Spray Foam Insulation
Core spray foam pages that explain material types, costs, R-values, and common alternatives.
How Much Does It Cost to Spray Foam a House?
Spray foam is priced by the project, not by the house. Here's what the common jobs actually cost across Hamilton County — and how to estimate yours.
Quick Answer
Spray foam is priced by area and thickness, so cost depends on what you're insulating. Typical Indiana projects run about $2,500 to $6,000 for a crawl space, $3,500 to $7,500 for an attic, and $10,000 to $30,000 for a whole new-construction home. Most existing homes don't need foam everywhere — targeted jobs are common and far cheaper.
Why There's No Single Price
Spray foam is quoted by the board foot — one square foot of coverage at one inch of thickness — so the bill tracks how much area you cover and how thick the foam goes. A 200 sq ft rim joist and a 2,500 sq ft new build are completely different projects. That's why "how much to spray foam a house" has no one answer: it depends on which parts of the house you're insulating, the foam type, and the target thickness. The ranges below are based on real Indiana installed pricing (open-cell at $0.35–$0.45 per board foot, closed-cell at $1.25–$1.40) and corroborated by 2025 national cost data.
Typical Project Costs
| Feature | Typical installed range | Best-fit foam |
|---|---|---|
| Rim joist / band joist | $1,200 - $3,000 | Closed-cell |
| Crawl space encapsulation | $2,500 - $6,000 | Closed-cell |
| Attic at the roofline (retrofit) | $3,500 - $7,500 | Open-cell |
| Garage or bonus room | $1,500 - $4,000 | Open-cell or closed-cell |
| Whole new-construction home | $10,000 - $30,000 | Open-cell, closed-cell, or hybrid |
| Metal building / pole barn (1″ shell) | $1,600 - $4,800 | Closed-cell |
Rim joist / band joist
Typical installed range
$1,200 - $3,000
Best-fit foam
Closed-cell
Crawl space encapsulation
Typical installed range
$2,500 - $6,000
Best-fit foam
Closed-cell
Attic at the roofline (retrofit)
Typical installed range
$3,500 - $7,500
Best-fit foam
Open-cell
Garage or bonus room
Typical installed range
$1,500 - $4,000
Best-fit foam
Open-cell or closed-cell
Whole new-construction home
Typical installed range
$10,000 - $30,000
Best-fit foam
Open-cell, closed-cell, or hybrid
Metal building / pole barn (1″ shell)
Typical installed range
$1,600 - $4,800
Best-fit foam
Closed-cell
What Moves the Price
Five factors drive most of the variation in a spray foam quote. Foam type: closed-cell costs roughly three times open-cell per inch because it's denser and adds a moisture barrier. Thickness: a 6-inch attic application uses three times the foam of a 2-inch wall. Accessibility: tight crawl spaces and high rooflines take longer to spray. Old insulation removal: pulling out sagging fiberglass adds roughly $300 to $875. And new construction versus retrofit: open stud bays spray fast, so a new build costs less per square foot than tearing into finished walls.
Is It Worth It?
Spray foam's value is the air seal and high R-value in one step. The EPA estimates that sealing air leaks and adding insulation cuts heating and cooling costs by about 15% on average — and in Indiana's colder climate zone, closer to 16%. The biggest returns usually come from the leakiest parts of the house: the attic, crawl space, and rim joists. That's why most homeowners get more from a targeted job than from foaming every cavity.
Our Verdict
Don't budget for "spray foaming the whole house" unless you're building new — most Hamilton County homeowners get the best return from a targeted job (crawl space, rim joist, or attic). Run your square footage through the calculator for a project-specific estimate, then we'll confirm it on a free quote.
Frequently Asked Questions
Yes. Open stud bays and exposed rooflines spray quickly, so new builds cost less per square foot than retrofits where drywall has to come down first. If you're planning a remodel, insulating while the walls are open is the most cost-effective time to do it.
Rarely. The attic, crawl space, and rim joists account for most of a home's air leakage and energy loss, so targeting those areas delivers most of the comfort and savings at a fraction of whole-home cost. A free quote will identify where foam pays off most for your home.
For full coverage on a new build (walls plus roofline), national figures run roughly $10,000 to $30,000, with an average around $20,000. Most existing homes spend far less because they only foam targeted areas like the attic or crawl space rather than every cavity.
Closed-cell is denser, delivers a higher R-value per inch (R-6.5 versus R-3.6 for open-cell), and acts as a moisture barrier. You're paying for more performance per inch, which is why it's reserved for crawl spaces, rim joists, and metal buildings where those properties matter.
Related
Related resources
Related Services
Open-Cell Foam
Cost-effective spray foam for attics and interior assemblies where comfort and sound control matter.
- Lowest cost per board foot of any spray foam
- Noticeably quieter, reduces sound between rooms and from outside
- Great for attics, interior walls, and bonus rooms
Closed-Cell Foam
High R-value insulation with moisture resistance for crawl spaces, basements, metal buildings, and demanding envelopes.
- Highest R-value of any spray-applied insulation (R-6.5 per inch)
- Acts as a vapor barrier
- Won't absorb water — ideal for moisture-prone areas
Attic Insulation
Stop losing heat through the roof. We insulate attics for year-round comfort and lower energy bills.
- Reduce heating and cooling costs immediately
- Prevent ice dams in winter
- Create usable conditioned attic space
Crawl Space Insulation
Seal out moisture, pests, and cold floors with closed-cell foam applied directly to crawl space walls.
- Reduce moisture and mold risk
- Warmer floors in winter
- Stop musty crawl space air from entering your living space
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