Window leaking again... need tips on reliable caulk or sealant

Those hybrids are popping up everywhere now, right? I’ve actually tried a couple, mostly out of curiosity (and because the marketing on those tubes is always promising miracles). Sashco’s Lexel was one I used around an old double-hung that just wouldn’t stop leaking. It went on way easier than straight silicone and was paintable, but man, it took forever to fully cure in our damp spring weather. It’s definitely stickier, too—had to use mineral spirits to clean up my hands.

I still trust pure silicone for anything that’s going to get hammered by sun and rain, though. Like you mentioned, nothing else seems to flex with the wood year after year. The only thing I’d add is: don’t skimp on the brand. Cheap stuff can shrink or pull away after one season.

The soapy finger trick is a lifesaver. I used to end up with caulk all over my jeans until someone showed me that... now it’s just the occasional smudge on the dog.

I still trust pure silicone for anything that’s going to get hammered by sun and rain, though. Like you mentioned, nothing else seems to flex with the wood year after year.

Totally get where you’re coming from with that. I tried one of those hybrid caulks last fall (can’t remember the brand, but it had “advanced” in the name—like they all do now). It was supposed to be the best of both worlds: paintable like acrylic, flexible like silicone. Went on easy enough, but when winter hit, I noticed a tiny crack right where the old wood trim meets the brick. Not a huge deal, but it definitely didn’t hold up quite as well as I’d hoped.

Pure silicone is a pain to work with sometimes (I always end up with at least one ruined rag), but I’ll admit, it’s tough to beat for longevity. We’ve got a south-facing window that just bakes in the afternoon sun, and after three years, the silicone bead is still holding tight. The only downside is you can’t paint over it, which annoys me every time I repaint the trim.

Funny thing about cleanup—I thought I was being clever by using baby wipes to get caulk off my hands once. Didn’t work at all. Now I keep a little jar of mineral spirits in the garage just for these projects. And yeah, the soapy finger trick is gold... except my dog thinks it’s an invitation to lick my hands while I’m working.

One thing I’ve learned: don’t trust any caulk that costs less than a decent sandwich. The cheap tubes always seem to dry out or shrink back, especially if you live somewhere humid like we do. Sometimes spending a couple extra bucks saves a lot of headaches down the line.

Curious if anyone’s found a hybrid that actually holds up over time? I keep hoping someone will crack the code on something that’s paintable and lasts more than a season or two.

I’m with you on the frustration with hybrids. I tried one of those “paintable + flexible” caulks on our porch trim last year, and it looked great at first… but by spring, it was already pulling away in spots. Maybe it’s the wild temperature swings here (Midwest), but I’ve never had a hybrid last more than two seasons. The only thing that’s survived our sun and storms is pure silicone, even if it means living with that weird shiny bead around the windows.

The paintability thing is such a pain, though. I’ve tried those “siliconeized” acrylics, but they just don’t flex enough once winter hits. Every time I repaint, I wish someone would invent a caulk you can actually paint and trust for more than a year.

And yeah, cheap caulk is a total false economy. I bought a bargain tube once, and it was already half-cured inside before I even got it home. Lesson learned.

Anyone else notice some of the “30 year” labeled stuff barely lasts three? Feels like wishful thinking on the packaging...

I’m not totally convinced pure silicone’s always the best for exterior wood, even if it does hold up to the weather. I’ve run into adhesion issues on painted trim—sometimes it peels right off after a couple freeze-thaw cycles. The hybrids are hit or miss, but I’ve had decent luck with polyurethane sealants. They’re not as easy to tool and take forever to cure, but they bond like crazy and flex well in wild temps. Downside: paintability is still a pain, but at least they don’t crack or pull away as fast in my experience. Those “30 year” claims always make me laugh... maybe in a lab somewhere, but not on my 1950s windows.

Funny, I’ve had the same thing happen with silicone on painted wood—looked great at first, then a year later it’s dangling like a loose shoelace. Polyurethane’s been my go-to for the last couple windows, even though the cure time drives me nuts. Ever tried those newer “advanced polymer” caulks? I keep seeing them at the store, but I’m not sure if they’re just marketing hype or actually worth switching.

- Totally get the frustration with silicone—mine peeled off after one winter.
- Tried polyurethane, but yeah, waiting days for it to cure is a pain.
- Looked into those “advanced polymer” caulks too. Reviews seem mixed... some swear by them, others say they’re just pricier silicone.
- If you try one, let us know. Honestly, you’re not alone—keeping windows sealed is way harder than I thought it’d be.

That’s a common headache, honestly. I’ve seen silicone fail pretty fast in colder climates, especially if there’s any movement in the window framing or the prep work wasn’t spot-on. Polyurethane does stick better and has decent flexibility, but yeah, the cure time can really drag things out—especially if you’re dealing with unpredictable weather.

Those advanced polymer caulks are kind of a mixed bag. Some brands hold up really well, but they’re not all created equal. The price jump isn’t always justified unless you’re dealing with tricky substrates or need extra UV resistance. I’ve had decent luck with them on older wood frames where nothing else seemed to last.

One thing folks overlook is surface prep. Even the best caulk won’t bond right if there’s old residue, dust, or moisture. I usually run a bead of backer rod in wider gaps, too—it helps the sealant flex and last longer.

Frustrating as it is, sometimes it takes a couple tries to find what works for your specific setup. Hang in there—it’s not just you.

I keep seeing silicone get a bad rap in these threads, but I wonder if it’s always the material or sometimes just the application. I know you mentioned,

“I’ve seen silicone fail pretty fast in colder climates, especially if there’s any movement in the window framing or the prep work wasn’t spot-on.”

Polyurethane is definitely tougher and I get why people like it, but the cure time drives me nuts. I had one window where it took almost a week to fully set because the weather wouldn’t cooperate. That said, once it’s cured, it’s basically bulletproof. But if you’re in a spot with unpredictable rain or cold snaps, waiting that long with an open seam isn’t ideal.

As for those “advanced polymer” caulks, I’m still on the fence. Tried one on a tricky spot where two different siding materials meet—looked promising at first, but after two winters, it started pulling away at the edges. Maybe it was user error, or maybe just not compatible with one of the surfaces.

Totally agree about surface prep—no shortcut there. But sometimes I wonder if we’re all overthinking it a bit. My neighbor swears by old-school glazing putty on his wood sashes, and his windows are tight as a drum. Makes me wonder if some of these modern sealants are more marketing than magic.

Anyone else feel like there’s a bit of trial and error no matter what you pick? I’d love to find something that’s truly set-and-forget, but I haven’t landed on it yet.

I hear you on the trial and error thing—it feels like every window I tackle is a new experiment. I used one of those “forever flexible” silicones last fall, and it’s holding up, but the stuff is messy and you’ve gotta be patient getting a smooth bead. My buddy swears by polyurethane, but I just can’t deal with the long cure time, especially when the weather’s all over the place. Honestly, sometimes I think the prep and making sure everything’s bone dry matters more than the tube you pick. Haven’t found a true set-and-forget yet either... just less hassle, not no hassle.

Totally get what you mean about the prep—if there’s a shortcut for making sure those sills are actually dry, I haven’t found it. I swear, I spend more time with a hairdryer and paper towels than I do with the caulk gun. And yeah, that “forever flexible” stuff is like wrestling with sticky toothpaste. My lines end up looking like a toddler drew them half the time.

Polyurethane is supposed to be the gold standard, right? But man, waiting days for it to cure when rain’s always threatening... not worth the stress in my book. I tried it once in early spring, and of course, we got a freak cold snap. Ended up re-doing everything because it never set right. Lesson learned: patience is a virtue I don’t have when water’s dripping down my wall.

Lately, I’ve been experimenting with those hybrid caulks—sort of silicone-plus-something-else formulas. They claim to be paintable and flexible and quick-curing, but honestly, they’re only marginally less hassle. The main win for me has been using painter’s tape to mask off both sides of the bead before squeezing out any goop. Peel the tape as soon as you smooth it out and you get a pretty clean line... unless you forget to pull the tape while it’s wet (ask me how I know).

Has anyone here actually found a sealant that doesn’t start peeling or cracking after one winter? Or am I doomed to touch-ups every year until I move somewhere with no seasons?