Crawl Space Encapsulation:  What It Is And What It Isn't

Crawl space encapsulation is often misunderstood because it is marketed as a product rather than a process. Many homeowners believe encapsulation simply means installing thick plastic or wrapping the crawl space walls, but plastic alone does not stop moisture. True encapsulation is about controlling air and humidity so condensation can no longer form.

In humid climates, moisture enters crawl spaces primarily as warm, damp air. When that air contacts cooler surfaces beneath the home, it releases moisture through condensation.

Encapsulation works only when humid air is prevented from entering and indoor humidity is actively controlled. Without air sealing and dehumidification, plastic liners become cosmetic coverings rather than functional solutions.

A proper encapsulation includes sealing crawl space vents, sealing the crawl space door, sealing penetrations and gaps, installing a ground vapor barrier, and adding a dehumidifier to maintain stable humidity levels. Cleaning contaminated materials and correcting drainage issues must happen before the space is sealed. Skipping any of these steps results in trapped moisture, mold recurrence, and system failure.

Encapsulation is not waterproofing, mold treatment, or a visual upgrade. It is a building science solution designed to stabilize the crawl space environment year-round. When done correctly, it protects the structure, ductwork, plumbing, and indoor air quality for decades. When done incorrectly, it becomes an expensive mistake.

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