Swapped from spray foam to rock wool for my last build

I used spray foam insulation for years until a builder friend in Denver told me about rock wool. It cost me about $400 more for a 2000 sq ft house, but the sound dampening between floors is way better. Has anyone else made the switch and noticed a difference in noise?

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claire_ramirez1h ago

Holy crap yeah the noise thing is no joke. I helped a buddy reno his townhouse a couple years back and we used rock wool between the shared wall with his neighbor. That guy has a full drum kit and two little kids. My buddy says he barely hears anything now unless the drums are going hard. Spray foam is good for air sealing and can help with some sound but rock wool is a whole different beast for dampening vibration. Another thing I never see people talk about is how much easier it is to work with. That spray foam gets everywhere and sticks to everything. Rock wool you can cut with a bread knife and it just stays in place. No overspray cleanup, no nasty chemical smell lingering for days. Plus if you ever have to pull some out for a rewire or plumbing fix later its not a nightmare. Spray foam turns into concrete basically. So yeah the extra $400 is worth it for the peace and quiet alone.