Mildew and mold differ in appearance, growth habits, and health risks. Our guide explains these differences in more detail.

We often interchange mold and mildew, but the two have distinct differences. Both fungi flourish in damp environments and can cause home damage and health concerns. However, they differ in appearance, how they affect the surfaces they grow on, and their potential health risks. This guide details the differences between mildew and mold, their potential health effects, and how to prevent and treat them.

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What Are Mold and Mildew?

Mold and mildew are fungi that grow on damp surfaces to promote the natural decay of organic materials. Mold and mildew growth can begin within 24–48 hours after the fungal spores float into your home and land on wet surfaces. Such growth can cause damage to homes and lead to serious health conditions.

There are thousands of mold types and mildew found indoors and outdoors. These different types of fungi share a few factors in common, such as their appearance and growth environment, making them easily confused. For example, homeowners tend to mistake the mildew species Cladosporium for black mold since it’s dark in color and grows in damp spaces.

Here are some of the most common types of mold found in homes:

• Aspergillus: This mold has a cottony texture and ranges in color from yellow-green to blue-green. It usually causes allergic reactions, including those that impact airways.
• Cladosporium: You usually find this mildew in dark areas with poor airflow, such as basements and attics. It has a velvety texture and a greenish-gray color and can cause allergies and infections in rare cases.
• Stachybotrys chartarum (black mold): Many know black mold for its toxic qualities. It can range from dark green to gray and black, is sticky, and is found in damp places such as bathroom ceilings, wet carpets, and basements. It can cause a range of health issues, from allergic respiratory reactions to neurological symptoms such as confusion and dizziness.
• Trichoderma: This hidden mold is usually white and green. You can often find it in wallpaper, wooden furniture, or floors. It can cause wood to rot, severely damaging homes.

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What Are the Differences Between Mold and Mildew?

Mold and mildew share similar appearances and growth environments, but critical differences set them apart. Below, we’ll cover the differences in appearance, growth habits, and their impact on materials.

Mold Characteristics

• Eats through the surface it grows on and can grow upward, causing substantial damage
• Grows and spreads on organic matter, including leather, paper, clothing, and building materials
• Has a strong, musty smell
• Is usually dark in color, with the most prominent being red, green, or black
• Often appears raised and fuzzy

Mildew Characteristics

• Found on shower walls, windowsills, and other moisture-prone areas
• Grows outward on the surface it inhabits
• Has a flat structure with a powdery surface
• Is typically white or gray in color
• Its damage is less impactful than mold since it grows on surfaces

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How Do Mold and Mildew Form?

Mold and mildew form from spores that enter the home through doors and windows. The spores grow when they land on a surface with food, water, and oxygen. This growth begins within a day or two after coming into contact with a surface.

Here are a few common environments that encourage mold and mildew growth:

• In the wall surrounding the clothes dryer vent
• Laundry rooms
• Near dripping water (such as drainpipes and gutters)
• Near HVAC vents
• Showers and bathtubs
• Under carpeting

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Mold and Mildew Health Concerns

Many of the thousands of mold and mildew types that exist are completely harmless to humans. People come into contact with mold daily, but substantial mold exposure can lead to health concerns ranging from mild allergic reactions to neurological and immune system changes.

Health issues related to mold vary based on your personal health, exposure level, and mold type. Allergic reactions are the most common health problem related to mold. Common symptoms include red eyes, runny nose, skin rashes, and sneezing. Mold can also worsen asthma symptoms, causing shortness of breath and increased asthma attacks.

Certain molds are toxigenic, which means they produce toxic compounds that can cause serious health issues. Black mold is the most common example of toxic mold found in homes. Black mold causes allergic reactions, including coughing, lung bleeding, shortness of breath, sore throat, or wheezing.

However, the toxins black mold produces can lead to severe health conditions in some individuals, especially children and immunocompromised people. Severe symptoms related to black mold include anxiety, brain fog, confusion, dizziness, heart palpitations, memory loss, and seizures.

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How Do You Prevent Mold and Mildew?

Moisture control is the best way to prevent mold and mildew growth. Follow these tips to help you detect moisture hot spots and improve ventilation to prevent mold and mildew growth:

• Keep an eye on your humidity levels: Keeping humidity levels between 30% and 50% can help you avoid mold growth. Use a dehumidifier in hot, humid climates, and install insulation or storm windows in colder climates.
• Leave the washer door open: Prop the washing machine door open after a wash cycle until the interior is dry.
• Use a dehumidifier: Opening windows, using fans, and operating dehumidifiers in damp areas and during humid months can prevent mold growth in moisture-prone areas.
• Ventilate damp rooms: Open windows and vents to ensure adequate airflow in bathrooms, laundry rooms, kitchens, basements, and other damp areas.
• Watch for leaks: Routinely check pipes for visible signs of leaks and look for water damage on your ceiling.

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How To Treat Mold and Mildew

Prevention is the best way to avoid damage from mold and mildew. Recognizing the early stages of mold is your best bet for a successful remediation. Take these steps to safely remove mold when you find it in your home:

1. Repair the Moisture Problem

Identify the cause of the moisture that is encouraging mold growth and fix it. Otherwise, the mold will return soon after you remove it. If mold is present where no leaks or flooding occurred, ventilate the area with a dehumidifier.

2. Limit Mold Spore Exposure

Put on rubber gloves, goggles, and a face mask before you begin removal work. Close the door to the room you’re working in or hang a plastic tarp to avoid spreading mold spores through your house. Open windows and run an exhaust fan to move mold spores from the affected room out of the house.

3. Remove Mold From Nonporous Surfaces

Household cleaners, such as ammonia, bleach, or vinegar, can remove mold from surfaces that don’t absorb water. Never mix cleaning products, as they can create dangerous fumes. If you’re using bleach or ammonia, you can create a solution composed of one part cleaning agent and one part water. You can also use undiluted white vinegar instead of a household cleaner.

Spritz any affected areas with the cleaning solution, and let it sit for 15 minutes to an hour. Brush away tough stains with a scrub brush and wipe the area thoroughly with a clean cloth before letting it dry completely.

4. Remove Mold From Porous Surfaces

It’s hard to effectively treat some porous surfaces, such as carpets, ceiling tiles, cloth, and wallpaper, for mold, so you can remove light mold from wood and drywall.

Follow these steps to remove mold from wood:

1. Remove mold and mildew from wood by using a vacuum with a high efficiency particulate air (HEPA) filter to suck up loose mold spores.
2. Clean the mold stain using a soft-bristled brush and a solution of one part dish soap and one part warm water. You can use vinegar or borax on tougher mold.
3. Dry the surface completely.
4. If any mold remains, sand the area with 100-grit sandpaper and vacuum the resulting dust.

Follow these steps to remove mold from drywall:

1. Remove mold from drywall by vacuuming the affected area with a vacuum fitted with a HEPA filter.
2. You can tackle the mold with a commercial mold control product, baking soda mixture, or hydrogen peroxide.
3. Dry the wall with a fan.
4. Cover the wall with a mold-killing primer after the area is completely dry.

If the mold is too deep to remove with the suggested measures, you must replace the wood or drywall.

5. Conduct a Safe Cleanup

Properly disposing of cleaning materials can prevent the redistribution of mold spores. Put all used materials, including your gloves, in a heavy-duty garbage bag and close it tightly. Take the bag outside or keep it tightly closed until trash day, and launder the clothes you wore with hot water.

6. Know When To Contact a Professional

Contact a professional for assistance if you don’t feel confident about safely removing mold from your home. It may also be a good idea to hire a pro when dealing with a severe mold infestation, including areas greater than 10 square feet and situations where removing building materials is necessary. Additionally, any homeowner with respiratory issues or a compromised immune system should call a professional to handle mold removal.

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Our Conclusion

Mold and mildew can cause substantial harm to your home and affect your health, and understanding the differences can help you determine how to remove them. Early detection and prevention is the best way to avoid mold and mildew damage, but some severe cases may require professional assistance.

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FAQ About Mildew vs. Mold

Is mildew as harmful as mold?

Mildew is less harmful than mold because it causes minor temporary respiratory problems. It spreads on top of surfaces instead of penetrating them, making it less damaging to structures and easier to clean.

What kills mildew?

You can kill mildew with bleach or a mild detergent. Spray the solution on the affected surface, wait for the cleaning agent to work, and scrub the mildew away with a brush.

What are the common types of mold and mildew?

There are thousands of mold and mildew, both indoors and outdoors. Some of the most common types inside the home are Aspergillus and Stachybotrys (black mold).

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