Spray Foam Insulation Cost Per Square Foot: 2025 Price Chart & Guide

Category: Cost Guides / Pricing

The #1 question homeowners ask is: "How much does spray foam insulation cost per square foot?"

The answer is tricky because contractors don't quote by the "Square Foot" (area); they quote by the "Board Foot" (volume).

If you don't know the difference, you might think a quote of $0.50 is a steal, only to realize the final bill is 6x higher because your walls are 6 inches deep.

In this guide, we provide a transparent 2025 Price Chart to help you budget for your project, whether you are insulating an attic, a 2x4 wall, or a metal building.

The 2025 Spray Foam Price Chart

Here is the average installed cost (Material + Labor) you can expect to pay in the US market right now.

Understanding the Math: Board Feet vs. Square Feet

To understand your quote, you need to know the formula:

1 Board Foot = 12" x 12" x 1" thick

If you have a 1,000 sq ft attic and you need R-38 insulation (which is about 10 inches of Open Cell foam), you aren't paying for 1,000 units. You are paying for 10,000 Board Feet.

• The Calculation: Area (Sq Ft) x Thickness (Inches) = Board Feet
• The Cost: Board Feet x Price per Bd Ft = Total Cost

Calculating this manually for an entire house with different wall depths, windows, and doors is a headache.

Open Cell Foam: The Budget Option

• Average Price: $0.40 - $0.60 per board foot.
• Best For: Interior walls (soundproofing), Roof decks (in moderate climates).
• Pros: Expands 100x, fills every crack, cheaper.
• Cons: Lower R-Value (~R-3.7/inch), not waterproof, not structural.

Cost Example: To insulate a standard 2,000 sq ft attic floor with 6 inches of Open Cell foam:

• Total Volume: 12,000 Board Feet.
• Estimated Cost: $4,800 - $7,200.

Closed Cell Foam: The Premium Option

• Average Price: $1.00 - $1.60 per board foot.
• Best For: Metal Buildings, Basements, Crawl Spaces, Exterior Walls (2x4).
• Pros: High R-Value (~R-7.0/inch), waterproof, vapor barrier, adds structural strength.
• Cons: Expensive, lower yield.

Cost Example: To insulate the walls of a 30x40 Metal Shop (approx 1,680 sq ft of surface area) with 2 inches of Closed Cell:

• Total Volume: ~3,360 Board Feet (plus 15% for corrugation waste).
• Estimated Cost: $4,000 - $6,000.

4 Hidden Factors That Affect Your Quote

If your quote is higher than the chart above, it’s likely due to one of these factors:

1. Removal & Disposal: Removing old fiberglass batting is nasty work. Expect to pay $1.00 - $2.00 per sq ft extra for removal.
2. Job Size (Minimums): Contractors have to heat up their rigs and drive to you. If you only need one wall sprayed, they will charge a "Minimum Trip Charge" (usually $2,000 - $2,500).
3. Difficulty/Height: Spraying a 20ft high ceiling requires scaffolding or lifts. This adds labor cost.
4. Masking: If the house is already finished (drywall is up, floors are down), the labor to cover everything in plastic is huge.

Stop Guessing. Get an Exact Estimate.

Charts are great for ballpark figures, but every home is different. Your window sizes, stud spacing, and roof pitch all change the price.

Use our Advanced Calculator to input your exact dimensions and get a realistic material and labor estimate in seconds.