That’s pretty much my experience too—polyurethane is a pain to work with, but it just doesn’t budge. I tried one of those newer “easy clean” hybrid caulks last year, and it started peeling by spring on the sunny side. Out of curiosity, did you use backer rod or just fill the gap straight? I’ve had better luck with backer rod, but sometimes it’s hard to fit in tight spots.
I get why people love backer rod, but honestly, I’ve skipped it plenty of times and never had a leak—at least not yet. Maybe I’m just lucky or maybe my gaps aren’t as big as I think. The one thing I do notice is that if you overpack caulk in a small spot, it seems to crack more. I’m not totally sold on the idea that backer rod is always necessary, especially with those tiny old window frames. Maybe it’s overkill unless you’ve got a monster gap.
I get what you’re saying about backer rod maybe being a bit much for those skinny gaps. I’ve skipped it a couple times too, especially on my 1940s windows where the gaps are barely wide enough for a putty knife. Haven’t had any major issues so far, but I do wonder if it’s just a matter of time or if those tiny cracks just don’t let much water in. The whole “overpacked caulk cracking” thing rings true for me—if I try to fill a deep spot with just caulk, it always seems to shrink and split after a season or two.
I guess the main thing I’ve noticed is that backer rod really helps keep the caulk from sinking in over time, especially in bigger joints. But with the little ones, sometimes it feels like you’re just jamming foam in for no good reason. I’m more likely to use it around doors or on exterior siding seams than windows, honestly.
Curious if you’ve ever had to redo any of the spots you skipped the rod on? Or maybe you live somewhere drier than me (I’m in the Midwest, so rain finds every weakness eventually). I’ve also wondered if certain caulk types handle movement better—like, does silicone crack less than latex if you overfill a joint? Never really tested that side by side.
I’m always torn between doing things “by the book” and just going with what’s worked in the past. Sometimes it feels like the manufacturers are just trying to sell you more stuff, but then again, maybe there’s a reason the pros do it that way. Has anyone actually seen a leak that was clearly because they skipped the backer rod? I’d love to hear if that’s a real risk or just theory.
I’m always torn between doing things “by the book” and just going with what’s worked in the past.
Totally get this. I’ve skipped backer rod plenty on tiny gaps and honestly, haven’t seen any leaks that I could blame on that. Midwest weather’s rough, but as long as the caulk’s good and the gap isn’t huge, it seems to hold up. I do notice silicone flexes better than latex, but it’s messier to work with. Sometimes I think the “by the book” way is overkill for old windows, but maybe I’ll eat my words one day.
- Same here, I’ve skipped the backer rod too unless it’s a big gap—never had a problem.
- Silicone definitely holds up better for me, but yeah, it’s sticky and unforgiving.
- For older windows, sometimes I just do what’s practical. If it’s lasted 40 years already, I figure I’m not making it worse...
- That said, I did have one spot where water snuck in behind the trim because I got lazy with caulk—lesson learned.
Ha, I’ve definitely gotten a little too relaxed with caulk before and paid for it after the next storm. It’s always the one spot you think “eh, that’ll be fine” that ends up leaking, right? I agree about skipping the backer rod unless the gap’s big enough to swallow a pencil—otherwise, it just feels like overkill.
Silicone is awesome for keeping water out, but man, I swear it gets on everything. I end up with more on my hands than the window. For my old wood windows, I mostly just patch up the obvious gaps and hope for the best. They’ve survived decades of Michigan winters, so I figure a little extra caulk can’t hurt.
One thing I did try last year was running a bead along the top edge of the trim, not just the sides. That seemed to help a lot with wind-driven rain. Not sure if it’s the “official” way, but hey, whatever works.
Running a bead along the top edge is actually pretty smart—wind-driven rain loves to sneak in there. I’d just say, before you caulk, make sure everything’s dry and clean or it won’t stick right. For silicone mess, blue painter’s tape on both sides of the joint keeps things tidy, then just pull it off before the caulk skins over. I’ve seen folks skip that and end up with a smeary mess that’s way harder to clean up than just taping for two minutes.
Totally agree about taping—learned that lesson the hard way when I redid my basement windows. Thought I could just “be careful” and skip it...ended up with silicone everywhere, including my jeans. Also, don’t forget to tool the bead with a wet finger or spoon—makes a big difference on looks and seal.
Yeah, taping is one of those things I tried to skip too, thinking I’d just be neat about it. Ended up with a mess and had to scrape dried caulk off the trim for days. One thing I’ve wondered—anyone ever try those foam backer rods for bigger gaps? I used them around my old wood windows and it seemed to help, but I’m not sure if it’s overkill. Also, I’ve found painter’s tape peels cleaner than masking tape if you’re doing the edges. Just my two cents.
I tried skipping the tape once too and yeah, ended up regretting it—took way longer to clean up than just taping in the first place. For the backer rods, I used them on a couple of bigger gaps around my basement windows. They worked pretty well, actually. Just shoved them in, then caulked over. Didn’t seem like overkill to me, especially if you want to save on caulk and get a tighter seal. Painter’s tape is definitely less hassle than masking tape... learned that one the hard way too.