Things You'll Need
Spray paint machine
Metal paint primer
Colored metal paint
Metal paint top coat
If you can't afford to have your metal roof painted professionally, you can do it yourself. Metal roofs are easy and inexpensive to maintain because they are sturdy and you can change the color to whatever you like at any time. You will need to pay attention to the specific chemicals that are in the top coat if you want the paint to last for as long as possible. With the right supplies and the correct procedure, you can paint your metal roof the color you like without spending a lot of money.
Scrape any existing, flaking paint off of the metal roof with a putty knife. Take special care not to put any holes in the metal. Use a pressure washer filled with cold water to remove the very small, stubborn flakes of paint that remain. Eliminate any mildew on the surface of the metal by pressure washing with warm water mixed with bleach and trisodium phosphate. Allow the surface to dry completely.
Fill a spray paint machine with a metal paint primer. There are specific paint primers on the market that are for galvanized and other types of metal, and you can choose between white primer (for lighter colors) or gray primer (for darker colors). Spray one coat of the metal paint primer on the metal roof and allow it to dry at least two hours. If needed, apply a second coat and let it dry for two hours. Empty the tank on the spray paint machine when you are finished and clean out any remaining paint with a lacquer thinner.
Fill the spray paint machine with the color paint that you have chosen for your roof. Use a brand of paint that is specially made for use on metal roofs. Apply your first coat, wait at least 2 hours for it to dry and add a second coat.
Spray clear top coat over the paint to protect it. Make sure the top coat that you choose is made for the climate that you live in. If you live in a dry climate, a top coat with silicone alkyd or acrylic urethane is better suited to protect your metal roof. If you live in an area that is humid or rainy most of the year, a top coat with aliphatic urethane is necessary.
If you're working on a high roof, secure yourself with a safety harness to a secure spot on the roof.