What Does Black Mold Smell Like in a Home?

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What does black mold smell like

Before I begin speaking on the dangers of black mold in a home, let me first introduce myself. My name is Victor Coppola- I am a building biologist at GreenWorks with decades of indoor mold and air-quality testing experience. I have come across countless homes that contain different types of molds throughout my career. But to me, black mold has always been the most concerning.

On many occasions, I have visited other people’s homes and caught the old musty scent of a black mold infestation. And when I inform the homeowners of this black mold smell, they often tell me, “It’s alright. It has been there for some time, and we are ok with it.”

Not to burst their bubble, but a black mold smell is a tell-tale sign of an unhealthy place to live. As much as people might try to minimize the severity of a mold growth issue, nobody enjoys waking up to the smell of black mold in the morning – and more importantly, it is extremely dangerous to your health.

But what exactly is black mold?

What does black mold smell like in a home? 1

The idea of a “black” mold can be misleading. Black mold is a nickname used for a type of toxic mold called “Stachybotrys,” which can range from greenish-black to oily-black in color.

In addition, black mold is categorized as toxigenic, not poisonous. When you say toxigenic, it means that although the molds aren’t outright harmful, they can produce toxins (often called mycotoxins).

The problem arises when these mycotoxins attach to the spores that the molds release. The spores aren’t released all the time, but a slight vibration caused by a door opening or some hammer work can cause the mold colony to be disturbed. When this happens, a cloud of almost invisible spores gets released into the air and causes poor indoor air quality, which can lead to serious health problems.

So, what exactly are the dangers of black mold, and how can you smell it growing in your home? Let’s discuss.

Black Mold Smell is a Sign of Danger Waiting to Happen

I’ll start by saying that mold is pervasive in many homes as it can grow on any surface exposed to moisture and multiplies quickly. In fact, mold spores can start growing on any damp surface within 24 to 48 hours. I’ve detected mold growing in homes with leaky pipes, flooding, and even in areas where a homeowner didn’t completely clean up a spill.

But I admit: after detecting indoor mold growth for so many years, the thought of black mold still really makes me cringe. The musty odor of black mold is pungent and certainly not something I would want lingering in my home. Plus, it’s one of the more dangerous types of indoor mold you can encounter.


Why is Black Mold So Dangerous?

If you can smell black mold, it means that it is in your lungs and airway. Of course, inhaling any mold is not great for your health. But you should really keep your nose peeled for black or toxic mold – as it’s much more harmful than other types.

You might have black mold if you or someone in your house starts to display allergies or sudden illnesses. Black mold can abruptly produce or trigger allergic reactions and lead to severe health troubles, especially in children and people with compromised immune systems.

Children are at high risk of developing respiratory illnesses, such as asthma, from poor air quality caused by black mold. And people with a weakened immune system are highly susceptible to developing a mold infection.

Prolonged exposure to black mold can also cause health troubles or illnesses in healthy adults. Here are a few additional symptoms that can occur from black mold.

  • Coughing
  • Throat Irritations
  • Depression
  • Anxiety
  • Sneezing
  • Memory Loss

These types of conditions can lead to long-term illnesses and, in some cases, even result in death.

Black Mold Can Destroy Your Property

Mold in wall cavity

In addition to adverse health effects, black mold can also damage the structure of your home and your belongings.

Black mold can destroy the structure of your home when it takes over large areas, especially floors, walls, and ceilings. When this happens, you will need removal services or even a demolition team to eliminate it. This can be extremely expensive, especially if you need to rebuild large portions of your home. I’ve seen firsthand how challenging it can be to remove black mold growth from home. 

Plus, it’s almost impossible to remove black mold from personal possessions, such as furniture, clothes, and toys. As a result, many homeowners I’ve worked with have had to throw away belongings with sentimental value due to black mold growth. 

How Can You Tell if You Have Black Mold in Your Home?

Toxic black mold inside walls

Detecting black mold in a home is simple: just follow your nose!

What Does Black Mold Smell Like?

If you smell a musty, earthy smell that seems to be out of place, it might be a sign that a mold colony is nearby. Some experts say that the smell of black mold is close to that of dirt and rotting leaves.

Black mold odor comes from MCOCs (Microbial Volatile Organic Compounds), which is the off-gassing of molds as they feed and reproduce. If you can smell mold growth in your home, then spores are moving through the air and compromising the air quality.

This foul odor tends to be found in moist areas in the home because black mold likes to settle on water-saturated cellulose-based materials. This includes (but is not limited to) materials such as cotton, lumber, cardboard, or gypsum board.

Is Your House a Victim of Black Mold?

Houses that have been flooded or have poor roofing are very prone to black mold, especially when these house issues don’t get resolved right away. So, you might notice the musty odor of black mold if your house has a history of flooding or roof leaks.

Even if your home hasn’t suffered any water damage, you may still have black mold growth hiding in your home. Black mold odors might lead you to dark, moist places in a house where mold commonly grows. This includes areas such as inside attics, cabinets, bathrooms, and other enclosed places.

Got Moisture, Odor, and Mold Issues?

Damp rising interior wall

When moisture seeps into the wall cavity and rises via capillary draw.

You don’t have to wait until you can detect a black mold smell before you make a move. This is why I believe everybody should have their homes checked at least once a year for black mold.

However, if your home starts to give off an out-of-place musty odor, then it’s imperative to contact a mold testing expert to have it checked right away. The health and safety of you and everyone in your house depend on it.

How Can You Test for Black Mold?

There are do-it-yourself mold testing options that are available at many hardware stores.  However, you should be wary of their accuracy. There have been many instances where at-home tests have been wrong; some have even been moldy upon purchase.

The best way to identify and eradicate black mold is by having it professionally tested and removed. Professional mold inspectors, like myself, will accurately detect the types of mold growing in your home and the level of severity.

How Does GreenWorks Professional Mold Detecting Help?

What does black mold smell like in a home? 2

GreenWorks is a professional mold-detecting company. Our team will accurately test for black mold and other types of indoor mold found in homes using the following process:

1) Client Interview

Our team starts by interviewing you to better understand the home and any mold-related issues you’ve been experiencing. This includes information about water damage, past repairs, and any health issues you or your family have had recently. Interviewing our clients helps us determine which mold test to use.

2) Olfactory and Visual Investigation:

We then conduct a visual inspection of your home and see if we can smell any musty odors that indicate mold growth.

When mold is visible or odorous, it means the issue has been going on for a while. So, this investigation helps us determine where mold is growing in your home and the level of severity.

3) Tech-Supported Mold Inspection

Sometimes, especially in its early stages, black mold is difficult to detect with the naked eye. In this case, our next step is using technology to aid our mold investigation. These tools help us find cool and damp areas in a home where mold might be growing.

Our inspectors will also gather samples that are analyzed by the lab. This will tell us without a doubt if mold is present.

4) Mold Report

Once our team has searched your entire property for mold, we will provide you with a written report of our findings. This includes the cause(s), locations, and types of molds found in your home. Professional mold removal service requires you to show them this mold inspection report beforehand.

You will receive the final report within a few days, and the inspection only takes a few hours to run.

If You Smell Signs of a Black Mold Infestation, You Should Act Now!

You should not wait to face health issues or structural damage to your home due to a tiny mold colony. If you smell a musty odor or notice signs of mold – contact your friendly professional environmental services company today to have your house checked and gain back your peace of mind.

To get a free consultation or schedule a mold inspection in the Walltownship, NJ area with GreenWorks, visit our contact page or call (732) 223-2073.



First published: Sep 21, 2016
Updated: June 30, 2021

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Victor Coppola

Victor Coppola is a Building Biologist with decades of diverse environmental experience spanning natural resource management and contaminated sites to Indoor Air Quality (IAQ) and building hygiene matters. He focuses on the three most prevalent issues degrading today's built environment: Moisture Odor & Mold (M.O.M.). Mr. Coppola and his Team are sought out by individuals and professionals concerned about IAQ to those actually suffering from Biotoxin Illness. His hybrid blend of environmental interests and services enable him to give a unique perspective into today's changing environment. Think your home is killing you, better call Victor and his Team at GreenWorks.
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kathrina lewis
kathrina lewis
7 years ago

The mycotoxins produced by toxic black mold are neurotoxic. This means they kill neurons in the brain, which impairs a person’s mental ability significantly. These mycotoxins also cause nervous disorders, such as tremors, personality changes, mood swings and irritability.

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