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Sound prevention interior rooms of house

How can you prevent sound from penetrating from room to room in a 20 year old 2 story house built with 2x4 framing and drywall partitions. There is no insulation in the interior walls with the exception of the master bedroom suite? Should interior walls be insulated? Is there a standard building code that applies? Primary problem is between the upstairs bedrooms. Thanks for helping...

Timothy Miller
Re: Sound prevention interior rooms of house

Howdy, no code i'm aware of about insulation in interior walls. You could have cellulose blown into the cavities to help deaden the noise or open one wall up and install rock wool insulation for acoustic control.

Re: Sound prevention interior rooms of house

A couple of things could help.
Put FG insulation in the wall. I'm not familier with blown-in insulation for noise reduction, but it should help and may be be easier to install.
Make sure electric boxes don't share the same stud cavity. Stuff plenty of insulation around them and caulk them around the edges. The idea is to block a direct path for sound.
If air returns use a stud cavity and it shares the wall with another bedroom, there is another source for sound transmission. That one is hard to insulate, but if the drywall is remove on one side extra mass such as a layer of drywall or an inch of rigid fg insulation could be glued to the one face without affecting the airflow much.
Caulk the bottom plate or drywall with flexible caulk.
Another possible path for sound is over the wall, but with existing construction that would be hard to deal with. With new you could stuff the space with insulation or even have it continue 16" or 24" on each side.
I probably missed a thing or two. Get the kids headphones or play loud music when you're amorous. Either way, they know what's going on.

Re: Sound prevention interior rooms of house

I have tried using fiberglass for sound insulation and it just doesn't work. Spray foam, especially open cell works great. It will be quite expensive to install foam solely for sound proofing, apart from normal thermal insulation. Dense packed cellulose will work well also. Again you are faced with a costly project if you are only doing soundproofing and not exterior wall insulation.

Sound is transmitted through the air and through vibration through framing materials. Cellulose and foam does a great job for cutting down air borne sound, but nothing for sound carried through materials. There is a drywall made specifically for soundproofing. It is expensive though. There are other methods of spacing sheetrock from the framing materials to reduce that kind of sound transmission.

You should be able to find details by Googling sound proofing.

Re: Sound prevention interior rooms of house

Please don't dense pack anything. No foams (open or closed cell) either. You'll wind up coupling the two sides of the wall and things could get worse. Lightweight application of fiberglass is as good as it gets. Anyone doubting this should read the several hundreds of pages of data produced by the National Research Council of Canada.

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