From the 2006 IRC. (underlining is mine)
N1102- - BUILDING THERMAL ENVELOPE- - -
N1102.1 Insulation and fenestration
criteria.The building thermal envelope shall meet the requirements of
Table N1102.1 based on the climate zone specified in Table
N1101.2.The area around the window is part of the wall, thus, that space
is required to meet the 'Wood Frame Wall R-Value' column for your climate zone -
Zone 2 R 13.Then (to continue
with the 2006 IRC).
- N1102.4 Air leakage.
- - N1102.4.1 Building thermal
building thermal envelope shall be durably sealed to limit infiltration. The
sealing methods between dissimilar materials shall allow for differential
expansion and contraction. The following shall be caulked, gasketed,
weatherstripped or otherwise sealed with an air barrier material, suitable film
or solid material.
- - - 1. All joints, seams and penetrations.
- - - 2.
Site-built windows, doors and skylights.
- - - 3. Openings between window and
door assemblies and their respective jambs and framing.
- - - 4. Utility
- - - 5. Dropped ceilings or chases adjacent to the thermal
- - - 6. Knee walls.
- - - 7. Walls and ceilings separating the
garage from conditioned spaces.
- - - 8. Behind tubs and showers on exterior
- - - 9. Common walls between dwelling
- - - 10. Other sources of
Your reference N1102.1.10 is in the 2003 IRC, so the
2003 reference for the above thermal envelope wall insulation
- N1102.1.1 Exterior walls.
The minimum required
R-value in Table N1102.1 shall be met by the sum of
the R-values of the
insulation materials installed in framing cavities and/or insulating
sheathing applied, and not by framing, drywall, structural sheathing, or
exterior siding materials. Insulation separated from the conditioned space by a
vented space shall not be counted towards the required R-value.
answer - Yes, those cavities are required to be insulated *for both* thermal
insulation and air infiltration and exfiltration