Photo Source: Summerhill

Photo Source: Roxul (Rockwool)

3.1.1.1.(14) Insulation in rim joists and header areas where the floor and wall assemblies intersect must have a thermal value no less than that required for the above grade walls.

3.1.1.1.(20) requires assemblies that enclose common areas and are exposed to exterior or unconditioned space to conform to this section as well.