Greater Cincinnati quotes mostly price closed-cell at $1.50-$2.50 and open-cell at $0.50-$1.20 per board foot (1 sq ft, 1 inch thick). A rim joist usually runs $800-$2,200; an attic runs from about $4,500 for a shallow closed-cell deck to $15,000-plus at full depth.
More detail
Spray foam is sold by volume, so every quote reduces to one multiplication: square feet of surface, times inches of depth, times the price per board foot. That is why two attic quotes can sit thousands of dollars apart without either one being padded. Three worked examples at local rates. A basement rim joist 150 feet around, with a band about a foot tall sprayed 3 inches deep, is roughly 450 board feet, which is why most rim jobs land at $800-$2,200 once setup and the truck trip are counted. A 1,200 square foot roof deck at 3.5 inches of closed-cell is 4,200 board feet, or about $6,300-$10,500. Fill that same deck to 7 inches for roughly R-49 and the foam, and the price, doubles. Open-cell is cheaper per board foot but needs about twice the depth for the same R-value, so on a wide-open vented attic floor, blown cellulose over a sealed floor usually reaches R-49 for less; our spray foam vs cellulose comparison shows where each wins. For a national check, the HomeAdvisor cost guide updated in June 2026 lists installed closed-cell at $1.30-$3.10 and open-cell at $0.60-$1.60 per board foot, so local pricing sits inside that band. What moves a quote up: pulling out old insulation (the same source lists $1-$2 per square foot for attic removal), steep or partly finished attics that slow the crew, an ignition-barrier coating in attics and crawl spaces or drywall over foam in living space, closing soffit and ridge vents when an attic becomes unvented, and a ventilation upgrade when the house gets tight. There is no federal tax credit to subtract in 2026, because Section 25C ended for property placed in service after December 31, 2025, and Duke Energy Ohio no longer runs a general insulation rebate, so judge the job on its own savings; the 2026 incentives rundown lists what does exist, including the Duke Energy Kentucky envelope incentive on the Northern Kentucky side. To read a quote line by line, use our quote walkthrough, then run your own square footage through the spray foam cost calculator.