Why Moss Grows So Fast on Roofs in Western Washington (and How to Get Rid of It Without Damaging Your Shingles)

Why? Western Washington has the perfectly damp recipe for moss growth: lots of rain, plenty of overcast days, and shady trees everywhere.  Roofs here often stay damp for days, especially on the north-facing side, which gives moss the moisture it loves. We clean roofs in Tumwater, Shelton, and Spanaway all the time and the story is always the same: if there's tree cover and moisture, there's moss.

The problem is, moss isn’t just sitting there looking green. Its roots work their way into your shingles, lifting them up and holding moisture underneath. That can lead to rot, leaks, and early roof replacements which no one wants.

Here’s the safest way to deal with it: soft washing. Unlike pressure washing, which can blast shingles apart, soft washing uses low pressure and a cleaning solution that kills moss at the root. It works great for Olympia-area roofs because it’s gentle and long-lasting.

We also recommend staying off the roof. It might be tempting to get up there with a broom or hose, but it’s risky and usually ends up making the problem worse. Let a pro take care of it the right way.

So if you’re seeing moss starting to creep across your roof in Puyallup or Montesano, it’s probably time to do something before it starts causing problems. One soft wash can make a big difference.