Open Cell vs Closed Cell Spray Foam

Open-cell and closed-cell spray foam serve different purposes and have different performance characteristics. Selecting the right type for a given application depends on the performance requirement and the climate conditions.

• Closed-cell spray foam:
• Density: approximately 2.0 lb/cubic ft
• R-value per inch: approximately R-6.0 to R-7.0
• Cell structure: closed cells filled with blowing agent gas
• Moisture resistance: high — acts as a vapor retarder at 2"+ thickness
• Structural contribution: yes — adds racking resistance when applied to framing
• Air barrier: yes — at any practical application thickness
• Typical applications: exterior walls, rim joists, below-grade, metal buildings, roofing

• Open-cell spray foam:
• Density: approximately 0.5 lb/cubic ft
• R-value per inch: approximately R-3.5 to R-4.0
• Cell structure: open cells, gas escapes during curing
• Moisture resistance: low — permeable to moisture vapor
• Structural contribution: minimal
• Air barrier: yes — effective air barrier at standard installation thicknesses
• Typical applications: interior walls, attics, crawl spaces, sound control

When to use each: Closed-cell is preferred when: high R-value in limited space is required, moisture control is critical, or structural contribution is desired. Open-cell is preferred when: cost per R-value is a priority, thick applications are needed, or sound control is a goal.

Many spray foam contractors carry both products. A Logan Manifold system allows switching between materials on the same rig with an air purge between materials.