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Does sound proof insulation really work?

Posted by Shmomey (My Page) on
Sat, Jun 30, 12 at 9:47

I asked my builder to add sound proof insulation to the laundry room and media room. I have no idea how much more expensive it is. Those of you that have it...does it really work. Is the room sound proof? I have not experience with sound proof insulation.

If it is not worth the cost... I do not want to spend the extra money.


Follow-Up Postings:

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RE: Does sound proof insulation really work?

Sound proof? Not hardly. It will reduce the overall sound and muffle things some, but adding sound batts (assume that is what you meant) will not make anything soundproof. You would need to sound caulk around outlets, top and bottom plates, etc. then you still have the vibration waves through the studs them selves. I typically spec a sound gyp product like Quietrock, but its expensive and effective. Cheaper options include double stud or staggered stud wall and rc1 channels. I have also used open cell spray foam with decent results.


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RE: Does sound proof insulation really work?

Thicker and heavier drywall with steel studs still works.

Two layers of 5/8 thick on each side with sound insulation (heavy fiberglass) along with acoustic caulk on bottom plates and no open ceiling joists can be very effective.

When we build rooms for classified work the walls are slab to slab, acoustic caulk or foam, accost insulation, and a double drywall with staggered joints.

Along with metal foil, steel mesh (#9) and alarms and noise masking around doors (and drop seals on 'working' doors (as opposed to fire doors that are sealed better since they do not have to operate every day).

No wiring of ANY type is allowed in the barrier walls.

The hardest thing to stop is ceiling noise from walking on the floor above.
The concrete slabs are thickened up.

For residential work thicker drywall.

Mass is your friend.


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RE: Does sound proof insulation really work?

STC Wall Ratings

There may be some value to adding insulation, but without further measures--none of which are simple or inexpensive--any reduction in sound transmission is not particularly noticeable.


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RE: Does sound proof insulation really work?

"If it is not worth the cost... I do not want to spend the extra money."

Don't do it. You won't be sound proof with just some insulation. From what I've read, the only true way to sound proof a room is to build the room, and then build another room within it. Plus using the sound proof materials, double sheetrock, staggered 6" studs, etc. I researched this a bit when I built my current home theater over on AVS Forum (google it if you want more info on home theater etc).

If you're concerned about the cost of just the higher level insulation, I don't think you'll be happy with the result for the added cost.


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RE: Does sound proof insulation really work?

The term "sound proof" is used inappropriately in the original question. Reducing sound transmission to a more acceptable level is not sound proofing. You need to describe the level of noise in the room and the level of acceptable noise in the adjoining rooms.

Fiberglass insulation is not worthless but in such a small cavity the drop in noise transmission is barely noticeable especially if there are wall penetrations or spaces above the top plate as others have noted.

Essentially what the cavity insulation does is reduce the energy level of sound that enters the wall cavity through a crack before it can exit to the other side through another crack. The thin layer of insulation works only because the sound bounces around in it.

So, thermal fiberglass is cheap and helps a little bit but there is obviously no point in putting it in a wall that contains a door.

The first step in sound reduction is simply a second layer of drywall on ONE side of the wall. I doubt you are going to want to pay for QuietRock but it can't hurt to ask for a price.


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RE: Does sound proof insulation really work?

Whoa... I don't even want to ask my builder to quote me on quiet rock. I guess sound proof is not the right word. Do they even sell what is called sound reducer insulation versus regular insulation? I was suggested by home designer.


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RE: Does sound proof insulation really work?

Our master bedroom shares a wall with our great room (and its the tv wall). We had our insulation team use blown in cellulose insulation in that wall as well as all the walls around the 2 main floor bathrooms. We used a solid core door on our bedroom, which is in a small hallway off the great room. This solution has worked for us. We can go to bed and someone can be in the great room watching tv and we don't hear it. All I can say is - it has worked for us!


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RE: Does sound proof insulation really work?

"any reduction in sound transmission is not particularly noticeable. "

That is just not correct.

There is lenty of tohter data running around for higher value (and higher cost) walls.

Heavier gauge than minimum steel studs and double layers pf 5/8 drywall have been used in SCIF construction for a long time.

When they are done you can scream at the top of your lungs inside the room and NOTHING can be heard outside.

The same applies to the 'isolation rooms' used to allow practice for musical instrument players.

It can approach painfully load in the room with no noise audible on the outside.

It just costs money.

Most of the standards are designed to provide a more 'turn key' sound wall than actually having to spend engineering time and money to achieve higher levels.

'Standardization' makes building, contracting, and design easier.
It in no way represent any type of limit on what can be achieved, or the methods for higher levels.


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RE: Does sound proof insulation really work?

Absolutely acoustical insulation can provide a sound transmission coefficient of up to 65.

Cellulose insulation is an excellent sound proof insulation because it completely fills cavities leaving few air pockets for sound to travel in. Compared to fibre glass insulation, cellulose is approximately 3 x denser. The density of the product helps lessen the sound through walls and between floor levels.

Here is a link that might be useful: Soundproofing Insulation


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RE: Does sound proof insulation really work?

Cellulose may absorb a bit more sound than fiberglass but the difference between acoustical and thermal fiberglass insulation cannot be measured in the field.

The opinions I have expressed here come from the acoustical consultants who have helped me design multi-family housing.

If you rely on information from the internet you will find that the different manufacturers' associations publish biased information under many misleading names. Don't underestimate what insulation manufacturers will do to promote their products.


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RE: Does sound proof insulation really work?

The next time I build a two-foot high column to live in, I'll be sure to line it with cellulose for peace and quiet!

In fact, independent building scientists have concluded that the advantage of cellulose is limited to only one type of sound.

Viz, this excerpt from the linked paper below.

Here is a link that might be useful: Control of Sound Transmission Through Gypsum Board Walls


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RE: Does sound proof insulation really work?

Furthermore, the research cited above notes that, "If at least one of the [drywall] layers is not resiliently supported…sound absorbing material in the cavity is rendered ineffective.
…The type of sound-absorbing material has a relatively minor effect on the ability of the wall to control sound."

This post was edited by worthy on Fri, May 24, 13 at 16:07


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RE: Does sound proof insulation really work?

I'm surprised that no one has pointed out that sound is transmitted in a structure in one of two ways or both:

--Airborne sound;
--Structure-transmitted sound

The treatment for each type of sound is quite different, since the sound is transmitted differently. Put simply, airborne sound is mitigated by mass. Structure-borne sound is mitigated by isolating the structural members from one another.

A lot more can be said about each type of sound and its mitigation, but I think this is enough here.

Good luck on your project.


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RE: Does sound proof insulation really work?

I was astonished when I insulated my barn/woodshop. For reasons unrelated to sound control we used open cell spray form (4" thick) and after it was applied it was like walking into a tomb. The reduction in sound coming from the outside was striking (and unexpected, at least by me).


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