Question on insulation
My home is a typical 2-story with attached garage. One of my (2nd floor) bedrooms is extremely hot due to having the longest duct run. The room has one wall, part of which is shared with the garage attic. The attic and the remainder of the wall exposed to mid to late day sun.
I would like to add insulation board to the garage attic wall. Can I just affix the board to the existing studs? My concerns are about fire hazards and condensation issues (inside wall/craft paper backed FG insulation/insulation board).
As an aside, both my main and garage attics have full (open) soffit vents, front and back, as well as ridge vents. I have NEVER been able to demonstrate any airflow in either attic. They are extremely hot.
Any insulation experts on board?