Good point about the metal shifting—did you happen to notice if the flashing was fastened properly underneath? Sometimes the screws or nails loosen up over time, especially with temperature swings. Had a similar issue on a property last year; sealant looked perfect, but turns out the flashing itself had lifted just enough to let water creep in. Might be worth checking if it's still snug against the surface or if there's any play when you press on it...
Had a similar thing happen on a job last summer. At first glance, the flashing and sealant seemed solid, but when we pressed down, it flexed just enough to let water seep underneath. Turns out the nails had backed out slightly due to constant expansion and contraction from temperature shifts. Instead of just resealing, we ended up pulling the flashing off, checking underneath, and then refastening with screws instead of nails. Screws hold better long-term because they don't loosen as easily with temperature swings.
I'd suggest pressing firmly along the flashing to see if there's any give or bounce. If there is, it's probably worth pulling it back to check the fasteners. Might seem like extra work now, but it'll save you headaches down the road...
Had something similar happen on a roof we worked on last fall. At first, everything looked tight and sealed, but after a heavy rain, the homeowner called us back saying water was still getting in. We were scratching our heads because visually it seemed fine. But when we got up there and started pressing around, sure enough, there was just enough flex to let moisture sneak underneath.
Turns out whoever installed it before us had used nails too, and they'd loosened up over time. We ended up pulling the flashing completely off, checking underneath (thankfully no major damage yet), and then refastening with screws like you mentioned. Honestly, I was skeptical at first—figured nails had been standard for years, so why change? But after seeing how much more secure screws felt, I'm convinced.
Definitely agree it's worth the extra effort upfront. Better to spend an afternoon now than deal with callbacks later... Learned that one the hard way myself.
Had a similar issue at one of our properties last year. Maintenance swore the flashing was fine, but tenants kept reporting leaks after storms. I was skeptical too—figured tenants were exaggerating—but when we finally pulled it apart, same story: nails had loosened just enough to let water in. Switched to screws and haven't had a callback since. Sometimes the old ways aren't always best, I guess...
Switching to screws can definitely help, but I'd caution against dismissing nails entirely. Properly installed roofing nails, especially ring-shank types, can hold up remarkably well if they're driven correctly and into solid substrate. I've seen screws overtightened or stripped out, causing their own set of headaches down the line. Sometimes it's less about the fastener type and more about installation quality and regular inspections...just something to keep in mind before completely writing off traditional methods.
