Vapor Barrier

What is a Vapor Barrier?

A vapor barrier is a sheet of plastic that is laid down on the ground to trap moisture and prevent it from entering the living space of a home. The plastic sheeting that is used is made of reinforced polyethylene plastic sheeting, also referred to as poly for short. The plastic comes in many different thicknesses. The minimum standard for a crawl space is a 6 mil sheet of plastic, which means it is 6 millimeters thick. One millimeter is equivalent to .001 inches so a 6-mil sheet of plastic thickness is .006 inches in thickness. The thickness does not change the amount of moisture but the higher the thickness prevents tearing.

More Facts On Controlling Water/Moisture In Your Crawl Space

Why use a Vapor Barrier?

The primary reason is to prevent unwanted moisture into the home. If moisture from the crawl space enters the living space it will increase the relative humidity and potentially cause mold and mildew to grow inside the home. If this happens it can be a health hazard to people. Another preventative measure for a sheeting barrier is used for is to prevent wood rot. If there is high moisture content in the crawl space it can cause the wood in the crawl space to rot over time.

Are there any other benefits to a sealed crawl space?

A wet crawl space is a conducive condition for pests such as wood destroying insects and rodents. By using a vapor barrier this reduce the likelihood of pests entering the crawlspace and then into the home. Other benefits of covering bare ground are that it prevents wiring mishaps caused by moisture or rust and corrosion of wires it provides and extra insulation to improve a home’s energy efficiency and gives a cleaner, easier access to the crawl space.