That’s been my experience too—north sides just never stay clean, no matter what the shingle label promises. I’ve found copper helps, but only right below the strip, like you said. One thing I’ll add: if you’re doing a re-roof, using a ridge vent plus adding soffit vents really does slow down the algae. It’s not a cure-all, but it keeps things drier up there. I agree on the warranties—never seen one actually pay out for stains. At this point, I just tell folks to plan on a low-pressure wash every couple years... less hassle than fighting with exclusions.
At this point, I just tell folks to plan on a low-pressure wash every couple years... less hassle than fighting with exclusions.
Couldn’t agree more. I tried chasing those “lifetime algae warranties” once—might as well have tried catching a greased pig. I did the copper strip thing too, but honestly, the squirrels seemed more interested in it than the algae. My north side still gets those streaks, just slower now. Ridge and soffit vents helped a bit here in humid Georgia, but nothing’s magic. Low-pressure wash and call it a day... just part of owning a roof, I guess.
- Tried the copper strips too—squirrels here in NC just chewed them up, so that was a bust.
- My Atlas shingles are only a couple years old, but I’m already seeing those dark streaks on the north side.
- Low-pressure wash every other year seems to be the sweet spot for me. Not perfect, but keeps things looking decent.
- I did notice trimming back some tree branches helped a bit with airflow and sunlight. Not a cure-all, but less shade = less algae.
- Honestly, I stopped stressing about it. Just part of the deal with these roofs, especially in humid spots.
Low-pressure wash every other year seems to be the sweet spot for me. Not perfect, but keeps things looking decent.
That’s interesting—do you use any kind of cleaner with the low-pressure wash, or just water? I’ve heard some folks swear by adding a little bleach, but I’m always worried about runoff hurting the plants below. Also, about those copper strips... has anyone tried zinc instead? I’m not sure if squirrels would go after that too, but maybe it’d last longer? The tree trimming tip makes sense; I noticed after we cut back our big oak, one side of the roof stayed cleaner for longer. Still, in NC humidity, it feels like a losing battle some years.
I’ve always just used water with the low-pressure wash, mostly because I’m paranoid about chemicals messing up the flower beds. A neighbor of mine did the bleach thing once and ended up with a patchy lawn for half the summer—his wife still brings it up every time we talk roofs. I get why folks use it though, especially when that green stuff gets stubborn.
Copper strips worked pretty well for us on the north side, but I tried zinc last year after reading it’s supposed to be just as effective and a bit cheaper. Honestly, I haven’t noticed much difference yet, but maybe it takes a while? Only weird thing is, I caught a squirrel gnawing at the edge of one strip this spring. Not sure if it was after the metal or just bored, but now there’s little teeth marks along the gutter line. Squirrels are relentless around here.
Tree trimming made a huge difference for us too. We had this old maple that shaded half the roof and kept everything damp—once we took out a few big limbs, that side dried out way faster after rain. Still, like you said, NC humidity is no joke. Some summers it feels like you clean in May and by August it’s back to looking swampy.
Has anyone tried those “algae-resistant” shingles they advertise? I’m skeptical they’d hold up long-term in our climate, but maybe worth it next time we have to re-roof. Or do folks just stick with regular Atlas and keep fighting the good fight?