For a lot of families, the basement is one of those out-of-sight-out-of-mind places where seemingly tiny problems can fester up into a major issue. Especially if you are talking about an unfinished basement with low airflow and plenty of ambient moisture.

In warm conditions, naturally-occurring mold spores that float around in the air around us can find a moist, warm place to germinate into an active mold colony. Once this starts the presence of mycotoxins and second-generation mold spores can start to make people sick. Especially those family members with respiratory health conditions, the elderly, and family members who are prone to inflammatory conditions. Not to mention, an unaddressed mold problem can even start to gradually damage the structure of your house.

Unfortunately, eliminating mold in a basement can be a challenging task. Many homeowners are unsure of when to call in the professional, or whether they can deal with a mold problem themselves. If you’ve discovered mold in your basement, and you aren’t sure how to handle it, the following article can help answer some important questions.

How Did Mold Get Into My Basement?

Microscopic mold spores exist everywhere in nature. They float through the air looking for a warm, moist place to germinate. They have the potential to grow vigorously in certain porous substances like woodwork, drywall, fabric upholstery, and old carpet.

Some mold strains are relatively benign, but some can be very dangerous to your health. Especially the so-called “Toxic Black Mold” known as Stachybotrys chartarum. Though even if the mold in your home isn’t “Toxic” the mold spores and mycotoxins removed by seemingly benign mold colonies can still cause increased respiratory irritation and other health problems.

Some mold spores can germinate into an active colony in less than 48 hours, under the right conditions. In a basement that is seldom seen by human eyes, a mold colony can grow out of control.

Common Strains Of Mold Found In Basements

The NIEHS (National Institute of Environmental Health Sciences) has identified five different strains of mold that are commonly found in basements.


This mold colony can be shades of brown, black, or gray. It is relatively slow-growing and is most common in soil. It is a likely type of mold in basements with a dirt floor.


Oddly enough this is the same type of mold used as the basis for the antibiotic penicillin. It is a generally fast-growing mold that usually looks green or white.


This is a relatively benign form of mold. Though in some rare cases, it can cause an infection called Aspergillosis. This condition can be very damaging to individuals with a weakened immune system or respiratory conditions such as asthma.


This is another relatively fast-growing type of mold that produces active colonies that appear in shades of brown, olive, and black. Just like Aspergillus, it can cause health problems in sensitive individuals.

Stachybotrys Chartarum

This is the fearsome “Toxic Black Mold, Stachybotrys chartarum which appears black to greenish in color. These mold colonies tend to be very fast-growing and are known for thriving on building materials such as drywall, wood, gypsum board, and wallpaper. It can cause significant symptoms in sensitive individuals as well as affect perfectly healthy adults and pets.

How Do I Detect Mold In My Basement?

Some signs of mold are easy to spot and some can be more challenging. If you have noticed one or more of the following things in your basement, you should be strongly suspicious of a mold problem.

Discolored blotches on walls and porous materials

  • A pervasive “Earthy” or “Musty” odor
  • Family members coughing & sneezing
  • Family members with persistent headaches
  • Vulnerable family members having increased health problems
  • Noticeable odors when the HVAC system turns onYou might also notice sensitive or vulnerable family members’ health symptoms going away when they are on vacation, only to have them reoccur shortly after returning home.

Can I Test For Mold In My Basement?

Some at-home mold testing kits are sold online and inbox hardware stores, but most of the time a comprehensive mold test will help find hard-to-reach colonies that might be lurking in crawlspaces and ventilation ducts.

How To Eliminate Mold From Your Basement

Once you have identified all the active mold colonies in your basement, you can start to put together a plan for removing them.

Mold-infested drywall and badly affected woodwork typically need to be removed from the basement and replaced with clean structurally sound materials. The problem here is that simply removing them can disturb the colony, causing it to release mold spores and mycotoxins into the air. These fresh spores then land somewhere to recolonize in a few days or a few weeks.

Before you attempt to remove mold-infested materials, you first need to clean them, to kill as much of the mold as possible. If possible, try to implement measures to prevent any accidentally released mold spores from migrating through the air of your home.

You also need to go the extra mile to protect yourself with high-quality air masks, gloves, and other personal protective equipment.

Best Products For Killing Mold

You might first reach for a bleach-based cleaning solution. Though while bleach will certainly kill surface mold, it works too quickly to kill the deep-down microscopic roots of an active mold colony. To truly kill the mold growing on a porous surface like wood, you need an oxygen-based cleaning solution or a solution that uses a volatile form of oxygen like hydrogen peroxide.

Preventing Mold From Recurring In Your Basement

It’s important to note that even the CDC, recognizes that you cannot completely eliminate 100% of the mold spores in your basement. Though removing the source of moisture and removing the mold colonies will go a long way toward preventing a recurrence of basement mold.

This means that even after you have killed active mold colonies and removed any severely mold-damaged materials, you will still need to take measures to stop the humidity and water problems that promoted mold growth in the first place.

This starts with any necessary repairs such as:

  • Sealing cracks in walls
  • Sealing leaky windows
  • Repairing any roof leaks
  • Addressing any & all gutter problems
  • Repairing any roof leaks and gutter problems

Once the repairs are done, you might also want to consider implementing a mold prevention strategy. This might call for things like using a basement dehumidifier in the summer months to keep ambient basement humidity levels as low as possible. You might want to also consider applying mold prevention solutions to vulnerable areas and areas that previously had active mold colonies.

When To Call In The Professionals

  • Knowing when to call in the professionals can be understandably challenging for some homeowners. Though it’s a good idea if:You are unsure of the severity of the mold problem
  • You suspect there is mold in hard to reach places
  • You don’t have access to high-quality personal protective equipment
  • There are sensitive family members who might react to accidentally released mold spores
  • The mold problem is severeWhen you bring in a professional cleaning and mold remediation specialist like Building Services, you can trust that all active mold colonies will be identified and strategically eliminated. Our highly trained and experienced mold remediation specialists have access to commercial-grade cleaning solutions and the equipment necessary to safely eliminate the presence of mold in your basement. We will also safely dispose of all severely mold-damaged materials following all pertinent regulations.

    We can also help you understand what caused the mold problem in the first place, so you can affect the necessary repairs to prevent future moisture issues. Then we can advise you on the best steps you can adopt as part of a highly effective mold preventing strategy.