Home » A Closer Look at Mold – Types, Classes, and Tips to Clean it

A Closer Look at Mold – Types, Classes, and Tips to Clean it

by krystle
mold types and classes

A Closer Look at Mold – Types, Classes, and Tips to Clean it

  1. Mold can grow almost anywhere! You might not see it but it could be there!.
  2. All types of mold prefer areas low on light and high on moisture – behind drywall/sheetrock, within wallpapers, carpeting, bathtub stains and etc.
  3. Mold spores or mold toxins can be present in food without you ever knowing.
  4. Many anti-biotics are manufactured thanks to mold types like Penicillium & more.
  5. Baking soda, borax, ammonia, oregano oil, neem seed oil, they all can help you clean up and get rid of mold, but bleach and peroxide will not handle Class A types of mold.
  6. The early stage of being sick from Mycotoxin will show no physical symptoms but it can affect the brain cavity.
  7. There is no such thing as mold allergy. You either fight it as a virus, or you end up sick (or even very sick).
  8. Mold toxins are even more dangerous if you use steroids, anti-biotics or even immune suppressing products.
  9. Candida Albicans is detected in the stomach and mouth of 40% to 60% of adults.It emits toxins, able to cause cancer.
  10. Most types of mold prefer to grow in a low pH environment, while Candida does it at pH of 7.

Yellow. Green. Brown. White. Black. Mold comes in these and many other colors, just like a box of crayons. However, unlike crayons, these invasive fungi are nowhere near as fun to work with. If your property has been affected by this highly persistent growth, simply wiping it away will not solve the issue. Below, we will discuss the effects of mold on health, its common varieties, and the cleaning techniques that you can use to prevent the growth from coming back.


What Are Mold’s Effects on Human Health?

Before we focus on the negatives, let’s begin by acknowledging some of the mold’s positive impacts on today’s society. For instance, Rhizopus, a type of mold, is responsible for releasing fumaric acid that is used to produce a type of local anaesthetic, known as cortisone. Aspergillus flavus, on the other hand, has been safely used in China for centuries in the making of cheeses and soy sauce. And Penicillium molds have led to the discovery of the popular antibiotic.

However, not all types of mold are as benevolent as the ones above. Besides looking unsightly, any mold species can become a major inconvenience once it enters the household. If the affected area is not sterilized in time, the fungi will release numerous spores into the air that, once inhaled, can trigger an allergic reaction. The symptoms will vary depending on the person’s age, the level of mold exposure, and their health condition. Here are some of them:

  • Chronic exhaustion and headaches;
  • Red eyes and increased light sensitivity;
  • Lesser ability to concentrate or remember;
  • Joint and abdominal pain, numbness;
  • Shortness of breath and chronic cough;
  • Mood, appetite, and temperature swings;
  • Disorientation or a feeling of lightheadedness.

How Is Each Type of Mold Classified?

Unfortunately, the growth’s color and texture are not enough to determine if the mold in your home is dangerous. That is why some countries have developed a special mold grading system. Here, the hazardous levels of each mold type are assessed on a scale from “A” to “C”, with “A” denoting the most dangerous molds and “C” – those that pose the least health risks.

  • Class A – these are the molds that can cause the most harm in a home or office environment. Any mold species belonging to this class should be removed as soon as possible to prevent the release of harmful toxins and the spread of airborne infections.
  • Class B – while not as dangerous as those found in class “A”, the continuous presence of this mold group can still cause allergic reactions or greatly exacerbate existing ones.
  • Class C – such molds are completely harmless to humans, even indoors. However, their knack for growing on almost any damp surface can often lead to structural damage.

How Many Types of Mold Are There?

Perhaps too many for us to count. Some of the more commonly encountered mold types are:

  • Acremonium. This genus has been said to contain almost 150 mold species! This makes them a very common sight on many wallpapered kitchens and damp basement walls. However, these fungi can also be spotted growing on insulation and drywall surfaces. They are typically brown, gray, or white in appearance. Hazard rating: Classes A, B, or C, depending on the species.
  • Cladosporium. You will frequently encounter this one. This genus comes in green, brown, gray, or black colors and is comprised of around 40 species. Common gathering spots include painted walls, wood, carpets, wallpapers and other damp organic surfaces. Hazard rating: Classes B or C, depending on the species.
  • Aureobasidium. The natural habitat of this type of mold is the great outdoors. It’s considered to cover approximately 15 species. Inside the home, it can be found thriving on wallpapers, wooden and painted surfaces, and the areas near damp window frames and caulking. Comes in pink and black varieties. Hazard rating: Classes B or C, depending on the species.
  • Alternaria. Contains about 50 species. Unlike the Acremonium, you will not see these black or grey fungi in your home, unless the spores have been tracked from the outside. Hazard rating: Class B.
  • Botrytis. Most notable as a plant parasite, this genus can thrive just as well in poorly-ventilated bathrooms or other areas of your home with unusually high levels of humidity. Allergic reactions or even asthma can be developed over time, so sprucing up the affected area is highly recommended. Comes in various shades of gray. Hazard rating: Class B.
  • Chaetomium. Has a distinctive musty odour and can be found on water-damaged carpets and window frames. Initially red, it soon assumes a brown color. Hazard rating: Class B.
  • Ulocladium. These olive-brown species love water and are often found in damp bathrooms, kitchens, basements, or growing on the sills of foggy windows. An abundance of Ulocladium is often a tell-tale sign that you’re dealing with water damage. Hazard rating: Class B.
  • Penicillium. There are about 200 known species. Penicillium molds that are found in the air or the soil. Their main purpose is to cause food and other perishable goods to spoil, and their presence usually indicates high moisture levels in the environment. Indoors, they will cling to various damp surfaces, such as walls and wallpapers, floors, and carpets. Colors range from blue and yellow to green and white. Hazard rating: Classes A or C, depending on the species.
  • Aspergillus. Yellow-greenish in color and often encountered indoors. Neglecting its presence can lead to respiratory infections or may even cause inflammation of the lungs – a condition known as hypersensitivity pneumonitis. Hazard rating: Classes A or B, depending on the species.
  • Fusarium. Springs to life even at lower temperatures and is most often spotted growing on water-damaged carpeting and fabrics. Its prolonged presence can cause mild allergic reactions, asthma, and severe respiratory conditions. Orange in color. Hazard rating: Classes A or B, depending on the species.
  • Trichoderma. Like most molds, this genus is also after damp carpets, wallpaper, and any other organic surface that it can muster the energy to grow on. These species, however, can release mycotoxins that are highly toxic to humans and can cause many health problems down the road. They come in dark brown, yellow, and orange colors. Hazard rating: Classes A or B, depending on the species.
  • Stachybotrys. An extremely dangerous fungi, also known as “black mold”. Mold species under this genus produce mycotoxins wherever they are disturbed, which can cause a long list of serious infections. They usually grow on materials that contain cellulose and that have remained damp for a long period of time. Such surfaces include cardboard and gypsum board, ceiling tiles, wood, and other organic materials. Hazard rating: Class A.

What Can Be Done to Keep Mold at Bay?

Battling mold can be tricky, especially if the fungi has been around for quite some time. Here are a few tips from Fantastic Cleaners (London) on how to successfully clean up, remove and prevent mold from coming back.

  • Find the root of the problem. Usually, mold appears for a reason. It may grow due to faulty insulation, leaky pipes, damaged guttering, or simply because you forget to leave the bathroom door open each time you have a shower. Whatever the case, identifying the source of dampness first will ensure that your disinfecting efforts will not go to waste.
  • Wear protective clothing. Get a cartridge-type respirator, preferably with a P100 filter. Anything lower than that will still let the spores pass through. Make sure to also wear rubber gloves and safety goggles, especially if you’re scouring the affected surfaces.
  • Don’t sweep or dust the mold. If you do that, you will unleash a small Pandora box in the comfort of your home! Instead, treat the moldy areas with a mold cleaning spray. Once you’ve treated the fungi, gently sanitize the surfaces using a damp cloth and wipe with a dry cloth.
  • Wipe the condensation away. Condensation is like a magnet for muld. Regularly dry and vacuum damp spots on your walls and ceiling to deny the dormant spores a chance to grow into mold by feeding on wood, cotton, cardboard, and other organic surfaces.
  • Dispose of water-damaged items. Most often, you will spot the mold when your carpeting or insulation have already been damaged beyond repair. Mix some water with dish soap in a garden sprayer to decontaminate the affected surfaces. Next, place the items inside a double-bag before discarding. Finally, treat all adjacent surfaces in your home with a mixture of water and bleach before making any repairs.

Mold is a difficult problem to deal with on your own and sometimes it is beneficial to call a top mold remediation specialist to help with your mold issue. The mold removal specialists from Sm Enterprise NJ advise:

“WARNING: Never, ever attempt to mix bleach with other cleaning products that contain ammonia or traces of ammonia since the reaction will produce highly toxic fumes! This will not only pose a risk to you, but your family, pets and even neighbours. Regardless of the type of mold. DIY has caused more problems than solved.”

What are the most common areas where mold can grow in your home?

Types of mold most frequently showing in kitchens and bathrooms:

  • Cladosporium cladosporioides (hazard class B)
  • Cladosporium sphaerospermum (hazard class C)
  • Ulocladium botrytis (hazard class C)
  • Chaetomium globosum (hazard class C)
  • Aspergillus fumigatus (hazard class A)

The types of mold that grow on or under wallpapers:

  • Cladosporium sphaerospermum
  • Chaetomium spp., particularly Chaetomium globosum
  • Doratomyces spp (no information on hazard classification)
  • Fusarium spp (hazard class A)
  • Stachybotrys chartarum (hazard class A)
  • Trichoderma spp (hazard class B)
  • Scopulariopsis spp (hazard class B)

The types of mold regularly found on under mattresses and carpets:

  • Penicillium spp (Esp. Penicillium chrysogenum) (hazard class B);
  • Penicillium aurantiogriseum (hazard class B);
  • Aspergillus versicolor (hazard class A);
  • Aureobasidium pullulans (hazard class B);
  • Aspergillus repens (no information on hazard classification);
  • Wallemia sebi (hazard class C);
  • Chaetomium spp., particularly Chaetomium globosum;
  • Scopulariopsis spp.

Types of mold most frequently found growing on window frames:

  • Aureobasidium pullulans (hazard class B);
  • Cladosporium sphaerospermum (hazard class C);
  • Ulocladium spp (hazard class C).

Types of mold commonly often present in basements (cellars):

  • Aspergillus versicolor (hazard class A);
  • Aspergillus fumigatus (hazard class A);
  • Fusarium spp (hazard class A).

Types of mold most frequently growing in flower pot soil:

  • Aspergillus fumigatus (hazard class A);
  • Aspergillus niger (hazard class A);
  • Aspergillus flavus (hazard class A).

Types of Mold – The Conclusion:

Molds (spelled “mould” in the UK) stands for a microscopic organism that is capable of growing almost anywhere, as long as conditions are right. Most types can grow inside buildings, as well as outdoors. Mold colonies can develop easily when you have a damp and wet area.


While some species are far from hazard, others are extremely dangerous and can cause severe health issues.

No matter what is the exact type of mold at hand, it should not be taken lightly, but handled with extreme caution!

“Dmitri Kara is a proactive citizen of the web. Blogging fan, social media activist and an active citizen of the web. ”


Want The Inside Scoop?

Related Articles


Fatima October 21, 2019 - 3:09 am

Nice article – finding root of the problem is definitely most important point. Cleaning out your gutters at least once a year will do wonders in preventing growth of mould, and health issues as a result of mold. Thanks for sharing these tips! :)

Blitz August 2, 2022 - 6:51 am

I agree with Fatima, cleaning out your gutters is very important! I guess many don’t think about external mould as a big problem in comparison to internal mould, however external can cause internal as well as a host of damage!


Leave a Comment

Want The Inside Scoop?