TL;DR
Closed-cell spray foam is a two-component polyurethane applied by heated spray rig that expands into a dense, rigid insulation of about two pounds per cubic foot. It insulates near R-6.5 per inch, blocks air movement completely, qualifies as a vapor retarder at around 1.5 to 2 inches, and adds racking strength to framing.
What it means
Closed-cell spray foam is a two-component polyurethane applied by heated spray rig that expands into a dense, rigid insulation of about two pounds per cubic foot. It insulates near R-6.5 per inch, blocks air movement completely, qualifies as a vapor retarder at around 1.5 to 2 inches, and adds racking strength to framing. Crews use it on rim joists, crawlspace walls, unvented roof decks, and pole barns; its higher cost per board foot versus open-cell is the main trade-off in quotes.
Where it sits in the glossary
Closed-cell 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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