Mould and mildew are often used interchangeably, but they are not quite the same thing. Both are types of fungi that thrive in damp conditions, yet they look different, grow differently, and carry different levels of risk. Knowing how to tell them apart helps you decide when a simple cleaning will do and when it’s time to call a professional.
What Is Mould?
Mould is a fungus that grows in multicellular filaments and tends to penetrate the surfaces it colonises. It usually appears fuzzy or slimy and comes in shades of green, black, blue, or grey. Because it can grow deep into materials like drywall and wood, mould is harder to remove and more likely to cause structural and health problems.
What Is Mildew?
Mildew is a specific type of mould that grows flat on surfaces. It typically looks powdery or downy and appears white, grey, or yellow, often turning brown or black over time. Because it stays on the surface, mildew is generally easier to clean than deeper mould infestations.
Common Types of Mildew
Basidiospore Mildew
This form spreads through airborne spores and is commonly found in damp indoor environments where humidity is high.
Aureobasidium Mildew
Often seen on wooden surfaces, painted walls, and around windows, this type can trigger allergic reactions in sensitive individuals.
Botrytis Mildew
Frequently associated with plants and produce, botrytis thrives in moist, poorly ventilated spaces and can affect indoor greenery.
Rhizopus Mildew
This fast-growing type is commonly found on food and in humid areas, and it can spread quickly if conditions stay damp.
Appearance: Mould vs Mildew
The easiest way to tell them apart is by texture and colour. Mildew is flat, powdery, and light coloured, while mould is raised, fuzzy or slimy, and usually darker. If the growth has penetrated the material rather than sitting on top, you are most likely dealing with mould.
Health Effects: Mould vs Mildew
Mildew exposure can cause headaches, coughing, and respiratory irritation, particularly for people with allergies. Mould can be more serious, potentially triggering asthma attacks, sinus infections, and other health issues, especially with toxic varieties like black mould. Neither should be left to grow unchecked.
Where Does Mildew Grow?
Mildew favours warm, damp, poorly ventilated spots. In homes and businesses it commonly appears in bathrooms, kitchens, basements, and around windows, as well as on fabrics and paper stored in humid conditions.
Is Mildew Dangerous to Clean?
Small patches of surface mildew can often be cleaned safely with proper protection and ventilation. However, if the growth is widespread, keeps returning, or you’re unsure whether it’s mildew or a deeper mould problem, it’s safer to have it professionally assessed.
How to Prevent Mould and Mildew
Controlling moisture is the key to prevention. Keep humidity low, fix leaks promptly, ventilate damp rooms, and clean up spills quickly. If mould or mildew keeps coming back despite your efforts, our team at Mold Removal Winnipeg can identify the source and remove it for good.
