Types of house mold

Updated July 20, 2017

There are various types of household mould that can be found anywhere that moisture and oxygen are present. Mold may cause health problems because the tiny spores can be inhaled; mould is also a common allergen. Infestations of mould may be easily seen or they may be hidden in areas such as underneath appliances or behind walls.


Aspergillus is a mould that is commonly found outdoors, in plants, decaying plant matter and soils. It is also commonly found in household dust, some food items and spices. Aspergillus can appear grey, yellow, green, brown, white or even black. Aspergillus will grow on walls, paper products, clothing and insulation, among other places.


Cladosporium is a very common airborne mould found in areas that are damp and dark, such as toilet bowls and refrigerators. Cladosporium can also be found in wood, such as moist windowsills, and in fabrics and other porous areas. Cladosporium can be green, grey, black or brown. Cladosporium can produce toxins but is not known to be highly toxic, however, it is listed as a potential allergen.


Alternaria has been known to cause allergic reactions and thrives in dusty areas, damp areas, in soil and on plants, around windows and on walls. Alternaria, which can appear black or grey, does not require a lot of dampness to survive, and it can produce toxins.


Penicillium is commonly known as the mould that makes penicillin possible. Penicillium is commonly found on foods such as fruit and cheese, as well as insulation and walls. It may appear green, white or blue. Penicillium can produce toxins and is a potential allergen.


Ulocladium is commonly found in damp areas such as bathrooms, kitchens and basements and perhaps around windows. Ulocladium usually appears black or grey. Ulocladium is considered an allergen and produces hay fever or asthma; it is unknown if it produces toxins.


Acremonium is harder to locate as it tends to grow in insulation and drywall. It appears white, brown or grey and grows in damp places. Acremonium is considered a toxic mould and can be detected by its distasteful smell.


Often referred to as black mould or toxic black mould (which is a common term, not a scientific one), stachybotrys grows in very damp surroundings and creates toxins. Stachybotrys appears black on surfaces, and it can display no visible to little visible evidence.

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About the Author

Ambriel Maji is a Pennsylvania-based freelancer who started writing in 2004. She has written various diabetes articles for the Bayer Corp. and now works as a ghostwriter. She enjoys writing about health and wellness, gardening and DYI home improvement. Maji is pursuing a practical nursing diploma as well as a bachelor's degree in business administration from Herkimer Community College.