Best approach for insulating garage to keep room above it warm
We currently took possession of our 20 year old house last year, and noticed over the winter that the room over half the garage gets very cold, especially the floor.
Inside the garage, the portion under the room's floor is dry walled with blown in insulation in it. The other half of the garage's ceiling is exposed plywood, with nothing above it but shingles.
In the summer its very hot, and the winter is very cold in the garage, more extreme than it sometimes actually is outside... which probably means that the cold air is being trapped in the garage, cooling down the drywall, insulation, and eventually the room above it. (in the summer, the room above the garage is fine).
Should I remove the drywall and insulation and put in proper insulation?
Continue insulating the rest of the garage's roof?
or... and other ideas?