I want to decrease sound transmision through some internal walls that are currently just drywalled. What is best way to achieve?

Cut holes and fill the void between studs with cellulose insulation.

Add acoustical panels to sheetrock?

Remove the door from your daughter's bedroom and ban the boyfriend from the house.

If that doesn't solve the problem, or you've got a media room that's too loud, you can try rockwool insulation in the walls and double the sheetrock. If you want to go a bit further you can buy rubber sound isolation clips: https://www.soundaway.com/soundproofing-isolation-clips-s/32.htm

There is also a product called quietrock which is two layers of Sheetrock with a rubbery layer in between.

For even more sound isolation, you can frame a room within a room. (Easier with 10' ceilings.)

Basically adding mass reduces the amplitude of any vibrations in solids and isolation makes the sound jump from solid to air and back losing energy with each jump.

Good luck.

I was thinking of ways to do it without removing existing sheetrock

May look into some of the expanding foam. I had a guy that worked for me said he hired a crew that came in and drilled 3 small holes in each cavity and injected foam into the cavity. He said it was relatively low cost.

He has a daughter with some auditory issues (same as my son) and he said it was night and day difference.

We are building now and having my sons room spray foamed on all 4 walls and a solid wood door.

Can also do a Quietrock overlay.

Think Mass and Decoupling.

Thanks for ideas. I was thinking of methods with existing drywall. Foam options I guess.

davido said:

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Can also do a Quietrock overlay.

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This


I've installed it in a few applications

One was to block out tv noise from a shared master/living room tv wall

One was to block out snoring between bedrooms

Owner was very pleased with the results both times


It's a pain to work with because it's very heavy and won't snap compared to regular drywall and is usually around $50-$60 a sheet but I wouldn't hesitate to use it again if blocking sound is your objective

Sprayed in cellulose would only be two holes in each stud bay.

Great advice all. Thanks.

If it just a certain room, such as a media room, you can add acoustic panels. They are basically fabric over acoustic foam. You may also be able to add one to a hallway to absorb sound. Pretty cheap and easy addition if you can make the look work. I had a coworker put them in their home office, and the sound difference on video meetings was huge. Also, add curtains to your loud rooms to help absorb some sound.

https://www.atsacoustics.com/item--ATS-Acoustic-Panel-24-x-36-x-2--1046.html?d=GPGEN01&kw=1046-E&gclid=EAIaIQobChMIxbyptJWF7gIVVQutBh2pGg_ZEAQYAiABEgI_TPD_BwE