I’ve wrestled with those black streaks for years—honestly, I think they’re tougher than the green stuff too. The sprays help a bit, but I’ve noticed after a few years of using them, the shingles do seem a little faded in spots. Not sure if it’s the spray or just age, but I’m wary about overdoing it. I actually put zinc strips on our last house, and while it wasn’t a miracle, it definitely slowed down the streaks near the ridge. If your roof’s not too steep, installing them isn’t that expensive, but don’t expect a totally spotless roof either. For me, it was worth it just to cut back on the hassle.
I hear you on the black streaks being worse than the green stuff. I was honestly surprised by how stubborn they are—thought a couple rounds of spray would do the trick, but nope. I’ve tried a few of those roof cleaners too, and I swear the shingles look a little more washed out every time. Maybe it’s just the sun, but I’m not convinced those chemicals are totally harmless, especially if you’re hitting the same spots year after year.
I looked into zinc strips after reading about them here and on a couple other forums. Ended up putting them on the back side of my roof (the side that gets less sun and always seems to stay damp). I’ll say, it’s not a magic fix, but it did slow things down. The streaks didn’t disappear, but they didn’t spread as fast either. I guess my main hesitation is that it only really helps right below the strip, so the lower half of the roof still gets hit unless you go wild and put them all over—which feels like overkill.
One thing I wish I’d known: if your roof’s already got a bunch of streaks, the strips won’t clean what’s there. You’ve got to get it cleaned first, then install the strips to keep new stuff from coming back. That was a bit of a pain, honestly. Also, if you’re in a spot with a lot of trees (like me), you’ll still be fighting debris and shade, which seems to make everything worse.
I’m not totally sold on any of these fixes, to be honest. Sprays feel like a short-term band-aid, and the strips are more like a slow-down than a solution. I guess I’d rather have a few faded streaks than risk damaging the shingles or my landscaping with chemicals. If I had to do it again, I’d probably just stay on top of gutter cleaning and trim back as many branches as possible. Less shade, less moisture, less algae... in theory, anyway. But yeah, the hassle never really goes away.
- Totally get where you’re coming from. Black streaks are a pain and honestly, I’ve never seen a spray that actually fixes the problem long-term.
- Zinc strips do help, but yeah, only in a narrow band. I’ve seen folks try to double up and it just looks odd.
- Chemicals can definitely fade shingles over time—seen it on a few jobs after repeat treatments.
- Trees and shade make everything worse, no doubt. Trimming branches and keeping gutters clear is underrated, but it’s probably the most effective thing you can do without risking shingle damage.
- At the end of the day, a little discoloration beats premature roof failure or killing your landscaping with runoff. Sometimes “good enough” really is good enough...
