Can Mold Grow on Concrete?

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No wonder you're looking at this title twice. Mold on concrete is something you probably don't expect to see. But there it is, on a concrete floor, wall, patio or walkway. Concrete itself does not promote the growth of fungi; it crops up when moisture from a leaking pipe, humidity or condensation interacts with organic material on the concrete, such as carpet padding, drywall or paper. So put first things first: Clean up the area and then fix the water problem so the mold doesn't return. The steps to prevent mold are straightforward -- you won't have to look twice.

Things You'll Need

  • Humidity meter

  • Dehumidifier (optional)

Step 1: Waste No Time

Get into high gear if you see a water leak or pool of water. Clean up and dry the area immediately and thoroughly to prevent further mold growth.

Step 2: Redirect Water Sources

Inspect your home's water sources and channels to see if they're contributing to mold growth. Focus on your downspouts and your air conditioner's drain lines. If you're perplexed about where a puddle of water or condensation is coming from, call a licensed home inspector to help pinpoint the problem.

Step 3: Lower Indoor Humidity

Keep indoor humidity levels below 60 percent – even better, between 30 percent and 50 percent. You can measure relative humidity with a humidity meter, a nifty instrument available at most home improvement stores. While you're at it, check appliances that produce moisture – such as your dryer and stove – to ensure that they're vented properly.

Step 4: Improve Indoor Ventilation

Encourage air flow by opening doors and windows when possible. Use floor or table fans to help keep the concrete dry.

Step 5: Consider a Dehumidifier

Installing a whole-house dehumidifier or portable dehumidifier might be the final step for stubborn moisture problems indoors. Consult a licensed heating, ventilation and air conditioning technician to ensure that you purchase the correct size for the area you are trying to treat.


Remember that a central air conditioner not only cools your home but also reduces humidity. But it must be the proper size; a system that is too small probably won't remove moisture. Call a licensed HVAC expert to inspect your system to ensure that it is the right size for your home.

Check your HVAC filter every month and replace it when it becomes clogged with dust and dirt. A clean filter will help prevent mold and keep your air conditioner running efficiently.


M.T. Wroblewski

M.T. Wroblewski

With education, health care and small business marketing as her core interests, M.T. Wroblewski has penned pieces for Woman's Day, Family Circle, Ladies Home Journal and many newspapers and magazines. She holds a master's degree in journalism from Northern Illinois University.