Garage Insulation

[Euro838]

Hi all,

A friend of mine is insulating their garage, it's a typical 20x22 size, So how many bags of the R20 pink insulation should be required and how many bags of R40? Any tips or suggestions or recommendations would be greatly appreciated. Thanks.

[TKRIS]

All the bags have a sq.ft coverage area given.
IMS, the pink Owens Corning (pink panther shit) is ~88sq.ft/bag for walls (16" on center).
The ceiling shit (R20 for 24" centers) is around 135 sq.ft/bag


With those numbers in mind, it's pretty easy math. Just remember to subtract the size of your overhead door, otherwise you'll end up with a pissload too much wall insulation.

EDIT:
Slow news day:
Assuming 8' walls and a 16x8 door=544sq.ft wall
544/88=6.1818. 6 bags should do, because you've got a man door and a couple windows, but you might need 7 bags.

ceiling=22x20=440sq. ft.
440/135=3.26 bags. If you're double insulating (I prefer to do two rows of R20 instead of 1 row of R40 because it allows better coverage and tighter wraps around trusses, etc.) you'll need 7 bags of 24"o/c

So there you have it:
7 bags of 16"O/C
7 bags 24"O/C (could just do 4 bags/single layer as well)