Noticed recently my roof has these weird dark streaks running down it, kinda like someone spilled something oily or dirty water ran down. At first I thought it was just dirt from rain or something, but it's not washing off with regular rainstorms. Did a bit of googling and seems like it might be algae or mold? Never had this issue before, so I'm wondering if anyone else dealt with this and how you got rid of it...is there some DIY trick or do I gotta call in the pros?
"At first I thought it was just dirt from rain or something, but it's not washing off with regular rainstorms."
Had something really similar happen to our roof last spring. Those dark streaks you're describing are often caused by algae growth—Gloeocapsa Magma is the technical name, if memory serves. It's pretty common, especially in humid climates or shaded areas where moisture lingers longer.
I tackled it myself to save some money. Picked up a roof cleaning solution from the local hardware store—usually a mix of bleach and water with a surfactant to help it stick—and used a garden sprayer to apply it. Let it sit about 20 minutes, then rinsed thoroughly with a hose (gentle spray, no pressure washers, as those can damage shingles). Took a couple rounds, but eventually cleared it right up.
Just make sure you're careful about landscaping below—cover plants or wet them down beforehand to protect from runoff. DIY is doable, just be patient and cautious up there...
