I'm looking to soundproof my basement ceiling to reduce noise from the upstairs, but I have some concerns. I initially considered using faced fiberglass insulation or rockwool, but rockwool is pretty expensive. Plus, I'm not comfortable leaving fiberglass insulation exposed, especially since I want to keep access to the mechanicals in the ceiling without covering it up with drywall. I also worry about having a large area of fiberglass above where my kids play. I have a nice black ceiling, and I'm thinking of wrapping the fiberglass in black plastic to address my concerns. However, I'm worried about moisture accumulation inside the plastic since there shouldn't be much temperature difference between the two levels. Could a lack of airflow make this approach problematic? Any suggestions?
1 Answer
You're right to think about how effective fiberglass will be for sound dampening—it’s not the best option. If you use faced fiberglass, it should stay put fine. You might also want to check out encapsulated fiberglass that’s already wrapped in plastic; it's designed for stuff like this. Here's one I found: [Johns Manville ComfortTherm](https://www.lowes.com/pd/Johns-Manville-ComfortTherm-R-13-40-sq-ft-Encapsulated-Fiberglass-Roll-Insulation-with-with-Sound-Barrier-15-in-W-x-32-ft-L/3033536). But if you're really after soundproofing, consider adding mass like mass loaded vinyl. It can be pricey for a whole ceiling though, so keep that in mind.
I looked for that fiberglass option too but it was out of stock when I checked. Surprisingly, the soundproofing from fiberglass isn't that far off from rockwool, so you might be onto something!
Is mass loaded vinyl effective enough if I mount it between the joists? Would that really help reduce the noise from above?