Like any household or outdoor item, regular cleaning will extend the life of your metal roof. For a metal roof, periodic cleaning helps maintain the integrity of the panels and removes particles on the surface that could degrade the paint system. Fortunately, paint systems such as PVDF are durable and engineered to last, but will still benefit from periodic cleaning to keep up the strength of the resin and coating.
There are chemicals present in certain atmospheres, such as acid rain and pollution particles, and here in the Charleston area the salt air that can cause premature degradation of a metal roofing paint system. An easy way to determine if your roof is degrading is by inspecting the paint to see if its surface is chalking. Chalking is the white residue that can become visible on a painted or coated metal surface over a period of time.
As panels are exposed to sunlight and UV rays, the paint system’s resin begins to break down and degrade. Once the resin starts to break down and continues to be exposed to the sun, Charleston salt air, and pollutants, it loses its adhesion to the surface and those degraded particles begin to turn white. These particles will over time become visible to the naked eye on the surface of the metal. Often times, the difference can be subtle; however, if you wipe the panel with your finger, you should notice the chalky residue on your skin.
Keep in mind, most metal roofing paint warranties will not cover excessive chalking in the presence of pollutants, this is why it’s important to regularly clean your metal roof. Keeping your metal roof clean from these various particles will significantly lessen this sort of wear and tear.