Choosing fiberglass

knightfly · Post by **knightfly** » Sun Dec 18, 2005 6:04 am

Julian, sorry for the delay; every time I think my life can't get any crazier, it DOES...

If you mean your question about the two walls you can't fill, maybe this link will help

http://www.maconline.org/tech/materials/ssdata.html

Keep in mind that those are all STC ratings, and don't mean much for LOW frequency (drums) - for that, your best bet is more MASS, no air space between it and the original walls.

HTH... Steve

Julián Fernández · Post by **Julián Fernández** » Mon Dec 19, 2005 7:58 am

Thanks steve!
It´s always nice to see stc predictions!

Anyway, my main question is how to improve insolation on the hollow brick walls and the filled-brick wall...
Before putting the ceiling i can fill the 8cm air gap between the walls and the steel studs...
I´m not sure if I should use...

a) 50kg/m3 rigid panels
b) 16kg/m3 non-rigid batt
c) leave it unfilled

Should i treat the walls using the same approach?
Thanks again...

knightfly · Post by **knightfly** » Wed Dec 21, 2005 10:49 am

In-the-wall insulation - it's a toss-up between rigid 2.5 PCF and the 16 kG (1 PCF) stuff; the heavier costs a bit more and gives maybe 2 dB better STC, but no better LF results - the lighter stuff is best bang for buck for the insides of walls.

And yes; a ceiling is pretty much just a horizontal wall, except that gravity helps keep insulation against the inner panels for damping, and helps the ceiling fall down easier if not built right

IOW, what works for a wall will work for a ceiling, except for framing sizes and ways to hold insulation in place... Steve