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Mold in the crawl space
Mold in a crawl space is a moisture reading you can see. Cleaning it off without changing the moisture buys a few months.
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The short version
- The cause
- Damp air and wet ground under the house.
- Fix first
- The source of the moisture: drainage, leaks or humid air.
- Call a company when
- The mold covers more than a small patch, or the wood is soft.
Signs from inside the house
- A musty smell on the ground floor.
- Floors that feel damp or cupped.
- Condensation on ducts and pipes below.
- Allergy symptoms that ease when you are away.
Signs in the crawl space
- White, grey or black growth on joists.
- Standing water or wet soil.
- Sagging or wet insulation.
- Wood that is soft when probed.
What the EPA says
- Moisture firstYou "must clean up the mold and fix the water problem." Cleaning alone means it will likely return.
- The 10 square foot lineBelow about 10 square feet, most people can handle cleanup themselves. A crawl space is usually well past that.
- Choosing a company"Make sure the contractor has experience cleaning up mold," and check references.
- Hidden growthIf you suspect hidden mold, the EPA suggests considering an experienced professional.
What a mold company will do
- Find where the moisture is coming from.
- Fix or refer drainage, plumbing and ventilation problems.
- Clean the framing and remove ruined insulation.
- Recommend ways to keep the space dry, such as a vapor barrier.
The EPA does not recommend biocides as a routine part of mold cleanup. Be cautious with a quote built around fogging or spraying alone.
Related guides
Crawl space encapsulation: what drives the cost
Mold remediation: what drives the cost
Mold testing: when it is worth paying forSources
- US Environmental Protection Agency: mold, moisture and your home