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Spray Foam Insulation Cost Calculator

Calculate the cost of spray foam insulation for your project. Compare open-cell vs closed-cell foam and get instant estimates for walls, attics, and more.

💡 Quick Answer: How much does spray foam insulation cost?

Open-Cell: $1.00-$1.50/sq ft installed | Closed-Cell: $1.50-$3.00/sq ft installed
For a 1,500 sq ft attic: $2,500-$9,000 depending on foam type.

🟢

Open-Cell Foam

Estimated Cost

$0 - $0

Board Feet0
R-ValueR-0.0
Cost per Sq Ft$0.00

✓ Best for: Interior walls, soundproofing
✓ More affordable option
✓ Flexible, expands more

🔵

Closed-Cell Foam

Estimated Cost

$0 - $0

Board Feet0
R-ValueR-0.0
Cost per Sq Ft$0.00

✓ Best for: Exterior, basements, moisture areas
✓ Higher R-value per inch
✓ Vapor barrier, adds strength

📐 What is a Board Foot? 1 board foot = 1 sq ft covered at 1 inch thick. Your project: 1,000 sq ft × 3.5" = 0 board feet

⚖️ Open-Cell vs Closed-Cell Spray Foam

Feature🟢 Open-Cell🔵 Closed-Cell
Cost per Board Foot$0.40 - $0.75$1.00 - $2.00
R-Value per InchR-3.7R-6.5
Density0.5 lb/cu ft (light)2.0 lb/cu ft (dense)
Moisture Barrier❌ No✅ Yes
Air Sealing✅ Yes✅ Yes
Soundproofing✅ Excellent⚠️ Good
Structural Strength❌ No✅ Adds rigidity
Best ForInterior walls, atticsExterior, basements, roofs

📐 How to Calculate Spray Foam Insulation Cost

The Formula

Board Feet = Area (sq ft) × Thickness (inches)
Material Cost = Board Feet × Price per Board Foot
Installed Cost = Material Cost × 1.8 (labor)

Step-by-Step:

1
Measure the Area

Calculate square footage of walls, ceiling, or floor to insulate

2
Determine Thickness

Based on your climate zone and application (walls: 2-3.5", attic: 6-10")

3
Calculate Board Feet

Multiply area × thickness to get total board feet needed

4
Choose Foam Type

Open-cell for budget/soundproofing, closed-cell for moisture areas

5
Get Total Cost

Board feet × price per board foot, plus labor if professional install

🛠️ DIY vs Professional Installation

✅ DIY Pros

  • Save 40-50% on labor
  • Small projects feasible
  • Kits available at hardware stores

❌ DIY Cons

  • Requires safety gear
  • Risk of improper application
  • No warranty coverage

💡 Recommendation: DIY is suitable for small areas under 200 sq ft. For larger projects, professional installation ensures proper coverage, even thickness, and comes with warranty protection.

🌡️ R-Value Guide

Walls: R-13 to R-21

3-4" closed or 4-6" open

Attic: R-38 to R-60

6-10" closed or 10-16" open

Basement: R-10 to R-15

2" closed recommended

💰 Energy Savings

  • 30-50% reduction in heating/cooling costs
  • Pays for itself in 5-7 years
  • Reduces HVAC workload
  • Qualifies for energy tax credits

Frequently Asked Questions

For 1,500 sq ft (such as an attic), spray foam insulation costs approximately $2,500-$4,500 for open-cell foam or $5,000-$9,000 for closed-cell foam with professional installation. DIY costs are roughly 40-50% less but require proper equipment and safety gear. The exact cost depends on thickness required, accessibility, and your location.

A 40x60 metal building (2,400 sq ft of wall/ceiling area) typically costs $4,000-$7,000 for open-cell or $8,000-$15,000 for closed-cell spray foam insulation. Metal buildings usually need closed-cell foam for moisture barrier properties. The total depends on whether you're insulating walls only or walls plus ceiling.

A 30x50 shop (1,500 sq ft) costs approximately $2,500-$4,500 for open-cell or $5,000-$9,000 for closed-cell spray foam. For workshops, closed-cell is often recommended because it provides better moisture resistance and adds structural rigidity to metal buildings.

A 55-gallon drum of spray foam (one component of a two-part system) typically covers 2,000-3,000 board feet when paired with its counterpart. At 1-inch thickness, this equals 2,000-3,000 sq ft. At 3-inch thickness (common for walls), it covers approximately 670-1,000 sq ft. Coverage varies by foam density and application technique.

Spray foam typically pays for itself in 5-7 years through energy savings of 30-50% on heating/cooling costs. It also provides air sealing (reducing drafts), moisture barrier (closed-cell), noise reduction, and can increase home value. It's especially worth it in extreme climates, older homes with air leaks, or when you plan to stay long-term.

Open-cell foam ($0.40-$0.75/board ft) is lighter, more flexible, provides soundproofing, and has R-3.7 per inch. Closed-cell foam ($1.00-$2.00/board ft) is denser, acts as a moisture/vapor barrier, adds structural strength, and has R-6.5 per inch. Use open-cell for interior walls and soundproofing; use closed-cell for exterior walls, basements, and areas needing moisture protection.

💡 Disclaimer: These are estimates based on national average prices. Actual costs vary by location, contractor, accessibility, and current material prices. Always get multiple quotes from licensed insulation contractors before starting your project.