Quick fix or redo: dealing with damaged aluminum flashing

I get why folks like EPDM - it’s tough stuff, and recycled is a nice bonus. But I’ve always wondered about long-term compatibility with aluminum flashing, especially if you’re dealing with older roofs. Ever had any issues with the membrane shrinking or pulling away at the seams after a couple seasons? I tried a plant-based underlayment once (wasn’t cheap), but it handled freeze/thaw cycles surprisingly well and didn’t have that wrestling match factor. Curious if anyone’s seen EPDM degrade faster in full sun or if that’s just my paranoia talking...

Quick fix or redo: dealing with damaged aluminum flashing

I’ve run into this exact combo - EPDM with old aluminum flashing - on a handful of jobs, and it’s definitely not always as straightforward as the sales reps make it sound. The thing with EPDM is, yeah, it’s tough, but it’s also got a mind of its own when it comes to movement. I’ve seen it shrink back from seams, especially where it meets metal flashing that’s been around a while. Usually takes a couple years, but you’ll notice the edges start to curl or pull away, especially on the south-facing slopes where the sun just bakes everything.

One job sticks out: 1960s ranch, low slope, original aluminum flashing. We put down new EPDM, and by year three, there was a solid half-inch gap at the edge in a few spots. Turns out, the old aluminum had oxidized just enough that the adhesive didn’t really bond long-term. We ended up having to clean everything back to bare metal and use a primer before re-adhering the membrane. Not a fun redo, but it held up after that.

As for full sun, I wouldn’t call it paranoia. EPDM does fine in most climates, but in places with brutal sun and big temp swings (I’m in the Midwest), I’ve seen it get chalky and brittle faster than advertised. The recycled stuff seems a bit more prone to that, but maybe that’s just the batches I’ve worked with. I’ve never had it totally fail, but it definitely loses that nice flexible feel after a few seasons.

Plant-based underlayment is interesting - I tried it once on a porch roof. It was way easier to handle, but the price tag made me wince. No shrinkage issues, though, and it didn’t get stiff in the cold, which was a nice surprise.

If you’re dealing with old flashing, I’d say it’s worth the extra prep - clean, prime, maybe even swap out the worst sections. Otherwise, you’re probably looking at patch jobs down the line. And yeah, EPDM’s tough, but it’s not invincible, especially when the sun’s got nothing better to do than cook your roof all summer.

- Totally agree about the prep work - skipping that step always comes back to bite you.
- Had a similar issue with EPDM pulling back on my garage roof, especially after a couple of wild summers.
- Cleaning and priming the old aluminum made a world of difference for me too, though I was tempted to just patch and go at first.
- Sun exposure really does a number on these materials... Midwest heat is no joke.
- Honestly, your approach sounds spot-on. Sometimes the extra effort upfront saves way more hassle (and cash) later.
- Haven’t tried plant-based underlayment yet, but your feedback’s got me curious - might give it a shot next time if I can stomach the price.

Sun exposure really does a number on these materials... Midwest heat is no joke.

No kidding - the sun just cooks everything up there. Ever notice how the flashing gets all chalky after a couple seasons? I’ve tried patching in a hurry before, but it never holds for long. Did you end up replacing the whole section, or just spot-fix? Curious if anyone’s had luck with those “miracle” tapes they sell at the big box stores... I’m always skeptical, but sometimes desperate times call for desperate measures.

And about the plant-based underlayment - does it actually breathe better, or is it just marketing hype? The price tag’s a bit wild, but if it keeps things cooler, maybe it’s worth a shot.

- Midwest sun is brutal - I've seen flashing go chalky and brittle in under three years, especially on south-facing spots.
- Tried a few of those “miracle” tapes during emergency repairs. They held up through one season but peeled off after the first real freeze/thaw cycle.
- Usually end up replacing whole sections when it gets bad. Spot fixes just don’t last for me, especially with all the expansion and contraction.
- Looked into plant-based underlayment last year. The breathability claims seem half legit - did notice less condensation in attic spaces, but honestly, the price jump is tough to justify unless you’re dealing with constant moisture issues.

Usually end up replacing whole sections when it gets bad. Spot fixes just don’t last for me, especially with all the expansion and contraction.

I get where you’re coming from, but I’ve actually had decent luck with spot repairs - at least as a short-term solution. Used a high-quality butyl tape on a north-facing dormer last fall, and it’s still holding up after a pretty wild winter. Maybe it’s just luck or the angle, but I’m not ready to write off spot fixes entirely. Full replacement is pricey, especially if you’re new to all this.

“Full replacement is pricey, especially if you’re new to all this.”

That’s exactly why I keep trying to get away with spot repairs. My wallet just laughs at the idea of swapping out whole sections every couple years. I’ve got a 1970s ranch with a low slope, and the aluminum flashing around my chimney started looking rough last spring. I used some butyl tape and a dab of roof cement, figuring it’d buy me a season or two. Still holding, knock on wood.

I get the argument about expansion and contraction, especially in places with wild temperature swings. Here in Michigan, we go from freezing rain to 90 degrees in a few months, so nothing really lasts forever. But honestly, I’d rather patch things up for $20 now and see how it goes than drop hundreds on new flashing when the rest of the roof is still hanging in there.

I do keep an eye on it after storms. If water starts sneaking in or the tape peels up, then yeah - time to bite the bullet. But for me, spot fixes are like duct tape for the house: not perfect, but they keep things together until I can budget for a real fix.

Maybe it’s just my luck (or stubbornness), but I’m not convinced full replacement is always necessary right out of the gate. Sometimes “good enough for now” is good enough... especially when you’re paying for groceries and gas on top of home repairs.

Man, I totally get the “good enough for now” mindset. I’ve patched flashing with whatever I had on hand - one time I even used an old license plate (don’t judge). Ever had your patch job survive a Michigan winter? That’s like winning the lottery around here.

License plate as flashing - now that’s creative. I’ve seen all sorts of “temporary” fixes during inspections, and honestly, some hold up better than expected. But Michigan winters are brutal on metal, especially if there’s any gap or rust. Those quick patches might keep water out for a season, but over time you risk hidden rot or ice damming. If you notice any leaks or staining inside, it’s probably time to swap out the patch for proper flashing. Sometimes the peace of mind is worth the extra effort... even if the patch has survived a few blizzards.

I’ve actually used a flattened coffee can as a patch once - looked ridiculous but it kept the water out for a whole winter. Still, I get nervous about what’s happening underneath when I can’t see it. Ever had a patch job that looked fine from the outside, but turned into a bigger headache later? I’m always torn between “if it ain’t broke, don’t fix it” and just biting the bullet for a full redo.

Ever had a patch job that looked fine from the outside, but turned into a bigger headache later?

Oh man, story of my life. I once used a piece of scrap aluminum and some duct tape to fix a flashing issue behind my chimney - looked solid, but come spring, the inside wall was bubbling like a bad science project. My rule now: if I can patch it and actually see what’s going on underneath, I’ll risk it. If it’s hidden, I usually end up ripping it out and doing it right...eventually. The “if it ain’t broke” thing is great until you start smelling mold.

Patch jobs are tempting, but I learned the hard way that flashing is one spot you don’t want to skimp on. I tried a quick fix with caulk and some leftover metal around a vent pipe - looked fine until a heavy rain, then water found its way in and trashed the drywall. If there’s any sign of damage or hidden rot, I’d just bite the bullet and pull it all out. It’s a pain, but chasing leaks behind walls is way worse. If you can see everything and it’s dry, maybe a patch works...but I wouldn’t gamble on it twice.

Had a tenant who thought duct tape was the answer to everything, including flashing. Spoiler: it’s not waterproof, and neither is wishful thinking. I get the urge to just patch and move on - no one wants to rip up half their roof for a tiny leak - but honestly, every time I’ve tried to shortcut flashing repairs, it’s come back to bite me. Sometimes literally...mold is no joke. If there’s even a whiff of rot or soft spots, I yank it all out and do it right. Otherwise, you’re just setting up future-you for a headache (and probably some angry phone calls).

Had a seller once who tried to “fix” a flashing leak with a combo of duct tape and what looked like some kind of craft glue. I only found it because the attic smelled weird, and when I poked around, the insulation was damp and there was this little patchwork masterpiece above the chimney. The thing is, from the outside, you’d never know - shingles looked fine, no obvious gaps. But inside? Water had been sneaking in for months. Mold was already starting behind the drywall.

I get why people want to just slap something on and hope for the best - especially if it’s just a drip or two - but every time I’ve seen that, it’s ended up costing way more in the long run. Once you’ve got rot or mold, you’re not just replacing flashing anymore...it’s framing, insulation, sometimes even electrical if it’s bad enough.

I do wonder if there’s ever a “good enough” quick fix for flashing, though. Maybe some of those newer tapes or sealants? But honestly, I haven’t seen one yet that holds up through a couple seasons of freeze/thaw.

That “craft glue and duct tape” combo sounds like something my uncle would’ve tried after a few beers. I’ve seen those miracle tapes advertised, but in my experience, nothing really stands up to a proper metal-to-masonry seal - especially once winter hits and everything expands and contracts. I did try one of those butyl rubber tapes on a vent boot last year as a stopgap, and it held for maybe six months before the leak came back. At that point, I just bit the bullet and replaced the flashing. Honestly, if you’re already seeing moisture or mold, it’s past the point of quick fixes anyway.

I’ve seen a lot of those “miracle” tapes fail once the temps swing, too. Curious - did you notice any corrosion or pitting on the aluminum itself when you pulled the old flashing? Sometimes that’s what really does it in, especially if moisture’s been trapped for a while.

Curious - did you notice any corrosion or pitting on the aluminum itself when you pulled the old flashing?

Yeah, that’s usually the first thing I check. If there’s any white powdery stuff or little pits, that’s a sign moisture’s been hanging around way too long. I’ve seen “miracle” tapes just trap water underneath, especially after a freeze-thaw cycle. Sometimes the tape looks fine but the metal underneath is toast. Honestly, once the aluminum’s pitted, patch jobs are just buying time. Full redo’s the only thing that really lasts in my experience.

Title: Quick fix or redo: dealing with damaged aluminum flashing

Yeah, I’ve run into that same issue with the so-called “miracle” tapes. They look like they’re doing the job, but once you peel them back after a season or two, it’s a mess underneath. I had a spot behind my chimney where the tape actually made things worse - trapped moisture, and then the aluminum started to pit and flake. At first glance, everything looked sealed up tight, but the metal was basically crumbling underneath.

I get why people want to patch instead of replace - sometimes you just don’t have the time or budget for a full redo. But honestly, every time I’ve tried to stretch out old flashing with patches or sealants, it’s just kicked the can down the road. Especially in places that see a lot of freeze-thaw cycles (I’m in Michigan), those little pits turn into big problems fast. Water gets in, freezes, expands... next thing you know, you’ve got leaks inside.

One thing I’ll say is if the corrosion is just on the surface and hasn’t eaten through, sometimes you can clean it up and get another year or two out of it. But if you’re seeing actual holes or deep pitting, it’s not worth messing around. Full replacement is a pain but way less hassle than dealing with water damage later.

I’ve also noticed that certain spots - like valleys or anywhere debris collects - seem to go bad faster. Maybe it’s just my roof design, but those are always the first places I check now. If you’re already pulling up flashing and see white powder or rough spots, probably best to just bite the bullet and redo it right.

Not saying patches never work, but in my experience they’re more of a temporary band-aid than a real fix.

I’ve had mixed luck with patching too, especially with those tapes that promise the world. Used one on a dormer joint last fall - looked fine through the winter, but by spring, I noticed the paint bubbling on the ceiling below. Pulled up the tape and, yep, moisture had gotten trapped and the aluminum was all chalky underneath. I guess it did slow down the leak for a bit, but ended up being more work in the long run.

I get the temptation to just slap on a patch, especially when you’re staring down a busy weekend and the weather’s turning. But every time I’ve tried to stretch old flashing, it’s just come back to bite me. Maybe if you’re in a dry climate, you can get away with it, but here in upstate NY, the freeze-thaw just chews up anything less than a full replacement.

I will say, I’ve managed to squeeze an extra year out of flashing by sanding down surface corrosion and hitting it with a good sealant, but once you see holes or flaking, it’s game over. Water always finds a way.

But every time I’ve tried to stretch old flashing, it’s just come back to bite me.

That’s been my experience too. Tried patching a section over my porch with one of those “miracle” tapes - looked solid for a few months, then the first big thaw hit and water started dripping right onto my coat rack. I think the tape just hid the problem long enough for it to get worse underneath. At this point, if I see chalky aluminum or any pinholes, I just bite the bullet and replace the whole piece. It’s a pain, but chasing leaks is worse.