I’ve actually seen moss come back even quicker after a rough scrape—almost like it gets “pruned” and grows back thicker. Especially in the damp PNW, it’s relentless.
That’s exactly what happened on our place. First time I tried scraping, I figured I’d done a pretty thorough job—got up there with a stiff brush, made a mess of myself and the yard. Not even six months later, the moss was back, and honestly looked healthier than before. Maybe it’s like when you mow grass too short and it just gets mad at you.
I’m always wary about using chemicals because of runoff (and pets), but I tried one of those so-called gentle moss killers last year. It did slow things down, I’ll admit, but the stuff isn’t cheap and you have to reapply every year or so. Between that and the fact that my roof’s on the older side (asphalt shingles, 18 years old), I’m starting to wonder if hiring someone with proper gear would be worth it in the long run. DIY saves cash up front, but if you’ve got to keep buying treatments—or risk damaging shingles with all that scrubbing—it adds up.
Guess it comes down to how much time you want to spend up there versus what you’re willing to pay for less hassle. In this climate, seems like there’s no permanent fix anyway...
I’ve seen the same thing—scraping just seems to annoy the moss and it comes back with a vengeance. I get why folks want to avoid chemicals, but honestly, scrubbing too hard on older shingles can do more harm than good. I’ve been called out to fix leaks where someone got a little too enthusiastic with a wire brush. If your roof’s pushing 20 years, sometimes it’s safer (and cheaper in the long run) to let pros handle it with low-pressure washes and proper treatments. Not saying DIY never works, but up here in the PNW, it’s a losing battle most years.
I get where you’re coming from, but I’ve seen plenty of DIY jobs that turned out just fine, even on older roofs. Sure, you can’t go at it with a wire brush or pressure washer—those’ll wreck shingles fast. But gentle hand tools and patience can keep moss at bay for a few years, especially if you’re up there regularly. Not everyone wants to shell out for pro treatments every other season. That said, if you’re not comfortable on a ladder or the roof’s steep, yeah, better safe than sorry... but I wouldn’t call it a lost cause for DIYers, even in the PNW.
But gentle hand tools and patience can keep moss at bay for a few years, especially if you’re up there regularly.
Yeah, that’s pretty much spot on. Light scrubbing with a soft brush and maybe a moss treatment (the kind you sprinkle on and let the rain do its thing) works fine if you keep up with it. I’ve seen some folks in the PNW go years without major issues just by staying on top of maintenance. The key is really knowing your limits—if the roof’s steep or sketchy, no shame in calling a pro, but DIY isn’t off the table if you’re careful.
I’ve managed a few buildings with older composite shingle roofs, and honestly, regular light cleaning makes a huge difference. We had one spot that kept getting mossy—north side, always shady—and just using a soft brush every spring kept it under control. Tried the sprinkle-on moss killer too, and it worked, but you’ve gotta be careful not to overdo it or let runoff hit your plants. I’ll admit, there was one roof that was just too steep for comfort... called in the pros that time. Sometimes it’s just not worth risking a fall.