Blow-In Insulation as Partial Soundproofing in a wood-frame Apartment Building?

wshaw · 17th April 2008, 10:02 PM

Hi All--

I am a hobyist recordist and semi-pro drummer, living in Brooklyn, New York. I live on the top floor. I've turned a room into a music studio, and installed heavy carpeting in hopes of blocking downward sound leakage. But I wonder how I might improve vertical sound isolation.

Like thousands of other apartment buildings built between 1930 and 1960, mine has heavy plaster walls, but is wood frame construction. There's nothing in between my oak floor and the ceiling of the apartment below except joists and open air. So horizontal acoustic isolation is good, but vertical is pretty poor.

Specifically, does anyone have any information of experience with using blow-in insulation as acoustic treatment? I'm thinking that if I filled in that open airspace between floors with blow-in insulation, that might provide some significant improvement, invisibly.

Anyone have any ideas/suggestions?

avare · 17th April 2008, 10:21 PM

Do not fill the space entirely. Leave a gap at the top so that the insulation doe not short out the leaves.

Andre

wshaw · 17th April 2008, 10:41 PM

Leaves?

Do you have any data as to how much sound absorbtion is provides?

Thanks!

avare · 17th April 2008, 11:02 PM

Each layer is generically referred to as a leaf. In your case one leaf is the floor layer, and the other is the ceiling.

Where are you coming from with your question about amount of sound isolation? you have provided a vague at best description of the current construction. As a general guide, 6 - 10 dB of improvement in isolation at mid and high frequencies will be achieved. Low frequencies will not be significantly affected. I am not trying to overwhelm you, but with the vagueness of information you have given, the best I can suggest is looking at NRC IR 811 for ceiling constructions specifically, and IR 761 for detailed testing comparing different types of insulation. IR 761 deals with walls, but a wall is just a ceiling turned on its end acoustically speaking.

Andre

wshaw · 17th April 2008, 11:08 PM

Thank you very much! Very helpful information!!!

planet red · 17th April 2008, 11:56 PM

Quote:

Originally Posted by avare

Do not fill the space entirely. Leave a gap at the top so that the insulation doe not short out the leaves.

Andre

Just curious.. how much sound gets transfered thru insulation? If it touches the next leaf slightly in a couple spots will it cause a noticeable difference?

I just helped a friend frame up a new room and some of the pink insulation barely touches the next leaf in a couple places but its impossible to push it all back in the tiny gap between the rooms.

Its just barely grazing the wall.. is it going to noticeably effect the performance of the room?

avare · 18th April 2008, 02:44 AM

Planet Red:

That should be fine.

Andre

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17th April 2008, 10:02 PM	#1
wshaw Gear maniac Join Date: Feb 2005 Posts: 235	Blow-In Insulation as Partial Soundproofing in a wood-frame Apartment Building? Hi All-- I am a hobyist recordist and semi-pro drummer, living in Brooklyn, New York. I live on the top floor. I've turned a room into a music studio, and installed heavy carpeting in hopes of blocking downward sound leakage. But I wonder how I might improve vertical sound isolation. Like thousands of other apartment buildings built between 1930 and 1960, mine has heavy plaster walls, but is wood frame construction. There's nothing in between my oak floor and the ceiling of the apartment below except joists and open air. So horizontal acoustic isolation is good, but vertical is pretty poor. Specifically, does anyone have any information of experience with using blow-in insulation as acoustic treatment? I'm thinking that if I filled in that open airspace between floors with blow-in insulation, that might provide some significant improvement, invisibly. Anyone have any ideas/suggestions?

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17th April 2008, 10:21 PM	#2
avare Lives for gear Join Date: May 2004 Location: Hamilton, On Canada Posts: 948	Do not fill the space entirely. Leave a gap at the top so that the insulation doe not short out the leaves. Andre

17th April 2008, 10:41 PM	#3
wshaw Gear maniac Join Date: Feb 2005 Posts: 235	Leaves? Do you have any data as to how much sound absorbtion is provides? Thanks!

17th April 2008, 11:02 PM	#4
avare Lives for gear Join Date: May 2004 Location: Hamilton, On Canada Posts: 948	Each layer is generically referred to as a leaf. In your case one leaf is the floor layer, and the other is the ceiling. Where are you coming from with your question about amount of sound isolation? you have provided a vague at best description of the current construction. As a general guide, 6 - 10 dB of improvement in isolation at mid and high frequencies will be achieved. Low frequencies will not be significantly affected. I am not trying to overwhelm you, but with the vagueness of information you have given, the best I can suggest is looking at NRC IR 811 for ceiling constructions specifically, and IR 761 for detailed testing comparing different types of insulation. IR 761 deals with walls, but a wall is just a ceiling turned on its end acoustically speaking. Andre

17th April 2008, 11:08 PM	#5
wshaw Gear maniac Join Date: Feb 2005 Posts: 235	Thank you very much! Very helpful information!!!

18th April 2008, 02:44 AM	#7
avare Lives for gear Join Date: May 2004 Location: Hamilton, On Canada Posts: 948	Planet Red: That should be fine. Andre