[Shag]

I'm preparing to install insulation (R13, 3.5" thick, 9.5" joist height) in my ceiling today, and have a quick question before I start. Should I install the insulation at the top of the joist cavity (against the floor above), or at the bottom of the cavity? Should the open space be above or below the insulation? My intention with the insulation is to help sound control (I know it's not the best solution, but it's all I'm able to do).


Any help ASAP would be most appreciated.

 

[Ethan Winer]

Shag,


If you can afford enough fiberglass to fill the entire cavity, that would be my choice.


--Ethan

 

[Shag]

Ugh. Guess I bought the wrong stuff.


Would it be a bad idea if I just double-layered the R13? My local Home Depot doesn't carry R30...

 

[RRBOOGIE]

Go ahead and put two layers of the R13 up. For the extra money it is worth it to fill as much of the joist cavity as possible. I was told that it is best to have the air gap on the sub floor side of the insulation. Happy insulating!