Back in 2017, I got called out to check a flat roof on a strip mall after a freak hailstorm—this was out in the high desert, bone dry most of the year. The owner told me he hadn’t done any kind of thermal scan in almost a decade, just the usual walk-around after big winds or heavy rain, and honestly, his roof looked pretty decent at first glance. The membrane was still flexible, seams looked tight, no obvious ponding.
But when I started poking around the flashing near the HVAC units, I found a soft spot. Pulled back the membrane and, sure enough, there was some moisture that had been creeping in for who knows how long. No visible leaks inside the building yet, but it wouldn’t have taken much longer before something showed up. That’s the thing—sometimes those hidden spots can go years without making themselves known, especially if you’re not seeing water stains or bubbles.
I get why folks in drier climates don’t feel the need to go overboard with inspections. Most of the time, you’re fine just keeping an eye on things and fixing issues as they pop up. But after seeing how sneaky moisture can be, I do think it’s worth doing a more thorough check every few years, especially around penetrations and edges. Doesn’t always have to be thermal imaging—just someone who knows what to look for and isn’t afraid to poke around a bit.
Funny thing is, I’ve seen roofs in wetter climates last just as long as those out here, as long as the maintenance is on point. In my experience, it’s less about how often you inspect and more about how closely you pay attention when you do. If something feels off—even just a little squishiness underfoot—it’s worth digging deeper. That’s saved me and my clients more than once from a much bigger headache down the line.
Funny thing is, I’ve seen roofs in wetter climates last just as long as those out here, as long as the maintenance is on point.
That “little squishiness underfoot” you mentioned is exactly what worries me—by the time you feel it, there’s usually been moisture for a while. Out of curiosity, did you end up recommending a full membrane replacement or just localized repairs? I’ve seen both approaches, but sometimes patching just delays the inevitable if the insulation’s already compromised.
That’s the dilemma, right? I’ve had a couple roofs where we tried patching first, but if the insulation’s already soaked, it just turns into a mold trap. Did you ever have luck drying out the insulation, or was it a total tear-out every time?
Did you ever have luck drying out the insulation, or was it a total tear-out every time?
I’ve actually seen it go both ways, but I’d say it depends a lot on how fast you catch it. There was this one job last fall—flat roof, old built-up system—where we found a small leak early on. We pulled back a section and the insulation was damp but not totally soaked. Used fans and dehumidifiers for a few days and it dried out pretty well, no musty smell or anything. But honestly, that felt like dumb luck... Most times, especially if the water’s been sitting for a while, it’s game over for the insulation. Mold sets in quick, and then you’re just chasing problems if you try to save it.
If it’s fiberglass board, sometimes you can salvage a bit more than with polyiso, which just turns into a soggy sponge. Still, I wouldn’t bet on drying being a real fix unless you’re super early. It’s always a judgement call—sometimes the boss will try to save costs with patching and drying, but in my experience, full tear-out saves headaches down the line.
I get where you’re coming from, but I’ve actually had decent luck drying out insulation—at least with smaller leaks and when we catch them early. We had a section over a tenant’s office that got wet after a storm, and with some quick action (pulled up the membrane, ran fans and dehumidifiers), it dried out fine. No lingering odor or complaints months later. I do agree, though, if it’s been sitting or if it’s polyiso, it’s usually not worth the risk. Still, I wouldn’t say it’s always a lost cause. Sometimes you can save a lot on labor and materials if you act fast.