Title: Building Base Structures—What If You Had to Start Over?
Cellulose definitely gets a lot of points for being green, but I get where you’re coming from on the paranoia front. I had a similar experience with ancient fiberglass—basically, it was like opening up a pillowcase full of dust. After that, it’s hard to trust anything that isn’t locked in place.
I actually redid the insulation in my own place about five years ago. Decided to try dense-pack cellulose in the interior walls, mostly for sound control between rooms. At first, I was skeptical about settling too. The installer really emphasized the importance of proper density—apparently, if it’s packed tight enough (they used something like 3.5 lbs per cubic foot), settling is minimal. I checked behind a switch plate about two years later and didn’t see any voids, but I can’t say I’ve cut open a wall to be totally sure.
One thing I noticed: rooms insulated with cellulose felt warmer in winter, but also less “echoey.” It’s subtle, but there’s a kind of muffled quiet that’s hard to get with other materials. Haven’t had any cold spots yet, but I did make sure they used netting to hold everything in place during install. Kind of overkill, maybe, but after living with crumbling batts, I wasn’t taking chances.
If I were starting from scratch again, I’d probably still lean cellulose for interior walls—mainly for acoustics—but might consider mineral wool for exterior walls just for that “set it and forget it” peace of mind. Mineral wool is pricier, though, and not as eco-friendly, so there’s always a trade-off.
It’s funny how much past headaches with insulation shape what you trust going forward. The green angle is great, but sometimes you just want to never think about it again... especially after you’ve spent hours vacuuming up fiberglass fluff from every possible crevice.
It’s funny how much past headaches with insulation shape what you trust going forward.
That hits home. After tearing out old pink fiberglass in my attic—itchy for days—I swore I’d never use it again. I haven’t tried mineral wool yet, but the “set it and forget it” part is tempting. Did you notice any difference in humidity or moisture issues after switching to cellulose? That’s the one thing I still wonder about, especially in older houses.
Did you notice any difference in humidity or moisture issues after switching to cellulose?
Honestly, that's where I lean a bit different. Cellulose is great for air sealing, but in older homes with questionable roof ventilation, it can get tricky. I've seen cellulose hold onto moisture longer than fiberglass, especially if there's a minor leak or just high humidity. Not saying it's a dealbreaker, but I wouldn't call it "set it and forget it" unless you've got your attic airflow dialed in. For me, mineral wool's moisture resistance is underrated—costs more up front, sure, but I've had fewer callbacks about musty smells or damp spots. Just my two cents from crawling around too many attics...
Yeah, totally hear you on the moisture thing. Cellulose is awesome for air sealing, but if your attic ventilation is sketchy, it can be a bit of a gamble. I’ve seen a couple older houses where cellulose got a little clumpy after a humid summer—nothing catastrophic, but enough to notice. Mineral wool is pricier, but man, it shrugs off dampness like nothing else. If I could do it over, I’d probably pay more attention to venting first, then pick insulation... live and learn, right?
Totally get where you’re coming from—venting’s one of those things you don’t think about until you see what happens without it. I’ve had to rip out clumped cellulose before, and it’s not fun. Honestly, you’re not alone... everyone’s got that “if I could do it over” moment. Good call on mineral wool, though. It’s pricey, but sometimes peace of mind is worth it.
