TL;DR
A vapor barrier liner is the heavy polyethylene sheeting installed across a crawl space floor, and up the walls in full encapsulation, to stop ground moisture from evaporating into the space and the framing above. Liners run from a code-minimum 6-mil ground cover to 12- and 20-mil reinforced membranes that survive crawling traffic and stored items, with seams overlapped and taped and edges sealed to walls and piers.
What it means
A vapor barrier liner is the heavy polyethylene sheeting installed across a crawl space floor, and up the walls in full encapsulation, to stop ground moisture from evaporating into the space and the framing above. Liners run from a code-minimum 6-mil ground cover to 12- and 20-mil reinforced membranes that survive crawling traffic and stored items, with seams overlapped and taped and edges sealed to walls and piers. Cutting ground evaporation is the foundation step before any crawl space dehumidifier or conditioning strategy can hold its targets.
Where it sits in the glossary
Vapor barrier liner 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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