use standard 3.5 inch rolls and don't forget the ductwork

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In Reply to: Best material for sound proofing open ceiling basement? posted by Darryl on February 7, 2004 at 14:33:50:

It may not be the way your ductwork is installed, but if the takeoffs for the floor above are on the same trunk line as the takeoffs for the basement the sound can easily travel through the duct.
If that is the case the solution is to reconfigure the ductwork before you cover it up.
As far as insulation goes -
I'm sure that you have other ways to proceed, but the way I would choose is would be to buy rolls of 3.5 inch rolled insulation that normally installs in walls. If you are in the US, this is probably the best bet.
These rolls (versus batts)are the cheapest way to purchase fiberglass insulation per pound (density). I don't know why, but in my area it is substantially cheaper than any batt after calculating the cubic inch cost. Instead of using 6 inch batts in my crawl space, I pulled the facing off the second piece that went up (it comes off easily). Since you will have living space above, you should pull off both pieces of vapor barrior before installation. Should be quick - easy and cheap.

This should help your problem considerably but will not _solve_ it.
Sound travels also by transmittal through framing and joists - to best eliminate sound transmission you would need to construct a ceiling in some manner that the framing and construction for the ceiling did not contact the joists that contact the floor - that is not feasible in this space.
Carpets or area rugs on the floor above will help also if you don't already have them.
Best guess? Very likely that 6 or 9 inches (compressed slightly) will very likely diminish transmission to an acceptable level. I can think of no cheaper, easier way.
FWIW, I used 3.5 inch rolls with the vapor barrier removed in the interior walls that I redid in a recent renovation. Reasonably effective and did what I hoped. Downside is that now if one spouse calls to another in another room you have to walk to another room to be heard.
When the HT is too loud - sound still travels through the door, but doesn't make it back to the bedroom like it used to.
Regards
Ken L

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Follow Ups Full Thread

Topic - Best material for sound proofing open ceiling basement? - Darryl 14:33:50 02/07/04 (5)

use standard 3.5 inch rolls and don't forget the ductwork - Triodeuser 17:09:05 02/07/04 (1)

Thanks for the suggestions, I appreciate it! <nt> - Darryl 06:05:08 02/08/04 (0)

Darryl: Also check the local tax codes. Where my... - DeKay 16:20:36 02/07/04 (2)

Wow, never thought of that, thanks for the warning/tip!! <nt> - Darryl 06:04:14 02/08/04 (1)

Darryl: Well, I hope this is not the case in your area... - DeKay 09:36:40 02/08/04 (0)

Follow Ups

use standard 3.5 inch rolls and don't forget the ductwork - Triodeuser 17:09:05 02/07/04 (1)

Thanks for the suggestions, I appreciate it! <nt> - Darryl 06:05:08 02/08/04 (0)

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