Quick fix or redo: dealing with damaged aluminum flashing

- Totally agree on the sanding - if you skip it, you’re just asking for trouble down the line.
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“I’ve seen a few folks try to shortcut with just a wipe-down and sealant, but it never seems to last more than a season or two, especially if there’s any chalky residue left.”

- On the self-adhesive flashing tape: I’ve used it on a detached garage roof where I couldn’t get up there safely for a full repair. Lasted about 18 months before it started peeling at the edges. Not bad for a stopgap, but I wouldn’t trust it on anything critical or exposed to a lot of sun.

- Coastal corrosion is a pain. I’m about 10 miles inland, but even here, the aluminum gets that powdery look after a few years. Tried a marine-grade clear coat once - helped a bit, but it started flaking after two summers. Haven’t found a magic bullet yet.

- Has anyone tried switching to galvanized or even copper flashing in those salty spots? Wondering if the upfront cost is worth it compared to replacing aluminum every few years.

Copper flashing holds up great near salt air, but the price can be a shock - plus, it’s a magnet for thieves in some neighborhoods. Galvanized is a step up from aluminum, but it’ll still rust out eventually if you’re close to the coast. If you’re already dealing with corrosion every few years, copper might actually save you hassle (and money) long-term, especially if you’re paying someone to replace flashing each time. Just make sure you’re not mixing metals where they touch - seen plenty of weird corrosion when folks do that.

Copper’s definitely the gold standard near the ocean, but I’ve seen folks regret it after a theft or two. Sometimes, stainless steel flashing is a solid compromise - less flashy, still tough against salt. Has anyone tried stainless in a coastal spot and had it hold up?

I actually swapped out some old aluminum flashing for stainless a couple years back - right on the coast, too. The salt air here eats through most metals, but the stainless has held up way better than I expected. No green stains or weird corrosion yet. It’s not as pretty as copper, but I’ll take that over having to patch leaks every winter. Only thing is, it was a bit trickier to cut and bend compared to aluminum. If you’re thinking of going that route, just make sure you’ve got the right tools... learned that the hard way.

Only thing is, it was a bit trickier to cut and bend compared to aluminum. If you’re thinking of going that route, just make sure you’ve got the right tools... learned that the hard way.

That’s a good point about stainless being tougher to work with. I ran into something similar last fall - was helping a neighbor swap out some corroded aluminum flashing on his shed, and we tried using his old tin snips on the stainless. Ended up chewing up the snips and barely making a dent in the metal. Ended up having to borrow an angle grinder, which made things way easier but definitely not as clean as working with aluminum.

One thing I’ve noticed is that even though stainless holds up better against salt air, it can still get surface rust if you nick it during installation or use the wrong fasteners. I always recommend using stainless screws or nails too - otherwise you get those weird rust streaks running down after a few months.

I’m curious - did you run into any issues with galvanic corrosion where the flashing meets other metals? Sometimes mixing metals (like stainless against galvanized steel or copper) can actually speed up corrosion in certain spots, especially near the coast. I’ve seen some weird pitting happen when folks don’t use a barrier or compatible fasteners.

Also, for anyone thinking about switching from aluminum to stainless: measure twice before cutting. Stainless is way less forgiving if you mess up your bends or cuts. I usually make a cardboard template first, just to be sure everything lines up before committing.

Has anyone tried any of those coated aluminum products? Supposedly they’re more resistant to salt air than plain aluminum, but I haven’t seen them in action long-term yet. Wondering if they’re worth the extra cost compared to just going with stainless and dealing with the hassle of installation.

I get the appeal of stainless for coastal spots, but honestly, I’ve had decent luck just sticking with aluminum and using a good quality paint-on coating. It’s way easier to work with, and if you seal up the edges and joints right, it seems to hold up for several years even with salt in the air. The coated aluminum stuff isn’t perfect, but it’s a lot less hassle than wrestling with stainless, especially if you’re not doing a huge run. I’d rather replace a piece every 7-8 years than fight with stainless every time I need to make a tweak. Maybe not the “forever” solution, but it’s a solid middle ground.

I’d rather replace a piece every 7-8 years than fight with stainless every time I need to make a tweak.

I get what you’re saying about aluminum being easier to work with. I’ve done both, and honestly, stainless is a pain to cut and bend unless you have the right tools. What’s worked for me on damaged aluminum flashing is:

1. Clean the area well, get rid of any loose corrosion.
2. Hit it with a rust converter if there’s any pitting.
3. Use a high-quality paint-on coating, especially on the seams and edges.

If the piece is really mangled, I just swap it out. Like you said, it’s not “forever,” but it holds up fine if you keep up with the coating every few years. I’m on the coast too, and haven’t had major issues. Stainless is overkill for most spots unless you’re right on the water.

If the piece is really mangled, I just swap it out. Like you said, it’s not “forever,” but it holds up fine if you keep up with the coating every few years.

That’s a solid approach, especially in coastal areas where corrosion is always lurking. Aluminum’s definitely more forgiving if you need to make on-the-fly adjustments - no contest there. I’ve seen plenty of jobs where folks went all-in on stainless, thinking it’d be a “set it and forget it” solution, but then they’re cursing when it’s time to cut or bend for a repair. Unless you’re right up against salt spray every day, aluminum with a good maintenance routine is usually more than enough.

I’d just add - sometimes people skip the prep and slap on a patch or coating, but like you said, cleaning and treating any pitting first makes a huge difference in how long it lasts. I’ve had a few clients surprised their “quick fix” held up a decade just because they took the time to do that extra step. Stainless has its place, but for most roofs, you’re not missing out by sticking with aluminum and keeping an eye on it every few years.

- Agree with swapping out if it’s really mangled - sometimes it’s just not worth patching.
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“Aluminum’s definitely more forgiving if you need to make on-the-fly adjustments - no contest there.”

I’ve wondered about this too - my flashing’s got a couple of dings, but nothing major. Is it really worth replacing a whole section if it’s just a bit bent? I did a patch last fall and it’s holding up, but I’m not sure how long that’ll last. Prepping the area was a pain, but I guess it beats water getting in. Anyone else notice aluminum gets these weird white spots if you don’t seal it up right?

Anyone else notice aluminum gets these weird white spots if you don’t seal it up right?

Yeah, I’ve seen those spots - happened on my shed roof after I rushed a patch job one rainy weekend. Figured it was just dirt at first, but nope, that chalky stuff stuck around. I ended up sanding it down and using a low-VOC sealant, which helped a bit. Honestly, I’d rather patch than replace unless water’s actually getting in... but prepping is always more work than I think it’ll be.

That chalky white stuff is usually oxidation - aluminum reacts with moisture and air, especially if the sealant’s not solid. I tried just scrubbing it off once, but it came right back. For me, cleaning, then hitting it with a self-etching primer before sealing made a difference. It’s a pain, but if water’s not getting in, I’d stick with patching too. Full replacement only if it starts leaking or corroding through. Prepping always takes longer than you think... but skipping it just means more work later.

That chalky buildup is a classic sign the flashing’s been exposed for a while. I’ve seen folks just paint over it, but honestly, if you don’t get all the oxidation off first, it’ll bubble up again under the paint or sealant. Did you check if the flashing’s still solid underneath? Sometimes it looks worse than it is, but if you can poke through with a screwdriver, that’s when I’d start thinking about replacement. Otherwise, yeah, a good cleaning, primer, and sealant usually buys you a few more years. Just takes patience... and a bit of elbow grease.

if you don’t get all the oxidation off first, it’ll bubble up again under the paint or sealant

Couldn’t agree more - skipping the prep just means you’re back up there in a year, scraping off flaking paint. I’d add, if you’re already putting in the work, consider using a low-VOC primer and sealant. It’s better for your lungs and the runoff won’t mess with your garden beds. I’ve had decent luck with that combo on my own place, and it held up through a couple rough winters.

That’s spot on about the prep work - nothing’s more frustrating than seeing bubbles or peeling after you’ve already spent the time and money. I’ve found that even a little leftover oxidation can mess up the whole job, especially if you’re dealing with older flashing that’s already pitted. I used to think a quick wire brush and rinse would do it, but after a couple of failed attempts, I started using an etching cleaner before priming. It made a noticeable difference.

Low-VOC products are a good call, especially if you’re working in a tight spot or near anything you’re growing. I’ve tried a few brands and, honestly, some of them go on a bit thinner, so you might need an extra coat, but it’s worth it for the peace of mind. If you’re already up there, might as well do it right and not have to mess with it again for a while.

If you’re already up there, might as well do it right and not have to mess with it again for a while.

Ain’t that the truth. I’ve seen more “quick fixes” on flashing than I care to admit - usually ends up with me getting called back out six months later when the patch job peels or leaks. Curious, has anyone tried those peel-and-stick aluminum repair tapes? I’ve seen mixed results, especially in spots that get a lot of sun. Sometimes feels like you’re just buying time until you have to redo the whole thing anyway...

Tried those tapes on a low-slope porch roof a couple summers back - looked fine at first, but after one brutal July, the edges started curling up. Sun just cooked the adhesive. Ended up replacing the whole section anyway. Might buy you a season, but I wouldn’t trust it long-term, especially in hot climates.

I get where you’re coming from, but I’ve actually had better luck with the tapes - though I’m up in the Northeast, so maybe the milder summers help. Used a butyl-based flashing tape on a dormer joint three years ago, and it’s still holding tight. I wonder if the type of tape or prep makes a difference? I cleaned the aluminum with acetone and roughed it up a bit before applying. Not saying it’s a forever fix, but for spots where a full redo isn’t practical, it’s saved me some hassle. Curious if anyone’s tried the newer UV-resistant tapes - they’re supposed to handle heat better, but I haven’t tested them in real-world conditions yet.

- Tapes can work short-term, but I’ve seen a lot of failures after a couple freeze-thaw cycles, especially on north-facing slopes.
- Prep definitely matters, but even with good cleaning, adhesion drops off over time - UV and temp swings are rough on most tapes.
- I’ve checked out a few UV-resistant types on inspections, but after two years, some were already peeling at the edges.
- For anything structural or where leaks could cause hidden damage, I still lean toward a proper flashing replacement, even if it’s a pain.
- Quick fixes are tempting, but they can mask bigger issues down the line... seen it too many times.

I’ve noticed the same thing with tape - looks fine at first, then a couple of seasons later it’s curling or just gone. We did a patch job on my uncle’s garage last year with one of those “extreme weather” tapes, but after a brutal winter, it was already letting water in. I get the appeal of a quick fix, especially when you’re short on time or budget, but it’s tough to trust it for anything long-term.

Has anyone tried a hybrid approach, like using tape as a temporary seal until you can replace the flashing properly? Wondering if that actually buys you any real time, or if it just adds another layer to remove later.