Sound Dampening from Loose Insulation

[oldQ]

What would be the relative noise reduction from filling the space between a ceiling and first floor between the I-joists with blown in loose insulation? What would be the practical design considered as most effective? Considering costs? Is there a a type of insulation one needs to install by blowing in? Trying to reduce the sound in the lower level of a residential home from the 1st floor noise by filling the space between the I-joists with insulation. Thanks much!

 

[SlideRuleEra]

Johns Manville has information on using insulation for noise control. See this link for the first page:

http://www.lessitch.com/insulation/building_insulation/2629.htm

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[MiketheEngineer]

You might check with the Gypsum Association - they have some useful tables

 

[Tmoose]

A lot of the impact of Footsteps on a non-carpeted floor above will pass right through the joists to the finished ceiling and be radiated as noise. Several inches of fluffy stuff is good for reducing the noise (shouting and TV) upstairs if there is a complete gypsum ceiling on the lower face of the joists. NRC ratings are for sound coming thru, not footsteps. There are a few low frequencies common in popular thumping music that come right thru residential wall construction, and I believe they are related to the bending frequencies of the wall system, so insulation won't do much.


In our house I used the resilient metal channels (Z shaped or mesh sided) sold by the gypsum companies, no insulation, and the upstairs bedrooms are carpeted. Pretty good for privacy and TV, although in a rental property I might do more. Gotta provide short drywall screws to prevent short-circuiting the resilient channel.