How to Conquer the Mold in Your Basement

Here’s how to address this serious issue lurking in your basement.

Man with a protective mask removing mold on a wall with a sponge and cleaning agent.
Image: cmannphoto/getty

Basements are often the forgotten spaces of our homes. For families that don’t use them as cozy movie night retreats, they serve as storage areas, laundry rooms, or a place for guests to stay. However, they can also be a breeding ground for a silent, unwelcome guest you need to get rid of — mold. 

If you’ve ever noticed a musty odor or discoloration on your basement walls, you might have a mold problem. This comprehensive guide will explore what you need to know about basement mold, from its dangers to effective removal and prevention methods.

Safety First: Is It Safe to Be in a Basement with Mold?

Homeowners may wonder whether it's safe to spend time in a space contaminated with mold. The short answer is maybe. 

Mold does pose a serious health risk. Those with asthma, allergies, and immune deficiency issues are far more at risk. Mold spores are everywhere, and most people can coexist with a low quantity of mold. But high quantities can cause even healthy people to experience long-term issues including allergies, cough, sore throat, shortness of breath, and skin and eye irritation.

Those who are immunocompromised are at greater risk of lung infection. If anyone at home is coming down with symptoms related to mold exposure, consult a health professional. 

Mold needs four things to grow: oxygen, a certain temperature range, organic material, and water. We can’t control the first three, but we can control water to stop mold growth. Be sure to rule out the existence of mold before waterproofing your basement.

Note that time is of the essence when mold shows up. Mold damages whatever it touches, so once you notice indicators like musty mold odors, act quickly.

Minimize your time in the affected space and focus on swiftly addressing this issue to keep your family safe.

Is It Safe to Sleep in a House with Mold in The Basement?

It's best to spend as little time as possible in a home with mold. If you don’t have other accommodations during the basement mold remediation, sleep in a room that isn't mold-infested, and keep the following tips in mind:

  • Have your HVAC and humidifier system inspected and ductwork cleaned before you continue using it. 
  • Throw away items infected with mold.
  • Let fresh air in through windows or other ventilation systems.
  • Seal off the basement door with plastic tarps.
  • Change and wash your clothes after leaving the basement.
  • Designate the cleanest room at home as your sleeping area and seal it off with plastic tarps. 
  • Avoid bringing shoes into the sleeping area.
  • Shower from head to toe before tucking in for the night.

How Do I Get Rid of Mold in My Basement?

The first step in removing mold and mildew in your below-ground space is to recognize the signs. Once the mold is removed, you can begin mold remediation, or assessing and sanitizing the materials that the mold affected. Let’s review signs of mold.

Signs of Mold in a Basement

If you know your basement is prone to dampness, investigate it periodically for signs of mold. A musty smell and black spots or stains are strong indicators of mold. You may also find mold hidden behind peeling or bubbling paint or wallpaper.

The time to search for water is when you first suspect mold is present. Focus on finding where the water is entering. Thermal imagers are a great way to visually examine a large area for water entry. Pro tip: Many libraries have thermal imagers that you can check out to use at home. It’s also vital to have a moisture meter to prove or disprove the existence of water. 

Have you experienced watery eyes, sneezing, and other allergy symptoms after spending time in the basement? These may be signs your basement has a mold problem. Mold can grow around air conditioning vents, pipes, humid areas like bathrooms, and anywhere in your home where condensation gathers. Basements often check off more than one of these boxes.

Removing Mold from Your Basement

Brown and black mold along the bottom of a wall in a basement.
Image: Epiximages/getty

The size of the mold area determines who should clean it up.

If the mold covers an area less than 10 square feet, and you aren’t immunocompromised, you could consider DIYing the mold removal from a nonporous surface by taking these steps:

  • Use PPE equipment like an N-95 respirator, gloves, and goggles to avoid contact with mold or mold spores.
  • Find and fix plumbing leaks. Allow the area to completely air dry.
  • Scrub moldy surfaces with detergent and water. Wear rubber gloves if you choose stronger cleaning solutions or disinfectants.

If the mold covers an area greater than 10 square feet, is black mold, or has taken over valuable furniture, it’s best to hire a professional. Basement mold removal can cost $1,500 to $4,000. If you choose to waterproof your basement after removing the mold, the cost can be $10 to $50 per square foot, with the average job between $3,000 to $7,000.

When hiring a professional to remove the mold in your basement, ask if they have experience cleaning mold following EPA guidelines.

Get Rid of Basement Mold for Good

After mold is removed from your basement and the space has been cleaned, take steps to keep it from returning. Consider these steps to help prevent moisture build-up in your basement.

  • Regularly inspect and repair pipe and foundation leaks.
  • Minimize clutter in your basement and keep the area well-ventilated.
  • Keep humidity levels below 60% with a dehumidifier and humidity tracker (hygrometer).
  • Use mold-resistant building materials in your basement.
  • Consider waterproofing the space.

How Can I Prevent Mold in the Basement?

Keeping your basement dry and clean is essential to prevent mold. If you live in a humid climate, you can install a dehumidifier or air conditioner in the basement. For some homeowners, leaks or bad plumbing may be causing basement dampness. Look for damaged or worn-out rain gutters, which may be leaking water around your home. Check for French drains or other drainage systems that may be clogged and not functioning properly.

Do Dehumidifiers Really Help With Mold in a Basement?

A dehumidifier can be a powerful tool in fighting basement mold. Again, it’s best to keep humidity levels under 60%, preferably 30% to 50%, at home. Moisture humidity meters can help you track the humidity in your basement. If mold is already in your basement, a dehumidifier will help you reduce humidity levels.

Benefits of Using a Dehumidifier in Your Basement

A dehumidifier is an easy, at-home solution to a recurring mold problem. Here's how a dehumidifier can help keep you and your possessions safe.

  • Mold prevention: Mold growth slows when humidity is at the right level.
  • Improved air quality: Removing excess moisture reduces musty odors and allergens that can result from mold.
  • Protects belongings: A dry basement will prevent damage to furniture, clothing, and other household items.

Frequently Asked Questions About Mold in the Basement

What is Mold?

Mold is a cluster of microscopic organisms that help break down matter in the natural world. It can grow almost anywhere. Indoors, it can grow on any contaminated surface if there is moisture in the air. It can enter your home through open doors and windows, air conditioning, clothing, and shoes.

Does Homeowners Insurance Cover Mold in the Basement? 

Homeowners' insurance may cover mold in the basement, depending on your policy and the source of the mold. Some policies may cover mold in the basement resulting from a broken pipe or water damage caused by extinguishing a fire. Consult your insurance provider to understand your policy and coverage.

Can Mold in the Basement Affect Upstairs Rooms?

Yes, mold spores can travel through the home's ventilation system to the upper floors of the house. Mold can also spread through pipes or ducts, and through carriers like pets or people who may unknowingly have mold spores on their clothes, shoes, fur, hair, etc., after spending time in the basement.

Banish Mold from Your Basement

Mold in your basement is more than a cosmetic issue — it’s a hazard for your family. By identifying the potential sources of moisture and mold, and vigilantly preventing and removing it, you can keep mold out of your basement.

For most mold cases, you'll benefit from hiring a mold remediation professional who has experience following Environmental Protection Agency guidelines and can accurately evaluate the situation. These strategies should equip you to keep mold out of your basement for good and keep your family healthy.

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