Insulation comes in multiple types, for different applications such as the DIY-friendly blanket or batt perfect for unfinished walls, foundation walls, floors, and ceilings.You can also use foam board for walls, floors and ceilings and unvented low-slope roofs. Sprayed foam and blown-in insulation are good for existing and new wall openings, unfinished attic floors and other hard-to-reach places.