Crawl Space Ventilation vs. Encapsulation

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So, your crawl space has moisture. The question now becomes, what are you going to do about it? Will natural ventilation adequately remove the moisture or should you have your crawl space sealed, also known as encapsulated?

Moist crawl spaces can lead to wood rot, fungus, mold, poor indoor air quality, and even pest infestations. Wood rot can cause costly structural home repairs. Because of the problems moisture causes, both in air quality as it funnels up into the home and the way wet wood can compromise the structural integrity of the home, it’s not really an option to leave a crawl space wet. So, which option should you choose: ventilation or encapsulation?

Pros and Cons of Natural Ventilation

 A while back, one of the ways builders used to prevent moisture from getting into crawl spaces was to use natural ventilation, by installing grates into the foundation to keep the elements out while allowing air through. This method didn’t, however, account for the high humidity that is carried in the air. Here are some pros and cons of using natural ventilation in your crawl space:


  • The cost of crawl space ventilation is much lower than crawl space encapsulation
  • Keeps out some moisture


  • Through tests conducted by the Environmental Protection Agency EPA and Advanced Energy, it has been found that especially in the southeastern United States, ventilated crawl spaces did not keep out moisture as well as properly sealed closed spaces.
  • The air quality is lower than in sealed crawl spaces
  • The RH (Relative Humidity) level is higher than with sealed crawl spaces

What is Encapsulation?

 Crawl space encapsulation is a process of sealing a crawl space to protect it from moisture through the use of reinforced vapor barriers, sealants, and water removal devices. Vapor barriers are large plastic sheets that keep moisture out. The point of encapsulation is to keep the water in the soil instead of having it spread the house.

Pros and Cons of Crawl Space Encapsulation

Crawl space encapsulation has been the most successful way to keep moisture out of crawl spaces in recent years. Here are the pros and cons:


  • The most effective way of keeping moisture and humidity out
  • Reduce heating, air conditioning, and energy costs
  • Keeps out pests


  • The cost of encapsulation is higher than ventilation

One of the ways to learn about how your particular crawl space can be protected from moisture is to have a moisture inspection. PESTOUT is currently offering free moisture inspections ($125 value) and will go over the different options and costs of moisture control for your crawl space. PESTOUT has qualified, experienced moisture control experts to help you take care of your crawl space, and ultimately your home.

Click here to schedule an inspection or call (757) 856-6557