The roof coating paint I use, Wattyl Solagard Roof, is tough 100% acrylic satin finish with such exceptional resistance to sun and weather that it comes with a 15 year warranty. Solagard roof is self priming and formulated to give exceptional adhesion and contains mica for extra protection against the elements.
2 coats = 10 Year warranty against flaking, blistering and peeling.
3 coats = 15 Year warranty against flaking, blistering and peeling.

Process:

Waterblast
Re-screw if needed
Rust treat if needed
Seal joins with paintable silicone
Apply roofing patches if needed
2-3 coats of Solagard Roof paint