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What Causes Musty Smells?

If you’ve ever smelled decaying wood or a stack of wet, musty towels left in a pile after a long weekend, you’ve smelled the stale, earthy odor of mold and mildew. The growth of mold spores causes musty odors. Mold spores are present everywhere, and when they land in a welcoming environment, such as moisture and food, they begin to multiply and start to emit gasses that our noses can detect. Unfortunately, mold spores multiply quickly, and it doesn’t take a huge colony to create odors. Promptly clean small areas of mildew (fungi that appear flat on a surface) or mold (fungi that appear raised and usually fuzzy), and then monitor the site to prevent return growth.

If the mold area is larger than 10 square feet, you may need professional mold abatement. For small colonies of mildew on fabrics or walls, you can follow these tips to get the source of the musty smells under control.

Are Mold and Mildew Dangerous?

Exposure to mold and mildew in the home can be dangerous and even hazardous to your health. Some people are more sensitive to mold and mildew than others or may already have asthma that mold and mildew can exacerbate. The problem can still cause respiratory and other bodily symptoms of varying degrees that may include:

• Stuffy nose

• Wheezing

• Coughing

• Red or itchy eyes

• Itchy skin

• Shortness of breath

• Fever

Locate the Source of the Musty Smell

It’s time to take a look and start sniffing around. Until you identify the source of the musty smell, you’ll never be able to get rid of it—and it can get worse. Begin your search in areas that are often warm and moist, like a bathroom. Check for mildew growth in the shower, on the shower curtain, and leaks around sinks, tubs, and toilets.

In the kitchen, look for leaks around the sink and dishwasher. Check under and in the refrigerator and small appliances that use water, like coffee makers and tea kettles. Be sure to also check the trash can, as mildew could be growing under the disposable trash bag liner.

In the bedroom and living areas, look around the window seals for leaks and under your potted plants that can leak. Check closets for mildew caused by storing damp shoes or clothes.

Don’t forget to take a trip up to the attic, basement, and garage to check for damp areas around windows, water heaters, and vents.

Check for leaks around the wash machine and around the doors of front-load washers tend to harbor mildew in the laundry room. Be sure that your dryer vent is clean and that the outdoor vent is not blocked outside, so there is good airflow to eliminate moisture.

Repair any Leaks and Control Excessive Moisture

To get musty smells under control, repair any leaks that you find as quickly as possible. It’s the best way to gain control over the odor. In areas with excessive moisture, install ventilation fans, place moisture barriers over damp soil, or redirect water flow on the home’s exterior.

Increase the Air Circulation

Whether you are able find visible evidence of mildew or not, a musty smell signals that you need to increase air circulation in the home. Open windows and doors, turn on ceiling and attic fans, or add fans to each room. Starting your HVAC system can also help draw out odors and capture mold spores in the filters. Be sure that the system has clean filters and replace them often to help remove musty smells.

Install a Dehumidifier

Since mold and mildew need moisture to thrive, lessening the humidity level in a home can help keep mildew under control. Try to keep your interior humidity no higher than 50%. To gauge the moisture level in your home, get a hygrometer or humidity sensor. Some HVAC systems have dehumidifiers as part of the unit, or you can get a free-standing dehumidifier. Keep the dehumidifier clean and regularly empty the water-collection bin.

How to Clean Mildew

When you see evidence of mildew, it’s essential to get rid of it before or after you solve the problem causing the issue. For a minor spot or two of mold, you don’t have to use bleach, and you can use a bucket of warm water and a couple of squirts of dish detergent to wipe away the mold spores.

For a more moderate mold area, use bleach to clean up the mold. In a 1 gallon bucket of water, dilute 1 cup of chlorine bleach. This solution effectively kills mildew on surfaces like ceramic tile and grout, cement walls, and washable fabrics. You can also use a more natural approach by spraying the area with distilled white vinegar. Allow the vinegar to work for an hour, and then scrub away the mildew with a sponge or microfiber cloth dipped in baking soda.

You should clean washable fabrics harboring mildew with the hottest water suitable for the material, a heavy-duty laundry detergent, and, for white fabrics, chlorine bleach. Follow the cleaning guidelines for mildewed shoes and dry clean only clothes.

Some Ways to Remove Mold

Whatever kind of mold you have, if you have more than 10 square feet of it, the Environmental Protection Agency advises against remediation on your own.

But if you have a small quantity and want to clean it up on your own, you will need a few materials in preparation:

Protective gear like goggles, rubber gloves, and a respirator/N95-type mask

A window fan to exhaust the air out of the room; it should stop the spores from settling in the room.

Wet/dry vacuum to thoroughly vacuum the area to rid it of airborne spores; you can clean the wet/dry vacuum interior afterward. Seal the A/C and heating vents to stop spores from traveling; also, turn off the HVAC system

Trash bags are necessary to remove the mold-covered materials

Fix plumbing leaks and other water problems as soon as possible. Locate the source of the mold. If it’s in or on the wall or sheetrock and you have experience changing sheetrock, you can cut out the affected part of the wall. You will need to change out that area of wall insulation too.

Scrub mold off hard surfaces with detergent and water. Dry all items completely. When you’re sure the mold has been eliminated, seal any wood surfaces with a pigmented shellac or an oil-based primer. Repaint cleaned wall surfaces with latex paint that contains a mildewcide to help stop future mold growth.

Throw away any moldy absorbent or porous materials, such as ceiling tiles and carpet. Mold may be difficult or impossible to remove entirely from those materials.

If you can’t find the source of the mold, you should call a professional. Or, hire a professional if you think it’s hiding under wallpaper and fear that removing it will lead to a massive release of spores.

Other Ways to Get Rid of Musty Odors

Deep clean carpets and upholstered furniture: Whether you do it yourself or hire a professional, deep cleaning carpet and upholstered furniture can get rid of mildew spores and freshen a home. Clean on a dry, breezy day so that the fabrics will dry quickly.

Clean and declutter every space: Stacks of papers and books can trap moisture and lead to a musty odor. Clean and dust every surface and dispose of as much clutter as possible in every room.

Add odor absorbers: Commercial odor absorbers that use activated charcoal are available to hang in closets or spaces that lack good air circulation. Or, use a bowl of dry baking soda, coffee grounds, or kitty litter to help absorb odors, and be sure to change these products frequently.

Add pleasing scents: Once the mildew is gone, you can add a more pleasing scent by simmering spices or citrus peels, lighting candles, using diffuser sticks, essential oil diffusers, or commercial air fresheners.

Prevent Mold and Mildew

If you know you have a mold or mildew trouble spot in your house, then be proactive. If the bathroom or kitchen is the source of your problem, then clean with mold-killing products. Also, the next time you redo the paint on the walls in the bathroom or kitchen, use mold-inhibiting paints to keep the spores away.

The key to maintaining a mold- and mildew-free home is being diligent. It can be challenging in climates with high humidity or poor ventilation. Still, if you remove the spores, keep surfaces dry, and mechanically provide good air circulation, you can stop it from returning.