What are the Most Common Types of Indoor Mold?

You may be surprised to learn that mold isn’t just a single unpleasant house guest. Mold is actually a family of fungi with many unique species. They grow not just in your home, but outside as well. What are the most common types of indoor mold? Let’s take a look.

What are the Most Common Types of Indoor Mold?

While there are dozens of types of mold, there are four in particular that tend to grow inside the home. These indoor molds tend to grow in specific areas throughout the house.


Cladosporium is a very common type of mold that grows both indoors and outdoors. Its appearance is usually black or greenish-black but is sometimes brown in color.

Outdoors, it most commonly grows in leaf mulch, soil, and rotting vegetation, all of which have high levels of moisture.

Indoors, it is usually found in areas that have experienced water damage, are exposed to moisture, or are located in high-humidity areas like kitchens, laundry rooms, or bathrooms.

Cladosporium grows in a diverse variety of places in the home, including:

  • common types of indoor moldWalls
  • Wallpaper
  • Vinyl
  • Wood
  • Painted surfaces
  • Floors
  • Cabinets
  • Paper
  • Carpets
  • Windowsills

Cladosporium is considered a type of ‘black mold’ and may be harmful to the health. This type of mold is known to a decrease in air quality and may be a trigger of asthma attacks. Cladosporium may also worsen the symptoms of individuals who have allergies.

Testing and removing Cladosporium from your home is recommended to be handled by mold remediation experts.


Penicillium is a type of mold that may sound familiar. In fact, the drug penicillin is derived from certain strains of this mold. Members of this family of mold are usually blue or green in color.

While penicillin is useful in medicine, penicillium is a less welcome house guest. Penicillium grows in damp or humid conditions and is an indicator of increased moisture levels in the home. This type of mold also causes food to spoil.

Penicillium grows in a diverse variety of places in the home, including:

  • Walls
  • Wallpaper
  • Damp building materials
  • Damp carpets
  • Leather
  • Food

Like many types of mold, penicillium can worsen allergies and should be handled by a certified professional to ensure thorough removal from the home.


Alternaria is a type of mold that is typically green, black, or grey in appearance. There are over 200 subspecies.

Alternaria is typically an outdoor mold with concentrations of spores at their highest between spring and fall. When it does occur indoors, it’s an indicator of elevated levels of humidity.

common types of indoor moldAlternaria grows in several different places in the home, including:

  • Textiles
  • Food
  • Cardboard and paper
  • Plants
  • Soil

Much like other types of mold, Alternaria can trigger mold allergies and worsen the symptoms of seasonal allergies. It’s important to note that this type of mold can lead to infections and complications in individuals with compromised immune systems. Therefore, it’s especially important to keep Alternaria out of your home – or have it removed professionally once it’s taken hold!


Aspergillus is a widespread type of indoor and outdoor mold. Much like other types of mold, it decreases the quality of air in the home and can trigger allergies. In some cases, exposure to Aspergillus can cause a lung condition known as Aspergillosis, which you can learn more about at Mayo Clinic.

Aspergillus grows in a diverse variety of places in the home, including:

  • Carpets
  • Kitchens
  • Bathrooms
  • Basements
  • Soil
  • Wallpaper
  • Paint
  • Leather
  • Insulation
  • Humidifier water
  • Decomposing wood
  • Plastic

Removing Aspergillus is important for those who have compromised immune systems and allergies to prevent complications from illness.

Mold Remediation with Tidal Wave Response

Regardless of which type of mold you have found in your home, Tidal Wave Response can remove these unwanted house guests. Our technicians are trained and certified in not only the cleanup but will locate and remedy the problem causing the mold so that you can rest easy.

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