Spray Foam Thickness Calculator for Walls
Here’s a comprehensive table covering all you need to know about spray foam thickness for walls, including insulation type, R-value per inch, recommended thickness, and typical applications.
Spray Foam Insulation Thickness Guide for Walls
| Foam Type | R-Value per Inch | Recommended Thickness | Application | Notes |
|---|---|---|---|---|
| Open-Cell Spray Foam | R-3.5 to R-4.0 | 3.5″ (for 2×4 walls) 5.5″ (for 2×6 walls) | Interior walls, residential applications | Provides air sealing but less moisture resistance |
| Closed-Cell Spray Foam | R-6.0 to R-7.5 | 1-2″ (minimum) 3.5″ (for 2×4 walls) 5.5″ (for 2×6 walls) | Exterior walls, basements, high-moisture areas | Acts as a vapor barrier, stronger insulation |
| Hybrid (Flash & Batt) | R-6.0 (foam) + batt R-value | 1-2″ foam + fiberglass batt | Cost-effective hybrid approach | Provides air sealing with additional insulation |
| Commercial/High R-Value Needs | R-6.5 to R-7.5 | 4-6″ | Industrial, extreme climates | Max energy efficiency |
Additional Considerations
- Building Codes: Always check local building codes for minimum R-value requirements.
- Vapor Barrier: Closed-cell foam acts as its own vapor barrier, while open-cell may require an additional layer.
- Air Sealing: Both types provide air sealing, but closed-cell is superior for moisture control.
- Cost: Open-cell is more affordable, while closed-cell is more expensive but provides a higher R-value.