Green Stuff Growing on Your Siding? Here's What It Actually Is

The green stuff on your siding is algae, mildew, or moss — fed by shade and North Carolina humidity. If it's slimy to the touch and comes back in the same shaded spots every year, you have a moisture problem that soft washing will fix. A garden-hose rinse won't reach it, and a pressure washer will make it worse.

Self-check first

Before you call anyone, run this quick check on the affected wall:

• Does it come back in the same shaded spots each year? Algae and mildew thrive where the sun doesn't reach.
• Is it slimy to the touch? Algae and moss are slimy; pollen and dust are dry and brush off easily.
• Does it wipe off with a wet rag, then reappear in two weeks? That's living growth, not surface dirt.

If you answered yes to two of those three, you have organic growth that needs soft washing — not a rinse, and not a blast. The growth is anchored to the siding, and removing it means killing it at the root.

Algae or mold — does it matter?

For treatment purposes, not much. Algae is green and slimy. Mildew is often gray or black. Mold is usually black, pinkish, or fuzzy. All three feed on the same thing — moisture held against an organic surface — and all three respond to soft-wash chemistry. What you don't want to do is blast any of them with high pressure. High pressure forces water behind the siding, where it stays wet and grows more of exactly what you're trying to kill.

Will it stain permanently?

Most growth lifts completely on the first wash, and the siding reads clean the day we finish. Long-standing growth can leave a faint shadow on older vinyl, and we're honest about that on the walk-through — we won't promise a brand-new look on siding that's been stained for years. What we will promise is that the colony is dead and the surface is clean, so the growth comes back slowly instead of immediately.

If your siding is green, see our Soft Washing in Shelby, NC page or call (704) 300-1482.