TL;DR
Open-cell foam is spray polyurethane insulation whose cells remain interconnected, curing soft and spongy at about 0.5 pounds per cubic foot and roughly R-3.5 to R-3.8 per inch. It expands a hundredfold to fill cavities and seals air leakage exceptionally well, but it is vapor-permeable and absorbs water, so it stays out of below-grade and exterior applications.
What it means
Open-cell foam is spray polyurethane insulation whose cells remain interconnected, curing soft and spongy at about 0.5 pounds per cubic foot and roughly R-3.5 to R-3.8 per inch. It expands a hundredfold to fill cavities and seals air leakage exceptionally well, but it is vapor-permeable and absorbs water, so it stays out of below-grade and exterior applications. Its lower cost per inch makes it the usual choice for interior walls, sound control, and thick attic rooflines in milder climates.
Where it sits in the glossary
Open-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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