faced or unfaced insulation

wiggs

I just built a garage with a second floor.The second floor has a bathroom with shower.I know exterior walls get faced insulation with the face towards the inside of the building.I am not sure about the bathroom,the garage ceiling or the ceiling of the second floor.Any input is appreciated.

Oldman

Any insulation that will hold in heat or A/C should be installed with the craft side towards the inside of the house, outer walls paper in, ceiling paper towards floor, floor paper towards ceiling, interior walls (Noise controll) use uncrafted. As far as the garage ceiling I would face the paper upwards toward the roof and install a sheet of 10 mill plastic in on the garage ceiling

wiggs

I like the plastic idea,but I won't be able to glue the drywall ceiling.Something I forgot to mention was the trusses are pre-enginered.Made just of 2x4's in triangular shapes not T.G.I.'s, the ones made with plywood and a 2x4 top and bottom.The trusses are 22in. deep.I'm refering to the garage ceiling.

Oldman

Well you could always install it with the paper down and install the plastic on top, then instead of gluing the plywood subfloor for upstairs just use decking screws instead. I use a screw gun now instead of nails just because it's less mess and no chance of sqeaks

Bonus

I don't understand why you would want a vapour barrier between the two heated parts of the building; if the garage is unheated then you want the vb on the "warm in winter" side of the insulation. Again, if the garage is unheated, you don't need a vb on the ceiling, the plywood will do it for you. If you put a vb on both sides of the ins. I think you're asking for moisture trouble. Just my $0.02

wiggs

The subfloor upstairs is already down.I have to insulate from the underside (first floor).When refering to the gluing it was the drywall ceiling of the first floor (garage portion).Thanks for the replies.