What Does Spray Foam Insulation Cost?
Professional spray foam insulation installation typically costs $2,000 to $12,000 for a single-area job such as an attic or crawl space, averaging around $5,000. A whole-house retrofit runs $10,800 to $26,300. The price depends on the foam type, the area covered, and the installed depth, and installers commonly hold a minimum charge near $2,000, so a small job does not buy a small price.
Open-Cell Spray Foam: $0.44 to $0.65 per Board Foot Installed
Open-cell spray foam is the more affordable option. It is priced by the board foot – one square foot at one inch of depth – at $0.44 to $0.65 installed, material and labor together. Depth is what turns that unit rate into a job: an attic sprayed 6 in. deep is six board feet for every square foot of floor, so a 1,000-square-foot attic is 6,000 board feet and costs $2,640 to $3,900 in open-cell foam. Bulk foam material on its own runs about $0.10 per board foot for open cell and about $0.40 for closed cell, so material is only a fraction of an installed price and quoting the material rate alone understates a job badly. Open-cell is appropriate for interior applications where moisture resistance is not required. (For more on this, see What Affects Spray Foam Insulation Cost?.)
Closed-Cell Spray Foam: $1.15 to $2.00 per Board Foot Installed
Closed-cell foam runs roughly three times the open-cell rate for the same depth, at $1.15 to $2.00 per board foot installed. It is also sprayed thinner, because it delivers more R-value per inch: at 3 in. on a roof deck or a rim joist that is $3.45 to $6.00 for every square foot of surface, so 1,000 square feet of roof deck runs $3,450 to $6,000. Contractor quotes for attic spray foam in an existing home reach $5,900 to $12,000 at the high end. Closed-cell is required for moisture-exposed surfaces (basement walls, crawlspaces, rim joists) and for applications requiring a vapor retarder.
Labor Is Already Inside the Board-Foot Rate
No residential spray foam installer sells this work by the hour. The trade quotes by the board foot, and those are installed rates with labor already inside them, so there is no separate hourly charge to add on top of the numbers above. The application itself is fast a skilled crew applies spray foam quickly once the proportioner equipment is running. Setup, masking, and cleanup account for a significant portion of the labor time. For small projects, the setup and mobilization cost makes the effective rate per square foot higher than for large projects, and installers hold a minimum charge near $2,000: contractor-quoted crawl space projects run $2,100 to $3,600, rim joists $2,100 to $2,800, and attic projects start near $2,970 even when the sprayed area is small. (For more on this, see How Long Does Spray Foam Insulation Last?.)
Spray Foam Insulation Cost at a Glance
| Cost Factor | Typical Range | Notes |
|---|---|---|
| Open-cell foam | $0.44 to $0.65 per board foot installed | lighter and more affordable; a board foot is one square foot at one inch of depth, so an attic sprayed 6 in. deep is six board feet for every square foot of floor |
| Closed-cell foam | $1.15 to $2.00 per board foot installed | denser with better insulation and moisture resistance, at roughly three times the open-cell rate for the same depth |
| Attic or roof deck | $2,970 to $12,000 installed | a 1,500 sq ft attic at 6 in. of open cell lands near the floor; a closed-cell roof deck reaches the top |
| Crawl space or rim joists | $2,100 to $3,600 installed | a rim joist alone is $2,100 to $2,800 and a crawl space $2,100 to $3,600, each quoted as its own job |
| Overall range | $2,000 to $12,000, averaging $5,000 | one area of a house; a whole-house retrofit runs $10,800 to $26,300 |
Cost figures on this page were checked against published pricing on September 2, 2026. How we source cost data.
Planning Your Project Budget
The cost ranges in this article are based on industry data and are intended as planning benchmarks, not fixed prices. The actual cost for your project depends on your specific home, your local labor market, the current price of materials, and the scope the contractor confirms after a site inspection.
Always get at least two written quotes on equivalent defined scope before committing to any home services project. Wide price variation between quotes usually reflects differences in material quality, scope completeness (what is included and what is not), or contractor overhead and experience level rather than simple price competition.
Use the cost data in this article to ask better questions during the quoting process: What material is included? What does that per-square-foot or per-linear-foot rate include and exclude? Are permits, cleanup, and disposal included? What is the warranty on labor? These questions turn a quote into a comparable basis for decision-making.
Working With a Contractor on This Project
Getting the right outcome on any home services project starts before the work begins. A few consistent practices make the difference between a smooth project and a frustrating one.
Get at least two or three quotes. A single quote gives you no basis for comparison. Two or three quotes reveal the market rate for the work, expose scope differences between bidders, and let you assess contractor communication quality before any commitment is made. The lowest bid is not automatically the best value if the scope is thin or the materials are underspecified.
Ask for licenses and insurance before work starts. Verify current general liability insurance and, for any work involving workers on your property, workers compensation coverage. Licensing requirements vary by state and trade; confirm the specific requirements in your jurisdiction. A licensed contractor who carries appropriate insurance protects both parties if something goes wrong during the project.
Get the scope in writing. A written proposal that specifies materials, labor scope, timeline, what is included (permits, cleanup, disposal), and warranty terms is the foundation of a professional engagement. Verbal agreements on any of these points invite misunderstanding. For any project over $500, written scope is non-negotiable.
Clarify the payment schedule upfront. A reasonable payment schedule ties major payments to project milestones: a deposit at signing, a payment at material delivery or project start, and a final payment at completion after a walkthrough confirms satisfaction. A contractor who requires full payment upfront before work begins is a red flag in any trade.
