Just don’t expect miracles—algae’s stubborn.
Couldn’t agree more. I’ve put zinc strips on dozens of roofs and, honestly, they help, but they’re not a cure-all. Especially in wet climates like the PNW, you’ll still get some streaks after a couple years. I always tell folks: it slows things down, but you’ll still need to get up there now and then if you want it spotless. Scrubbing’s a pain, but sometimes it’s the only way to get rid of the really stubborn stuff. If you hate ladders, zinc is better than nothing, but don’t toss your brush just yet...
Zinc strips are one of those “sounds good on paper” solutions, but in practice, they’re more like a speed bump for algae than a brick wall. I’ve seen plenty of folks get their hopes up, thinking they’ll never see another green streak again. Reality check: if you’re in a place with constant drizzle or heavy shade, that stuff finds a way. Atlas shingles do have some algae resistance built in, but even the best granules lose their punch after a while.
What’s wild is how much roof orientation matters. South-facing slopes on my own house stay pretty clean—sunlight does half the work. North side? That’s where the moss parties happen. I put zinc up there, and yeah, it slowed things down, but after two years I was still up there with a soft brush and a hose. Not fun, but better than letting it eat into the shingles.
One thing I’ll say—don’t get too aggressive with scrubbing. I’ve seen people go at it with wire brushes or pressure washers and end up blowing off granules or even damaging the shingle mat. Then you’ve got bigger problems than algae stains... If you’re going to do it, stick to gentle methods and maybe schedule it for late spring when things are dry but not baking hot.
If you’re dealing with storm debris too—branches, leaves, all that—cleaning more often helps keep algae from getting started in the first place. And gutters... don’t get me started on clogged gutters feeding roof algae. It’s all connected.
Long story short: zinc strips help, but don’t expect miracles, especially if your roof’s already got a few years on it. Maintenance is just part of the deal if you want your shingles to last. At least it gives you an excuse to check for other issues while you’re up there—loose tabs, popped nails, that kind of thing. Sometimes those little checks save you from bigger headaches down the road.
That’s pretty much been my experience too—zinc strips slow things down, but they’re not magic. I’ve noticed the same with roof orientation. The north side of my folks’ place is always green, even with algae-resistant shingles. I’m curious, has anyone tried those copper strips instead of zinc? I’ve heard they last longer, but not sure if they’re worth the extra cost.
Copper strips are definitely pricier, but in my experience, they’re a lot more effective than zinc—especially over the long haul. We replaced zinc with copper on our shed roof about five years ago (Pacific Northwest, so moss is relentless here), and honestly, the difference is pretty obvious. The copper side stays cleaner, and it’s barely started to tarnish. I do wonder about the environmental impact, though… copper runoff isn’t great for plants, right? Still, if you’re tired of scrubbing algae every year, it might be worth the splurge.
We’re in the Willamette Valley, so I can totally relate to the moss battle. I’ve tried both zinc and copper strips over the years, and honestly, I had similar results—copper just seems to keep things cleaner for longer. We put copper on our main house roof about six years ago after getting tired of scrubbing green fuzz every spring. The initial cost was a little painful (especially compared to zinc), but the difference in maintenance has been huge. There’s still a bit of moss near the gutters where the runoff doesn’t hit as much, but otherwise, it’s been way less work.
The environmental side is tricky. I did some digging before we installed ours—copper ions can be rough on aquatic life if they wash into streams, and some plants are sensitive too. We ended up adding a rain barrel system for the downspouts that collect most of the runoff from the copper side, partly to keep it out of the veggie beds. Not sure how much it helps, but it feels better than nothing.
One thing I noticed: copper strips seem to work best when they’re installed close to the ridge line, so rainwater carries those ions down over the whole roof. We tried putting a strip halfway down once (thinking it’d double the effect), but it actually left weird clean lines and didn’t do much for the lower half.
If anyone’s considering this route, I’d say weigh the upfront cost against how much time you want to spend on a ladder with a scrub brush every year. For me, not having to haul out the pressure washer every spring is worth it... but yeah, there’s always that tradeoff with what ends up in your soil.