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Community and Q&A

Mold Removal from Crawlspace Floor Joists

user-1138423 | Posted in General Questions on

How do I remove mold from wood floor joists in crawl space and prevent future mold due to moisture in the crawl space? I found molds on my first floor supporting wood joists in the crawl space. I need to remove the mold and prevent future molds. I am planning to install new Class 1 vapor retarder on crawl space dirt and close out all vents on foundation walls except two for cross ventilation.

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  1. GBA Editor
    Martin Holladay | | #1

    The most important first step is to make sure that your crawl space is dry. You can't do anything about the mold problem until you tackle the moisture problem.

    Here is an article that talks about fixing a wet basement. Most of the advice in that article also applies to crawl spaces, so I suggest that you read it: Fixing a Wet Basement.

    After implementing some of the measures discussed in that article, you may want to take the advice provided in this article: Building an Unvented Crawl Space.

    As far as the existing mold is concerned, you will hear conflicting advice on the issue. Once the space is truly dry, you can either (a) ignore the mold, or (b) wash the moldy joists with ordinary soap and water and a scrub brush, or (c) wipe the joists with a solution of household bleach and water.

    The main point is: once you get the area dried out, you won't have a mold problem any more.

  2. user-6782788 | | #2

    I had my modular home delivered in late January along a 2.5 hr route from the factory under wet sloppy snowy salty grimy conditions from Maine to NH. The bottom was completely unwrapped and exposed to splash and spray on the entire undercarriage of the wooden floor joists. The modules are now set on the foundation and the home is all enclosed now so access is from the basement. How could this road grime be cleaned from the floor joists? The factory will be paying for a professional service to complete this.

  3. plumb_bob | | #3

    I would say an old fashioned scrubbing with soap and water with a bristle brush would work. When the cleaning is done have large fans and a dehumidifier put in the space to take out the moisture.

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