Many types of fascia boards don't need to be painted since they are constructed with coloured material like vinyl. If you decide to use wooden fascia boards, then you may need to paint them every 3 to 5 years to ensure that they look good and are protected from the weather and moisture.
Choose two different colours to use to paint your fascia boards. One colour should match the primary shade of your home, while the other should be the same as the rest of your trim. Due to the fascia's proximity to rain gutters, some people prefer to paint them the same colour as the drain channels to help them blend in better.
Cover all surfaces of your fascia boards with paint primer and give them at least 24 hours to dry. While you can often get away with painting only the external sides of your fascia, it must all be primed in order to protect the wood and ensure that the paint will stick. Note that some of your fascia boards may already be primed.
Tape off the fascia boards so that you're painting the colour that covers the largest surface area first. Since you'll be painting the other area later, don't worry too much if your taping isn't exact and some paint gets on the other spots.
Use a small paintbrush to coat shorter boards, but consider using a roller to quickly paint your longer pieces. For new fascia boards, remember to paint them outside for adequate ventilation.
Allow 24 to 48 hours for the paint to dry and then tape off the edges so you can apply the second colour. Use a hand brush for better accuracy when painting the undersides and ends of the boards. Consider applying a second coat of each colour before you install the fascia.
Repaint your fascia boards every 4 to 5 years to help them last longer, but remember that you don't need to re-prime them. Tap the ends of the boards with a screwdriver before painting. If the ends are mushy, then you should consider replacing the wood, since it is starting to rot.
If you are planning to use a latex-based paint, be sure that you use a latex primer. This type of primer may also be used for oil-based paints. Lightly sand weathered fascia boards by hand before you repaint them.