I hear you on the UV tape, but I’ve actually had decent luck with the 3M all-weather stuff—at least on shaded north slopes. It’s definitely not a fix-all, but sometimes it buys a season or two if you’re in a pinch. That said, I agree step flashing and a good polyurethane sealant under the flashing is way more reliable long-term. I’ve seen too many folks slather caulk over exposed seams and end up with a sticky mess by August. Texas sun just doesn’t play fair...
I’ve seen too many folks slather caulk over exposed seams and end up with a sticky mess by August. Texas sun just doesn’t play fair...
That’s the thing—caulk just doesn’t hold up in our heat, and I’ve seen it fail even faster on metal roofs. I get the appeal of the 3M tape for a quick patch, but I’ve run into issues when it’s used as a “set it and forget it” fix. UV breaks it down, especially on south or west exposures. If you’re already up there, I’d say take the extra time to tuck the flashing right and use the sealant only as backup, not the main line of defense. Learned that the hard way on a job last summer—looked fine in spring, but by fall, water was sneaking in around the fan collar.
- Totally agree—Texas heat just eats up caulk and tape, especially on those west-facing slopes.
- I’ve had better luck with butyl tape under the flashing, but even that’s not foolproof.
- Flashing is key. If it’s not tucked right, water finds a way in no matter what sealant you use.
- Curious if anyone’s tried those newer UV-resistant sealants? I’m skeptical, but maybe they hold up better...
I’ve tried a couple of those UV-resistant sealants over the past few summers—Sashco Lexel and OSI Quad come to mind. They definitely last longer than standard silicone, but honestly, nothing’s bulletproof in direct Texas sun. The real difference for me has been making sure the flashing is lapped right and tucked under the shingles, not just relying on the sealant. I still use butyl tape as a backup, but I don’t trust it alone. If you’re dealing with west-facing slopes, maybe consider doubling up on the flashing or using a metal diverter above the fan. It’s extra work up front, but I’ve seen fewer callbacks that way.
I’m with you on not trusting sealant alone, especially in Texas heat. I used Quad Max last year and it held up better than silicone, but after one brutal summer, I still saw some cracking around the edges. My roof’s a low-slope asphalt shingle, and I learned the hard way that if the flashing isn’t tucked just right, water finds a way in no matter what you smear on top. I haven’t tried a diverter yet, but doubling up the flashing made a noticeable difference for me—just wish I’d done it from the start instead of chasing leaks later.