If your roof has dark streaks running down it or green patches near the edges, you're looking at living growth, not dirt. In South Florida's heat, humidity and rain, roofs are a perfect place for it to grow.
What the streaks are
The black streaks are algae. They feed on roofing materials and spread across the roof over time, which is why one dark patch often turns into a whole stained section. Green, fuzzy patches are usually moss, which tends to grow where the roof stays damp and shaded.
Why it's worth cleaning
- It holds moisture against the shingles or tiles.
- Over time, growth can break down shingles and tiles early.
- A dark roof soaks up more heat than a clean one.
- It makes the whole house look older and less cared for.
Why we don't pressure wash roofs
Blasting a roof with high pressure can crack tiles and strip the granules off shingles. Instead we soft wash: a cleaning solution goes on at low pressure, kills the algae, moss and bacteria at the root, and then gets a gentle rinse. The growth dies instead of just getting knocked loose, and the roof isn't damaged.
What it looks like after
The photo on this page is a real flat tile roof halfway through a soft wash: the left side is still streaked, the right side is clean. See more on our roof cleaning page and in the gallery.