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How to Get Rid of a Musty Smell in Your Basement

If musty odors are keeping you from using your basement, it’s time for that to change. With a bit of effort, you can eliminate funky smells from your below-grade spaces for good.

Empty basement iStock

Pungent, musty odors can make a basement unbearable to spend time in. If strong enough, these awful odors can even work their way up into the rest of the house. Instead of ignoring the problem, learn how to get rid of it.

1. Find the Source

The first step to getting rid of musty smells in your basement is identifying where they’re coming from. Most of the time, the smell is simply a symptom of the actual issue, which is mold or mildew caused by moisture.

Here are some areas to check for cracks or leaks that could be causing the smell:

  • Basement windows (Do the wells improperly direct water toward the house, instead of away from it?)
  • Basement exterior entrances
  • Windows from the floor above
  • Exterior doors from the floor above
  • Bathroom and kitchen plumbing from the floor above

It’s also possible that the cause of the issue is groundwater. If the grading around your home pitches back toward your basement, water will eventually work its way in. In this case, re-grading the property might be the best option. You can also hire a contractor to dig around the foundation and install a French drain to divert water. For extremely wet basements, a trough around the interior leading to the sump pump might be necessary to control groundwater.

If your finished basement smells musty, but you’re sure there are no leaks behind the walls, the odor could be coming from a dry floor drain or p-trap under a sink. Since these drains don’t see frequent use, the fluid in the trap that blocks sewer gasses can dry up. Pouring a few cups of water into these drains from time to time might make the difference, as they’re often the issue when a dry basement smells.

Keep in mind that musty smells could also be due to pet odors on furniture or carpets. If everything is watertight and dry, and your traps are full of water, there’s a good chance that the issue is in the fabric of your carpets or upholstered furniture.

2. Make the Repairs

Even if you are able to get rid of the musty smell in your basement temporarily, it will come back if you don’t resolve the issue. Troublesome windows and doors will leak whenever it rains, and cracked or leaky pipes will continue to cause problems until you replace them. If your cold-water pipes sweat, you can insulate them with pipe wrap.

Severe leaks in the foundation may require excavating outside and applying a waterproofing membrane. Otherwise, you can coat the interior of the foundation with a waterproofing treatment.

Be sure to address any wet materials as well. You can remove mold from damp drywall, concrete, and wood, but soaked drywall or insulation is easier to remove than repair.

3. Control the Humidity

Once you make your repairs, you need to dry your basement. The easiest way to remove moisture is to use a dehumidifier. These devices pull moisture out of the air and condense it into a removable tank that you can remove and empty. In some cases, you can route a drain hose to a floor or sink drain, removing the need to empty the tank. Dehumidifiers are excellent for basement settings.

Shoot for a humidity level of roughly 50 percent so the space stays comfortable without encouraging mold growth (which occurs at over 60 percent). You can also use a box fan or window fan to improve the ventilation and air movement for faster drying.

4. Tackle the Smell

With the moisture under control, you can finally tackle that musty aroma. The process is straightforward, and you may already have the supplies on hand.

Place bowls of baking soda around the basement. The baking soda will begin to absorb the odors and should make a significant difference over the course of a few days. You can also use bowls of white vinegar or clean cat litter—both will absorb odors as well. For especially foul-smelling spaces, you can also use a product specifically designed to absorb moisture and musty odors, such as DampRid.

While the deodorizers are absorbing the smells, clean the entire basement as well as possible. A mixture of equal parts water and white vinegar is inexpensive, and you can use it to spray surfaces or mop the floor. Be sure to pay special attention to areas where mold was present.

Carpeting and upholstery can trap odors and continue to smell musty long after a basement is clean and dry. If you have carpets or upholstered furniture in your basement, consider renting a carpet and furniture steamer to give them a deep cleaning.

With these tips, your basement should be smelling fresh within a week. It’s important to watch for leaks, ensure p-traps remain full and continue controlling the humidity levels with a dehumidifier. If you maintain this regimen, your basement should remain odor-free for years to come.