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.
