Understanding the Difference Between Mildew and Mold

While many people often mix up the terms "mold" and "mildew," they are not identical. Therefore, you can't skip your neighbor's Jell-O gathering by claiming you need to tackle a severe mildew/mold issue in your crawl spaces.

Scientifically, both are fungi (organisms that produce spores) and can release a musty odor. Beyond their classification, they share some similarities but remain distinctly different.

Spores of mold and mildew are omnipresent. When you spot mold or mildew, you're actually seeing a massive colony comprising millions of tiny spores. Discover how to distinguish and address mildew vs. mold in the following sections.

What Is Mildew?

Mildew represents mold in its initial phase and generally grows rapidly. Its spores spread through water, air, or insects. Both mold and mildew thrive on porous, organic materials such as wood, paper, food, insulation, carpet, or clothing — common items found in most households.

The primary distinction between mold and mildew lies in their surface behavior. This is somewhat of a wordplay, as mildew tends to grow on surfaces like shower walls, windowsills, and other moisture-prone areas.

Mold, on the other hand, consists of microscopic fungi that invade and grow beneath the surface of whatever material they attach to.

The powdery, fluffy spores you notice on books and boxes stored in your basement? That's mildew. The good news is, it only affects the surface.

Tips to Prevent Mildew Growth

If you discover mildew, you can remove it to stop the spores from multiplying or causing damage. Ensure the room is well-ventilated and consider using a dehumidifier. Bathrooms should be equipped with an exhaust fan to expel warm, moist air. Also, inspect window seals to avoid condensation.

What Is Mold?

Mold is a more serious issue. It can appear fuzzy or slimy, growing on the surface of organic materials before penetrating them. Mold typically appears in colors like white, blue, green, brown, gray, or black.

Mold becomes problematic when it grows indoors. Over time, it decomposes the organic materials it inhabits, often causing significant structural damage to homes and possessions, necessitating mold remediation and expensive repairs.

Mold can also have serious health implications. It releases allergens that may trigger severe allergic reactions, such as hay fever-like symptoms — sneezing, runny nose, red eyes, and skin rashes.

Mold can provoke severe reactions, including asthma attacks, in individuals allergic to it. Even those without allergies may experience irritation in the eyes, nose, throat, and lungs due to mold exposure.

Medical professionals and researchers are continually studying the impact of mold inhalation. In 2012, the National Institute for Occupational Safety and Health (NIOSH) published guidelines highlighting that exposure to dampness and mold in buildings is linked to respiratory symptoms, asthma, hypersensitivity pneumonitis, rhinosinusitis, bronchitis, and infections. In 2019, NIOSH updated its guidance on assessing dampness in structures to mitigate health risks.

Exposure to mold often happens during the cleanup of homes or buildings after flooding. According to the U.S. Centers for Disease Control and Prevention (CDC), mold can begin growing within 24 to 48 hours in a flooded structure if it isn't dried properly.

Removing and Preventing Mold

Unlike mildew, which can be cleaned easily, the CDC states that mold removal is challenging. It requires a certified mold remediation professional accredited by organizations like the National Environmental Health Association (NEHA) or the American Industrial Hygiene Association (AIHA).

However, there are steps you can take to prevent mold growth. The CDC recommends the following measures:

In essence, the goal is to eliminate damp areas and control moisture levels in your home.

Similarities and Differences Between Mold and Mildew

Both are filamentous fungi, characterized by multicellular structures with branching hyphae that create a tangled network. They thrive in damp, moist environments and can grow on various household items.

However, mildew is generally easier to remove. This distinction highlights the key differences between mold and mildew.