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5 Common Basement Mold Types (With Pictures)

Mold on wall_Jezael Melgoza_Unsplash

Basements are especially susceptible to mold and mildew due to their location and underlying foundation. Mold refers to the various types of fungi that commonly grow in or around homes and other building structures.

It grows under certain specific conditions and is known to cause allergic reactions. Mold can be especially hazardous depending on the type and extent of its infestation. If left untreated, basement mold can spread throughout different areas of your home, so it’s important to identify it and treat it as soon as possible. But what are the different types of basement mold? house divider

The 5 Common Basement Mold Types

1. Black Mold (Stachybotrys)

Black Mold_Fevziee_Shutterstock
Image Credit: Fevziee, Shutterstock
Fungi Class: Sordariomycetes
Common Locations: Damp places, HVAC systems

This is the most common type of basement mold (and bathroom mold) as well as the easiest to identify. It’s black and appears in small or large spots on walls, ceilings, and in between tile grout. There are many species of Stachybotrys. You’ll commonly see it in basements, bathrooms, sewers, and other areas that are damp and cool.

Stachybotrys halonata and Stachybotrys chartarum are the most common types within this species and they’re more toxic than many others. They can sometimes be found indoors and in ventilation systems. Both species can be linked to indoor air quality problems, and it’s usually caused by excessive moisture in most cases.

2. Aspergillus

Fungi Class: Eurotiomycetes
Common Locations: HVAC systems, indoors, flooded areas

There are over 100 types of molds within this fungi species. It can appear or black or bluish-green tints with a cloudy, almost fuzzy appearance. And though most aspergillus is non-toxic, many species are particularly dangerous in large numbers.

They can emit toxins in the air that trigger asthma issues and allergic reactions. Bad infestations can also cause respiratory irritation and lung infections if inhaled.

Some aspergillus species can be toxic and create aflatoxins–compounds that can encourage cancer growth. The spores of aspergillus fumigatus can be found in all parts of the environment and around your home’s foundation.

3. Penicillium

Penicillium Mold_Olpo_Shutterstock
Image Credit: Olpo, Shutterstock
Fungi Class: Eurotiomycetes
Common Locations: High-humidity locations in/around the home

Penicillium is found in most natural environments and is commonly used in drug and food production. It’s also known to be the source of many antibiotics. But, this mold can cause allergic reactions when grown in large numbers in your basement.

It normally appears in round, fuzzy greenish blots with white edges. It spreads quickly through the air and can cause heart or asthma-related problems. Penicillium, like other molds, thrives in high-moisture areas — which is why basements are a prime location.

4. Serpula

Serpula Mold_LariBat_Shutterstock
Image Credit: LariBat, Shutterstock
Fungi Class: Polychaeta
Common Locations: Wood-based structures

Serpula lacrymans eat almost exclusively wood structures found outdoors or indoor areas (commonly basements, attics, and crawl spaces). Although it can be irritating, it actually isn’t a serious health threat to humans. But it can cause structural damage to your home if growing in large numbers — so it’s important to mitigate it ASAP.

It can cause dry rot and destroy beams fairly quickly, even without substantial moisture. If you notice beams, joists, or floors with mushroom-like growths appearing on them, it could be a sign of a serpula infestation.

5. Ulocladium

Fungi Class: Dothideomycetes
Common Locations: Damp carpets, furniture, and drywall

The allergenic household mold can be found in moist areas such as bathtubs, showers, and window trims that are susceptible to condensation. It can also be found in appliances such as carpets, dishwashers, and traditional clothes washers.

You can also find it along the rubber seals in your fridge or freezer, especially if the cooling system is malfunctioning. Ulocladium looks like black mold but isn’t as dangerous. However, any visible mold should be a cause of concern. Ulocladium can also be found in drywall (due to plumbing leaks) and thrives in damp environments.

divider 5Usual Reasons for Mold in Basements

Mold spores can actually grow anywhere, but most require certain living conditions to grow. Let’s take a look at the most reasons why you may find mold growing in your basement.

Sump Pump Failure

Sump pump failure can cause mold overgrowth in a matter of days. And if the pump is not properly maintained, it can also lead to mold issues due to excess water on the floor or beneath the surface of the slab.

Water Heater Issues

When a water heater fails it could cause stagnant water to pool. leading to damaged floors and walls. And if the water heater is leaking (which commonly happens before a failure), it could lead to excess moisture and mold growth where the water has leaked.

Bad Ventilation

A lack of good ventilation is one of the most common causes of basement mold. Poor ventilation causes condensation. This, in turn, causes excessive moisture in the basement, which is the perfect environment for mold to grow.

Too Many Organic Materials

This may come as a surprise, but too many organic materials in a moist basement can also exacerbate mold growth. Materials such as wood furniture, carpets, old clothes, and cardboard, combined with humidity levels of 55% or higher can cause mold issues.

Basement Ventilation_Robert Kneschke_Shutterstock
Image Credit: Robert Kneschke, Shutterstock

Ways to Prevent Mold in Basements

You’ll need to be vigilant in order to prevent mold growth in your basement. Let’s look at how you can keep your basement free from mold.

Reduce the Humidity

Mold growth thrives in moist environments. Basements can have very moist conditions even without flooding or plumbing leaks. It is important to control the humidity in your basement (it shouldn’t be over 55%).

A basement dehumidifier (which can be attached to your furnace) is the best way to achieve this. The dehumidifier can be set to maintain the basement’s humidity at the desired level.  And to make sure that humidity levels are at an acceptable level, consider purchasing a hygrometer. You can get one online for about $10.

Repair All Plumbing Leaks ASAP

Leakages can cause water pooling and wet spots, which can cause mold if left unattended for long periods. Because basements are below-ground level, moisture can easily get trapped. This commonly leads them to become very moist and mold-ridden faster than other levels of a home.

You should immediately fix any leaks and dry your basement with a heater or let it air out. So have any plumbing leaks fixed as soon as possible and keep an eye on your water heater if it starts leaking.

Avoid Clutter

You won’t get much airflow if your basement is cluttered with clothes, unused furniture, construction debris, trash, etc. And if your basement isn’t well ventilated, it makes it even more conducive to fast mold growth. This problem can typically be avoided by ensuring that clothing, boxes, and other similar items are well-organized and stored away.

Try not to keep too many loose items hanging around in your basement — especially out in the open. It’s best to leave enough space for airflow. Also, avoid placing your belongings and furniture against the wall, or on the floor of your basement–which can also block vents and normal airflow.

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The more ventilation your basement has, the less likely it is to develop mold infestations that can lead to structural issues and potentially hazardous living conditions for you and your family. Keeping your basement mold-free means being proactive in reducing humidity, clutter, and monitoring for water leaks.

See also: 10 Types of Mold in a Crawl Space

Featured Image Credit: Jezael Melgoza, Unsplash

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