The 12 Types of Mould And How To Recognize Them

July 10, 2019

Regardless of the type of mould that you find in your home, it’s a problem. It can be hard to get rid of (mould removal is no easy feat) and can quickly spread. It thrives in moist areas that are common in the home like underneath your sink or behind a wall so it’s important to know where to look and recognize what you’re up against.

Here are the 12 most common types of mould and ways you can identify them in your home. Due to the health effects associated with mould growth, always call a professional for help instead of trying to remove the problem yourself. Better safe than sorry.

1. Acremonium

This toxic mould generally starts small and moist but turns into a powdery substance that could be pink, grey, orange or white. You’ll find this in small moist areas in the home like humidifiers, cooling coils, drain pans and window sealants. The toxicity is dangerous and could lead to various health problems including bone marrow and immune system diseases. If that wasn’t bad enough, it’s been known to grow alongside black mould or other strains as well.

2. Alternaria

This is an allergenic mould which means you can tell it’s there if you have allergic reactions like coughing, watery eyes etc. It’s the most common form of mould, found in showers or bathtubs (could mean water damage) and is recognized by its velvety texture with dark green or brown hairs. It spreads incredibly quickly and can lead to asthma symptoms so it’s important to act fast.

3. Aspergillus

Another allergenic mould that has toxic capabilities, Aspergillus is a common mould found in American homes. It can form thick layers on the walls with its long flask-shaped spores. With over 185 species and various colours, it could lead to certain allergic reactions or respiratory infections.

4. Aureobasidium

This allergenic mould is commonly found on wooden surfaces. It appears pink, brown or black but becomes darker in colour as it ages. It could lead to eye, skin or nail infections if you touch it so be careful when treating the moulded area not to make direct contact with your skin.

5. Chaetomium

Typically seen where there is severe water damage, Chaetomium has a texture like cotton. While the colour starts as a white or grey it turns to black over time and generally has a musty odour. Make sure not to touch as this could also lead to skin and nail infections.

6. Cladosporium

Another allergenic mould, this type of mould almost looks like suede and is generally an olive green or brown colour. Typically causing allergic reactions including respiratory issues, it is commonly found in fabrics in the home like carpet.

7. Fusarium

Flickr/Zak Hughen

This allergenic and toxic mould is pink, white, or red in appearance and spreads quickly as it grows on food. Just make sure you check your food because this could lead to allergic reactions like a sore throat or worse, nervous system damage from the toxins.

8. Mucor

Another allergenic mould that looks white and is found in thick patches. You’ll find this in damp carpets or near air conditioning units. Mould exposure could lead to extreme health risks like a fungal infection.

9. Penicillium

Flickr/Scot Nelson

Blue green in appearance and velvety texture identify this allergenic mould. Its mould spores can move through the home through the air leading to respiratory issues or symptoms of asthma. You’ll generally find this where there is water damage, notably in mattresses or wallpaper.

10. Stachybotrys (Black Mold)


This toxic mould is slimy in texture and a dark green or black colour. Found in damp areas that have been humid for weeks at a time, it could lead to severe health issues.

11. Trichoderma


This allergenic mould is white with green woolly patches. You’ll find it under wet areas with condensation build up like fabric, wallpaper, or even air conditioning filters. It has five subspecies and though most are non-pathogenic, some produce mycotoxins which could lead to health problems.

12. Ulocladium

Black in appearance, this is generally found in rooms in your house with the highest moisture following bad water damage or condensation. Bathroom/basement etc. This mould is easily confused with other types so always call a professional because it could lead to severe health issues like hay fever.

Source: Wide Open Country, by Courtney Campbell