Install vapor barriers over all exposed earth in crawl spaces and basements
Soil can be a major source of moisture entering a building.
An impermeable ground cover will significantly reduce the problem. The barrier doesn't have to be completely sealed to be effective, but it should cover all exposed surfaces and have generous overlaps at the seams. If the barrier also is intended to control soil gases, sealing the barrier may be important. In areas that will receive periodic foot traffic for maintenance of mechanical equipment, the ground cover should be durable and provide enough traction for safety. If a basement is not located under a wood floor, and if other soil gas problems are not anticipated, leaving an earthen floor exposed may be acceptable.
Green points
NGBSNational Green Building Standard Based on the NAHB Model Green Home Building Guidelines and passed through ANSI. This standard can be applied to both new homes, remodeling projects, and additions. /ICC-700: 6 points for installing a 6-mil vapor retarder on a crawlspace floor. It should extends up walls far enough to be attached with glue and furring strips.
Learn more in the Green Building Encyclopedia
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