How to Get Rid of That Musty Basement Smell

Identify the cause behind your musty-smelling basement and find out what you can do to eliminate the foul odors for good.

Most musty basement smells are a symptom of a mold or mildew problem caused by excessive moisture.

That unmistakable musty smell, often described as being similar to that of a pair of wet socks or a wet dog, is the signature scent of mold and/or mildew. Most basements are damp and dark - ideal conditions for these fungi to thrive. Not only can their musty odor make its way up into the rest of your home, but mold spores can also cause allergy symptoms and structural problems.

If your basement smells musty after rain, when the weather is humid, or all the time, simply removing the odor won’t eliminate the problem. The first step to getting rid of the musty smell in your basement is identifying the source. Most of the time, the smell is a symptom of a mold or mildew problem caused by moisture. This guide will help you identify what’s making your basement smell musty and outline solutions for getting rid of the odors for good.

1. Look for leaks and condensation in the basement

   Two common problems in a basement are condensation and water leaks. Depending on the source, some problems can be easily handled by a savvy homeowner while others require hiring a professional.

   

   Condensation on uninsulated pipes is a common source of basement moisture.

   Start by checking for these common causes of moisture in the basement and consider installing a dehumidifier to keep the moisture level in check (read more on this below):

   • Condensation dripping off uninsulated pipes is a very common problem - and one of the easiest and least expensive to fix. If your pipes are “sweating,” wrap them in foam insulation to prevent condensation, which forms when warm, humid air comes in contact with the cooled pipes. If the water is coming from a leak, call a plumber to have it fixed.
   • Water leaking through a basement window is usually easy to spot. When it rains, keep an eye out for water running down the glass or a puddle below the window. If you have window wells, remove leaves and other debris that could be clogging them. Install covers over the window wells to avoid clogs. Most small leaks around the window frames can be fixed with caulk and weather stripping. However, old rusty metal windows or rotted wood windows should be replaced.
   • Water coming through a crack in the basement wall or seeping up through the floor sometimes requires installing a sump pump and drainage system, depending on the severity of the problem. While it’s recommended that you hire a contractor who specializes in basement waterproofing, there are some things you can do yourself to keep the water away from your basement. If your basement leaks when it rains or you spot water seepage, the causes can include leaky gutters, poor grading, hydrostatic pressure, and other factors. A basement waterproofing contractor can help with proper diagnosis and solutions to keep your basement dry.

2. Lower the humidity level with a dehumidifier

   You have probably noticed that your basement tends to be cooler than the upper levels of your home during the warmer months. It might not seem like a cool basement is a bad thing, but when warmer air from upstairs meets the cooler air in the basement, it condenses on cold surfaces, including basement walls, furniture, and water pipes. This condensation contributes to odor-producing mold and mildew.

   

   A SaniDry Sedona self-draining dehumidifier can keep basement humidity under control.

   Moisture from the soil can also seep into the basement through the foundation, increasing the basement’s humidity level even further.

   If water leaks and drainage issues have been repaired and you still notice a musty smell, consider installing a basement dehumidifier to control moisture and make the air feel more comfortable. Humidity levels should be kept between 45-55% to prevent mold and mildew growth.

3. Clean up all mold or mildew spores

   If the foul smell in your home wasn’t bad enough, mold and mildew can stain your walls, floors, and ceilings; decay wood studs and drywall; and damage carpets. Mold exposure can cause health effects, including a stuffy nose, sore throat, coughing, wheezing, burning eyes, or a skin rash - with more severe reactions reported in people with a mold allergy or asthma (Centers for Disease Control).

   Once water leaks have been fixed and the humidity level in your basement is under control, mold and mildew stains should be cleaned up. If your moldy basement still has moisture issues, consider hiring a Basement Systems contractor to fix your waterproofing issues and treat mold stains at the same time. It should be noted that cleanup of moldy areas larger than 10-square-feet (about a 3-foot by 3-foot patch) should be handled by a professional experienced in mold remediation (United States Environmental Protection Agency).

   Follow these tips for thorough mold cleanup and prevention:

   • Remove or discard damp or moldy cardboard boxes and upholstered furniture.
   • Scrub away mold and mildew stains on the walls, floors, and ceiling using household bleach and a brush.
   • Remove or replace damaged drywall and carpet that can’t be dried quickly. Consider using non-organic wall and flooring materials that are designed to be installed in areas with a lot of moisture.
   • If the mold damage in the basement is extensive or if you’re unsure of how long the problem has been there, consider hiring a professional experienced in mold remediation.
   • If there’s damaged items that are important, such as paper documents; expensive, such as artwork or antique furniture; or of sentimental value that you can't clean yourself, hire a professional who specializes in cleaning mold-damaged items.

To help you identify if a basement water problem is the culprit or schedule a no-obligation evaluation and basement waterproofing cost estimate with the Basement Systems contractor near you.