That’s a tough spot—leaks above the kitchen are no joke. I’ve seen a few cases like your neighbor’s, especially in areas with heavy rain and debris. Those deck-mounted seals look slick on paper and are definitely less work up front, but in practice, I just don’t trust them as much over time, especially if you’re dealing with needles and standing water. Flashing is a pain to install right, but it’s the tried-and-true method for a reason.
On metal roofs, it gets even trickier. Some of the newer rubberized seals claim to be compatible, and manufacturers love to tout their “lifetime” ratings, but reality is... that’s in perfect conditions. Once you throw in temperature swings, constant moisture, and all that organic gunk, things can start to break down faster than you’d think.
I get why folks want a shortcut—it’s tempting. But if you’re in a wet climate, I’d stick with flashing every time. It might mean more work now, but finding water spots on your ceiling in March is way worse.
I see this debate come up a lot, especially as more folks are adding solar. Honestly, I’ve yet to see a deck-mounted seal system that holds up as well as traditional flashing over a decade or more—especially in climates where you get freeze/thaw cycles, wind-driven rain, or a lot of debris buildup. The rubber gaskets and butyl pads look great when they’re new, but the reality is, UV exposure, temperature swings, and organic matter like pine needles or moss will wear them down. I’ve inspected a handful of roofs where those seals started to fail after just a few years, and it’s always the same story: water finds its way in, and you don’t notice until there’s staining or, worse, mold inside.
Flashing, on the other hand, is a pain to install perfectly—no argument there. But if it’s done right, with proper overlap and sealant where needed, it’s about as close to “set it and forget it” as you can get in roofing. Especially on metal roofs, where expansion and contraction are constant, flashing just has more forgiveness. I’ve seen 20-year-old flashings that still look solid, while the synthetic seals nearby were crumbling.
That said, I get why the deck-mount kits are popular. Less labor, less mess, and they’re marketed as “roof-friendly.” But in my experience, most leaks I’ve traced back to solar installs have been from shortcuts—usually someone trusting a sealant or gasket to do what good old-fashioned flashing would’ve handled better. If you’re in a dry, mild climate and the roof is simple, maybe you get away with it. But anywhere else, it’s not worth the risk.
One thing I’d add: whatever method you use, make sure whoever’s installing it actually follows the manufacturer’s instructions to the letter. I’ve seen jobs where even flashing failed because someone skipped a step or used the wrong fasteners. And double-check that your installer’s warranty covers roof penetrations—not all of them do, and you don’t want to be stuck with a leak and no coverage.
Bottom line, shortcuts on the roof rarely pay off long term. Flashing’s not glamorous, but it works.
That’s super helpful, thanks for sharing all that detail. I’ve been stressing about this exact thing since our roof is only a few years old and I really don’t want to mess it up with a solar install. The part you mentioned—
—is honestly my nightmare scenario. Did you ever see a deck-mount system that actually held up, or is it just not worth the gamble? I’m leaning toward flashing now, even if it’s more work.“water finds its way in, and you don’t notice until there’s staining or, worse, mold inside”
I’ve been in and out of a lot of attics over the years, and I’ll tell you—water’s sneakier than most folks realize. I get why you’re sweating it, especially with a newer roof. I’ve seen a handful of deck-mount systems that looked fine for the first couple years, but then, almost like clockwork, there’d be some staining on the plywood or a bit of musty smell. Sometimes it’s just a tiny drip that only shows up after a big storm or when snow melts fast. By the time you spot it inside, the damage has usually been cooking for a while.
One job sticks out: asphalt shingle roof, maybe 5 years old, homeowner went with one of those “no-flash” deck-mount setups because the installer swore by them. Three years later, I was there for an unrelated inspection and noticed some weird discoloration near the rafters. Traced it back to one of the solar mounts. The sealant had started to crack—a combo of sun and freeze-thaw cycles, I think. Not catastrophic, but enough to need some repairs and a chunk of shingles replaced. The kicker was, the warranty didn’t cover water intrusion from “improper installation,” so they were on the hook.
I’m not saying every deck-mount is doomed, but in my experience, flashing is just more forgiving. Even if it’s more work upfront or costs a bit extra, it’s like paying for peace of mind. Especially if you’ve got a roof you want to last another 20+ years. Sealants and gaskets are fine for a while, but once they go, they go fast.
If you’re in a spot that gets wild weather—lots of rain or freeze-thaw—flashing is almost always worth the hassle. I know installers love to say “these new systems are bulletproof,” but roofs have a way of humbling even the best sales pitch.
That’s a solid reminder about water sneaking in when you least expect it. I actually had a similar worry after reading a bunch of reviews—everyone swears by the new deck-mounts, but my gut kept saying, “Why risk it?” Especially after seeing this:
“Sealants and gaskets are fine for a while, but once they go, they go fast.”
When I bought my place last year, the inspector said the same thing about shortcuts. I went with traditional flashing for the peace of mind—even though it took longer and cost more. If you’re planning to stick around for a while, it’s one less thing to stress over every storm season.
