I’ve seen more damage than good—granules gone, edges curling, sometimes leaks show up after.
Pressure washing really does more harm than good—I've seen shingle roofs lose a ton of granules after just one cleaning. Had a client last year who ended up with leaks right after. Those algae-resistant shingles help, but like you said, not perfect. Sometimes just trimming back trees for more sun makes a bigger difference than folks expect.
Yeah, I’ve seen the same thing—pressure washing just beats up those shingles way faster than people realize. Folks think it’s a quick fix, but all that water under pressure can really push granules off and even force water up under the tabs. I get why people want their roofs to look clean, but honestly, letting the sun do its thing after trimming back branches usually works out better in the long run. Not saying algae is pretty, but leaks are a whole lot worse.
I’m actually dealing with this right now—bought my first place last fall, and the roof’s got asphalt shingles that are maybe 12 years old. After a couple of those spring storms, I noticed some of the granules in the gutters and a few spots where the shingles look kinda patchy. I was tempted to just rent a pressure washer and blast off all the gunk, but then my neighbor warned me about what you’re saying—basically, it can do more harm than good.
What’s weird is, I see people around here (Midwest) pressure washing their roofs every year like it’s no big deal. Maybe it’s just habit? I’m not wild about the algae stains, but honestly, leaks freak me out way more. Has anyone tried those roof cleaning sprays that claim to work without scrubbing or pressure? Or is that just another gimmick?
Also, for folks who switched to metal after shingle headaches—how bad is the noise during storms? I keep hearing mixed things and don’t want to swap one problem for another.
Pressure washing shingles is one of those things that looks satisfying in YouTube videos but can really mess up your roof in real life. I learned the hard way a few years back—rented a washer, went to town on some moss, and ended up with a bunch of bare spots where the granules just washed right off. The roof never looked the same after that, and I swear it aged faster.
Those “spray and forget” cleaners are hit or miss. I tried one (Wet & Forget, I think?) on the north side where the algae was thick. It did lighten up after a few months, but it wasn’t dramatic. No scrubbing, though, so at least I didn’t risk damaging anything. If you’re patient and just want it to look a little better, it’s not a total gimmick—but don’t expect miracles.
As for metal roofs, my cousin has one and says storms sound like someone drumming on a tin can if you’re in the attic or have vaulted ceilings. Downstairs, not so much. He loves not having to worry about shingles blowing off, but yeah, the noise is real if you’re sensitive to that kind of thing.
Pressure washing shingles really is one of those things that seems like a good idea until you see the aftermath. I’ve seen a lot of folks do exactly what you described—those granules are basically the only thing keeping UV from trashing your shingles, so once they’re gone, the roof ages in dog years. The “spray and forget” stuff is about as good as it gets for DIY without risking more damage, but yeah, it’s slow and not magic. Metal roofs are a trade-off—noise is real, but you don’t get those surprise leaks after every windstorm. Every roof’s got its quirks, I guess.
