How to Treat Mold in a Crawl Space

Crawl spaces often have many of the conditions known to promote the growth of mold. Among these conditions are high humidity, heat retention and absence of direct sunlight. Several long- and short-term solutions are available for controlling mold in such areas. The treatment will also depend on how long the mold has been established in the crawl space.

A high-powered vacuum can be used to remove thin layers of mold from a crawl space.

Things You'll Need

  • Dust respirator

  • Long-sleeved shirt

  • Pants

  • Plastic gloves

  • Tape

  • Safety glasses

  • Plastic barrier sheet

  • Floodlight

  • High-power shop vacuum (5-10 horse power)

  • Mold scraper

  • Paintbrush

  • Mold-inhibiting paint

Step 1

Protect yourself completely from the mold and other possible environmental hazards in the crawl space. Wear a long-sleeved shirt and pants that completely cover your legs. Put on the plastic gloves and tape them closed beneath the sleeves of your shirt. Secure the dust respirator around your nose and mouth, and put on your safety glasses.

Step 2

Spread the plastic barrier sheet onto the floor around where you will be removing the mold. This sheet will capture any mold that falls off while you are vacuuming. The plastic sheet also will provide a barrier between you and the ground. Setup the floodlight so that you can see all of the mold you wish to remove. Depending on the ventilation in the crawl space, set up fans to increase the air flow while you work.

Step 3

Use the shop vacuum to remove the light covering of mold in the crawl space. Try different attachments to determine which is most effective at removing the mold. Use a scraper to remove mold that is difficult or impossible to extract using the vacuum.

Step 4

Paint the surfaces where you have removed the mold, using a paintbrush and mold-inhibiting paint. If you have a large surface area to cover, the mold-inhibiting paint can be sprayed onto the surfaces in the crawl space. Allow the paint to dry.

Step 5

Determine why mold got established in the crawl space, and correct the cause to avoid having to remove mold from under your home again. Corrective procedures may include installation of external drainage systems to end drainage problems; correcting the slope of the ground around your home to make sure water can't flow into the crawl space, and improving waterproofing of the external framework of your house.


If you are unable to remove all of the mold yourself with your high-powered shop vacuum, you may want to contact a duct-cleaning service. These services have industrial-strength vacuums that are better than shop vacuums at removing mold and other materials.


Wearing safety gear for this job is extremely important. Inhaling mold spores can be harmful to your health. Take all necessary precautions before you start on this project.