Planning to replace windows myself - what should I remember?

Good points on sealing around the frames - I learned that one the hard way. A few quick things I'd add from my own DIY window swap:

- Measure twice...then measure again. Seriously, nothing worse than realizing your new window is half an inch off.
- Don't underestimate cleanup. Old caulk and insulation bits get everywhere.
- If you're doing upstairs windows, rope in a buddy. Balancing a window solo on a ladder isn't exactly fun (ask me how I know...).

Good luck with the project!

"Measure twice...then measure again. Seriously, nothing worse than realizing your new window is half an inch off."

Couldn't agree more. I'd also stress checking the window opening for squareness - if it's out of square even slightly, you'll be fighting alignment issues all day. Trust me, been there...

Yeah, measuring's important, but honestly I'd worry less about perfect squareness and more about leaving yourself a bit of wiggle room. Shims and caulk can hide a multitude of sins...ask me how I know.

"Shims and caulk can hide a multitude of sins...ask me how I know."

Haha, yeah, this hits home. I've seen plenty of DIY window installs that ended up looking great because someone knew how to finesse the details. Honestly, you're spot on about leaving some wiggle room - it's way easier to shim a slightly loose window into place than it is to fight one that's too tight.

One thing I'd add from experience is to double-check your rough openings before ordering windows. Manufacturers usually list recommended rough opening sizes, and they're there for a reason. If your opening is too tight, even shims won't save you from frustration (or worse, having to reorder). But if you leave yourself a bit of extra space, you've got room to adjust for out-of-square frames or slight measurement errors.

Also, don't underestimate the value of flashing tape and proper sealing techniques. Caulk is great for finishing touches, but good flashing and sealing around the window frame will save you headaches down the road - especially if you live somewhere with harsh weather. I've seen too many cases where water infiltration caused hidden damage behind trim and drywall because someone skipped that step.

And hey, don't stress too much about perfection. Windows are rarely perfectly square - even in new construction - and most people won't notice minor imperfections once the trim's up and everything's painted. As long as you're careful with sealing and waterproofing, you'll be fine.

Good luck with the project - sounds like you've got a pretty realistic approach already figured out.

Haha, totally agree about flashing tape - it's a lifesaver. I've fixed way too many windows where someone skipped that step and ended up with moldy drywall down the line. Also, don't skimp on insulation around the frame. Spray foam (the low-expansion kind) works wonders for sealing gaps and keeping drafts out. Learned that one the hard way after a chilly winter...

Flashing tape's definitely important, but honestly, spray foam isn't always my go-to. I've seen it expand more than expected - even the low-expansion stuff - and warp frames slightly. Usually prefer backer rod with a quality caulk for tighter control and less risk of headaches later...

Good point about the spray foam - I've had a similar experience. Last summer, I helped my brother-in-law replace a few windows at his place, and we went with spray foam because it seemed quick and easy. Even though we used the low-expansion stuff, one of the frames ended up slightly bowed. It wasn't super noticeable visually, but opening and closing that window was never quite as smooth as the others. We ended up having to trim back some foam and re-shim it... kind of defeated the purpose of saving time.

Backer rod and caulk definitely give you more control, especially if you're particular about getting things just right. Have you found certain brands or types of caulk work better for windows? I've mostly stuck with silicone-based stuff myself, but I've heard good things about polyurethane sealants too.

Also curious - do you usually install flashing tape around all four sides or just the top and sides? I've seen people skip the bottom edge to allow any moisture that does get in to drain out, but I'm not totally convinced that's always necessary. Seems like opinions vary a lot on that one.

Anyway, sounds like you've got a solid plan going already. Window replacement can be intimidating at first, but once you've done one or two, it's pretty satisfying seeing everything sealed up tight and looking sharp. Good luck with your project!

Interesting to hear your experience with spray foam - I ran into a similar issue myself. A couple years back, I replaced the windows in our sunroom and figured I'd save some hassle by using the low-expansion foam. Well, it expanded more than I expected (or maybe I was just too generous with it), and one of the windows ended up binding slightly when opening. Had to spend an afternoon carefully cutting away excess foam and redoing the shims - definitely not the shortcut I'd hoped for.

As for caulk, I've mostly stuck with silicone too, but last year I tried a polyurethane sealant on our garage windows after a friend recommended it. It's held up really well so far - seems tougher and more flexible through temperature swings than silicone. Might be worth experimenting with if you're looking for longevity.

Regarding flashing tape, I'm in the "skip-the-bottom" camp myself. When we did our kitchen windows, I left that bottom edge open to let any trapped moisture escape. Haven't had any issues yet... but like you said, opinions definitely vary on that one.

Ran into similar foam trouble myself - seems like "low-expansion" is a loose term sometimes, huh? Curious about your polyurethane caulk experience though... did you find it messy to work with compared to silicone? I tried it once around an exterior door, and cleanup was a pain. Also, skipping bottom flashing tape makes sense, but did you slope the sill at all for drainage? I've always wondered if that's enough insurance against water buildup.

I dunno, skipping flashing tape - even at the bottom - always feels a bit risky to me. I get the logic behind sloping the sill, but water has a sneaky way of finding its way in. Last summer, I spent a weekend redoing a window that leaked because the previous owner trusted "gravity drainage"... wasn't fun. Cleanup-wise, silicone drives me nuts too, but at least it peels off easier once dry. Polyurethane caulk seems to weld itself permanently onto my hands and everything else nearby.

"Polyurethane caulk seems to weld itself permanently onto my hands and everything else nearby."

Haha, you're not kidding - polyurethane caulk is basically industrial-strength superglue disguised as sealant. I've had shirts permanently retired because of that stuff. Totally agree on the flashing tape too; gravity drainage sounds nice in theory, but water doesn't always follow the rules. Learned that lesson after a storm left me scrambling with towels at 2 a.m. Better safe than soggy...

Yeah, polyurethane caulk is relentless - had to learn the hard way myself. Another thing I'd add is don't underestimate how long it'll actually take. You think you'll knock out a window or two in an afternoon, but then you find rot or uneven framing and suddenly it's a weekend project. Also, double-check your measurements before ordering windows... nothing worse than realizing you're off by half an inch after delivery. Been there, done that, unfortunately.

I get what you're saying about the timing... but honestly, isn't it better to just budget extra time from the start rather than assume it'll be quick? I'm planning my first window replacement soon, and I'm already assuming I'll find some hidden mess underneath. Also, about measurements - wouldn't it be safer to have someone experienced double-check them instead of relying only on your own measurements? Seems like a small hassle compared to dealing with returns or reorders...

Fair point about budgeting extra time, but honestly, sometimes diving right in without overthinking it works out fine too. When I replaced mine, I measured myself twice (okay, maybe three times...) and it ended up spot-on. Sure, expert double-checking sounds safe, but it's not rocket science - just measure carefully and trust yourself a bit. Worst-case scenario, you learn something new and have a good story for later, right?

Yeah, measuring carefully usually does the trick, but honestly, the bigger headache for me was dealing with unexpected rot once the old windows came out. You checked your frames for any hidden surprises yet?

Yeah, hidden rot can definitely throw a wrench in things. Good call bringing that up. I've seen plenty of DIY window replacements where folks measured perfectly, ordered the windows, and then got blindsided by rotted sills or framing once the old units came out. If you haven't checked yet, I'd suggest poking around with a screwdriver or awl - especially at the corners and bottom edges - to see if there's any soft wood lurking beneath the surface. Better to find out now than mid-installation when you're already committed.

If you do find rot, don't panic - it's usually fixable. Just cut out the damaged sections and replace them with fresh lumber treated for moisture resistance. And make sure to seal everything up tight afterward with flashing tape or a good-quality caulk to prevent future issues. It's an extra step, but trust me, you'll thank yourself later when your new windows stay solid and leak-free for years.

"Better to find out now than mid-installation when you're already committed."

Yeah, totally agree with this. Another thing worth mentioning is to double-check your rough opening measurements after removing the old window. I've seen plenty of DIYers measure just the window itself without accounting for shims or insulation space. Leaving yourself about a half-inch gap on each side makes installation smoother and helps with insulation later. Learned that one the hard way a few years back...

Good point about leaving space for shims - seen too many windows jammed tight into openings. Had a client once who measured perfectly but forgot to check if the framing was square. Ended up having to redo half the job...lesson learned.

"Had a client once who measured perfectly but forgot to check if the framing was square."

Yeah, squareness is easy to overlook. When I replaced my kitchen window last summer, I triple-checked measurements and thought I was golden. But when I dry-fit the window, one corner stuck out awkwardly - turns out the framing had settled unevenly over time. Ended up spending half a day shimming and adjusting. Curious now, do older houses typically have more issues with framing being out of square, or is it just random luck?

Older homes can definitely shift more over time, but honestly, I've seen plenty of newer builds with framing that's off too. Sometimes it's rushed construction or just sloppy workmanship... age isn't always the culprit.