Open vented crawlspaces in Western North Carolina's humid climate draw in moisture, driving subfloor relative humidity above 80% and rotting floor joists. We install engineered closed crawlspace encapsulation systems with heavy multi-ply 20-mil antimicrobial membranes sealed airtight to foundation stem walls.
Old building codes mandated open foundation vents under the false assumption that outside air dries dirt subgrades. In Western NC's warm, humid summers, hot ambient air enters cool crawlspaces, reaches its dew point, and condenses directly on wooden subflooring, feeding white rot fungus and buckled hardwoods.
We install commercial-grade 20-mil multi-layer virgin polyethylene liners reinforced with polyester cord grids. Tear-proof and puncture-resistant, our membranes are pinned and taped 6 inches below termite inspection lines on masonry walls, creating a zero-permeance vapor seal.
Every open foundation vent is permanently sealed with insulated covers. We apply R-15 closed-cell expanding spray foam along perimeter rim joist bands, stopping conditioned air loss and sealing exterior insect entry pathways.
All conversions adhere strictly to NC Residential Code Section R409, requiring continuous 100% ground covering, mechanical drying equipment, and dedicated termite inspection gap bands.
While thin 6-mil plastic tears easily, building code and durability standards recommend heavy 12-mil to 20-mil fiber-reinforced antimicrobial liners.
Yes. Sealing crawlspaces from hot summer humidity and cold winter drafts typically reduces heating and cooling utility costs by 15% to 25%.
Our heavy commercial reinforced liners are engineered for 25+ years of continuous durability without degradation or outgassing.