Author Topic: Insulation?  (Read 5100 times)


  • Guest
« on: January 22, 2007, 11:07:21 PM »
Hi, I'm remodeling my house and about to start installing insulation for the purpose of a noise barrier and for energy efficiency. I have 2x4 studs and my bedroom has a street close to it. The street isn't really busy, but I would like to cut down on the sound while remodeling instead of later.

I've read about chambers and putting up sheetrock with an airgap, but I'm really just looking to see how much noise I can cut out by using insulation. How much of a reduction in R-value would I lose if I were to stuff R-31 insulation to fit between the studs?

Would it be better to just use R-19? If I were to use R-31, is there some kind of soundproofing material I can put between the insulation and sheetrock? How much of a difference would this kind of setup make?



  • Guest
Re: Insulation?
« Reply #1 on: January 23, 2007, 03:12:14 AM »
You'll  find, as they did in the '70's, that Owens Corning has hyped their fibreglass insulation mercilessly for soundproofing.  It has little sound blocking qualities, but truely- it's better than nothing!  But so is "Anything".  Now they call it "Pink" and have "Tony the Tiger"  pushing it, but its the same but now with  Color!  (Go figure). For thermal insulation, properly installed, it's fine.  But don't hang your hat on it's acoustical properties.  (It's not there).

The best "bang for your buck" is MLV (Mass Loaded Vinyl)  See about it at:

And together with Green Glue, it's even better.

BJ Nash



  • Guest
Re: Insulation?
« Reply #2 on: January 23, 2007, 06:54:31 PM »
The insulation is not the most important element in a soundwall.  All it does is absorb the sound bouncing around in the cavity.  Cotton, fiberglass, mineral wool, it's pretty much all the same - 4-7 points added to the STC (30-40 percent quieter). 

It's much more important to have a decoupled wall (res. channel/staggered stud/double stud), add mass (double drywall/MLV), and seal the gaps, edges and penetrations.  You can add 30 points of STC (88 percent quieter) by upgrading the wall.

Green Glue dampens some of the vibration in the drywall panels.     

Don't jam R-30 into a 6" wall.  You'll get WORSE performance than R-19, both thermally and acoustically.   


  • Guest
Re: Insulation?
« Reply #3 on: January 26, 2007, 06:07:54 AM »
Quite true, John.  Decoupling is very imnportant, see
about floating a wall/ceiling.

BJ nash