Just watch out with bleach—too strong and it’ll eat your shingles faster than the moss will.
I get what you’re saying about bleach, but honestly, I’ve used a super diluted mix on some stubborn moss patches and never had an issue—at least not yet. Maybe it depends on the shingle brand or how old they are? My uncle’s place had 30-year-old asphalt and the moss was brutal. He tried zinc strips, sprays, even copper wire... nothing really worked long-term until he finally replaced half the roof. Sometimes it just feels like a losing battle if you’ve got big trees overhanging.
Maybe it depends on the shingle brand or how old they are?
That’s been my experience too. I tried a light bleach mix on newer shingles and didn’t notice any damage, but on the older part of the roof, the granules seemed to loosen up faster after a couple seasons. The shade from maples in my backyard makes it worse—moss just keeps coming back. Has anyone actually had luck with those “no-scrub” moss removers, or is that just marketing?
I hear you on the moss—once it gets a foothold, especially under trees, it’s like a never-ending battle. I’ve got a patch on the north side of my house that’s always shaded by a big oak, and no matter what I do, it creeps back every couple years. Tried the “no-scrub” stuff (the kind you spray on and supposedly let the rain do the work) and honestly, it was a mixed bag. It did lighten up the moss after a few weeks, but didn’t really kill it off completely. Maybe if you’re starting with just a little green fuzz, it works better, but for thick patches? Not so much.
I’m with you on the bleach mix—on newer shingles, it seems fine in moderation, but older ones get brittle and lose granules fast. I think some of those “no-scrub” products are just diluted bleach anyway, but they market them as gentler. I’m skeptical. Plus, if your shingles are already showing their age, anything wet or chemical-heavy seems to speed up the wear.
One thing that actually helped me was installing zinc strips near the ridge. When it rains, a bit of zinc washes down and keeps moss from coming back (at least for a while). Not a miracle cure, but I noticed less regrowth after I put them up. It’s not cheap if you have a big roof, but it beats climbing up there every spring with a scrub brush.
Honestly, I think some roofs are just doomed to need more TLC depending on shade and age. If you’re dealing with older shingles and heavy tree cover, sometimes it’s just about slowing the moss down rather than getting rid of it for good. At least you’re not alone—seems like half my neighborhood is in the same boat.
- Zinc strips are decent, but I’ve seen mixed results, especially on low-pitch roofs or spots where water doesn’t flow evenly. Sometimes the moss just finds a way around.
- Honestly, I’m not sold on the “no-scrub” stuff either. Some of my clients tried it and the moss was back in a season. Plus, runoff can stain siding or plants.
- For heavy shade, I usually recommend trimming back branches if possible. More sun = less moss, even if it’s just a little.
- Replacing old shingles might be the only real fix long-term. I know, not cheap, but sometimes patching just drags things out.
- Every roof’s different, but I’d be careful with chemicals—seen too many warranties voided over that.
I get the hesitation with chemicals, but has anyone actually had a warranty denied just for using a moss treatment? I’ve read the fine print on mine (asphalt shingles, Pacific NW) and it mostly warns about pressure washing or using harsh stuff like bleach. I’ve used a diluted potassium salt spray a couple times—didn’t see any issues, and the moss took a lot longer to come back. Maybe it’s a brand thing? Or just depends how aggressive you get with it. Curious if others have had real pushback from manufacturers.
