North Carolina revised its building code in 2018, leading to some brand-new regulations regarding encapsulated crawl spaces, including cleared-up wording for exceptions to the venting requirement. The building code still treats a vented crawl space as the default, but it’s coming to realize that unvented crawl spaces are very much preferable. Now you can have an unvented crawl space as long as you meet the following requirements:

  • Air-sealed crawl space perimeter wall 
  • Tight-fitting access panels or doors that have a latch mechanism and insulation 
  • A certain amount of coverage with the vapor barrier 
  • A method of crawl space moisture control that may include a dehumidifier, supply air, house air, exhaust fan, or conditioned space

Additionally, all crawl spaces, both vented and unvented, have the following requirements:  

  • Complete separation of the crawl space with adjoining basements, porches, and garages 
  • A termite inspection gap of 3-4 inches 
  • A vapor barrier of at least 6-mil covering all exposed earth

This can seem like a confusing array of requirements, but a crawl space expert can walk you through it. Remember that these are the minimum; for example, although the vapor barrier must be at least 6-mil, there’s nothing saying that it can’t be more robust, like JES’ preferred 20-mil CrawlSeal™ vapor barrier.

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