Indoor Air Quality and the Crawlspace

Help Customers Breathe Easy

crawlspace mold

Moisture control is more than just about pest prevention; it’s about public health

In addition to preventing termites and other wood-destroying organisms (WDO) from settling in a structure, moisture control helps with indoor air quality, too.

Did you know that up to 60 percent of the air you breathe inside your home comes from the crawlspace and basement?

I recall one client whose interior walls were so wet, water was seeping down them. Upon inspection, we found mold everywhere, even in the attic.

Additional investigation of the outside foundation walls, living area and attic indicated mold problems. We realized the problem originated in the crawlspace. Scary as the situation was, though, it was easily resolved with a moisture control program.

Using the correct materials is key to keeping mold from occurring and/or recurring. Take the following steps to prevent mold from growing.


  1. Remove all debris, including wood products and stored articles.
  2. Level the ground and install a sump pump as needed. Look for areas where water may accumulate or has drained previously.
  3. Check to see if water is appearing through or under the foundation walls. If water is present, you may need to waterproof outside.
  4. Treat all surfaces, including the subfloor and foundation walls, with an oxygen-based cleaner such as UltraMean2. This will clean the surface mold as well as the deeply embedded roots inside any porous materials. Scrubbing might be necessary. Rinse as needed and let dry.
  5. The understructure should be treated with UltraBan-PRO plus Bora-care. UltraBan-PRO not only acts as a barrier to prevent future mold growth but when added to a liquid borate, it enhances borate retention by as much as 30%, prolonging it’s useful life in preventing mold, termites, powder post beetles and other wood ingesting insects. Following the label, the entire understructure should be treated, including foundation walls and supports.
  6. Apply a 100 percent ground cover using 10-mil. (or stronger) polyethylene, and seal all vents. Note: The polyethylene should be clear, not white, for termite inspection purposes. Cover the foundation walls and piers, too. Seal all seams on the ground cover, piers, walls, around vents and foundation walls because these are entry points.
  7. Install an industrial dehumidifier of sufficient size for the space, with a sump pump to remove condensing water to the outside in a drain system designed to remove water from the foundation.


  1. Because attics also can contribute to moisture control in a structure, consider adequate ventilation, insulation and heat.
  2. Follow steps 1, 4 and 5 for the aforementioned basements/crawlspaces as needed. For best results, add cellulose insulation as necessary and install a Radiant Barrier to the underside of the roof decking between the rafters.

Outside of the Home

  1. Make soil grade changes as needed in low areas – a half-inch grade per foot away from the structure for at least 10 ft. out.
  2. Install gutters with covers and downspouts to direct water away from outside walls.
  3. In some cases, it might be necessary to install French drains (also known as weeping tile) to redirect water away from the perimeter walls. Consider waterproofing these walls.

Moisture control and mold remediation are important issues. Mold might be a nuisance to some, but deadly to others. Because termite professionals inspect the areas where moisture and mold originate, they have an opportunity to offer their customers a solution to these problems.

5 Comments on “Indoor Air Quality and the Crawlspace

  1. Great point you bring up. Pest control professionals often detect mold before home owner might simply because they may recognize it better or frequent the craw spaces more often. Certain molds can kill you and most will damage your health so all homeowners should keep an eye out for this or perform your own inspection occasionally.

    • Humidity monitors are very helpful in determining if you have a mold problem. Relative Humidity at and above 70% is where problems start. Recommended inspection is annual. Humidity is highest in warmer months.

      • Have you ran into many other pest control professionals who are also trained at identifying mold?

      • Yes, over the past twenty years or so many Pest Control Operators have been trained in identifying mold in structures. Mold remediation isn’t what we do, our expertise is generally limited to the crawl space dealing with ground moisture coming into crawl spaces with limited ways to reduce that moisture to acceptable levels!

  2. Thanks Paul

    Toni Markey Markey OFOA Inc DBA Orkin PO Box 975 Dadeville, Al 36853 256-392-9990


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