Fungal Niches in the Home (What type of mold grows where in the home?)

Fungal Niches in the Home (What type of mold grows where in the home?)
on November 5, 2013 in Florida Mold Articles

Fungal growth in the Home
A brief discussion on what types of fungus grows in what types of home environments.

In nature different type of living organisms thrive in different environments, it the home it is no different. Some molds prefer some environments while other prefer other environments. Let’s look at just a few common molds and the types of indoor environments they prefer.   

Has any part of your home experienced flooding in the past? Is any part of your home currently humid, or damp? Moldy micro-environments in the home are varied, and the types of mold that do best in different moist indoor environments can vary.
Did you know that:


Penicillium chrysogenum is one of the most common species of fungus in the entire world. It can grow as the result of various common houseold moisture problems including high humidity, condensation, and leaks. When it comes to fungal growth in the home Penicillium chrysogenum is quite diverse and will adapt to many environments.
What makes P. chrysogenum stand out is that this mold and likely some very close relatives that resemble it grows quite well in humid environments even when no leaks have occurred. It grows on clothes in a humid closet, or on furniture in a humid home. It does not require any leaks at all, this fact confuses many homeowners and even some mold inspectors who mistakenly believe that you need a leak for mold to grow.  It does perfectly well in a humid environment. When white spots appear on furniture and on clothes in closets it is usually this mold. Send a sample to the lab and they will confuse you with mis-identification of this fungus, but if you have the same lab culture it, or do DNA analysis, they will identify it as Penicillium chrysogenum almost every time.

will grow as the result of various moisture problems including very high humidity, leaks, and condensation formation but it dominates in areas of condensation. You will find it as black dots on cold metal AC registers where condensation forms. This mold is also common on the interior surfaces of AC units and AC ducts. Like most molds it is not confined to one type of moisture issue, and can grow in various environments including on water damaged walls, under wall paper, and on window sills, but it dominates in low nutrient environments such as metal AC parts, where condensation forms. Have sooty black mold on a harsh low nutrient surface that no other mold wants to grow on? If you see soot like black mold outdoors on a metal fence, concrete sidewalk, or a tile roof, it may be Cladosporium.

Stachybotrys chartarum
also known as toxic back mold does best in very wet environments, it loves areas of flooding or more severe leaks. Get cellulose containing building materials soaking wet after a flood and in time this mold will often grow. Based on literally thousands of inspections I have seen a pattern with this mold. I have found that after a flood occurs one of the above molds ( Penicillium of Cladosporium mold may grow, but if the water damage is left un attended for many weeks, months, or years then toxic black mold is more likely to form.

While many molds grow after flooding this one requires a little more time to colonize surfaces as it is not the first on the scene. Toxic black mold will produce toxins so we call it toxic mold, but it will likely cause the same exact health problems as non-toxic molds in most cases.

Chaetomium looks like cinnamon to the naked eye, under the microscope the spores look like tan lemons.  Like Stachybotrys it does best in areas of flooding or leaks. If you get cellulose containing building wet Chaetomium will likely form some place nearby. It seems to love to grow behind water damaged baseboards. One difference between this one and toxic black mold is that it does not take as much time to show up after a flood.

To be honest mild to severe health consequences connected with mold infestation can occur regardless of the type of mold you have, regardless of what moisture issues caused it. Plumbing flood induced toxic mold, or humidity induced Penicillium, or condensation induced Cladosporium, it makes no difference. All molds are a problem when growing indoors.

Instead of becoming traumatized by fears of one specific type of mold you must focus on resolving the problem. If your mold inspector can tell what caused the problem then you have started on the right path to correcting the issue. Your inspector should identify causes, and also what areas of your home may be infested with fungal growth. You must not waste time having an inspector identify the locations of infestation, and do not waste time having a separate remediator remove the mold problem.

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