http://www.AsktheBuilder.com founder Tim Carter describes a vapor barrier that's underneath a concrete slab that's about to be poured. Carter reveals why it's mission critical to install a vapor barrier.

Discover more about vapor barriers at askthebuilder.com:
http://www.askthebuilder.com/high-performance-vapor-barriers/
http://www.askthebuilder.com/house-wrap-vs-vapor-barrier/
http://www.askthebuilder.com/vapor-retarders-will-stop-odors-and-moisture/