Can you paint a metal roof? If so, what technique?
Yes. I painted my shop roof with a pole and roller.
This would be a great question to ask at a store that specializes in paint such as Sherwin Williams or Benjamin Moore. They've always been helpful at guiding me in the right direction on what kind of prep work I need to do along with the best primer and paint to use. Since roofs are so exposed to the elements, you will need a high-quality paint that can withstand the heat and rain.
most are coated so it may not stay/stick long term need to use metal etcher first then a sealer after paint info. https://www.youtube.com/results?search_query=diy+painting+metal+roofs
You'll need to use a DTM = direct to metal paint. However, I'd think this through long and hard before painting. Once you paint, you'll have to keep it up forever whereas a metal roof can stand on its own forever.
I agree with Robyn. I've used DTM paints, full acrylic variety, with unbelievable results. However, we prepped religiously prior to painting. We sanded any uneven spots, primered bare metal areas, washed with TSP and rinsed. Then sprayed using an hvlp sprayer. This has endured multiple hail storms with no damage.