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Permanent Vent Sealing
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4 products
4 products
What You Need to Know
Crawl space vent covers provide permanent sealing of foundation vents during encapsulation or conditioning projects, eliminating outdoor air infiltration to create the controlled environment essential for effective moisture management. By blocking humid summer air and cold winter air from entering through foundation vents, these covers prevent condensation, mold growth, and the air quality issues that plague traditionally vented crawl spaces.
Why Sealing Vents Is Essential for Encapsulation
Traditional crawl space design relied on passive ventilation through foundation vents to manage moisture. Modern encapsulation reverses this approach—sealing all vents, installing vapor barriers, and using dehumidifiers for active moisture control. Vent covers are the critical first step in this transition, blocking the outdoor air infiltration that would otherwise introduce humidity into your sealed space and force dehumidifiers to work inefficiently. Up to 50% of the air in your home originates in the crawl space, making proper sealing essential for indoor air quality and energy efficiency.
Outward vs. Recessed Mounting Options
Vent covers come in two primary installation styles, each with distinct advantages. Outward-mounted covers attach to the exterior foundation wall over existing vent openings—no need to remove old vents or work inside the crawl space. These surface-mount designs accommodate slight size variations and install quickly from outside. Recessed covers install from inside the crawl space, fitting into the foundation opening for a flush exterior appearance. They provide a cleaner look but require crawl space access and removal of existing vents for best results.
Sizing Considerations
Foundation vent openings typically measure 8" × 16", but actual dimensions vary. Outward-mounted covers offer more size flexibility—large covers (21" × 13") and small covers (18" × 10") accommodate variations in opening size and condition. Recessed covers require more precise fitting, with standard depth (1¼") fitting most foundation walls and shallow depth (¼") for thinner walls or special applications. Measure your foundation openings before selecting covers to ensure proper fit.
Durable ABS Construction
Quality vent covers use ABS plastic with UV stabilizers—material that won't rust, rot, warp, or deteriorate like wood or metal alternatives. This weatherproof construction withstands decades of exposure to sun, rain, temperature extremes, and ground-level moisture. Available in black and white to match foundation exteriors. The material accepts adhesive or fastener mounting and can be insulated by gluing rigid foam to interior surfaces for added thermal protection.
Installation Methods
Vent covers install with exterior-grade fasteners (concrete anchors or masonry screws) or construction adhesive. Fasteners provide the strongest permanent attachment, while adhesive offers a clean look without penetrations. Some installers use both methods for maximum security. All covers can be insulated by adding rigid foam insulation to interior surfaces, creating thermal barriers that prevent heat loss and protect pipes from freezing while maintaining the encapsulation seal.