Fungal Growth in the Home

A Brief Discussion on What Types of Molds Grows in What Indoor 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.

Pen / Asp

Pen / Asp is an abbreviation for Penicillium and Aspergillus.
There are a few hundred species of Penicillium and a few hundred species of Aspergillus so it is impossible to give any one specific indoor environment they thrive in best. Some grow well in humid environments in the absence of any leaks, others require large amounts of moisture for growth to occur. Let’s look at one specific species of each below. Penicillium chrysogenum and Aspergillus niger.

Penicillium chrysogenum

This is one of the most common species of fungus in the entire world. It can grow as the result of various common household 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 call it Pen Asp. If you have the same lab culture it, or do DNA analysis, they will identify it as Penicillium chrysogenum almost every time.

Aspergillus niger

This is one of the water indicator molds. It requires building materials to be very wet before it grows. It is common on cellulose rich building materials after floods and leaks occur indoors.
It looks like Stachybotrys.

Though hard to identify visually as it resembles many other black colored molds, it’s spores are quite distinctive under the microscope. They look like sea urchin shells without the spines.

Cladosporium

will grow as the result of various moisture problems including leaks, and condensation formation but it dominates in areas of condensation. A little condensation is not enough for Stachybotrys or Chaetomium, but it is all the water Cladosporium needs. You will often 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, and the exterior of air handlers inside humid attics.

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. It dominates in low nutrient environments such as metal AC parts, where it does not have to compete with other molds because other molds do not compete well on metal. 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.

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. I have found that after a flood occurs one of the above molds (Penicillium of Cladosporium mold may grow. When water damage is left un attended for many months, or years then toxic black mold is more likely to form. Curious about what this mold looks like when growing indoors click here. To see what it looks like in your petri dish home test kit click here.

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

This is a very common mold to find after floods. It 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 but it does not take nearly as much time to show up after a flood. It is very common behind et baseboards and behind wet wall paper.

Tips: Here are links to some items we recommend. Please read and follow the disclaimer at the bottom of this page before clicking on the links.

One home mold test kit that can give more information than petri dish test kits is the My Mold Detective test kit. It can allow you to take air samples. When sent to the lab the lab results will indicate the type of spores in the air and the numbers per cubic meter of air.

A small air purifier may be beneficial for improving air quality in one room.

A larger air purifier with a true HEPA filter and carbon and a powerful fan like the Austin Air filter is much better for a room or a small home. For years we have highly recommended Austin Air Filters to many of our clients.

Important information to read before buying anything related to maintaining cleanliness or air quality in your home.

QUESTION

Should I buy a mold test kit instead of having a mold inspection done?

ANSWER

You can buy a mold test kit; they provide information on the types of spores that were sampled. Many people enjoying doing a simple test. Never use any type of mold or other air quality home test kit in place of a mold inspection or other indoor air quality investigation by a qualified mold inspector or indoor air quality consultant.

If you have an air quality problem or mold problem the services of a mold inspector or indoor air quality consultant will be beneficial. The goal of such a consultant is to help find the problem, and to diagnose the cause of the problem, and to provide written information on what needs to be done to correct the problem.

QUESTION

Should I buy an air purifier in place of getting rid of mold or other sources of air quality problems?

ANSWER

You can buy an air purifier. They can remove some spores, dust, and chemicals from your air. They often improve your overall air quality. But if you have a mold problem or other air quality problem you need to have the moisture, or humidity problem, or other defect corrected by a properly and fully qualified contractor. Next have the moisture, humidity, mold, or other air quality problem removed by a properly qualified professional remediator.

Can I do my own remediation?

Many people clean very small simple mold problems as part of routine indoor and outdoor cleaning. Such is done on hard, smooth, easy to clean surfaces such as shower tile, or patio furniture. Such as done on surfaces that homeowners would typically clean and that are too small for mold remediators to address. Radon mitigation, lead paint abatement, Asbestos removal, and all environmental cleaning must be done by the appropriately qualified, and where applicable licensed professionals.

Never do your own remediation of true mold problems or, other forms of environmental contamination. You could expose your lungs, your family, and your home to mold, asbestos, or lead.

At A Accredited Mold Inspection Service we do mold inspections in South East Florida.

In other areas of the US try IAQA.org or ACAC.org. Put you zip code in and find a remediator or inspector. The two above national organizations have high standards.

Of course, we cannot guarantee the company you find at IAQA or ACAC will be any good, so research the companies credentials and reputations.