How to Install a Crawlspace Vapor Barrier

In very warm, humid climates such as the Southeastern United States, crawlspace encapsulation is often the most effective way to solve and prevent moisture damage. Although crawlspace vents were originally designed to facilitate humidity exchange with the outside air, they may contribute to mold and rot in some geographic locations as saturated air condenses on crawlspace walls, foundation footings and the underside of flooring. This can lead to mold and mildew, waterlogged insulation — which reduces R-value and causes sagging — as well as poor air quality inside the home. While a professional mold remediation specialist can help you determine if a crawlspace encapsulation is the best way to address moisture problems in your crawlspace, it’s helpful to understand how the job is done and what challenges a specialist may encounter.

In addition to ensuring the proper humidity level is maintained in a crawlspace, it’s crucial that the landscape is sloped away from the home to divert water away from the foundation. The best time to address this issue is during the home’s construction. It may also be necessary to re-landscape after building on an addition, as digging a new foundation can change the slope of a parcel of land; newly compacted soil will begin to settle over time.

Drainage problems can also be remedied with a combination of other solutions:

• Waterproof the outside of foundation walls to prevent water from wicking
• Install underground pipes to carry runoff from downspouts the proper distance away from the foundation
• Install French drains around the perimeter of the home

Here's how a technician might address your crawlspace mold or moisture problem.