TL;DR
Closed-cell foam is insulation whose tiny gas bubbles are fully encapsulated rather than interconnected, giving it high R-value per inch, rigidity, and strong resistance to water absorption. In the two-pound spray form it delivers roughly R-6 to R-7 per inch, acts as a vapor retarder at adequate thickness, and measurably stiffens walls and roof decks.
What it means
Closed-cell foam is insulation whose tiny gas bubbles are fully encapsulated rather than interconnected, giving it high R-value per inch, rigidity, and strong resistance to water absorption. In the two-pound spray form it delivers roughly R-6 to R-7 per inch, acts as a vapor retarder at adequate thickness, and measurably stiffens walls and roof decks. The same cell structure appears in rigid boards like XPS and polyiso, which is why these products tolerate damp locations that would ruin open-cell or fibrous insulation.
Where it sits in the glossary
Closed-cell 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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