I ran into a ton of weird stuff when I opened up my 1930s place—random fire blocking, old newspapers, even a bird’s nest. Blown-in worked okay in the spots we could reach, but there were definitely gaps where the insulation just couldn’t get around all the obstructions. As for moisture, I was worried too, but I made sure to patch up any exterior cracks first and haven’t had issues (yet). Soundproofing improved a bit, but honestly, temperature difference was way more noticeable. If you’re super concerned about hidden surprises or wiring, opening the walls is safer but yeah... it’s a huge mess.
How Long Does It Really Take To Insulate A House?
Those old houses are like time capsules, right? I’ve seen everything from antique bottles to what I think was a petrified squirrel. Honestly, blown-in insulation’s always a bit of a gamble for weird layouts—sometimes it’s like trying to fill a sandwich with peanut butter without opening the bread. If you want every nook covered, yeah, opening the walls is best, but that’s a whole different level of chaos (and dust). I usually tell folks: if you’re after perfect coverage and need to check wiring, brace for mess and double the time you think it’ll take. But patching cracks first is clutch—nice move there.
sometimes it’s like trying to fill a sandwich with peanut butter without opening the bread
That’s spot on. I’ve done a few of these and honestly, if you’re just doing blown-in from the attic or exterior, you can knock it out in a day or two. But once you start opening walls, all bets are off—found a bird’s nest in one once. Patchwork takes longer than folks think, too.
- Couldn’t agree more about the patchwork—always takes longer than you plan for, especially if you’re juggling multiple units.
- I’ve had crews run into random stuff in old walls too... one time it was a stash of old newspapers from the ‘50s.
- Curious—has anyone tried dense-pack cellulose vs. spray foam? I’ve heard mixed things about cost and mess, but haven’t pulled the trigger yet.
Dense-pack cellulose is definitely less expensive up front, but it can get messy—especially if you’re dealing with older lath and plaster. I’ve found spray foam gives you better air sealing, but the cost adds up fast, especially on multiple units. One thing to watch: cellulose settles a bit over time, so you might not get the same R-value long-term. Both have their place, but I lean toward spray foam for anything with a lot of weird voids or irregular framing.
