Those dark streaks on your roof are algae, not dirt. Here's what causes them in Florida's climate and how to remove them safely.
If your roof has dark streaks running down it, you are not looking at dirt or worn shingles. You are looking at a living organism called Gloeocapsa magma — a blue-green algae that feeds on the limestone filler in asphalt shingles and thrives in Florida's heat and humidity.
Central Florida is one of the worst climates in the country for it. Constant moisture, warm nights, and the shade from our oak canopies give the algae everything it needs, and it spreads fastest on north-facing slopes that stay damp longest.
High pressure strips the protective granules off asphalt shingles and can crack tile, voiding many roof warranties. The only safe method is a low-pressure roof cleaning in Lakeland that uses a soft-wash treatment to kill the algae at the root, so the streaks are gone rather than just knocked loose.
Because a soft-wash kills the organism, streaks typically stay gone for several years — far longer than a rinse that only removes the surface layer. Most Central Florida homeowners have it done every three to five years and pair it with a house washing in Lakeland to match the rest of the exterior.
If the streaks are visible from the street, they have been growing a while — the sooner they are treated, the less permanent staining is left behind. See our Lakeland pressure washing services for an upfront quote.
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