Temporary patches always seem to turn into long-term headaches for me.
That’s been my experience too, especially on sun-exposed sides. Did you notice if the old flashing was corroded or just the sealant failing? Sometimes it’s just the caulk breaking down, but if you’re seeing mildew or leaks, a full redo’s usually safer. Curious—did you use aluminum again or try something else?
I’ve seen a lot of flashing where the sealant just gave up, especially on the south side where the sun bakes it. Aluminum itself usually holds up unless it’s in contact with pressure-treated wood or gets hit by runoff from copper or steel—then you’ll see pitting or white corrosion. If it’s just the caulk, you can sometimes get away with resealing, but if there’s any sign of water getting behind, I always recommend pulling the old stuff and starting fresh. I’ve had better luck with galvanized steel in some spots, but it’s heavier and a pain to cut. Aluminum’s still fine if you keep it isolated from other metals.
Yeah, that southern exposure really cooks the caulk. I’ve seen some jobs where the flashing looked fine but water still snuck in—usually because the sealant just turned to dust. Galvanized is tougher but man, lugging those sheets up a ladder isn’t my favorite workout. Aluminum’s way easier if you keep it away from anything that’ll corrode it... learned that one the hard way with a copper gutter once.
I ran into the same issue last summer—south-facing flashing just crumbled at the seams. Here’s what worked for me: I scraped out all the old caulk (which basically fell out in chunks), cleaned the aluminum with rubbing alcohol, then used a high-quality polyurethane sealant. I did learn the hard way not to mix metals, too... had some gnarly corrosion where the aluminum touched an old copper downspout. If you’re patching, just double-check for any hidden pinholes or cracks—water finds the tiniest gaps.
Had a similar mess on the north side of my place—flashing was flaking apart, and I didn’t want to shell out for a full replacement. I scraped, cleaned, and used a tube of that polyurethane stuff too, but I went cheap on the caulk once and it peeled after one winter. Lesson learned: don’t skimp there. Also, I used painter’s tape to keep the lines neat, but it left some sticky residue... not sure if that’s just me being impatient. Anyone else have that issue with tape?
