I've looked at a lot of warranties over the years, and you're right—most of them are way more worried about pressure washing or using straight-up bleach than something like potassium salts. I’ve never seen a claim denied just for using a mild moss treatment, but I have seen folks get in hot water for scrubbing too hard or using weird homebrew mixes. Out of curiosity, did your warranty mention anything about zinc strips? Some brands seem to love those, others not so much...
- Haven’t seen zinc strips mentioned in my paperwork, but I know a neighbor had issues with his warranty after installing them himself—apparently the brand wanted their own installer to do it.
- I’ve always stuck to the mild moss treatments too, just to play it safe.
- Curious if anyone’s had luck with copper strips instead? I’ve read they work about the same, but maybe less controversial with warranties.
- My roof’s asphalt, Pacific Northwest, so moss is a constant battle... anyone else dealing with that year-round?
Copper strips have actually worked better for me than zinc, at least on my old place near Olympia. Didn’t mess with the warranty either, since the installer put them in when I got the new shingles. Moss is still a pain, but it’s not as bad as before. I do think copper stains a bit more though—just something to watch for if you care about streaks.
Interesting you mention copper staining—I've actually seen more streaking from zinc in wetter climates, especially on lighter shingles. Sometimes folks forget to check if their gutters or flashing are compatible with copper, too. If you’re worried about stains, have you tried those newer composite strips? They claim to be less visible, but I haven’t seen enough roofs with them yet to say for sure.
I’ve seen those composite strips advertised, but I’m not totally sold yet. My neighbor put them on last year—honestly, you can still spot them if you’re looking, though they do blend better than the old zinc or copper. As for stains, I’ve had more trouble with zinc too, especially after a wet spring. Had to scrub some ugly streaks off my light gray shingles a couple summers back. Compatibility with gutters is a big deal—learned that the hard way when my copper flashing started turning green and left marks on the aluminum gutters. Sometimes feels like every “solution” just trades one problem for another...