There is a common misbelief that vinyl siding can't develop mold. Yes, it's nonporous, but water can still drain behind it or attach to sticky debris. When this happens, especially if you have foam backing, trapped moisture causes mold and mildew.
Because of human and environmental factors, residue will inevitably stick to your siding. Power washing is essential because vinyl is vulnerable to damage against debris.
How Various Particles Damage Your Siding
There are many ways for particles to stick to your siding: cars fly by, windstorms, lawn mowing, cookouts with grease, etc. The debris can scratch, fade, and discolor the surface of your siding, so it's essential to remove it regularly.
What you may need to know is that organic particles like sugars from trees and plants also collect on your siding. Water will stick to this and the dirt from the wind, causing mold and mildew to grow. Fungus feeds on dirt and dust as well.
Read on to learn what to do about it.