Skip to main content

    Roof Cleaning Tips & Guides for Madison Homeowners

    Those black streaks running down your shingles aren't dirt — they're algae, and they're slowly eating the limestone filler in your roof. This section explains how soft washing removes streaks and moss without the damage a pressure washer causes, and when a cleaning can push a roof replacement years down the road.

    A roof is the most expensive surface on your house, which is exactly why I treat roof cleaning differently from everything else we wash. Madison roofs grow two things: black algae streaks on the sunny south and west slopes, and moss on the shaded north sides — especially under the mature tree canopies in Maple Bluff, Shorewood Hills, and the older east side. Both look bad, and both actively shorten shingle life if you leave them alone.

    The guides here explain what's actually growing up there, why the fix is a gentle soft-wash treatment rather than pressure, how long results last in our climate, and how to tell the difference between a roof that needs cleaning and one that genuinely needs replacing — because sometimes a cleaning honestly buys you five more years, and sometimes it's lipstick on a roof that's done. I'd rather tell you which one you have than sell you the wrong service, and these articles are written the same way.

    What are the black streaks on my roof — and can they be removed?

    They're a cyanobacteria called Gloeocapsa magma — algae that feeds on the limestone filler inside asphalt shingles and spreads downhill with rainwater, which is why the streaks run vertically. We remove them with a soft wash: a low-pressure treatment that kills the growth at the root. Never let anyone put a pressure washer on your shingles — it strips the granules that protect them.

    Roofs Articles

    8 articles

    Ready for a Quote Instead of a Research Project?

    206+ Google reviews (4.9★), fully insured, and a custom quote in 60 seconds — no phone call needed.

    Get Free Instant Quote