Spray Foam Insulation Cost Calculator
Spray foam is priced by the board foot — one square foot at one inch thick. Enter your area, thickness, and price per board foot to estimate material cost.
Ballpark material prices: open-cell foam about $0.45–$0.65 per board foot, closed-cell about $1.00–$1.75. Professional installation labor is extra — often doubling the total.
How the spray foam insulation cost calculator works
One board foot of spray foam covers one square foot at one inch of thickness, so the math is simple: multiply your square footage by the inches of foam to get total board feet, then multiply by your price per board foot. A 1,000 sq ft attic at 3 inches is 3,000 board feet.
The default $1.25 per board foot suits closed-cell foam; open-cell runs much cheaper per board foot but needs greater thickness for the same R-value. Remember this estimates material only — contractors usually charge $1.50–$3.00+ per board foot installed.
board feet = sq ft × inches · material cost = board feet × $/board foot
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Spray foam insulation cost calculator FAQ
What is a board foot of spray foam?
One board foot is one square foot of area at one inch thick. A 10 × 10 ft wall (100 sq ft) sprayed 2 inches thick needs 200 board feet.
What is the difference between open-cell and closed-cell foam?
Open-cell is softer, cheaper ($0.45–$0.65/board ft), and a good air sealer but absorbs moisture. Closed-cell is denser, pricier ($1.00–$1.75/board ft), adds structural strength, and resists water.
How thick should spray foam be?
It depends on climate zone and whether you use open or closed cell — attics often get 3–6 inches of open-cell or 2–3 inches of closed-cell. Check local energy code for required R-values.
Does the estimate include labor?
No — material only. Professional installation typically adds as much as the material itself, so budget roughly double the figure above for a turnkey job.
How many board feet are in a typical attic?
A 1,000 sq ft attic at 3 inches is 3,000 board feet. Larger homes of 2,000 sq ft at 5 inches reach 10,000 board feet.