How tricky is it to make a window bigger?

Yeah, I’ve run into that too—think you’re just swapping out a window and suddenly you’re tracing mystery wires or finding insulation that’s basically dust. Good call on swapping the header, especially in an old house. I’m always curious, did you notice any drafts after opening things up? Sometimes making a window bigger can mess with the air sealing, especially if the original framing wasn’t tight. Did you have to do much to get it airtight again?

Yeah, air sealing gets tricky fast when you’re opening up old walls. I’ve found that even if the original window *looked* tight, once you start pulling things apart, you realize how much air was sneaking through all those weird gaps and old insulation. When I made a window opening bigger in my 1960s ranch, I had to go back and really pay attention around the new framing—spray foam in the big gaps, but also making sure the sill was flashed right and the housewrap overlapped properly. The original framing was pretty sloppy, honestly, and I think the new window ended up being tighter than what was there before.

One thing I ran into: after expanding the opening, the old sheathing didn’t always line up perfectly with the new framing, so I had to patch in some plywood and tape the seams to keep everything continuous. If you skip that step, you’ll definitely feel drafts later. And yeah, don’t trust the old insulation—mine was basically gray lint at that point.

It’s a pain, but if you take the time to detail the air barrier and insulate right up to the frame, you can actually improve things compared to what was there before. Just takes more time than you’d expect...

That’s exactly what I ran into with my ‘70s split-level—nothing lined up quite right and there were all these weird voids behind the trim. Did you have trouble matching the exterior siding around the new opening? That part took me forever.

Matching siding is a pain, especially with older homes where nothing’s standard. I remember thinking I’d just pop in a new window and patch it up, but the original siding was discontinued—had to hunt for something close and ended up repainting the whole side. You’re not alone; those little surprises are just part of the territory with these houses. But honestly, once it’s done, you barely notice the imperfections.

Yeah, matching siding is one of those things you don’t really think about until you’re standing in the yard with a new window and a weird patch job staring at you. I totally get it—my place is from the late 60s, and every exterior project turns into a scavenger hunt for materials that don’t exist anymore. Last time I tried to make a window opening bigger for more light (and to cut down on how much I crank the heat lamp in winter), I figured it’d be a weekend job. Nope. Took me three weeks just to find siding that was even close, and then it still looked off until I painted the whole wall.

Honestly, though, I’m all for making windows bigger—especially if you can upgrade to something energy efficient while you’re at it. The extra daylight makes a huge difference, and if you go with good low-E glass, you’ll notice your heating and cooling bills drop a bit. That said, getting the opening right is a whole thing. Sometimes there’s weird framing or old insulation that just falls apart as soon as you touch it. And if your house has any kind of oddball sheathing or vapor barrier setup (mine had tar paper and some mystery fiberboard), you might have to improvise.

One thing I’d say: don’t stress too much about the siding not matching perfectly. Once you repaint or let it weather for a season, nobody but you will ever notice. And honestly, half the houses on my block have little patches here and there—kind of gives them character. If you’re worried about drafts after making the opening bigger, spend the extra few bucks for some good spray foam insulation around the new frame. Makes a world of difference.

Funny how these projects always sound simple until you’re knee-deep in them... but hey, at least we get stories out of it, right?

I get the “let it weather” approach, but I’d push back a bit—if you’re in a spot with wild temperature swings or heavy rain, mismatched siding can mean hidden leaks or cold spots. I’d actually prioritize getting the flashing and vapor barrier right, even if the patch looks weird for a while. Aesthetics are fixable, but water damage is a pain long-term.

Can’t argue with you there—water always finds a way, and it never ends well. I learned that the hard way a few years back. Tried to patch in some siding after making a bathroom window bigger, figured I’d circle back and do the flashing “properly” once the weather warmed up. Well, surprise... by spring, I had a soft spot in the drywall and a musty smell. Turns out, the mismatched patch let just enough water sneak in during those freeze-thaw cycles.

Now, whenever I mess with windows or siding, I don’t care how ugly it looks for a bit. I get that flashing tucked right and make sure there’s a solid vapor barrier before I even think about cosmetic stuff. Siding can wait. Water damage just keeps on giving—mold, warped studs, all sorts of headaches.

Long story short, if you’re upsizing a window, spend the extra time on the waterproofing details, even if the patch job sticks out like a sore thumb for a while. You’ll thank yourself later.

Tried to patch in some siding after making a bathroom window bigger, figured I’d circle back and do the flashing “properly” once the weather warmed up. Well, surprise...

Couldn’t agree more about not cutting corners on the waterproofing. I learned the hard way too—on a kitchen window, no less. Thought I could just “caulk it up good” until I had time for proper flashing. Nope. Ended up with warped trim and a weird stain on the ceiling below.

One thing I’d add: check your sheathing for any sneaky gaps after you cut out for the bigger window. Even a tiny crack can let water in over time, especially if you get wind-driven rain. And don’t trust that housewrap to be perfect after you slice it—get some good flashing tape and overlap everything like your life depends on it.

Ugly patches are temporary, but rot sticks around forever...

Making a window bigger always sounds straightforward in theory, but in practice it’s one of those “simple” projects that can spiral if you’re not careful. I’ve been there—cutting out the rough opening, thinking I could just patch up the siding and revisit the details later. Weather (and life) never seems to cooperate.

You nailed it about waterproofing. It’s tempting to think caulk will save the day, especially when you’re racing against rain clouds or winter temps. But water always finds its way through any shortcuts. I’ve seen some creative “temporary” fixes over the years—plastic sheeting, duct tape, you name it—but they all end up biting you eventually.

One trick I picked up after a few close calls: before you even start cutting for the new size, map out exactly how you’re going to tie your new flashing into the existing housewrap and siding. That might mean peeling back a little more siding than you’d like, but it really pays off. And yeah, flashing tape is your best friend here—layer it so water always sheds down and out, never gets trapped behind.

I’d also say don’t stress too much if your patch job looks ugly for a few weeks while things settle or you wait for better weather. As long as everything’s sealed up and protected from water, looks are secondary for now. Permanent rot is way harder to fix than temporary eyesores.

And about those sneaky gaps in sheathing—can’t agree more there. Even a pencil-width crack can lead to trouble down the road. I usually run a bead of sealant or slap on some extra tape before closing things up, just for peace of mind.

Bottom line: take your time with these steps, even if it means living with an awkward patch for a bit longer. It’ll save you headaches (and money) in the long run.

I get the focus on waterproofing, but I’m not totally convinced that “ugly for a few weeks” is always the best route. For me, living with a rough patch drives me nuts—especially in winter when drafts sneak in. A few things I did differently:

- Measured and prepped all materials (flashing, trim, even paint) before demo to minimize open time.
- Used rigid foam board as a temp filler if weather turned bad—way better than plastic sheeting.
- Prioritized finishing the interior side fast so I wasn’t staring at insulation for days.

“As long as everything’s sealed up and protected from water, looks are secondary for now.”