The Shield Below: Ground Vapor Barriers within Crawlspaces

Hidden beneath our feet, crawlspaces play a crucial role in the structural integrity and health of our homes. These dark and often damp places can harbor moisture-related problems leading to potential health hazards and structural damage. Thankfully, vapor barriers made from polyethylene plastic sheeting are a relatively inexpensive method to help control moisture. In this article, we explore the significance of vapor barriers in helping to prevent water from the ground causing high humidity within the crawlspace and the rest of the home.

Understanding the Role of Ground Vapor Barriers
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Excluding the obvious sources of water vapor into the crawlspace such as interior water leaks and water intrusion from the exterior, the single largest source of humidity within a crawlspace is from the ground itself through water evaporation. Water from the exterior of the house will infiltrate to the interior ground surface of the crawlspace through simple capillary action where it then evaporates.

A vapor barrier is a thin, impermeable material typically made from polyethylene or similar plastics. When installed on the ground in a crawlspace it acts as a protective shield, preventing water vapor from the damp soil below from rising and infiltrating the crawlspace and living spaces above. This simple yet effective technique offers a multitude of benefits, ensuring a healthier and more comfortable home environment.

The Perils of High Humidity

High interior humidity levels can lead to a host of problems, some of which may not be immediately apparent:

1. Mold and Mildew Growth: Excessive moisture encourages the growth of mold and mildew, leading to unsightly stains, foul odors, and potential health issues for occupants.
2. Dust Mites and Allergens: Humid environments provide an ideal breeding ground for dust mites and allergens that can trigger allergic reactions and respiratory problems in sensitive individuals.
3. Reduced Comfort: High humidity levels make indoor spaces feel sticky and uncomfortable.
4. Structural Damage: Prolonged exposure to moisture can cause corrosion of metal in electrical, plumbing, and structural components and can rot wooden beams, floor joists, and other structural elements, compromising the overall integrity of the home.

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Mobile and manufactured homes often have unique challenges compared to traditional houses, including a higher susceptibility to moisture-related issues. Due to their mobility and often temporary installations, they are more prone to uneven ground, which can lead to poor drainage and increased moisture within the crawlspace.​

Benefits of Vapor Barriers

The benefits of installing vapor barriers in crawlspaces are significant:

• Mold and Mildew Prevention: High humidity levels and excess moisture create an ideal environment for mold and mildew growth, ultimately leading to corrosion of metals, wood rot, and damage to structural elements. By helping to maintain a dry environment, vapor barriers extend the life of your home's foundation and other systems.
• Improved Energy Efficiency: By keeping the crawlspace dry, the installed insulation's effectiveness remains intact, reducing the strain on HVAC systems and resulting in lower energy bills.
• Pest Mitigation: Vapor barriers on the ground can help to discourage and thwart infestation from subterranean termites, burrowing animals, and other unwanted critters.
• Radon Mitigation: Radon is present in our area, but not prevalent; click here for more information. Ground vapor barriers are a common mitigation measure against radon, should that be present, promoting a cleaner and safer living environment.

 
In the quest to protect our homes from moisture-related issues, the vapor barrier has emerged as an invaluable ally. From controlling moisture and preventing mold growth to enhancing energy efficiency and structural integrity, vapor barriers play a vital role in safeguarding our living spaces. Embracing this essential technology allows us to ensure the long-term safety, health, and comfort of our homes.