to the bare substrate.<