Roof
Black streaks on the roof
Those dark runs down your roof are a living stain, usually the roof algae Gloeocapsa magma. They are not dirt, and they are not a reason to pressure wash.
How to tell it is algae
It starts on the slopes that stay shaded and damp, usually the north side or under trees. It runs downhill in streaks because it follows the water. It gets wider every year. Rain does not wash it off. If the dark color is spread evenly and smells of smoke, that is something else, and I will say so when I see the photo.
What I do about it
I treat the roof with a soft-wash mix at low pressure and let it work. Nobody is up there with a turbo nozzle, so the granules stay on the shingle. The streaks lighten as the algae dies. Part of it shows the same day and part of it finishes over the next rains. That is normal, not a missed spot.
What stays after the algae is gone
Where the algae sat for years, the shingle under it can be worn. Deep granule loss under a streak will still look worn after the organism is dead. Moss and lichen are slower than algae and harder on a roof if someone tries to scrape them off with pressure; they get treated and left to release.
Will it come back?
Yes, eventually. The shade and the trees are still there. A treatment commonly holds a few seasons. Cutting back limbs that hang over the roof helps more than any product I could sell you.
Getting a price
A photo of the streaks and one from the yard showing the whole slope is usually enough. The house and the roof are two treatments, so tell me if you want both.
Call (706) 415-7564Get an instant priceSend photos for a straight quote
The price is agreed before the hose comes off the reel.