Types of Mold and How to Remove Them

Mold on tiles

Marcus Krauss / Getty Images

There's a fungus among us and it is mold. Mold spores are everywhere and when they find moisture and moderate temperatures (60 to 80 degrees Fahrenheit), they thrive and grow. While some fungi are beneficial, many can be dangerous to the health of humans and destructive to property.

The more common molds that most homeowners encounter can be classified into three categories: allergenic, pathogenic, and toxic.

  • Allergenic molds affect the 20 to 30 percent of the population who are susceptible to mold allergens. While extreme infestations can require removal by a professional, most allergenic molds can be removed with home disinfecting products.
  • Pathogenic molds cause disease and infection especially in young children and adults with compromised immune systems. Small infestations can be controlled with disinfectants but large colonies require professional removal.
  • Toxic molds produce poisonous chemicals called mycotoxins that intentionally harm any living organism including humans and animals. These are quite deadly and require a professional to kill the mold and dispose of any affected materials.

Once mold is discovered, you should hire a professional or use our guide to help identify the 12 most common types of fungi and develop a plan for removal. Once the mold is removed, it is essential to identify the moisture problem that led to the growth.

DIY Mold Cleaning Methods

If allergenic molds are caught early, you can easily remove them with household disinfectants. When using any of these products, make sure there is adequate ventilation in the area and wear protective gear like gloves, eye protection, and old clothes that can be washed in hot water to kill stray spores.

  • Chlorine bleach: Sodium hypochlorite or regular household bleach works best to destroy mold and remove any discoloration. It is quite harsh and should be diluted before using.
  • Hydrogen peroxide: Less harsh than chlorine bleach, hydrogen peroxide (three to 10 percent solution) will kill mold and lighten stains. While it does have a bleaching effect, it works more slowly than chlorine bleach but has no toxic fumes or residue.
  • Distilled white vinegar: Vinegar is acidic and slowly breaks down the structure of mold and kills it. Vinegar is non-toxic but mold stains may remain and additional scrubbing with a household cleaner may be needed. 
  • Baking soda and borax: Sodium bicarbonate (baking soda) and borax each have a high pH that inhibits the growth and survival of mold. Both products are inexpensive, non-toxic, and easy to mix with water. Borax is more effective than baking soda but not as effect as a stronger cleaning product.

Hire a Professional

For any mold classified as toxic or extensive mold problems, you need to hire a professional.

Tip

The rule of thumb is if the mold infestation covers 10 or more square feet, then a professional should handle the removal. Removing large mold colonies requires exposure to heavy-duty chemicals and permits for the proper disposal of infested building materials. Local public health departments can offer advice on mold testing and refer you to an expert mold remover.

  • 01 of 12

    Acremonium

    Acremonium mold

     Smith Collection/ Gado/ Getty Images

    Appearance

    Typically begins as a small colony of pink, grey, orange or white moist mold that turns powdery.

    Location

    Often found in home humidifiers, HVAC cooling coils, drain and drip pans, and near leaky windows.

    Summary

    Often found with Strachybotrys (black mold), it is highly toxic can impair brain function and impact bone marrow and immune systems. Requires removal by professionals.

  • 02 of 12

    Alternaria

    Alternaria mold

     Annetka/ iStock/ Getty Images Plus

    Appearance

    Dark green or brown velvety texture with protruding "hairs".

    Location

    Most often found in shower stalls, bathtubs, and near sinks. Its presence usually signifies water damage has occurred and the mold will quickly spread.

    Summary

    One of the most prevalent molds in a home, it is most harmful to those susceptible to asthma and is classified as an allergenic mold. Unless the colony has grown extremely large, it can be safely removed with proper cleaning.

  • 03 of 12

    Aspergillus

    Aspergillus mold

     Annetka/ iStock/ Getty Images Plus

    Appearance

    Typically has grey or green spores that can form thick layers of mold. However, multiple species of Aspergillus appear as different colors.

    Location

    Often appears on wooden surfaces.

    Summary

    Most species are simply classified as allergenic producing manageable allergic reactions. However, Aspergillus does produce mycotoxins that can be dangerous to the very young and those with compromised immune systems. Extensive infestation should be removed by a professional.

  • 04 of 12

    Aureobasidium

    Aureobasidium mold

     Ninjatacoshell/ Wikimedia Commons

    Appearance

    First appears as a pink, brown or black mold but turns dark brown as it grows and matures.

    Location

    Found in dark wet and water-damaged areas such as under carpets, behind wallpaper, and on wooden surfaces.

    Summary

    Protective clothing, including eye protection and gloves, should be worn during clean-up of small infestations because this mold can cause eye, nail, and skin infections.

    Continue to 5 of 12 below.
  • 05 of 12

    Chaetomium

    Chaetomium mold

     Wikimedia Commons

    Appearance

    Mold spores begin as white and cotton-like but darken to gray, brown or black. Distinguished by a musty odor.

    Location

    Thrives in water-damaged drywall, wooden surfaces, wallpaper, and under wet carpet and roof shingles.

    Summary

    Often mistaken as black mold, this is still a toxic mold that can cause neurological damage, autoimmune diseases, and allergic reactions. Removal is best handled by professionals.

  • 06 of 12

    Cladosporium

    Cladosporium mold

     Medmyco/ Wikimedia Commons

    Appearance

    Found in both cold and warm environments, it has a suede-like texture and is brown or olive green in color.

    Location

    Usually found on carpet, upholstery, drapes, and under floorboards.

    Summary

    Classified as an allergen, it typically will cause itchy eyes, runny nose, and sore throat. More serious reactions are asthma and lung infections. Small colonies can be cleaned away by the homeowner but larger ones require a professional.

  • 07 of 12

    Fusarium

    Fusarium Mold

     Annetka/ iStock/ Getty Images Plus

    Appearance

    Growth is pink, red, or white.

    Location

    Often found growing on food, it spreads quickly and can be found in carpet, wallpaper, and water-damaged materials.

    Summary

    While usually producing allergic reactions, extended exposure to Fusarium can cause lethal conditions to the brain and nervous system. Treat any clean-up with caution.

  • 08 of 12

    Mucor

    Mucor

     Satirus/ iStock/ Getty Images Plus

    Appearance

    Grows quickly to develop thick patches of white or gray mold.

    Location

    Found in extremely wet spaces where condensation has formed such as near air conditioners, HVAC ductwork, and leaky windows and doors.

    Summary

    Classified as allergenic, small patches can be cleaned by the homeowner. Larger infections require a professional because Mucor can cause mucormycosis, a fungal infection that affects the respiratory system and brain.

    Continue to 9 of 12 below.
  • 09 of 12

    Penicillin

    Penicillin

    Dr. Jeremy Burgess/ Science Photo Library/ Getty Images Plus

     

    Appearance

    Surface of the mold colony is velvet-like and blue-green in color. The mold spreads quickly.

    Location

    Often found in HVAC ducts, wallpaper, mattresses, and carpet.

    Summary

    Most of us know Penicillium as the beneficial mold used drug and cheese production. However, some species are more harmful and cause allergic reactions when inhaled. Small colonies can be cleaned by the homeowner with care. Larger infestations should be removed by professionals.

  • 10 of 12

    Stachybotrys

    Stachybotrys mold

     Science Picture Co./ Getty Images Plus

    Appearance

    Known as black mold, the colony has a dark green or black slimy texture.

    Location

    Most often found in areas inside a home that have been exposed to excessive water and humidity for weeks. Typically develops behind walls and ceilings on wood.

    Summary

    Highly toxic, Stachybotrys produces mycotoxins or poisonous chemicals. Exposure can come from skin contact, inhalation or ingestion and can be fatal to humans and animals. Removal and disposal of affected building materials must be done by professionals.

  • 11 of 12

    Trichoderma

    Trichoderma mold

     Wikimedia Commons

    Appearance

    Typically appears as white and green wooly colonies.

    Location

    Can grow on wallpaper, carpet, fabrics, and surfaces exposed to excessive moisture.

    Summary

    Usually non-pathogenic, Trichoderma can be cleaned by the homeowner using proper protective measures. It does produce an enzyme that attacks wood, textiles, and paper and can cause damage to building foundations.

  • 12 of 12

    Ulocladium

    Ulocladium mold

     Ninjatacoshell/ Wikimedia Commons

    Appearance

    Typically black and formed in clumps.

    Location

    Usually found in kitchens, bathrooms, and basements that have suffered water damage or areas that stay wet for long periods.

    Summary

    Classified as an allergen, it can cause symptoms similar to hay fever, asthma, and skin infections. Caught early, clean up can be done by a homeowner.