CodeBook — Building Code Research Tool

Material

Thickness (inches)

R-value: 5 per inch

Cross-SectionExterior → Interior

Needs R-19.4 more for Base Code

Currently R-0.6, need R-20. Add insulation or switch to higher R/inch material.

R-0.60

Total R-Value

Base Code

R-20

Stretch Code

R-25

Specialized

R-30

Zone 5A (Massachusetts)

Base code: R-20 cavity or R-13+5ci. Stretch code adds continuous insulation.