How Long Does It Really Take To Insulate A House?

The crew was in and out in two days, and the only real evidence was a few patched spots on the walls

That lines up with what I’ve seen - blow-in cellulose is usually a 1-3 day job for most homes, depending on square footage and access. One thing I’d add: if you’ve got knob-and-tube wiring, some insulation crews will want an electrician to sign off first. That can slow things down a bit. Otherwise, yeah, it’s way less invasive than demoing plaster. The dust from a full rip-out gets everywhere, no matter how careful you are.

The dust from a full rip-out gets everywhere, no matter how careful you are.

I get what you mean about blow-in being “way less invasive than demoing plaster,” but I actually found the patchwork after cellulose a little annoying. The spots never matched my old paint quite right. Demo is messy, but at least you can start fresh, you know?

I hear you on the patching - matching old paint is trickier than people think, especially if the walls have aged or faded over time. But I’d argue that even with demo, you’re still dealing with a ton of finishing work. New drywall isn’t always a magic fix for blending with existing trim or floors, and the waste from all that plaster isn’t great for the landfill either. For me, minimizing material waste and keeping as much of the original structure as possible usually tips the scale toward blow-in. Just wish there was a better solution for those patchy spots...

I get where you’re coming from about keeping the original structure, but honestly, I’ve had some blow-in jobs turn into a bit of a mess too. Maybe it’s just my luck, but I ended up with a bunch of settling and cold spots a year later. Patching is a pain, no doubt, but at least with new drywall you know exactly what’s behind the wall. I guess it’s a trade-off either way... just depends on how much hassle you’re willing to deal with down the road.

I hear you on the blow-in insulation turning into a headache. Had a client once who thought it’d be a quick fix - just poke some holes, fill ‘er up, patch and paint. Fast forward a couple winters, and they were calling me about cold drafts in the corners and weird lumps in the walls. Turns out, some of the old lath and plaster had gaps that let the cellulose settle way more than we expected.

On the flip side, ripping out all the old drywall or plaster is a whole other can of worms. You get to see what’s going on back there (sometimes more than you bargained for - hello, ancient mouse nests), but then you’re dealing with disposal, dust everywhere, and usually some surprises with wiring or plumbing.

Honestly, I lean toward less demo if the structure’s solid and you can air-seal decently. But yeah, it’s always a gamble. Sometimes you win, sometimes you’re patching holes and cursing under your breath... just depends how much chaos you’re willing to invite into your life for that R-value boost.

That’s the thing - sometimes it feels like you’re choosing between two headaches. I’ve always wondered if anyone’s had luck with dense-pack cellulose in old walls, or if settling is just inevitable over time. Does spray foam actually solve that, or does it bring its own set of problems?

Dense-pack cellulose is like that friend who promises to help you move, but then disappears halfway through. It works pretty well at first, but yeah, settling can happen, especially in old, uneven walls. I tried it in my 1920s place - helped a lot with drafts, but after a few years, I could feel cold spots creeping back in. Spray foam’s a whole different animal. It won’t settle, but it can get messy and if you ever want to run new wires or fix something inside the wall, good luck. Plus, if you don’t get the closed-cell stuff installed right, you might end up with weird smells or moisture issues. It’s kind of a pick-your-poison situation, honestly.

I get what you’re saying about dense-pack cellulose settling, but I’ve had a different experience in a couple of flips. If it’s installed right - like, really packed in there - it doesn’t settle much, even in older homes. The trick is making sure whoever’s blowing it in takes their time and hits every cavity.

“Spray foam’s a whole different animal. It won’t settle, but it can get messy and if you ever want to run new wires or fix something inside the wall, good luck.”

That’s spot on. I’ve had to cut through spray foam to fish new wiring and it’s a pain. Sometimes, for old houses where you might need to update stuff later, I lean toward mineral wool batts. Not as airtight as foam, but way easier to work with down the road. Just my two cents - there’s no perfect answer, but there are ways to make each option work better depending on your priorities.

I hear you on the mineral wool - I've used it in my last place and honestly, it was way less hassle than dealing with foam. I’m always watching the budget, so I went with batts and did most of it myself. Took a couple weekends for a small house, but it was doable. Anyone else find cellulose gets everywhere during install? I swear I was vacuuming up dust for weeks... but at least it was cheap and did the job. Curious if anyone’s found a method that’s both affordable and not a total mess?

“I swear I was vacuuming up dust for weeks... but at least it was cheap and did the job.”

That’s the story of cellulose, isn’t it? I did my attic with it last winter - thought I’d sealed everything, but the dust still found its way into every nook. On the plus side, it really did help with drafts in my 1920s place. If you ever try dense-pack cellulose, it’s a bit less messy, but you need the right blower. Still, nothing’s ever truly “clean” with old houses...

- Did blown-in cellulose in my 1915 bungalow last fall - took way longer than I thought.
- Prep was half the battle: moving boxes, sealing gaps, taping vents...
- Actual blowing? Maybe 6 hours for 900 sq ft, but cleanup dragged on for days.
- Dust got everywhere, even with tarps. Old houses just seem to suck it in.
- Worth it for the comfort, but man, I underestimated the mess.

Yeah, the dust is no joke - my 1920s place practically coughed up clouds for a week after I did mine. I hear you on the prep, too. I actually spent more time sealing up weird little gaps than on the insulation itself. Honestly, I thought cellulose would be less messy than fiberglass, but it still found its way into every nook. Still, the difference in winter drafts was huge... just wish I’d invested in better goggles.

Totally get what you mean about the dust - cellulose is sneaky. I’ve done a couple houses and every time, it’s like the stuff multiplies behind your back. But yeah, sealing up gaps is half the battle. At least you noticed a real drop in drafts...makes all the hassle worth it, right? Next time, goggles are non-negotiable.

“cellulose is sneaky. I’ve done a couple houses and every time, it’s like the stuff multiplies behind your back.”

Tell me about it. The first time I used cellulose, I thought I’d prepped enough - nope, that stuff finds its way everywhere. Sealing gaps is key, but honestly, people underestimate how much time cleanup eats up too. Drafts drop, sure, but you lose a day just tracking down stray dust. And yeah, goggles... learned that one the hard way. If you’re not sweating by the end, you probably missed a spot.

“you lose a day just tracking down stray dust. And yeah, goggles... learned that one the hard way.”

That’s the part nobody warns you about - cellulose dust gets *everywhere*. I remember the first time I tried blowing it into an attic, I thought taping up the hatch and laying down some sheets would be enough. Wrong. Couple hours in, looked like I’d crawled through a flour mill. Even found dust in my coffee mug the next morning.

Cleanup always takes longer than I think, but honestly, prep eats up a ton of time too. Taping off electrical boxes, sealing top plates, all those little gaps. I’ve had jobs where insulating took half the day, and the prep and cleanup each took a quarter. If you skip any of that, you’ll pay for it - either in drafts or hours spent vacuuming every nook and cranny.

Funny thing is, I used to think fiberglass batts were worse for mess. At least with those, you can see what you’re dealing with and (usually) keep things contained. Cellulose just floats on air currents and seems to multiply when you turn your back.

One trick I picked up - run a box fan out a window nearby. Helps keep the worst of the dust from settling in the house, though you’ll still be finding little tufts weeks later. And yeah, goggles are non-negotiable. Learned that after a solid hour of rubbing my eyes and regretting every life choice.

It’s worth it for the comfort boost, but “how long does it really take?” depends on how much you want to clean afterward. If it’s someone else’s house, double whatever time estimate you have in your head. If it’s your own place...well, you get to live with the dust for a while.

I get where you’re coming from about cellulose dust, but I’ve actually found the prep and cleanup for blown-in jobs can be streamlined a bit more than you’re describing - at least if you’re methodical. You mentioned,

“prep eats up a ton of time too. Taping off electrical boxes, sealing top plates, all those little gaps.”

I’d also argue that with the right equipment - like a proper respirator and a commercial-grade blower - the process is less messy than it used to be. The rental machines at big box stores are underpowered and tend to clog, which just makes everything take longer and creates more dust clouds.

I still think fiberglass batts are more tedious overall, especially in older houses with weird framing. At least with cellulose, you can fill odd cavities without a ton of custom cutting. But yeah, no matter what, you’ll be finding dust in weird places for weeks... that part never seems to change.

I get where you’re coming from about cellulose dust, but I’ve actually found the prep and cleanup for blown-in jobs can be streamlined a bit more than you’re describing - at least if you’re...

I hear you on the containment setup - painter’s plastic and zip poles definitely help, but man, I still end up tracking dust down the hallway no matter how careful I am. Maybe I’m just not as methodical as I think.

You mentioned commercial-grade blowers making a difference. Have you noticed a big jump in speed or just less clogging? I’ve only ever used the rental ones and yeah, they’re pretty weak. Curious if it’s worth hunting down a better machine for a one-time job or if it’s overkill.

How Long Does It Really Take To Insulate A House?

Painter’s plastic is basically my new wallpaper at this point, but yeah, even with all the prep, it’s like cellulose dust has a personal vendetta against my floors. I swear it finds its way into places I didn’t even know existed - like, how does it end up in my sock drawer when the attic’s two floors up? Some mysteries are just unsolvable.

About those commercial blowers: there’s definitely a difference, but whether it’s worth tracking one down for a single project… eh, I’d say it depends on your pain tolerance for frustration and how much you value your weekend sanity. The rental ones from the big box stores are kind of like trying to inflate a bounce house with a hair dryer - technically possible, but you’ll be there until next Arbor Day. The pro-grade machines move material way faster and don’t clog every five minutes, which means less time standing in a cloud of cellulose questioning your life choices.

That said, if you’re only doing this once and don’t have a buddy in the biz who can loan you gear, renting the basic machine might be fine as long as you’re not in a rush. Just budget extra time for clearing jams and maybe invest in some good tunes. If you’re even remotely tempted to do more than one house (or help out friends/family), then yeah, finding a real machine is totally worth it. Otherwise, just embrace the chaos and plan for an epic cleaning session after.

Also - pro tip - duct tape around your pant legs. Not glamorous, but hey, fewer dust bunnies hitching a ride to the living room.

I get what you’re saying about the rental blowers being slow, but honestly, I didn’t find them *that* bad for a one-off job. Maybe I just got lucky with a newer machine? Took me a full weekend for a 1,600 sq ft house, but I wasn’t racing. The dust, though - yeah, that stuff is relentless. I tried the duct tape trick and still found fluff in my ears days later. Sometimes I wonder if it’s just part of the experience...

I hear you on the dust - no matter what tricks I try, it always finds a way into places I didn’t even know existed. I’ve done a few of these jobs and honestly, the time it takes seems to depend more on prep and cleanup than the actual blowing. Curious, did you notice any difference in energy bills after you finished? I’m always weighing if the DIY hassle is worth it compared to just hiring it out, especially when you factor in your own time.