Drip edge is a metal corrosion resistant flashing that is installed at the edges of your roof deck to help control the flow of water away from the fascia or into the gutter to protect the underlying roofing components. Drip edge overhangs the ends of the roof decking at the rakes and eaves and has a small metal flange that is normally bent away from the fascia at a 45 degree angle. It is non-corrosive and non-staining so that your roof looks good but is structurally stable. Ideally you will want a pre painted from the factory drip edge so you will not have any rust happen over time. You will want a drip edge that either matches the fascia color, gutter color, or roof color. Keep in mind in most cases matching the fascia color or gutter color is your best option. As it does not take away from the perceived size of the fascia. If you use drip edge that is a different color Than the fascia your fascia will look smaller.
7 reasons you need to have drip edge installed for your roof system:
Keeps water away from the fascia and prevents water from rotting the fascia and soffit over time.
Keeps water from the edge of the decking due to water penetration during driving rains.
Conceals any openings at the bottom of the roof -- where there is often a gap between the decking and the fascia.
Helps seal the end of the roof line during ice dams that can occur during the winter months.
Solidifies fascia and deck boards together.
Helps to redirect water into gutters while rainin. (Drip edge has to lay over and into the inner wall of the gutter and cannot go behind gutter or water will not go into gutter and will drip behind)
Increases the lifespan of your roof system and increases its performance.