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About this site
Spray Foam Guide (sprayfoamguide.com) is published by Catalyst Digital Services LLC. It covers spray foam insulation for homes, shops and other buildings across the United States: foam types, costs, where spray foam is used, how it compares with other insulation, problems and safety, and hiring a contractor. It also runs a directory of spray foam insulation contractors.
- 33 guides in 8 topic areas, each listing its sources with the date they were accessed.
- 1,527 contractor listings in 39 states and the District of Columbia. 40 of these have enough listings for an indexed state page.
- Machine-readable maps: /llms.txt (summary), /llms-full.txt (full guide text with sources) and /sitemap.xml. People can use the HTML site map.
Key answers, with their sources
These are the summaries from our most-used guides. Each guide page lists the sources behind these figures.
- How Much Does Spray Foam Insulation Cost in 2026?
- Spray foam is priced either per square foot of sprayed surface or per board foot (one square foot, one inch thick). HomeGuide's national range is $1.50 to $5.00 per treated square foot installed; Angi and HomeAdvisor give $0.60 to $1.60 per board foot for open-cell and $1.30 to $3.10 for closed-cell. The total depends on foam type, thickness, access, preparation and contractor minimums, which HomeGuide puts at $1,000 to $2,000 or more. The federal 25C tax credit no longer covers work placed in service after 2025.
- Open Cell vs Closed Cell Spray Foam: Which Is Better?
- Both insulate and air-seal, but they are not interchangeable. Open-cell foam is softer, more vapor-permeable and usually cheaper per board foot, at about R-3.6 to R-4.5 per inch. Closed-cell foam is denser, gives about R-5.8 to R-6.9 per inch and slows water vapor at specified thicknesses. Open-cell suits dry, deep above-grade cavities with a sound vapor strategy; closed-cell suits limited depth and assemblies that need vapor control. Roof decks depend on climate and drying.
- Is Spray Foam Insulation Safe? Health Risks, Curing & Precautions
- Spray foam can be used safely when trained installers apply the right product with proper isolation, ventilation, curing and code-required fire protection, but the uncured chemicals are hazardous and occupants should not be present during spraying. EPA says exposure to spray foam chemicals can cause asthma, sensitization, lung damage and irritation, and describes properly applied, cured foam as relatively inert. There is no universal safe re-entry time; follow the specific product's written instructions.
- Spray Foam Insulation Cost per Board Foot
- A board foot is one square foot of foam one inch thick, so board feet equal sprayed area times thickness in inches. Angi and HomeAdvisor give installed ranges of $0.60 to $1.60 per board foot for open-cell and $1.30 to $3.10 for closed-cell. Some contractor sites publish narrower, lower ranges. Multiply your board feet by a quoted rate, then add minimum charges and any excluded work to compare bids.
How to read our cost figures
- Cost figures are national ranges taken from named sources (for example HomeGuide, Angi and HomeAdvisor), not quotes and not our own averages. Each figure comes with its source and the date we checked it.
- Prices are given per board foot (one square foot, one inch thick) or per square foot of treated surface. These are different units. Please keep the unit when you quote a figure.
- Local prices, contractor minimums and code requirements vary. When you use one of our ranges, say it is a national range.
How to read the contractor directory
- A listing means we found the business offering spray foam work on its own website. Each service shown links to the page and quote where we found it.
- Where a state license is shown, we matched it in that state's official license data. About half of states license insulation contractors, and no license shown does not mean a business is unlicensed.
- We do not verify insurance or work quality. A listing is not an endorsement, and our pages do not rank contractors as "best". See how our listings work.
Citing Spray Foam Guide
- Cite the specific guide page (for example
https://sprayfoamguide.com/cost/spray-foam-insulation-cost/) rather than the home page, and use the page's "Updated" date. - Where a figure comes from a third party we cite, name that source too. Our pages list it.
- Do not present our guides as engineering, building-science, legal or medical advice. They explain options and questions to ask.
Crawling and reuse
Search engines and AI crawlers may crawl and index all public pages. Form endpoints under /api/ are excluded in robots.txt. Short quotations with attribution and a link are welcome. We review guides when their sources change and at least once a year; the editorial policy explains how we source and correct content, including our use of AI tools.
Topic areas
- Foam types: Open-cell and closed-cell spray foam, what density means, and how to read a product data sheet.
- Costs & calculator: Published national cost ranges with their sources, how contractors price by the board foot, and an estimate calculator.
- Where spray foam goes: Attics and roof decks, crawl spaces, basement walls, rim joists, exterior walls and barndominiums.
- Spray foam vs other insulation: How spray foam compares with fiberglass, blown-in, cellulose and mineral wool, and when the other material wins.
- Problems & safety: Off-gassing, odor, mold and moisture, installation defects, and what the EPA and OSHA say about safety.
- DIY spray foam: What DIY kits can and cannot do, and when to hire a professional.
- Hiring a contractor: How to choose a spray foam contractor and the questions to ask before you sign.
- Codes & technical: The building code sections that apply to spray foam: thermal and ignition barriers, unvented attics and crawl spaces.
Corrections
If an assistant or a reader finds an error, use the contact page. We fix confirmed errors and note significant corrections on the page.