- Seen a lot of inspection reports recommending pressure washing, but every time I’ve seen someone go that route, it’s ended with shingle grit in the gutters and mystery leaks a few months later.
- Had one client last year—moss gone, but so were half the granules. Insurance flagged it on renewal.
- Light brushing and annual moss treatment has kept my own (asphalt, low slope, Seattle area) roof going strong at 18 years. Takes more time, but way less risk.
- Zinc strips only seem to help on simple gable roofs. Anything with valleys or lots of shade… not so much.
- Quick fixes might look good for an inspection photo, but you pay for it later.
Pressure washing always makes me nervous—seems like a shortcut that ends up costing more in the long run. I’ve seen a few roofs where the shingles looked “clean” but you could see the granules washed out in the gutters, and then there’s that weird patchwork look after a year or two. Light brushing does take longer, but I’d rather spend a weekend on a ladder than deal with insurance headaches. Zinc strips… yeah, hit or miss, especially under heavy tree cover. You’re not alone in thinking those quick fixes just aren’t worth it.
Pressure washing always seemed risky to me too. I get why people want that “like new” look, but I’ve seen neighbors end up with bald patches on their shingles after a few seasons. It’s wild how much those granules matter—once they’re gone, the roof ages in fast-forward. I tried the zinc strips a few years back (Pacific NW, tons of moss), and honestly, under dense trees it was a waste of money. Maybe if you’ve got more sun exposure they help, but shade just wins every time.
I’ve started using a soft brush and some eco-friendly cleaner—takes forever, but at least I’m not worried about voiding the warranty or dealing with leaks down the line. Insurance adjusters love to blame “improper maintenance” for any claim denial, so I’d rather play it safe. Curious if anyone’s found a truly low-impact way to keep moss off without spending every spring on the roof...
Pressure washing’s always made me nervous too—especially with composite shingles. I’ve seen a few properties where tenants got “ambitious” and ended up stripping off half the granules. Once that protective layer’s gone, you’re basically inviting leaks and early replacement. Zinc strips seem hit-or-miss; I’ve noticed they’re almost useless under heavy tree cover, just like you said.
We’ve tried copper wire along the ridge on a couple buildings, but honestly, the difference was barely noticeable unless there was decent sun and airflow. The only thing that’s really helped is consistent gutter cleaning and trimming back overhanging branches, but it’s definitely not a set-it-and-forget-it fix. Moss just loves the PNW, doesn’t it?
Zinc strips seem hit-or-miss; I’ve noticed they’re almost useless under heavy tree cover, just like you said.
I’m not totally convinced zinc or copper are the best answer for moss in the PNW, especially with all the shade we get. I’ve actually seen some green roofs—like sedum mats—hold up better than traditional shingles in these conditions. They’re heavier, sure, and not cheap to install, but I wonder if anyone’s run a cost comparison over 20+ years? My neighbor swapped to a living roof after his third round of shingle replacement and swears he’s had zero moss issues since.
The maintenance is different—more about weeding than cleaning gutters—but it seems like a tradeoff that could make sense for some properties. Has anyone else tried something like that? Or am I just being overly optimistic thinking green roofs can survive our winters without turning into a soggy mess? The idea of not stressing about granule loss or constant pressure washing sounds pretty appealing, though...