Hello I live in a cape cod that has shed dormers. I need advise on insulating the knee wall space in my bedroom because the room gets very very hot. It does have very old fiberglass insulation which has turned for the worst. As i see there is no ventilation in this area as well. I was thinking of doing some kind of foil faced foam board insulation. Dont know if that is the way to go. If anyone has any advise on this please let me know thanks.