Insulating A Garage
The garage itself doesn't need to be completely insulated, but any walls between the house and garage should be.
Insulate as you would any exterior wall, with insulation that includes a vapor retarder. The best choices for this type of application include ComfortTherm®, Kraft-faced, or unfaced with a separate vapor retarder film placed over the insulation.
Before installing insulation in garage walls, clear the area inside your garage of any obstacles. JM insulation is compressed and will expand rapidly when the package is opened, so you want enough space left in which to comfortably work.
Kraft-faced insulation must not be left exposed, but must be covered with gypsum board or another approved interior finish. Where an exposed application is required, use FSK-25 flame-resistant faced insulation.