That’s pretty much how I see it too. I’ve got Atlas shingles under a big old oak and a couple of maples, and the north side always gets those green streaks every spring. At first, I was out there with a broom and hose, trying to keep it spotless, but honestly, it just wasn’t worth the hassle. Like you said, unless you’re selling or there’s a real problem, a little algae isn’t the end of the world.
I did try the zinc strip trick a few years back—just tacked a roll along the ridge when I was up there cleaning gutters. It didn’t get rid of all the algae, but it definitely slowed it down. The rain seems to wash those ions down and keeps the streaks lighter. Not perfect, but better than nothing.
One thing I’d add: if you’re in a spot with lots of humidity (I’m in central Virginia), you really do have to keep an eye out for moss. Had a patch start up behind my chimney where it stays damp, and that stuff is stubborn. Ended up having to gently scrape it off and put down some copper mesh. Algae’s mostly just ugly, but moss will start lifting shingles if you let it go.
I’ve heard some folks swear by those “roof cleaning” sprays, but I’m not convinced they’re worth the money—or the risk of runoff killing your plants. Dish soap and a soft brush is about as aggressive as I’ll get now.
Honestly, after 15 years in this house, I’ve learned to pick my battles. If the roof isn’t leaking and the shingles aren’t curling or losing granules in big patches, I just keep an eye on things and focus on bigger projects. The trees aren’t going anywhere, so a little green is just part of the deal for me.
- Had the same “green streaks” show up on my north-facing slope this spring. Thought about power washing but read that it can mess up the shingles.
- Tried the zinc strips too—
That’s been my experience. Not a miracle, but less scrubbing for sure.“It didn’t get rid of all the algae, but it definitely slowed it down.”
- I’m in upstate NY, so humidity isn’t as bad, but still get some moss near the gutters. Used a plastic spatula to scrape it off—didn’t want to risk damaging anything.
- Looked into those roof sprays, but worried about runoff and pets. Ended up just letting most of it be. If it gets worse, maybe I’ll try copper mesh like you mentioned.
- Honestly, as long as there’s no leaks or missing shingles, I’m not stressing too much. The trees are staying, so a little green is just part of the look now.
