TL;DR
Spray foam is a two-component polyurethane insulation applied as a liquid that expands in place, sealing air leaks while it insulates. Open-cell foam runs about R-3.6 to R-3.9 per inch and stays vapor-open; closed-cell reaches R-6 to R-7 per inch, adds rigidity, and resists moisture, making it the choice for rim joists, crawl spaces, and unvented roof decks.
What it means
Spray foam is a two-component polyurethane insulation applied as a liquid that expands in place, sealing air leaks while it insulates. Open-cell foam runs about R-3.6 to R-3.9 per inch and stays vapor-open; closed-cell reaches R-6 to R-7 per inch, adds rigidity, and resists moisture, making it the choice for rim joists, crawl spaces, and unvented roof decks. Building code requires a thermal or ignition barrier such as drywall over it in living and many attic spaces, and proper mix ratios during installation prevent lingering odor.
Where it sits in the glossary
Spray foam is part of the Trade jargon group inside the ProFix Directory glossary. Browse every term in this category from the glossary index.
Why Ohio homeowners should know it
This is a term Ohio homeowners encounter when reading contractor quotes, hiring paperwork, or inspection reports. Understanding it well enough to ask one good follow-up question is usually all the protection a homeowner needs.
ProFix Directory keeps definitions short on the index page and saves the longer context — Ohio-specific rules, where the term comes from, and which ProFix tools touch it — for these per-term pages so the term is easy to cite and easy to share.
ProFix tools that touch this term
See also
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