Crawl spaces in Vermont homes represent one of the most overlooked yet consequential zones of building performance, frequently serving as the primary pathway for moisture intrusion, radon entry, and heat loss.
A properly engineered crawl space encapsulation system transforms this neglected zone from a source of building problems into a conditioned asset that enhances overall structural performance.
Vapor Barrier and Sealing Protocols
Encapsulation begins with a continuous heavy-gauge vapor barrier that covers the entire crawl space floor and extends at least six inches up foundation walls, sealed at all seams, penetrations, and terminations with butyl tape and mechanical fasteners. We specify reinforced polyethylene membranes of at least twenty mils thickness that resist puncture during installation and provide a durable long-term vapor seal. Foundation wall vents are permanently sealed, and the perimeter is air-sealed at the rim joist, band joist, and sill plate using closed-cell spray foam that simultaneously provides air sealing and insulation at these critical transition points.
Conditioned Air Management
An encapsulated crawl space must be integrated into the home's conditioned envelope, receiving a controlled supply of conditioned air that maintains relative humidity below sixty percent year-round. We install dedicated dehumidification systems in spaces where the HVAC system cannot provide adequate moisture control, with condensate drainage to the exterior rather than into the crawl space. A four-mil vapor barrier liner with integrated sump cover ensures that any ground moisture that accumulates beneath the barrier is directed to a sealed sump basin with a covered pump system, preventing evaporative moisture from affecting the conditioned environment above.
