12 Types of House Mold (Including Appearance, Location & Risks)

Have you spotted a mold problem in your house?

And what to know what type it is?

Or are you just on a preventative watch so you can take care of any mold problems before they turn into a real issue?

Either way, this guide will show you the 12 most common types of house mold you’ll come across.

It’s vital to know how to recognize mold so you can deal with it immediately.

Otherwise, serious health concerns and structural damage to your house can occur.

Below, you’ll find an overview of various mold classifications, followed by a list of each mold type (with appearance, common location, and risks).

At the end of this guide, we’ll also mention how an air purifier can help protect you against mold exposure and offer a few product suggestions in our best air purifier for mold and viruses list.

Mold Classifications

Did you know that not all mold is toxic?

It’s true.

In fact, some mold types have very little impact on human health at all, unless you have a direct allergy to it.

But, there are some molds that are toxic and it’s good for you to know which ones those are.

Here are the three mold classifications that pertain to the household molds listed on this page:

  • Allergenic: These mold types cause allergic reactions including sneezing, coughing, irritated eyes, and asthma attacks.
  • Pathogenic: These molds can cause health problems in people who are already suffering from an acute illness. The immune system reacts against the invading mold spores.
  • Toxigenic: These mold produce toxic substances that can lead to dangerous illnesses or even death. They’re most known as “toxic mold”.

Now that you know the types of mold classifications, you can better understand how, and if, each type of mold below will affect you.

Types of House Mold List

1. Acremonium

Classification: Toxigenic

Appearance: Acremonium is a slow-growing mold that starts out compact and moist then transforms into a powdery substance. It can be grey, pink, white, or orange.

Location: Acremonium is typically found in moist places, like humidifiers, window sealants, and drain pans. It can also be found in other places where condensation occurs.

Risks: Acremonium is dangerous and can cause health issues like immune system and bone marrow diseases. Sometimes it can be found growing alongside Strachybotrys (#10 mold type below) and other strands of dangerous mold.

2. Alternaria

Classification: Allergenic (One of the most common forms of allergenic mold.)

Appearance: Alternaria can be identified by its dark green or brown hairs and velvety texture.

Location: Alternaria is often located in bathtubs, showers, around or below leaking sinks, and places where dampness is present. It often makes the first appearance after a home suffers water damage.

Risks: Alternaria can cause people with allergies to develop hives, a cough, watery eyes, and other allergic reactions. Alternaria can also result in asthma or upper respiratory tract infections.

3. Aspergillus

Classification: Mostly allergenic but some species can be toxigenic.

Appearance: Aspergillus usually appears in thick layers with long and flask-shaped spores. There is no specific color that Aspergillus comes in as there are over 185 species known.

Location: Aspergillus grows along the walls of homes in large layers.

Risks: Aspergillus can cause asthma attacks, allergic reactions, respiratory inflammation, and inflamed lungs. Some forms of Aspergillus can produce aflatoxins which are known as deadly carcinogens.

4. Aureobasidium

Classification: Allergenic

Appearance: Aureobasidium is usually black, brown, or pink in color. Mold of this type that has been present for some time usually appears dark brown as it ages.

Location: Aureobasidium can occasionally be seen growing on wooden surfaces that are painted or behind wallpaper.

Risks: The biggest health concern with Aureobasidium is infections of the nails, skin, and eyes. If this type of mold contacts bare skin, it can result in dermatitis.

5. Chaetomium

Classification: Mostly allergenic but can be toxigenic depending on the species (it can produce mycotoxins).

Appearance: Chaetomium has a cotton-like texture and changes color over time. It begins as a white mold turning to gray to brown to lastly black.

Location: Chaetomium thrives in water-damaged buildings. This mold often grows on leaking roofs, drywall, or in basements. Anywhere in your home with moisture problems should be a concern for the possibility of this mold growing. Chaetomium often marks its presence with a musty odor.

Risks: Chaetomium often causes nail and skin infections. Individuals with compromised immune systems should be careful of the mycotoxins that this mold produces as it can lead to severe health concerns.

6. Cladosporium

Classification: Allergenic

Appearance: Cladosporium has a suede-like texture and is often grown or olive-green.

Location: Cladosporium is a type of house mold that grows in cold and warm conditions. It is found in fabrics, carpets, cupboards, and other indoor materials.

Risks: Allergic reactions such as breathing or respiratory issues might occur if exposed to this type of mold.

7. Fusarium

Classification: Both allergenic and toxigenic, depending on the species.

Appearance: Fusarium ranges in colors from white, red, and pink.

Location: Fusarium is a fast-growing mold that’s found in cold temperature homes with water damage. It naturally grows on food but is also in carpeting, fabrics, and wallpaper.

Risks: Fusarium can cause skin infections and allergic reactions like runny noses and itchy eyes. Extended exposure could result in life-threatening illnesses like a brain abscess or internal bleeding.

8. Mucor

Classification: Allergenic.

Appearance: Mucor grows in thick patches that spread quickly and are gray or white in color.

Location: Mucor grows in HVAC systems because of the condensation moisture that A/C units have. It may also grow in damp carpeting.

Risks: Exposure to this mold will affect breathing, worsen or cause asthma, and result in flu-like symptoms. A severe case could cause mucormycosis which is a fungal infection that greatly impacts sinuses. Mucor mold can be extremely harmful and a professional should be contacted before trying to remove it.

9. Penicillin

Classification: Allergenic

Appearance: Penicillin often has a velvety texture and is blue or green.

Location: Penicillin is often found in water-damaged homes as well as wallpaper, carpeting, and ductwork. Penicillin is a fast-growing mold and can spread quickly through your house.

Risks: Penicillin can cause asthma and pulmonary inflammation. If subjected for too long, this mold could lead to sinusitis or other health complications.

10. Stachybotrys

Classification: Toxigenic

Appearance: Stachybotrys often has a slimy texture and is black or dark green.

Location: Stachybotrys is found in damp or wet areas with high humidity levels, such as bathrooms, basements, and attics. It grows easily on woods, cardboard, paper, hay, and wicker.

Risks: Stachybotrys poses severe health risks, specifically in the sinuses and difficulty breathing. This mold can also cause pulmonary bleeding in young children and neurological problems. Stachybotrys is most commonly referred to as “toxic mold” or “black mold”.

11. Trichoderma

Classification: Allergenic

Appearance: Trichoderma grows with a wooly texture and is white with green patches.

Location: Trichoderma can be found in wet areas of carpeting, wallpaper, and fabrics. Since it usually grows in moist places, it is often around HVAC ducts as well.

Risks: Risks are usually low as Trichoderma is a non-pathogenic. However, some types of this mold produce mycotoxins which can cause allergic reactions, pulmonary, and hepatic (liver) infections.

12. Ulocladium

Classification: Allergenic

Appearance: Ulocladium is usually black in color.

Location: Ulocladium thrives in damp areas and is often found in bathrooms, kitchens, and basements. It sometimes grows alongside Stachybotrys, Chaetomium, and Fusarium molds. Finding Ulocladium is often a sign of visible or hidden water damage in a house.

Risks: With two different subspecies of Ulocladium, both pose serious health concerns. The effects of this mold are often skin infections, asthma-like symptoms, and hay fever. Ulocladium is often confused with other types of mold, so getting a professional to look at it is a good idea.

Air Purifiers Can Help

Now that you know what the most common types of house mold are, you may be wondering what you can do to protect yourself against these fungi.

According to the Environmental Protection Agency, the best way to control mold growth is to control indoor moisture.

That includes using a dehumidifier, fixing any water leaks, and repairing flood damage.

You can also keep mold spores out of the air is by using an air purifier.

Air purifiers work to filter the air by cleaning it of toxic substances, such as mold spores.

The best air purifier for mold spores is one that uses a True HEPA filter, Activated Carbon filter, and Ultra Violet light.

That combination of air cleaning technologies can reduce and destroy mold contaminants.

You can view our best air purifier for mold and viruses list to find the one that’s right for you and your house.

Depending on the size of the room (or rooms) you’re looking to protect will determine which product will be the best for your budget and needs.

We also have a guide that lists the 10 top air purifiers you can buy today that tackle a variety of other air quality issues (i.e. dust, pet dander, smoke, etc.).

You may want to check out page too if you’re interested in see what all is available.

For more information on mold clean up, advice on assessment, and links to resources, visit the Centers for Disease Control and Prevention.