I’ve seen the same thing with metal roofs right on the coast—folks pay a premium for “coastal” coatings, but give it a few years and you’ll still spot rust creeping in around fasteners or where the panels overlap. I always tell people, if you’re not up for rinsing things off now and then, salt will win every time. Honestly, even the so-called marine sealants aren’t foolproof... I’ve had to redo a few jobs where the only real fix was swapping in new panels. Maintenance is just part of the deal, like it or not.
Maintenance is just part of the deal, like it or not.
That’s definitely been my experience too. I’ve noticed the rust seems to start at the fasteners way before anywhere else, even with stainless screws. Have you found any particular brands or types of fasteners that actually hold up better in salty air, or is it just inevitable? I’m starting to wonder if the overlap design itself is part of the problem, trapping moisture and salt.
I’ve noticed the rust seems to start at the fasteners way before anywhere else, even with stainless screws.
- That’s a super common issue, especially near the coast. Even “stainless” isn’t always as tough as it sounds—some grades (like 304) just don’t cut it in salty air. I’ve seen better luck with 316 stainless, but honestly, nothing’s totally immune.
- Overlap design can definitely make things worse. Trapped moisture + salt = rust city. I see it all the time on siding and roof panels where water just sits in those seams.
- Some folks swear by coated fasteners (like ceramic or epoxy), but those coatings can chip off during install if you’re not careful.
- Regular rinsing helps, but who really wants to be out there hosing down their house every week?
You’re not alone—maintenance is just part of living by the ocean. If it helps, I’ve seen people get a few extra years out of their hardware by using a dab of marine grease or anti-seize on the threads before installing. Not perfect, but slows things down a bit.
I’ve wondered the same thing about fasteners—seems like no matter what you use, they’re always the first to go. I tried switching to 316 stainless on my shed roof and it did help, but after a couple years, even those started showing little rust spots. Anyone else tried using rubber washers or gaskets under the heads? I heard that can help keep moisture out of the seams, but I’m not sure how much difference it really makes in salty air. The idea of using marine grease is interesting... does it attract dirt or mess with the seal at all?
I hear you on the 316 stainless—I've swapped out plenty of corroded fasteners over the years, thinking each time I'd finally solved it. Even the so-called "marine grade" stuff doesn't seem to hold up forever when you're right near the ocean. Those little rust spots always creep in eventually.
Rubber washers do help a bit, at least in my experience, but they're not a silver bullet. The salt air just finds its way in, especially if there's any flex or movement in the roof panels. I’ve seen some folks try doubling up with sealant and washers, but then you run into issues with things getting brittle or the sealant breaking down over time.
As for marine grease, I've tried it on some exterior hinges and hardware. It definitely kept rust away longer, but yeah, it does attract dirt and grime. I’d be hesitant to use it under fastener heads on a roof, just because I’d worry about compromising the seal or making a mess if you ever need to replace something later.
Honestly, it's a constant battle. You’re not alone in fighting that losing war against rust.
