Spray-Applied
Open-Cell Spray Foam Insulation
Complete guide to open-cell spray foam insulation: R-value, installed cost, pros, cons, and best applications.
Key Specifications
3.5–3.7
R-Value per Inch
$0.70–$1.20
Material Cost/sqft
$1.50–$2.50
Installed Cost/sqft
17"
Depth for R-60
Cost Analysis (1,200 sq ft Attic)
| Option | Low Estimate | High Estimate |
|---|---|---|
| Material only (DIY) | $840 | $1,440 |
| Professionally installed | $1,800 | $3,000 |
*Estimates for a full install to Climate Zone 5 R-60 depth. Use the calculator for your specific situation.
+ Pros
- ✓Excellent air sealing in a single pass
- ✓Expands to fill irregular cavities and gaps
- ✓Improves indoor air quality by blocking pollutants
- ✓Lower cost than closed-cell
− Cons
- ✗Lower R-value per inch (3.5–3.7) than closed-cell
- ✗Absorbs water — not suitable for exterior applications
- ✗Requires professional installation
- ✗Higher upfront cost than blown-in products
Best Applications
- →Unvented conditioned attics (spray under roof deck)
- →Homes with extreme air infiltration problems
- →Cathedral ceilings and complex roof shapes
- →High-performance new construction
Comparing Insulation Types
Open-Cell Spray Foam is a spray-applied insulation. With R-3.5–3.7 per inch, it delivers solid performance for most climate zones.
View full insulation type comparison →Explore Other Insulation Types
Is Open-Cell Spray Foam Right for Your Attic?
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