Pressure washing makes me nervous, honestly. I’ve seen too many shingles lose granules or get lifted up, especially on older roofs. Once had a client who thought it’d be a quick fix—ended up with a leaky patch right above the porch. If you go that route, super low pressure and keep the nozzle moving... but even then, I’d rather try chemical cleaners or just let the copper do its thing over time. Those black streaks are stubborn, but sometimes patience is safer than power tools.
I hear you on the pressure washing—seen a few roofs take a beating from folks getting a little too aggressive with it. I’ve had better luck with those spray-on roof cleaners, but even then, I’m always a bit wary about runoff and what it does to the landscaping. Has anyone actually noticed the copper strips making a difference over a few seasons? I’ve got a couple properties where the streaks just keep coming back, even with decent sun exposure.
Copper strips actually did more than I expected, but it wasn’t instant. Took a good rainy season or two before I noticed the streaks fading. Still, it’s not a cure-all—on my north-facing roof, algae keeps coming back, just slower. I’m with you on the spray cleaners—runoff killed a patch of my lawn last year. If you’re dealing with stubborn spots, maybe try zinc strips too? They’re cheaper and seem to help a bit, though not as much as copper in my experience.
- Copper’s definitely more effective than zinc, but you’re right—it’s not magic, especially on those shady sides.
- For stubborn algae, I’ve seen folks use a combo: copper at the ridge, zinc lower down. Seems to slow things even more.
- North-facing roofs are just tough. Sometimes a gentle scrub with a soft brush helps, but don’t go too hard or you’ll wear the shingles.
- I’d skip the harsh sprays too—seen too many lawns and flowerbeds take a hit from runoff.
Sometimes a gentle scrub with a soft brush helps, but don’t go too hard or you’ll wear the shingles.
Man, I tried the “gentle brush” thing on my old man’s roof last summer, and let’s just say my definition of gentle must be different because I ended up with a handful of shingle grit and a sore arm. Maybe I just have zero self-control. Either way, didn’t see much difference in the algae, but the roof sure looked a little more... patchy.
I get the copper and zinc trick, but I swear by those little strips of copper mesh you tuck under the tabs here and there. Not perfect, but it’s less of a production than running metal the whole ridge, and you don’t have to climb up there as much. Still, north sides are just cursed. I’ve even seen folks try that “solar-powered fan” thing to dry it out faster, but that’s a whole other can of worms.
And yeah, those sprays are brutal on the grass. My neighbor’s lawn turned into a patchy mess after he got trigger-happy with the bleach bottle. His wife was not impressed...