How to eliminate mold and mildew in a basement

Mold gets a bad reputation. In the outside world, mold and mildew actually serve an essential task, by breaking down bio-matter, like dead leaves and insects, so that their nutrients can return to the ecosystem. Your basement, however, is a completely different story. According to the U.S. Centers for Disease Control and Prevention, about 10 percent of the population is sensitive to mold allergens, meaning that exposure to mold can lead to rashes, irritation, sinus congestion and difficulty breathing. Some kinds of mold, known as "black mold," can cause adverse health effects in anyone that comes into contact with them.

If you've found mold in your basement, it is important to act now, before it inevitably spreads to the rest of your house. Mold and mildew spread via spores, which can be transported through the air in your house to any place dark, warm and damp enough for mold to grow. The good news is that most of the time a mold outbreak can be handled completely DIY, so there's not necessarily a need to break out the checkbook. However, if you don't feel comfortable dealing with mold, or it is growing in a difficult-to-reach spot, it's worth consulting a professional.

Assemble your tools

  • Borax
  • White vinegar
  • Plastic sheeting
  • Measuring cup
  • Spray bottle
  • Mixing bucket
  • Face mask
  • Scrubbing brush
  • Rubber gloves
  • Trash bags (recommended)
  • Fan/dehumidifier (recommended)
  • Identify the leak

If there is a significant amount of mold growing in your basement, then there is sure to be a water source not far behind. Mold can only survive in humid conditions, so the first step is to find and seal the leak. If your basement floods, you should start by checking any portals to the outside, like windows and doors, to find out which one is letting the water in. Other common culprits include unsealed pipes, dryers that don't vent to the outside and leaks in the foundation of the house. Once you have identified the cause of the moisture in your basement, take steps to fix the problem. You won't have much, if any, success in removing your mold problem before you deal with the underlying cause.

Prepare the basement
Once you have fixed the moisture problem in your basement, it is time to begin sealing the basement off from the rest of the house. When you start cleaning off the mold, you are likely to cause a large number of spores to get released into the air, which you don't want circulating through your house. Turn off your heating or cooling system, depending on the time of year, and cover any air vents and doors to the rest of the house with the plastic sheeting. Don't forget to wear a face mask to protect your lungs.

You do want to vent as much air as possible to the outside, so open any windows or doors to the outside that you can. recommends that homeowners set up a dehumidifier and point a fan in the direction of a window, circulating air and spores out of the house. Remember to clean the dehumidifier after this before you use it anywhere else in the house.

Next, remove anything from the basement that isn't nailed down. If you plan to carry this stuff out through the rest of your house, put anything that will fit into trash bags in order to avoid contamination. Before you return anything to the basement, make sure you check it for mold.

Make your mixture
There are a number of commercial fungicides on the market, and most of them are rather expensive. According to, most of these products fair no better against mold than good old vinegar and borax. Vinegar has a strong smell, but it can't be beat for small, concentrated areas of mold. Borax is all-natural and will eliminate mold on large surfaces like sheetrock.

Undiluted vinegar can be used for small spaces, like cracks, but borax should be mixed with water. Mix in about one cup of borax per gallon of warm water and use it to refill your spray bottle as needed throughout the job.

Tackle that mold
If you have a finished basement that is developing mold, it may be more work to get all of the mold than in an unfinished basement. That said, a finished basement is generally less hospitable to mold, meaning you might have less, so on a case by case basis, it's a wash. If you do have a finished basement, remember that wherever you see mold, there is likely to be more hiding behind it. It's better to be safe than sorry, so you may have to tear up wall sheathing to get at the mold, which can be costly, but it's worth it to ensure your family's health and well being.

When you're ready, spray everything liberally with your cleaning solutions until you've covered everything that may have been in contact with the mold. It only takes one spore and the right conditions for mold to grow back, so be thorough and spray a little bit past where you see mold. Once everything is totally sprayed down, take a rest for an hour or two and let the mixture soak in.

When you come back, give everything another spray down to refresh the mold killing solution on your walls. Next, take out that brush and get to scrubbing, refreshing your water frequently. You really want to get every bit of mold out of your basement, so don't worry about overdoing things. When you're satisfied that all of your mold is gone, you should still spray everything down with borax again – just to be sure.

Finally, keep all of the windows and doors to the outside open and let everything dry. This is crucial, as any moisture could tempt your mold problem to return.

Nicely done, mold removal is hard work, but it's worth it for ensuring your and your family's health. While you're basking in the satisfaction of a job well done, consider investing in a home warranty. A TotalProtect® Home Warranty is the only home warranty that comes with a 180-day repairs guarantee, so even if your appliance breaks again, you will know that you're covered.

The information in this article is intended to provide guidance on the proper maintenance and care of systems and appliances in the home. Not all of the topics mentioned are covered by our home warranty or maintenance plans. Please review your home warranty contract carefully to understand your coverage.