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Mold in Crawlspace due to Damaged Vapor Barrier

Examples of how a damaged vapor barrier can cause mold in your crawlspace.

mold in crawl space missing vapor barrier

Mold on soil

Moldy Vapor Barrier

Mold on Vapor Barrier

examples of mold in crawlspace

Mold on Vapor Barrier

poor crawl space vapor barrier leads to mold

Bad Crawl Space Vapor Barrier

how to avoid mold in crawl space

Mold on Vapor Barrier

mold in crawl space due to wet vapor barrier

Flooded Vapor Barrier

Project Report > Mold in Crawlspace due to Damaged Vapor Barrier



  • Sufficient – Crawlspace insulation is sufficient (at least R-30), well secured, and provides good coverage.
vapor barrier mold insulation

Insulation Fallen on Vapor Barrier


  • Multiple air gaps present between crawl space and lower floor of the building.  This greatly reduces the energy efficiency of the home by allowing cold outside air to infiltrate the heated portion of the home.


  • At the time of inspection, no increased moisture content was noted in the framing or subflooring, but the mold growth suggests that moisture content is likely increased at specific times of the year.

Vapor Barrier:

Missing Vapor Barrier Near Sump Pump

Water Damaged Vapor Barrier

  • Damaged – Vapor barrier damaged and missing in areas, allowing excessive moisture transfer from damp soil into crawlspace framing.
  • Contaminated – Vapor barrier shows evidence of past flooding or is extremely soiled.


  • Current ventilation is adequate to exhaust normal amounts of humidity.

Other Contamination:

  • Evidence of past or present rodent infestation was noted, contaminating the insulation and vapor barrier, requiring removal and replacement.  Rodent feces, urine, and other associated debris may harbor bacteria, parasites, and odors.
  • A pest control specialist is recommended to provide a plan to resolve the current infestation and prevent future pest infestations

Trash and Debris:

  • Stored contents located in crawlspace, it is necessary for these contents to be completely removed prior to the start of any clean-up work.

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