I live in a new construction home where the bedrooms share a hollow wall, which allows too much sound to travel between the rooms. I'm not looking for complete soundproofing solutions like double drywall or rockwool, as those seem too extensive for my needs. I'm curious if less invasive options, like blown-in cellulose insulation, could help reduce noise transmission. Would this just involve cutting a small hole for the hose in the wall? Are there any other practical solutions to lessen the sound without a big overhaul? (By the way, both rooms will have sound machines to help!)
3 Answers
From what I've read, most cavity insulations don't differ much in terms of sound transmission class (STC) ratings. The mass and decoupling are more critical factors. So, I'd suggest going with whatever option is the easiest and most cost-effective. Also, check if there are any air returns or vents in that wall since sound can travel through those really well. Keeping beds pushed against the outer walls can help too!
You could try using mass-loaded vinyl on at least one side of the shared wall, or even both. It's effective and you can disguise it with acoustic foam tiles. Additionally, if you have bookcases, you can place them against the wall to add more mass. Just make sure to cover the entire wall from floor to ceiling!
Have you considered sealing off any air leaks between the rooms? Sometimes the gaps around electrical boxes and behind baseboards can really let sound through. While mass and decoupling are vital, blocking the air paths can also make a difference. You might find some neat tips in this video I linked too!
Thanks for sharing this info! I saw that your resource didn't include cellulose, which I've read might not be as effective. Just to clarify, there aren't any HVAC vents in that wall.