How Long Does It Really Take To Insulate A House?

Drafts love those weird corners and old trim, and no amount of fiberglass seems to stop them.

Yeah, that’s the thing with these old places - fiberglass just doesn’t cut it for all the nooks and crannies. I’ve seen people throw batt after batt in the walls and still end up with cold spots. Air sealing is where it’s at. I’m with you on stuffing every gap you can find, though sometimes I swear the house is inventing new ones while I work.

As for how long it takes to insulate a house, honestly, there’s no straight answer. If you’re talking about a full gut job where you can see all the studs, maybe a week or two if you’re moving fast and don’t hit any weird surprises. But with old houses? You’ll probably spend half your time just opening things up and figuring out what’s going on behind the walls. I once found an entire wasp nest (long dead, thankfully) inside a knee wall - took me an extra day just to clean that out before I could even start insulating.

Cellulose is messy as hell but does a way better job filling odd spaces than fiberglass. Just be ready for dust everywhere. And yeah, it’s worth it when you can finally walk around in socks in January without freezing your toes off.

If you’re doing it yourself, plan for more time than you think - especially if you want to do it right and not just slap stuff in there. And don’t forget about rim joists and attic hatches... those are classic draft magnets nobody thinks about until they’re sitting in a cold spot wondering why their insulation “isn’t working.”

Anyway, patience pays off. Once you get through all the layers (and random junk), it really does make a difference.

Honestly, I get the love for cellulose, but I’ve had better luck with spray foam in those weird spots. It’s pricier and takes some practice, but it seals up drafts way tighter than anything else I’ve tried. The mess is way less too - just gotta be careful not to overdo it or you’ll end up scraping off hardened blobs later. I know some folks worry about off-gassing, but for small areas like rim joists or attic hatches, it’s hard to beat. Just my two cents from a few too many winter projects...

I get where you’re coming from on spray foam, especially for those awkward nooks and crannies. But honestly, I’ve seen too many DIY jobs where folks end up with way more foam than they bargained for - sometimes it’s like a marshmallow explosion behind the drywall. You mentioned,

“just gotta be careful not to overdo it or you’ll end up scraping off hardened blobs later.”

Cellulose isn’t perfect either, but it’s a lot more forgiving if you need to go back and fix something. Plus, it’s easier to get a uniform R-value across big areas, especially in older homes with weird framing. Spray foam does seal drafts well, no doubt, but for whole-house jobs, I’d still lean cellulose or even dense-pack fiberglass just for the cost and flexibility. Maybe it’s just me, but I like being able to tweak things if I find a missed spot down the line... foam is pretty unforgiving once it sets.

Honestly, I’m still haunted by the time I tried spray foam in my attic and ended up with what looked like a mutant popcorn ceiling. The stuff just kept expanding... and expanding. I get the appeal for sealing drafts, but yeah, once it’s in there, it’s not like you can just “undo” it if you miss a spot or overdo it. I’m way too indecisive for that kind of commitment.

Cellulose seems more my speed - if I mess up, I can just add more or move it around without feeling like I’ve ruined everything. Plus, with an old house (mine’s got studs that look like they were put in by someone with a grudge against straight lines), the flexibility is a lifesaver. I do wonder, though, does cellulose settle over time and leave gaps? Or is that just one of those insulation myths? Either way, I’d rather vacuum up some dust than chisel out foam blobs.

I hear you on the spray foam - tried it once in a crawlspace and it turned into this weird, lumpy mess. Cellulose is way more forgiving, especially in older homes where nothing is square. It does settle a bit over time, but honestly, I’ve found it’s usually not enough to cause real gaps unless it was underfilled to start with. I’d take a little settling over the “popcorn ceiling” look any day.