Crawl Space Odors

Should you leave the old vapor barrier and debris behind when performing crawl space encapsulation? Can leaving old vapor barrier and debris be causing odors? We had a great Ask a Ninja from Georgia and wanted to share our thoughts:

"I purchased a home in March which had mold remediation and a 20 mil Dura Skrim vapor barrier installed (ground only). A Sante Fe dehumidifier keeps humidity in the high 40's; there are 2 open vents out of 9 in a 1400 sq ft space; no active vent fans. The crawl space smells, but not like cat urine. I believe it to be soil off gassing and it gets pulled into the HVAC. Can CSN add-on to my existing (newish) 20 mil barrier to complete an encapsulation or must we start over?"

Crawl Space Odors - Cat Pee

Not every odor you find in the crawl space smells like cat urine. Cat urine odors are prevalent in many crawl spaces. Crawl space encapsulation is not a guarantee your crawl space will not smell like cat pee. We feel the biggest reason for cat urine odors in crawl spaces is cheap reinforced vapor barrier. If you recently had the crawl space encapsulated with reinforced vapor barrier consider removing and replacing the plastic.

Crawl Space Odors - Soil Gases

Crawl space odors can also come from under the plastic and the odor can be hard to identify. Many homeowners want us to leave down the old vapor barrier. This can be a problem if the old vapor barrier was ever exposed to sewage or moldy debris. Most will not take time to wipe down the plastic before installing new plastic on top. trapping odors between plastic can create a hot bed for more bacteria. More bacteria can become more odors after crawl space encapsulation.

Debris Under the Vapor Barrier Causes Odors

This is one of the biggest overlooked items when dealing with crawl space odors. The debris under the plastic vapor barrier can grow mold, wood rot fungus, bacteria and slime molds. The percolate together and off gas some powerful odors. make sure you remove as much loose organic debris as you can prior to installing vapor barrier.

Do you need help battling an odor in your crawl space? If so, please contact Crawl Space Ninja or Basement Ninja and we will be glad to help. Also, let us know in the comments below if you'd like to suggest a future blog post.

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About Michael Church

Michael Church has been involved with indoor air quality since 2005 and feels the unhealthy crawl space is one of the major problems causing poor indoor air quality.

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