Author Topic: My exp. w/QuietRock, SoundStop, soundproofwindows  (Read 7136 times)


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My exp. w/QuietRock, SoundStop, soundproofwindows
« on: May 23, 2006, 12:22:47 PM »
I've used three products in my house.  One is the QuietRock 5/8" 4x8 sheets, the second is the SoundStop made by Knight-Celotex, and the third is the sound proof windows from

My thoughts...

1.  QuietRock.  At about $110 for a 4'x8' sheet, I considered this to be the best investment for through-the-wall noise.  In my wall, I tore off the old drywall, removed the old R-11, replaced it with R-15, then installed the new drywall.  I also bought some of their acoustical glue/caulk to install it (put a dab where you screw in the nails and around outlet boxes and windows).  My only recommendation to anyone is to buy another cartridge of caulk - you can use it elsewhere in your house.

2.  SoundStop from Knight-Celotex.  Wow - it's cheap (maybe $10 for a 4x8 sheet if I remember right)!  But, not that great.  I put a layer of this over the existing drywall (1/2" drywall), then another 1/2" drywall over that.  Not that great - maybe 30-40% perceived noise reduction.  If I had to do it over, I would use QuietRock 5/8".

3.  I bought a fairly large slider window from them (4'x6') for about $700 and installed it behind a new Sears double-pane window (which, by the way, let a LOT of noise through).  Worked Ok - removed about 50% of the perceived noise.  Kind weird performance - can still can hear dogs barking from the neighbors yard.  Disappointing company - great customer care before the sale - didn't hear a word from them after they charged my credit card.  If I had to do it again, I'd buy the Milgard sound control replacement windows.  I can't imagine it being much different than what I have now and I wouldn't have two windows in the wall.


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Re: My exp. w/QuietRock, SoundStop, soundproofwind
« Reply #1 on: November 24, 2006, 07:09:36 PM »
Hi Jesse W,

Thanks for sharing your info.  I had a couple of thoughts about what you said.

QuietRock is an adaptation of an old sound deadening liquid-paste.  It was originally called "Noise Killer" and was developed by an older gentleman in Arizona.  It dries hard.  It was used extensively for soundproofing metal surfaces in light aircraft, autos, trucks, etc.  When the patents and manufacturing equipment were sold to "Quiet Solutions" they moved all to Califonia, converted it into a finished building product of pre-manufactured sheets (drywall with Noise Killer inside), and started distributing it through building supply stores throughout the southwest.  While it is handy, it is heavy and expensive.

The newest (and most effective to date) "liquid" form of soundproofing is Green Glue.  Green Glue is totally different in concept, make up, and use.  Green Glue is a visco-elastic adhesive that is briefly discussed at  Be sure to check out the "slide show" on this page for more info.

The Knigt-Celotex material you mention is also classified as a "sound deadening board".  It is to be used as a dissimilar material in soundproofing assemblies.  The most widely used (and effective) way it is used is in an assembly where MLV (Mass loaded vinyl) is sandwiched between sheets of sound board and and drywall.  The MLV would have blocked our the remaining 40-50% perceived noise.  MLV is only 1/8" thick and gives 26-27 STC!  For a discussion of it and how it is often used see

I would have gone the Milgard replacement route as well.