For Ariana

Hi Ariana,

This is a steel frame building, non-residential.  It needs R25 c.i. in the roof and R13 + R5 c.i. in the walls.  Choice A doesn't have enough insulation in the walls that's c.i.  Choice B doesn't have enough insulation in the roof.  It has R24, but needs R25.  Choice C is the only one that has enough insulation in the roof and walls.  It needs R-5 or more c.i. = continuous insulation, which is not in between the studs.

Hope this helps!

Rebekka O'Melia, R.A., NCARB, B. Arch, M. Ed, Step UP ARE 5.0 Courses