TL;DR
A crawlspace vapor barrier is the polyethylene sheeting laid over exposed earth under a house to stop soil moisture from evaporating up into the framing, insulation, and air. Building code requires a minimum of 6-mil poly with lapped seams in many situations, while encapsulation-grade liners run 12 to 20 mil with taped joints and turn up the foundation walls.
What it means
A crawlspace vapor barrier is the polyethylene sheeting laid over exposed earth under a house to stop soil moisture from evaporating up into the framing, insulation, and air. Building code requires a minimum of 6-mil poly with lapped seams in many situations, while encapsulation-grade liners run 12 to 20 mil with taped joints and turn up the foundation walls. Even as a standalone measure in a vented space, ground cover alone can cut crawlspace humidity dramatically for a few hundred dollars in material.
Where it sits in the glossary
Crawlspace vapor barrier 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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