Under the house
Crawl vapor barrier
Bare soil under the house feeds moisture for months. What a ground cover actually does — and how it fails.
Soil under a crawl continuously releases water vapor. Without a ground cover, that moisture loads the air under the floor and often the living space above.
A continuous polyethylene sheet is the basic control. Overlap seams, seal where practical, and run the sheet up foundation walls. Thin plastic that shreds becomes waste, not a system.
A vapor barrier is not a flood fix. Bulk water from grade and gutters still has to be handled outside.
After the ground is covered, measure humidity. Persistent high readings may point to ventilation strategy or mechanical drying as a next step.
Educational only — not a contractor inspection or bid. When work is structural, electrical, or involves unknown vent chases, hire a qualified local trade.