Insulation, Radiant and Vapor Barriers - Garage Attic Floor

I have finished out the attic area of my garage and installed a split system heatpump and it is working great. Now I want to insulate the attic floor which is also the garage ceiling. The garage ceiling is not finished so I shouldn't have any problem insulating the attic floor from the garage. The question is what kind of insulation should I use? I don't want fiberglass dust coming down on my cars every time I use the attic space and I don't want to finish the garage ceiling at this time. Any idias would by greatly appreciated. Thany You.

Roger

Unfortunately any insulation you use on the ceiling will require you to cover it since its a fire hazard. Whatever you end up using foamboards cellulose sprayfoam make sure its R38 at least if you are in a cold area and its against the rooms subfloor otherwise it wont work.

deleted.... wrong thread.

"Unfortunately any insulation you use on the ceiling will require you to cover it since its a fire hazard. "

Huh ?????
Maybe I'm missing sumthin' here


What's wrong with spray applied cellulose ?

No, not that new water mixed grey stuff that gets
"mowed off" ready for drywall, I mean commercial
wall spray with glue.

I thought it meets fire code from factory mutual as exposed.
Last time I talked with them.

It also knocks down the sound quite a bit,
which might be nice in a garage.

Code typically requires at least a 5/8" fire rated sheet rock between a garage and a living space. We did a commercial space that required 2 5/8" layers. Basically it is to protect the living space from a fire in your garage.

I think that the commercially applied cellulose would be fine as long as it is properly protected. Check your local building codes and follow them and you will make sure your fire insurance is in effect and your house sell-able at a future date.

Jim

Jim,
Now I see what your saying, it's not the insulation
system that will burn, it's the code requirement
for fire protection of the flooring and occupants
above.
I read the last reply as saying the insulation had
to be covered, and of course foam would, but not cellulose.

Actually if the owner creates the upstairs room ,
he needs the fire protection, insulated or not.

Now I see it, thank you.

That is right. We had a wood/metal joist system in a commercial building that required two layers of 5/8" fire rated sheet rock. Each had to be fire taped and the joints overlapped.

We wanted to do one layer and do a fire rated dropped ceiling below but that was not allowed by code due to the testing of the joist system. Insulation type didn't seem to have a lot to do with it.

Jim