I get the appeal of those metal strips, especially in humid spots where algae just keeps coming back. But I’m not totally convinced they’re a long-term fix, at least not on their own. Here’s why: I put zinc strips along the ridge last summer, following all the instructions, and yeah, there’s a noticeable line right below them where the shingles look cleaner. But further down the roof, the algae still creeps in. It’s almost like you get this “clean stripe” effect and then business as usual everywhere else.
“Do you notice less algae right below where you put them?”
Exactly that—right *below* is better, but it doesn’t seem to spread much further unless you get a heavy rain that really washes things down. Plus, I read somewhere that some shingle warranties can get voided if you add anything to the roof, so I double-checked with Atlas before installing. They were vague about it, which made me nervous.
Honestly, what’s worked best for me so far is just regular gentle cleaning with a soft brush and hose (no pressure washer). It’s tedious but at least I know I’m not risking my warranty or ending up with weird streaks. If anyone’s found a way to make those strips work across the whole roof, I’d love to hear it...
I’ve had the same “clean stripe” effect with zinc strips on my own roof, and honestly, it bugged me. Like you said, unless there’s some serious rainfall, the run-off doesn’t seem to reach much further than a foot or two below the strip. I’m also in a humid area (Deep South), so algae is relentless most of the year.
The warranty thing is what kept me from adding more strips lower down, too. Atlas wasn’t exactly clear when I called—just a lot of “refer to your documentation” talk. It feels like they don’t want to outright say yes or no, which isn’t very reassuring when you’re investing that much in shingles.
Have you ever tried any of the spray-on treatments? I’ve heard mixed things—some folks claim they help for a season, others say it just makes the shingles look blotchy. I’m tempted to try one but don’t want to waste money if it’s not going to last. Seems like that plus gentle cleaning might be safer than relying too much on metal strips...
unless there’s some serious rainfall, the run-off doesn’t seem to reach much further than a foot or two below the strip
That’s been my experience too—zinc strips just don’t cut it in humid climates. The “clean stripe” look is annoying, and yeah, the warranty confusion is frustrating. I’ve tried a spray-on algae treatment once. It worked for maybe six months, but honestly, it left patchy spots and didn’t last through the next rainy season. Gentle cleaning with a soft brush seems safer if you’re worried about voiding your warranty. Not perfect, but less risk than messing around with more metal strips.
Gentle cleaning with a soft brush seems safer if you’re worried about voiding your warranty.
I get the caution, but honestly, brushing can wear down granules if you’re not careful, especially with older Atlas shingles. In areas with persistent algae, copper strips have given me better long-term results than zinc—just need to watch placement and overlap. The “clean stripe” is less obvious with copper, at least in my experience.
Copper strips really do seem to make a difference, especially if you’re in a humid spot where algae just keeps coming back. I’ve noticed the same thing about the “clean stripe”—it’s way less obvious with copper than zinc, which is a plus if you care about curb appeal. I get why folks are nervous about brushing, too. On my last place, I tried it and ended up with more granules in the gutter than I’d like to admit... Sometimes the “gentle” approach isn’t as gentle as we hope.