The short answer
Angi and HomeAdvisor put professionally installed closed-cell spray foam at $1.30 to $3.10 per board foot, where a board foot is one square foot one inch thick. That makes 1,000 square feet at two inches (2,000 board feet) about $2,600 to $6,200 before minimum charges and extra work. HomeGuide's per-square-foot range is $3 to $5. Closed-cell costs more than open-cell but gives more R-value per inch.
Closed-cell foam usually costs more than open-cell, but it provides greater nominal R-value per inch, is more rigid and offers lower water-vapor permeance. Whether that higher price makes sense depends on the building assembly, the thickness you actually need and how the installation is specified.
2026 pricing summary: Budget from a fully specified treated surface area × thickness calculation, not your home’s floor area. Use the spray foam cost calculator for your own dimensions.
Prices reviewed October 19, 2026. These are US planning estimates, not live quotations. Sources and calculation methods appear below.
Closed-Cell Spray Foam Cost at a Glance
| Measure | Estimate / explanation |
|---|---|
| Professionally installed cost per board foot | $1.30–$3.10[1][2] (Angi) |
| Published installed cost per treated square foot | $3–$5[3] (HomeGuide; its own scope assumptions) |
| 500 sq ft × 2 inches | $1,300–$3,100 calculated from Angi unit rates |
| 1,000 sq ft × 2 inches | $2,600–$6,200 calculated |
| 1,500 sq ft × 2 inches | $3,900–$9,300 calculated |
| Approximate nominal R-value | Often R-5.8 to R-6.9[4] per inch, depending on product |
| Main pricing variables | Thickness, access, area, preparation, job minimums and protective barriers |
Don’t combine these price bands without checking their units. A broad installed cost-per-square-foot range can refer to an assumed project scope and foam depth. An installed board-foot rate describes material volume, so multiplying it by thickness gives a calculated cost per treated square foot.
For all spray foam products, see spray foam insulation cost.
How Much Does Closed-Cell Spray Foam Cost per Board Foot?
A board foot is 12 inches × 12 inches × 1 inch of finished foam. Board-foot pricing helps compare projects with different depths.
Board feet = surface area in square feet × installed thickness in inches.
Estimated foam-volume charge = board feet × installed rate per board foot.
For example, a 600-square-foot surface sprayed 2.5 inches thick requires 1,500 theoretical board feet. At a hypothetical installed $1.80 per board foot, the foam-volume calculation is $2,700 before excluded extras or minimum-job fees.
Why Some Contractors Quote Lower Rates
Angi’s main spray foam report gives the $1.30–$3.10[1][2] range for professionally installed closed-cell foam. Its separate general insulation pricing article cites $1–$1.50 per board foot[5], and some contractors publish local prices closer to that band. These are different datasets, dates and scopes rather than a price anybody can guarantee nationally.
Treat price references as benchmarks, then request itemized quotations identifying installed thickness, foam product, minimum charges, protective materials and labor.
For the underlying unit math, read our board-foot pricing guide.
Closed-Cell Spray Foam Cost per Square Foot by Thickness
Multiply the board-foot rate by the thickness. At $1.30–$3.10 per board foot[1][2], closed-cell costs $2.60–$6.20 per square foot at 2 inches and $3.90–$9.30 at 3 inches. The full table by thickness is on the cost per square foot page.
Closed-Cell Spray Foam Cost by Project Size
The table below uses two inches of closed-cell spray foam and Angi’s published installed board-foot range.
| Surface to be sprayed | Board feet at 2 inches | Calculated installed foam cost |
|---|---|---|
| 250 sq ft | 500 | $650–$1,550 |
| 500 sq ft | 1,000 | $1,300–$3,100 |
| 750 sq ft | 1,500 | $1,950–$4,650 |
| 1,000 sq ft | 2,000 | $2,600–$6,200 |
| 1,500 sq ft | 3,000 | $3,900–$9,300 |
| 2,000 sq ft | 4,000 | $5,200–$12,400 |
| 2,500 sq ft | 5,000 | $6,500–$15,500 |
Small jobs can be substantially more expensive per effective board foot because contractors must transport equipment, prepare the worksite and pay the crew regardless of job size.
A 2,000-square-foot house does not automatically need 2,000 square feet of insulation. Calculate wall, attic, basement or roof-deck surface area separately.
Worked Example: 1,200 Square Feet at Three Inches
A contractor measures 1,200 square feet of exposed surface and specifies three inches of a particular closed-cell product.
- Surface area: 1,200 sq ft.
- Finished thickness: 3 inches.
- Required theoretical board feet: 1,200 × 3 = 3,600 board feet.
- At hypothetical $1.75/bf: 3,600 × $1.75 = $6,300.
- At hypothetical $2.40/bf: 3,600 × $2.40 = $8,640.
Both unit rates are examples within Angi’s published range, not local offers. Add separately charged removal, repairs, access and fire-protection work.
How Much Does Closed-Cell Spray Foam Cost for an Attic?
Closed-cell foam can be specified for certain roof-deck or attic-floor applications, but the correct insulation location is more important than the rate per board foot.
A roof deck has a different surface area from the attic floor. Moving the thermal boundary to the roofline also changes moisture management and potentially the performance of ducts and conditioned space.
Illustrative roof-deck estimate: 1,000 square feet sprayed three inches thick equals 3,000 board feet, or $3,900–$9,300 using Angi’s board-foot rates, before exclusions.
Three inches is not a universal attic recommendation. The right depth depends on the actual product, climate zone, roof assembly, local code and other insulation in the design.
Closed-cell’s lower vapor permeability can be beneficial in some assemblies, but can limit inward drying if roof sheathing becomes wet. Roof leaks and existing damage must be resolved before installation. Ask the contractor or designer to explain the intended drying path.
Read our attic spray foam insulation guide for the broader assembly decision.
Closed-Cell Spray Foam Cost for Metal Buildings
Closed-cell foam is frequently evaluated for metal buildings because it can supply both thermal resistance and air sealing in a relatively thin layer. However, proper condensation management still depends on the whole assembly.
A hypothetical metal-building project with 2,400 square feet of actual wall and roof area insulated to two inches uses 4,800 theoretical board feet.
At the published $1.30–$3.10[1][2] range, that’s $6,240–$14,880 before separately charged preparation, access, protection and other work.
Metal surfaces need appropriate substrate preparation and application conditions. Don’t assume spraying foam alone solves every condensation problem, especially if thermal bridges, air leakage at transitions or bulk-water intrusion remain.
Closed-Cell Spray Foam Cost for Crawl Spaces and Basements
Closed-cell foam’s lower vapor permeability can make it suitable for certain rim-joist, foundation and crawl-space details. But below-grade assemblies are not interchangeable, and insulation is not a repair for liquid-water entry.
A sample 700-square-foot surface sprayed two inches thick equals 1,400 board feet. At Angi’s range, the foam-volume calculation is $1,820–$4,340.
That excludes any drainage, groundwater management, dehumidification, access improvements or substrate repairs needed before installation.
Ask the installer to identify the exact location, code-required protection, pest-inspection considerations where applicable, moisture-control strategy and long-term drying behavior.
Is Closed-Cell Foam Worth the Extra Cost Over Open-Cell?
It can be, where depth is limited or the assembly needs closed-cell’s lower vapor permeance. Closed-cell costs more per board foot but needs fewer inches for the same R-value; at range midpoints, reaching about R-20 over 1,000 square feet costs roughly $7,100 in closed-cell against $5,900 in open-cell. The math is on the open-cell vs closed-cell cost page.
What Affects the Final Installed Price?
Depth, measured area, minimum charges, access, substrate preparation, fire or ignition protection and local labor all move the price. Small rim-joist jobs often carry a much higher effective rate because of the minimum. See the main cost guide.
DIY Closed-Cell Spray Foam Cost vs Professional Installation
HomeGuide lists closed-cell DIY kits at about $300–$500 for 200–250 board feet and $700–$850 for 600–650 board feet[6]. Those are materials-only prices with theoretical yields, so they are not comparable with installed bids, and two-component kits carry real chemical-exposure risks. See DIY spray foam insulation.
How to Compare Closed-Cell Contractor Quotes
Compare totals for the same scope. Example: Contractor A offers $1.75 per board foot × 2,000 = $3,500, excluding a $900 protective treatment; Contractor B offers $2.10 × 2,000 = $4,200 with it included. B is $200 cheaper overall. Use the quote checklist.
Questions owners ask
How much does closed-cell spray foam cost per board foot in 2026?
Angi's data reports approximately $1.30–$3.10 per board foot professionally installed. Other pricing guides and local installers report narrower or lower bands under different assumptions.
How much does closed-cell spray foam cost per square foot?
The answer depends on installed depth. At two inches, applying Angi's board-foot range gives $2.60–$6.20 per treated square foot mathematically, before additional project charges. HomeGuide independently reports $3–$5 per treated square foot under its methodology.
How much does 1,000 square feet of closed-cell insulation cost?
At two inches deep, 1,000 treated square feet equals 2,000 board feet. Using Angi's installed rate range, that is $2,600–$6,200 before separately charged extras.
How much does two inches of closed-cell foam cost?
At the published $1.30–$3.10/bf rate, two inches translates to $2.60–$6.20 per treated square foot. Actual pricing can vary with project minimums and scope.
Why is closed-cell foam more expensive than open-cell foam?
Closed-cell foam is denser and generally provides greater R-value per inch and lower water-vapor permeability. Manufacturing, materials and application characteristics contribute to price differences, though the final bid also reflects labor and site conditions.
Is closed-cell spray foam worth the money?
It can be where the assembly benefits from a high R-value in limited depth or from its particular vapor characteristics. It's not automatically the best choice for every wall or roof, especially where drying potential matters.
Is closed-cell foam suitable for metal buildings?
It is frequently considered for metal walls and roofs because of its insulating and air-sealing characteristics. Condensation performance depends on the whole metal-building assembly and proper installation.
Sources
- How Much Does Spray Foam Insulation Cost?, Angi. Accessed October 19, 2026. National consumer cost guide from a survey of Angi customers. No update date shown; title says "2025 Data". Its installed per-board-foot ranges match HomeAdvisor's page updated June 17, 2026.
- How Much Does Spray Foam Insulation Cost?, HomeAdvisor. Accessed October 19, 2026. National consumer cost guide, updated June 17, 2026. Installed cost per board foot; national ranges, not quotes.
- How Much Does Spray Foam Insulation Cost?, HomeGuide. Accessed October 19, 2026. National consumer cost guide dated December 1, 2025. Installed cost per square foot and minimum job fees.
- Frequently Asked Questions, Spray Polyurethane Foam Alliance (SPFA). Accessed October 19, 2026. Industry trade association. Page metadata shows modified April 27, 2026. Typical density, R-value per inch, air-barrier thickness and vapor permeance ranges.
- How Much Does Insulation Installation Cost?, Angi. Accessed October 19, 2026. Updated October 6, 2026. Gives lower per-board-foot spray foam figures under different assumptions.
- How Much Does a DIY Spray Foam Insulation Kit Cost?, HomeGuide. Accessed October 19, 2026. Written November 5, 2025. Materials-only kit prices.