How do published commercial and residential code requirements for combinations of continuous insulation and stud cavity insulation relate to in-wall condensation concerns?
The 2012 IECC includes minimum requirements for continuous insulation in combination with stud cavity insulation for wood stud walls. The requirements for these combinations differ between commercial and residential buildings. The required R values for continuous insulation are higher for residential buildings than for commercial. Considering cold climate applications, how do these requirements relate to in-wall condensation concerns?
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Albert,
Q. "Considering cold climate applications, how do these requirements relate to in-wall condensation concerns?"
A. They don't. Following minimum code requirements is no guarantee that you won't have a wet wall. These are minimum requirements, not optimal recommendations. To stay out of trouble, you sometimes have to exceed minimum code requirements for minimum foam thickness.
For more information, see Calculating the Minimum Thickness of Rigid Foam Sheathing.