Spray Foam Insulation Cost Calculator
Calculate the cost of high-performance spray foam insulation. Compare Open Cell and Closed Cell rates based on board feet and R-value requirements.
How is Spray Foam Cost Calculated?
Spray foam is not priced by the "square foot" alone, but by the volume (Board Foot). Open Cell averages $0.40 - $0.70 / bd. ft., while Closed Cell averages $1.00 - $1.60 / bd. ft. The thicker you spray, the more it costs.
Calculate Your Estimate
Project Location
Find rates for your specific area.
Project Dimensions
Enter the total surface area to be sprayed.
Insulation Type:
Add-ons & Prep Work:
Key Factors Influencing Spray Foam Prices
R-Value & Thickness
Energy codes drive the cost. An attic needing R-38 requires ~10 inches of Open Cell (cheaper material, more volume) or ~5.5 inches of Closed Cell (expensive material, less volume).
Prep Work
Removing old dirty fiberglass involves manual labor and disposal fees ($1.00/sq.ft.). Covering floors/windows and setting up ventilation adds to the overhead of the job.
Spray Foam Cost by Type
| Type | Cost per Board Foot | R-Value / Inch | Best Use |
|---|---|---|---|
| Open Cell | $0.40 – $0.70 | R-3.7 | Attics, Walls, Soundproofing |
| Closed Cell | $1.00 – $1.60 | R-7.0 | Basements, Metal Buildings, Pole Barns |
Additional Service Fees
| Item | Average Cost | Notes |
|---|---|---|
| Old Removal | $1.00 – $1.50 / sq.ft. | Removing fiberglass/cellulose. Vacuum required. |
| Ignition Barrier | $0.50 – $0.75 / sq.ft. | Required code coating for attics/crawlspaces. |
| Disposal Fee | $150 Flat | Hauling away debris. |
How to Estimate Spray Foam Manually
Spray foam is priced by the "Board Foot" (1 sq. ft. x 1 inch thick). Use this method to check your contractor's math:
Step 1: Calculate Surface Area
Measure Length × Width of the area to be sprayed. Example: A 20x50 attic roof deck = 1,000 sq. ft.
Step 2: Determine Thickness (R-Value)
How thick do you need it?
Open Cell (R-3.7/in): Needs ~10 inches for R-38.
Closed Cell (R-7/in): Needs ~5.5 inches for R-38.
Step 3: Calculate Volume (Board Feet)
Multiply Sq. Ft. × Inches of Thickness.
Example: 1,000 sq. ft. × 6 inches = 6,000 Board Feet.
Step 4: Select Unit Price
Open Cell: ~$0.65 / Board Foot.
Closed Cell: ~$1.50 / Board Foot.
Step 5: Apply the Formula
Combine all factors plus any removal/prep fees:
(Sq.Ft × Thickness × Price/BdFt) + Removal + Ignition Barrier = Total Cost
Example: 1,000 sq.ft. @ 3 inches (Closed Cell for shop) + Removal ($1,000):
Volume = 3,000 Board Feet.
Material = 3,000 × $1.50 = $4,500.
+ $1,000 Removal = $5,500 Total.
Frequently Asked Questions
What is a Board Foot?
A Board Foot is a volume measurement equal to a 12" x 12" square that is 1" thick. It is the industry standard for pricing spray foam because the total material used depends on both the area and the thickness applied.
Open Cell vs. Closed Cell: Which is better?
It depends on the application. Closed Cell is rigid, waterproof, and has a high R-value (R-7/in), making it ideal for basements, metal buildings, and exterior walls. Open Cell is cheaper, flexible, and expands more (R-3.7/in), making it perfect for residential attics and soundproofing interior walls.
Does spray foam save money?
Yes. By creating a perfet air seal, spray foam prevents conditioned air from leaking out. This can reduce HVAC energy consumption by 30-50%, often paying for itself within 3-5 years.
Is spray foam safe for my family?
Once cured (usually 24 hours), spray foam is inert and safe. However, during installation, it releases chemical fumes (isocyanates). It is critical that all occupants and pets vacate the home during spraying and for 24 hours afterward.
Can I do it myself (DIY)?
Small 'froth packs' are available for rim joists or touch-ups, but they are expensive per board foot. Insulating a whole house requires a high-pressure rig ($50k+ equipment) and professional training to mix chemicals at the precise temperature and ratio.
Do I need to remove old insulation?
Yes. Spray foam needs to bond directly to the substrate (wood, concrete, roof deck). Spraying over old fiberglass is a code violation and can trap moisture, leading to rot and mold.
What is an Ignition Barrier?
Spray foam is flammable. Building codes typically require it to be covered by 1/2" drywall (thermal barrier) or painted with a special intumescent coating (ignition barrier) if exposed in an attic or crawlspace.
Will spray foam rot my roof?
This is a common myth. If a roof leak occurs, open cell foam allows water to drip through (alerting you), while closed cell might hide it. However, proper roof maintenance is key. The foam itself does not cause rot; trapped water does.
How long does it last?
Spray foam is permanent. Unlike fiberglass which settles and fiberglass batting which can sag over time, spray foam stays in place and maintains its R-value for the life of the building (80+ years).
Does it block noise?
Open cell foam is an excellent sound deadener and significantly reduces outside noise or noise between rooms. Closed cell foam is too dense to be a great sound insulator but still blocks air-transported sound.