How-To Videos

How to Reduce Mold and Moisture Under Your Home

By: Allen Lyle
Man with headlamp inspecting crawlspace under house.

Allen Lyle inspecting crawlspace under house.

The crawlspace under your home can be a breeding ground for mold. Taking the following steps can keep it from happening:

  • Make sure the crawlspace has plenty of ventilation.
  • Fill in any low spots in the crawlspace with sand.
  • Cover the ground under the entire crawlspace with a layer of 6 mil or thicker plastic.
  • Put a layer of sand on top of the plastic to hold the plastic in place and absorb any excess moisture.

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5 Comments on “How to Reduce Mold and Moisture Under Your Home”

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  • Theresa Says:
    November 11th, 2017 at 9:21 pm

    There is a section under our house that has standing water that looks stagnant and has white mold on top of it.
    Is this safe? Willnit cause health issues?
    And what do we do?

  • emily Says:
    September 25th, 2016 at 5:39 pm

    I have a lot of moisture under my tiles. They are changing the color of my tiles. What can I do to fix the problem?

  • wayne clark Says:
    October 19th, 2014 at 7:55 pm

    I own a 50s house that has been extensively remodeled to include insulation in the rafters, knee walls in up stairs attic area and in between first and second floor.. We are experiencing high humidity issues (80 plus). The house is well insulated with the exception of the down stairs floors. In inspecting the under area, it has mold growing on the floor joist and sub floor. The under area is damp where the mold is growing but no signs of moisture. I am increasing the ventilation (leaving vents and access holes open) and plan to put down plastic. Question: Should I add insulation under the floor and treat the under floor area for mold?

  • Jared Says:
    August 25th, 2010 at 2:16 pm

    Great video. Another solution would be to install heavy plastic in your crawl space, and encapsulate to ensure that your sealing off unwanted moisture.

  • Larry Says:
    June 15th, 2009 at 4:15 pm

    Another solution would be to install heavy 20 mil plastic up the wall, fasten and seal it to the top of the foundation. Run the plastic along the ground and seal every seam that overlaps the ground and wall with tape. Then seal your vents and condition the space with existing HVAC or from the upstairs air. This will convert your crawlspace into a clean, healthy environment. If standing water is a problem, a drainage system may be needed prior to installation.

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How to Reduce Mold and Moisture Under Your Home