Noiseproofing Bedroom with Green Glue: Should I do exterior walls and/or ceiling?

Question

I would like to do some experimentation with soundproofing a bedroom using Green Glue, which is a noiseproofing compound intended to be sandwiched between sheets of drywall. The bedroom currently has painted drywall walls. I will be applying the Green Glue to the back of new 5/8" drywall, and screwing the new drywall to the existing drywall walls, creating a drywall and Green Glue sandwich.

My current plan is to at least do two interior walls that are up against noisier/higher traffic areas of the house. I'm wondering if doing those two walls will give me sufficient soundproofing to cut out a large amount of noise, or if I need to extend the soundproofing to the two following sections:

1. Ceiling - There is an attic above the ceiling, so I'm not worried about noise coming from directly above the room. What I am wondering about is sound leaking from other rooms through the attic/ceiling. Is it possible there will be a significant enough amount of sound leakage to where it would be louder than any sound still traveling through the walls or bedroom door (which will be a solid core door)?
2. Exterior Walls - From the research I've done, it looks like there may not be any benefit to soundproofing the exterior walls against sound from outside, unless I'm also investing in replacing the two large windows with soundproof windows. Is this a correct assumption? I'm also wondering if there is a possibility of significant sound leakage through the exterior wall from one of the adjacent rooms.

If it makes a difference, the main types of interior sounds I'm wanting to cut down on are TV, kids play, voices, etc. For exterior sounds, there's the neighbor's barking dog, and traffic.

Answer 1

It depends of how much noise you would like to reduce. if you looking from complete silence, applying sound-proofing sealant to two walls will do nothing but empty your wallet. If you want to reduce it to a level where you can read, write, or just not be bothered by it; then sound proofing two walls and the ceiling will help. The theory of sound proofing is to eliminate or reduce sound vibrations traveling through the walls. This is achieved by creating a air space between the layers of sheetrock where vibrations go to die. When you screw it to the wall, the metal of the screws will act as vibration transmitters and diminishing the effectiveness of the soundproofing glue. You will be better off by glueing it to the old wall.

If you have access to the room where the noise is generated, you can reduce the noise by sound-treating that room with sound absorbing furnishing and diffusing sound traveling by rearranging furniture, etc. A quick search for sound proofing art will bring an array of artsy and decorative items that serve that purpose.

Answer 2

The Green Glue is interesting stuff. But I am cheap and lazy and want some promise of benefit before investing time and labor. My ideas.

1: Hang blankets on walls suspected of transmitting noise.

2: Make noise of usual type and usual sites. Go into bedroom. Is noise reduced when blankets are up?

3: Hang blankets on door. Repeat. I think the hollow body thin modern doors actually amplify noise. Maybe the door is your culprit.

If addressing the walls with free and easy blankets gets the job done, then the Green Glue looks very cool. Or you could stick with the blankets, or purchase comparably thick paintings on velvet to serve. I have seen some excellent velvet paintings of dogs playing poker; you could get a variety of these and then invite your guest up to see the dogs, should circumstances warrant.

If it turns out the sounds are coming thru some other way then you have saved yourself the time and money. You could still get the dogs, though.

Answer 3

Adding green glue and another 5/8" drywall will reduce some noise, if the noise is coming through that wall. However, the noise could also travel in through the ceiling, floor, other walls, or through the screws that are attached in the new drywall if you attach to the studs. The added drywall and green glue may not be an acceptable reduction in sound if the sound is coming from other sources as well.

If you also do the ceiling, it will further improve, but it will not be fully soundproof. Same with the floor.

It really depends on the source of the noise. There are so many variables that it would take someone coming to your place to find the source or some experimentation.

For neighbor noise in a townhouse, for example, where only the wall is shared, I have seen soundproofing fully work with only adding new drywall to the wall with some soundproofing methods and sealing up some cracks.

It sounds like you have a house and that you simply want to insulate the house between noise from other dwellers in your house. For example, kids running around above your bedroom, as just an example.

The source of your noise is a major factor, and the direction of the source and the type of source, as in, high pitched, low frequency, vibrations from running above you, all are relevant factors.

The absolute best option which is foolproof if you do it right is to build a room within a room, decoupled from walls and ceiling, and a floating floor, with double 5/8" drywall with green glue in between, and rockwool as insulation. This is the common setup for most good home theatres.

However, room within a room is an expensive project and a big undertaking. It is also not for the faint of heart. Depending on the source of your sound, and depending on how much sound you need to reduce, it may not be necessary to build a full room within a room.

Shielding against talking in the other room against one wall, or shielding a bathroom, may have simpler solutions, depending on a variety of factors.

The best thing to do is to be sure where your noise is coming from and what directions and what types of noise. You don't want to start by wasting on a wall if really the only acceptable solution was to build a room within a room; but you don't want to go all out if it isn't necessary which could cause thousands of unnecessary expense.

After you determine the noise sources, and whether the sound is coming from multiple directions, then you can begin to devise a solution. It is best to have your full solution before ever beginning the project.

Unless cost is no object, in which case if you are exceedingly wealthy then you might as well just go all out for a total soundproofing option with the room within a room, if cost doesn't even matter to you.

But cost probably does matter to you, so make sure to do the above and determine the sources and types of sound or vibrations you are shielding against and have the full project planned out before starting any work. Just experimenting throwing some green glue and drywall up could end up being a big waste of money if it wasn't the solution to your problem.