How Long Does it Take for Black Mold to Grow

Most of us have heard that black mold is extremely dangerous. It’s due to the mycotoxins they can produce. Homes that are infested with black mold typically have to be renovated entirely – or even torn down. Scientific studies also suggest that exposure to black mold (professionally called Stachybotrys chartarum) can cause health issues.

But do you know how long does it take for black mold to grow in a person’s home?

Sadly, our clients, Joe and Cathy Cunningham, found out the hard way.  The Cunningham’s rec room had filled with a few inches of water following a steady weekend rain. This wasn’t the first time the room had flooded; however, they were a bit slower about getting around to cleaning it up.

A few days later, Cathy arrived home after work one evening to an unpleasant, musty stench in the home. They inspected the rec room but saw no signs of mold growth or anything unusual.

The Cunninghams then left for a long weekend away – and when they came home, they knew something was very wrong.

The smell of mold was overpowering to them.

So, How Fast Does Mold Spread?

This “chocolate slime mold” is an uncommon sight in residential homes. About the size of a hamster, these organisms can actually move in the direction of food sources and are known for solving complex mazes. They are seen more frequently in wooded environments. Not sure what this gal is doing in this house, but its not what you like to see.

Well, in this case, it took the mold less than three days to transform itself from “barely detectable” into a source of pungent smells so sickening that they couldn’t breathe when they walked in the home.

The home had been “closed up” for three full days, meaning that their warm and damp rec room was not getting proper airflow. As a result, the combination of excessive humidity and poor ventilation had turned their home into a hotbed for mold.

Mold spores reproduce on damp surfaces, and they tend to grow best in environments with little airflow and sunlight.

In the Cunningham’s case, leaving their previously flooded room boarded up for a few days created a feeding ground for black mold spores. It had sprouted behind the hidden, poorly ventilated wall cavity in their rec room.

What Does Black Mold Look Like?

What is it that makes mold so scary? And what should you look out for?

Let’s try to understand by learning a little about this tiny organism.

Detecting Black Mold Is Difficult

Molds are elusive and like to hide in damp dark spaces. Many times you can see them, but most often, you can’t. But if you have a good sense of smell, you can often pick up on the distinct musty, sometimes locker room / earthy aroma. If it doesn’t smell right, you better figure it out or call in a professional.

Molds are elusive and like to hide in damp, dark spaces. Many times you can see them, but most often, you can’t. But if you have a good sense of smell, you can often pick up on the distinct musty, sometimes locker room / earthy aroma. If it doesn’t smell right, you better figure it out or call in a professional.

Despite all appearances, discerning whether the mold is actually black mold is a bit trickier. Black mold is (surprisingly) not always black; it can also appear to be greenish or brown. Thus, only a lab test can confirm the presence of black mold, and anyone who pre-judges its existence is only guessing; another reason why expert advice is vital.

The distinctive odor of molds usually follows within 48 hours after a flood or other mishap involving an influx of moisture or water. However, it may not always appear right away. The slower-growing molds (like Stachybotrys) often take months to grow and are often difficult to detect initially.

But Cleaning Black Mold Is Vital Because of the Risk to Your Health

If the proper precautions are not used, exposure to black mold can cause:

•       Coughing and sneezing
•       Eye, nose, throat, and skin irritation
•       Fatigue
•       Headaches
•       Runny nose
•       Upper respiratory irritation

If left untreated, black mold can trigger more severe health concerns, such as:

•       Difficulties with breathing and sleeping
•       Nausea, vomiting, or diarrhea
•       Impaired concentration
•       Bladder or kidney pains
•       Balance issues
•       Rapid weight gain (loss)
•       Hair loss and irritating rashes

Mold is dangerous, and if you don’t take proper precautions, it can cause severe eye and skin irritation. Long-term exposure to black mold can cause allergic reactions, and infections can develop in more severe cases. In addition, children and people with weak immune systems are at greater risk of developing mold-related health problems.

Black Mold Smells like Must and Mildew

Small areas of molds are often concealed behind the wallboard and never really “breakthrough” to the visible side. But the clumping molds (like stachybotrys) often have a very distinct aroma when growing.

Small areas of molds are often concealed behind the wallboard and never really “breakthrough” to the visible side. But the clumping molds (like Stachybotrys) often have a very distinct aroma when growing.

The smell of black mold is quite distinctive, commingling mildew with a must. The odor is usually most noticeable after it comes into contact with a surge of air, such as when pushed through a home’s ducts.  Or after people have not been around the room’s indoor air for some time, such as in Joe and Cathy’s case.

What Do You Do When You Find Black Mold?

It is very important to hire professional services for all mold removal services. Thankfully, the Cunninghams called in Greenworks for professional mold inspection right away. Our team of technicians arrived to determine how much mold was growing and what the next steps were.

Getting rid of mold, thoroughly and permanently, is a highly specialized job that requires “confident expertise” – the kind that the Cunninghams received from GreenWorks.

This “Chocolate Slime Mold” is an uncommon sight in residential homes. About the size of a Hamster, these organisms can move toward food sources and are known for solving complex mazes.

Mold needs to be entirely eradicated; otherwise, it will grow right back. This means that you have to clean far below the visible areas of growth with the right penetrating biocides. Simply wiping down your walls with some bleach or household cleaners might not be enough to get rid of a black mold problem permanently.

Do I Need Professional Testing?

The short answer is: yes. If you suspect that mold is growing in your home, you should first schedule a mold assessment or inspection.

Technicians first need to determine which type(s) of mold are growing before effectively removing it. Some types of mold are more toxic than others and require that additional safety measures are taken. But most importantly, the “moisture trigger” has to be identified and corrected. Otherwise, the molds will just return.

Cleaning mold yourself just isn’t worth it. Even the CDC recommends homeowners “get help from experienced and qualified professionals. Hire a mold inspection or remediation professional….to inspect, repair, and restore the damaged parts of your home. Your state also may regulate mold remediation.”

Find the Solution in Greenworks

New Jersey residents turn to GreenWorks for professional mold inspections and expert mold remediation because we are truly experienced professionals. At heart, Greenworks is an environmental company that has convened the very best talent in the fields of building biology, hygiene, ecology, and site remediation.

While there is no black mold problem that we haven’t tackled, we know that no two homes are alike and that each one deserves our “Midas touch” of personalization.

We know that in order to remove mold, we must address the root cause so that another outbreak does not reoccur. As the U.S. Environmental Protection Agency (EPA) says, “If you clean up the mold but don’t fix the water problem, then most likely the mold problem will come back.”

While GreenWorks obviously cannot prevent future downpours and flooding, we help our customers take preventive measures. In addition, our technicians can show you how to control day-to-day moisture in your home.

As Joe and Cathy learned, dealing with black mold in the home can be dramatic and traumatic. But with GreenWorks at your side, it will always end on a safe and healthy note.

This article was originally published on May 27, 2015
Updated on August 12, 2021