Total R-Value of R-21 + R-10 Commercial Wall Assembly
A commercial wall assembly with R-21 batts and R-10 continuous foam sheathing reaches approximately R-31.9 total R-value.
How to use this tool
- Enter the R-value for each insulation layer (set unused layers to 0).
- Include sheathing and drywall R-values for a complete assembly calculation.
- The result shows total R-value and U-factor for the wall or ceiling assembly.
Find the total R-value of a high-performance commercial or energy-code-compliant wall with R-21 batts and R-10 continuous foam.
Frequently asked questions
- What does R-value mean?
- R-value measures thermal resistance — how well an insulation layer resists heat flow. Higher R-values mean better insulation. Values are additive when layers are stacked.
- What is U-factor?
- U-factor (or U-value) is the inverse of total R-value (U = 1/R). It measures heat transfer rate — a lower U-factor means better insulating performance.