Removing Mold From Your Home’s Basement Floor Joists

If you recently discovered mold growing on the wooden floor joists in your home's basement, then it is vital that you take immediate action to kill it, and to fix the moisture problems feeding the mold's growth.

Follow these steps to kill all of the mold and protect the structural integrity of your house:

Step 1: Put on a protective respiratory mask that is approved for use with mold spores. You can purchase a mask at your local home improvement store. Mold spores that are inhaled into your lungs can make you very ill, so this step is strongly recommended.

Step 2: Do a complete visual inspection of the entire basement area and look for any wood that shows mold or water staining. Since mold requires moisture to grow, you need to find any moisture coming into contact with your home's wood joists.

Step 3: Once you have located moisture locations, then you need to fix them before you can rid the area of the mold colonies. Some of the most common moisture removal methods include:

  • fixing any leaking plumbing
  • opening any closed vents leading into the basement
  • putting down plastic sheeting as a moisture barrier to prevent condensation 

If you do not make these repairs before you kill the mold, then it will just return.

Step 4: One of the most effective ways to kill mold spores is to spray them with chlorine bleach. You can mix a solution of one cup of bleach with a gallon of water and pour it into an inexpensive airless pest control sprayer.

When working with a bleach solution in a confined space such as your basement or a crawlspace, it is important that you do not saturate the wood too much with water. If you waterlog the wood fibers, then they will not dry in a reasonable time and more mold will grow. 

Step 5: Using the bleach solution, spray down all of the areas where you have identified mold and water staining. Spray a liberal layer of the solution, but do not spray so much water that the joists start dripping excessively. If you spray too much water, simply wipe it with a paper towel.

One application of bleach solution should kill all of the mold. However, if you notice any remaining black staining after about two days, then you should respray the area again and check to make sure there are no continuing water leaks that you need to repair. If all else fails, contact a mold remediation company.