Axiom Home Page Forums General Discussion Home Theater Sound Insulation

Can anyone recommend any good sound insulation materials for use between the floor joists of my basement ceiling?

Has anyone ever used resilient channels for hanging the ceiling sheetrock? Resilient channels are metal strips that attach perpendicular to the bottom of the floor joists, and then the sheetrock is screwed to the metal strip between the joists to minimize transmission of sound through the screws and joists. Are these overkill, or do they actually provide a tangible benefit?

We used Roxul Safe n Sound for our media room and between the ceiling joists.
The amount of sound transmission is vastly reduced. With 2x12" floor joists we had enough room to put up a couple of layers of batts with air pockets in between.
The sound control is great (note this is not sound proofing).

http://www.roxul.com/sw18169.asp

Hi BobG,

I have 9" floor joists. I used 7" of Roxul Safe n' Sound mineral, fire-proof insulation. I left 2" of air space between my floor and the top of the insulation as I was more concerned about sound entering from above (kids jumping on the floor, etc) than sound escaping from below. I glued and screwed 5/8", 4'X12' gyprock to the floor joists. By doing this, I've managed to achieve 20dB+ of noise reduction from frequencies of 400Hz and above. During movies, I'm afraid there's nothing that can stop LFE from my EP600 and the whole house shakes as a result. I can still hear the kids if they jump up and down although it is quite muffled compared to before. I don't hear people walking upstairs at all. Over-all, I am very happy with this arrangement.

I wanted to maximize my ceiling height so I stayed away from resilient channels. Also, I was worried about resonances with resilient channels because you don't have as much contact area as putting the gyprock right on the floor joists. I can tell you that with the 5/8" sheets on the floor joists, I don't hear any resonances no matter what the frequency or volume. It's as tight as bedrock as far as I'm concerned.

If you do go this route, remember to use a breadknife to cut the Roxul and don't compress it as it will lose its sound attenuation properties.

I have to second Mojo's comments.
Same thinking that we had and similar application, though we added more batts due to our 12" joist depth.
Sound decreases near 30dB from the media room to upstairs (actual music playback testing), if i recall. I think i posted the numbers sometime back.

Correction, decrease of 33dB in the room above.
The link is here.

Hi Bob,

You should understand that insulation won't do much to stifle LFE. I spent hours scouring the web on the subject when I was finishing my basement last year and that was the direction from most of the folks who appeared to know what they were talking about.