Replies

1. 
   WayneL5 | Jul 04, 2004 06:31am | #1

   Fiberglass thermal insulation is not dense enough to be all that good for insulation against sound transmission.  Sand will probably be too heavy for drywall below to hold.

   Are you concerned with airborne transmitted sound or impact noise?  The solutions for either are different.

   Here's a website that has a fairly detailed technical discussion of tested and proven methods to attenuate sound.  http://www.usg.com/Design_Solutions/2_3_4_acoustictips.asp

2. 
   DavidThomas | Jul 04, 2004 08:09am | #2

   As Wayne said, FG won't do much. Anything in the bays won't do a lot since sounds will still be transmitted through the joints.

   Easiest? Use resilent channel to mount a sheetrock ceiling an inch or two below current ceiling. The sound doesn't transmit through the RC (much) and that will help a lot with sound in both directions.

   David Thomas   Overlooking Cook Inlet in Kenai, Alaska
1. 
   lescab | Jul 04, 2004 10:09am | #3

   Thanks for the responses. I read the article about sound transmission. I'm mostly concerned with impact sounds. I did have a contractor install the resilient channel plus soundboard, then 1/2 inch sheetrock on a number of ceilings. But it seemed only to cut the noise about 30%. Against my better judgment I let the installer cut big holes in the existing ceiling to locate joists. Now I realize that those holes despite the added layers mentioned probably ruined much of my potential result. We simply added a 1/2 inch sheetrock over another ceiling and the installers mudded it up so extensively and Ithought excessively, but it seems to perform better acoustically than the channel system in the other rooms.

   What about blowing borated paper stuff into holes in my upper floor? I can't mess with the celing below in this case? Thanks again!

   Leslie

3. 
   reinvent | Jul 08, 2004 03:26am | #4

   Check out this link it might help.

4. 
   nikkiwood | Jul 08, 2004 04:01am | #5

   I have a similar situation in my house: a third floor kitchen with hardwood floors over second floor bedrooms.

   I packed FG insulation between the joists as tightly as I could, and it does seem to do the job for airborne sound transmission (voices, music, etc.). But it does nothing for impact sounds (shoes with hard soles).

   RC channel on the ceiling below would help enormously with the impact sound issue, but you said that wasn't going to happen in your situation. If down the line, impact sounds turn out to be a real irritant, you could install RC channel over the existing ceiling, with another layer of 5/8 sheetrock.

   I would also give some thought to flooring material for the kitchen; as far as sound is concerned, tile or hardwood floors are the worst, carpeting with a thick pad is the best. Laminate flooring (e.g. Pergo) might be an alternative. Ordinarily, it is installed atop a 1/4 layer of foam type material, and you might check to see if you could use 2 or even 3 layers of this material instead. Otherwise, cushioned vinyl sheet goods might be the best choice.

   Good luck.

5. 
   DanH | Jul 08, 2004 04:03am | #6

   Rather than fiberglass or foam, use blown-in cellulose. It's much better at damping sound and is cheap and easy to install.

1. 
   lescab | Jul 08, 2004 05:36am | #7

   Thanks everybody for the suggestions. I'll look into the blown in cellulose.

   Leslie

1. 
   MGMaxwell | Jul 09, 2004 01:39am | #11

   I've got cork tile, but I don't have my CO yet, and I can't tell you how it's doing with regard to sound transmission. I can tell you it's nice on the feet for cushion and lack of coldness on bare feet. The same source of tiles also sells big sheets of cork for underlayment specifically made to decrease sound transmission, and the website gives directions on the installation.

6. 
   caseyr | Jul 08, 2004 06:43am | #8

   Cork is becoming popular for kitchen floors and should help mute impact noise quite a bit.  I hope to install it on my house when I get around to building it.  I lived for a short while in a house with cork floors and liked it. 

   An advertising blurb:  http://www.floorfacts.com/corkfloors.asp

   I haven't seen it done, but you could possibly float a hardwood floor over some type of resilient subfloor material:

   http://www.acmewonderfloor.com/apps.html

   As mentioned, a dense resilient insulating material or sand would in the space between the floor and the ceiling below would dampen transmitted sound the best although considerable impact noise will be transmitted by the solid wood joists unless they are somehow isolated from the floor above or the the ceiling below. 

7. 
   sungod | Jul 08, 2004 06:35pm | #9

   Cellulose will be useless for sound.  Easyway is to float a piece of 3/4" partical board on top of foam, like they do with Pergo.

   Buy one sheet, place it on the floor, tap dance on it and you will  hear the difference.

1. 
   DanH | Jul 08, 2004 10:02pm | #10

   Cellulose is quite a good sound insulator, compared to fiberglass or rigid foam. It has significant mass and a high damping modulus.

8. 
   WayneL5 | Jul 09, 2004 03:45am | #12

   I don't know how much additional height you can accept in the kitchen, but if you could get a 3/8" thick layer of Homosote on top of the subfloor, it would help quite a bit for impact noise.

9. 
   JRuss | Jul 09, 2004 03:52am | #13

   2 layers of 5/8 drywall on a channel or other sound suppressor, you won't hear a thing. Insulation is a marginal solution in comparison, but it won't hurt to throw some in for the heck of it.

   Never serious, but always right.
10. 
    Fonzie | Jul 12, 2004 04:02am | #14

    One caution about the foam idea--I don't think you would want to surround electrical wires with insulation.