What are some cost-effective tips for reducing external sound from entering a room?

Question

I have a small office room that shares a wall with our living room. When we have guests over, their voices travel fairly well; they sound somewhat muffled but are still audible. As I work from home occasionally, I'd like to reduce any/all noise as much as I can.

I'm not sure where exactly the noise is coming from... we do have central heating air ducts but the register is on the opposite wall... there's not much of a gap for the office door... maybe it's just coming through the wall itself?

Oddly enough, if I check sound levels from the adjacent room (on the OTHER side of the office), the noise from the living room is still there too (maybe a LITTLE softer but not by much).

Could someone provide some "sound-proofing" tips? Or perhaps ways to troubleshoot this further? I'm on a limited budget so I can't really afford to tear down walls. Not sure if there's insulation...

-M

Answer 1

Step 1: Prevent air transmission between the rooms. Sweeps for the door or a heavier door; look at the heating registers and windows; things like that. You're saying the sound is muffled, which implies the high frequencies aren't making it in, so I don't think this is the major problem.

Step 2: Damp the transmitted vibration. Put big heavy bookcases on the wall between the two rooms (which side doesn't matter so much). Blow heavy insulation into the wall between. Hang a heavy quilt on the wall.

Step 3: Break up the sound in the source room. Use natural diffusers (heavy sofas with heavy foam pillows work great, or the aforementioned bookcase with loads of stuff on it), or buy foam diffusers to stick in the corners/edges of the room.

Step 4: Give up and wear sound-cancellation headphones...or install a white-noise generator in your office (either a fan-type one, or a water feature if you like more 'natural' sounds).

See also How Do You Reduce Floor Sound Transmission for more details.

Answer 2

You might want to drill a test hole in the wall to see if it's insulated, if not some blown in cellulose or expandable foam insulation should help. It's a bit of labor but a cheaper solution than tearing down drywall.

If you eventually want to go with the full monty and tear down the drywall there is a product called QuietRock, it's similar to drywall and hangs like drywall except it has sound deadening qualities, but since you're on a budget, the blow in cellulose insulation or sprayfoam insulation may be your best bet.

Answer 3

If the sound is reaching the other side of the office, it may be traveling along the ceiling. If there's another floor above the office, you probably don't have anything -- like insulation -- blocking sound waves from traveling along the joists and/or the spaces between them.

Something to consider for blocking sound coming through the walls or ceilings would be to add another layer of drywall, separated from the first with a thin layer of vibration-damping material: searching for this technique, I see lots of conflicting advice on what to use as the filling in the sandwich, from a thick bead of regular caulk, to specialty compounds, to rubber matting. I looked into this for soundproofing my bedroom walls when I had them open to replace the windows, but decided not to bother because the windows were doing a good job of reducing sound levels by themselves. If you go this route, there's probably a spectrum of performance and cost-effectiveness so you'd need to work out what's best for you.

EDIT: Thought of something else you could try: seal around the openings for electrical outlets and light switches with caulk, and use foam gaskets underneath the cover plates to help baffle the sound.

Answer 4

Three answers - insulation, insulation, insulation.

Blown in insulation is an option, requiring only relatively small holes to patch. As pointed out, sound can travel through a variety of conduits. So you may need to get some into the ceiling or floors too. Ducting between rooms can be a problem, especially metal ducts.

If not blown in, you can drill small holes into the wall cavity, then use the canned foam stuff. It will expand heavily, so be VERY careful here. Squirt a little in, then add more.

Next, add wall coverings, perhaps drapes. Soft surfaces will help. They make sound absorbent wallpapers. If the floors in the rooms are not carpeted, consider adding carpeting.

Answer 5

In addition to the insulation recommended, I would also look into a solid core door and maybe even a doorsweep.

Also look for the obvious like a registers on the shared wall.

Answer 6

Add furnishings to the living room that absorb the sound, like an area carpet, curtains, irregularly-shaped wall coverings, bookcases filled with books, stuffed furniture.

Answer 7

As we know sound travels in waves, when sound hits a wall some of sound will bounce back into the room and some will transfer through the wall. In this case you can use wall soundproofing panels with high density (material) plasterboard. Now a days, acoustic hangers are mostly used in the construction of walls and ceilings that are designed to reduce sound transfer from one place to another. Insulation will help you lot in this case.