Insulation Garage ceiling questions

[Tofast4U]

Hey guys working on insulation my Garage ceiling and have a question. Walls are 2x6, no problem there. Ceiling is 2x4 and 24 OC. Storage trusses. Question being do I use the 24 inch wide and 3.5 inch insulation or can I compact the 24inch wide 6 inch up there. Also I'm having a tough time finding 24 Inch unfaced insulation. Would there be a problem to use Faced, then Vapor barrier it. Also I'm putting up steel for the ceiling.

Floor is down for the storage area also.

 

[Falcon67]

If you compact fiberglass, it become useless. If you are limited by the 2x4 joists due to flooring, then R13 is all you get. If your area requires a vapor barrier, then I'd just put it under the kraft backing.

 

[KathyJB]

If you compact fiberglass, it become useless.

I found that out too late, but then again maybe not? I used r-19 for the walls of my garage, but not all the walls, I switched to the r-13 when I found out there was a big difference.
My garage is going to be resided with hardiplank and I was wondering, can I shave off a few inches once the insulation is exposed from the outside?

 

[Falcon67]

Yep - fiberglass batt peels off in layers fairly easily. You can use a long kitchen knife just to control your progress. Save the remnants and throw up in the ceiling 90 degrees to whats there now, if possible. Be sure you use gloves, long sleeves and a mask - the process will spew plenty of fiberglass threads.

 

[KathyJB]

Yep - fiberglass batt peels off in layers fairly easily. You can use a long kitchen knife just to control your progress. Save the remnants and throw up in the ceiling 90 degrees to whats there now, if possible. Be sure you use gloves, long sleeves and a mask - the process will spew plenty of fiberglass threads.

Lol, maybe I'm crazy but insulation doesn't bother me. Now the husband unit that's another story. Thanks for the heads up on shaving the insulation. I only have a few sections so it won't take long.