There Is No Such Thing as a Mold Free Home

Many of our client’s tell us they plan to find a remediator who will ensure a mold free home or they plan to sell their house and find a mold free home. We always tell our clients there is no such thing as a mold free home.  

 Mold is a common type of fungus. The oldest fungi fossil, named Ourasphaira giraldae, dates back to 1 billion years ago. All of that to say mold is ubiquitous! 

Fungus plays an important role in our environment. All living things; humans, animals, and plants alike, will, in death, be consumed and returned to the earth by fungi.  It is a friend and partner to various types of ecosystems both in and outside of the home. This is why mold is an important component of our natural ecology.  

Problems begin inside the home when there are uncontained and/or uncontrolled sources of water that lead to an abnormal and pathogenic fungal ecology.

Here are two important questions to think about: 

  1. How do I remediate my home and reestablish a normal fungal ecology so I can heal and reverse or reduce my symptoms? 
  2. Should I sell my home and find another home that has less sources of uncontained and/or uncontrolled water issues?

Let’s address the first question.

How do I remediate my home and reestablish a normal fungal ecology so I can heal and reverse or reduce my symptoms? 

All homes have a fungal ecology that is uniquely its own, like a fingerprint. In other words, each home has a unique microbiome just like the different microbiomes in our body (i.e., gut, respiratory, skin microbiome).  A homes microbiome is a complex community of different microorganisms living symbiotically, with various types of fragments, and their byproducts. 

This microbiome will be influenced by the age of the home, the number of occupants (people release their own microbial cloud), pets, location, prevailing winds and the surrounding (natural and/or industrial) landscape ecology. 

If a home has a healthy microbiome then the occupants are able to live there without triggering symptoms. When a home has an unhealthy microbiome mold and bacteria grow beyond normal healthy levels and the microbiome of the home becomes dysbiotic or imbalanced. This will trigger symptoms in people who are sensitive to mold.  

The dysbiotic microbiome of the home is what needs to be corrected through proper identification of sources, testing and remediation.  The best way to do this is to hire a certified mold inspector who specializes exclusively in mold inspections.  If you’re considering a mold inspector who also performs remediation consider this before going that route. After remediation is complete it is a good idea to perform post-testing to validate if the remediation was a success. If the remediation company is also the mold inspector this creates a conflict of interest. That is why it is a good idea to have a third party verify that your home was properly remediated.

It is important when trying to determine a home’s microbial impact that a wide net of sampling is performed to identify the full impact on the home. Doing so will help you understand the following: 

  • Where are the moisture sources and source areas of contamination in the home?
  • How are molds, their fragments and toxins being dispersed throughout your home? 
  • What types of other biotoxins are present?


The most important thing to do is to fix and correct the moisture source, water leak and/or high humidity. Then identify, locate and remediate all source areas of contamination.  This is where you will find the physical growth of mold occurring which may or may not be visible to the human eye.  This is why it is important to test and not guess.  

When looking for the existence of moisture look for building materials that are water damaged and any unusual looking substances that shouldn’t be present.  Staining, paint peeling, separation, buckling of building materials and sometimes even the most superficial abnormality could be just the tip of the iceberg. 

After the source areas are located, test the areas to validate whether you have mold there or not.  Once the source areas of contamination are validated with labs it is critically important to remediate them. If the mold in the source area is not physically removed during remediation the mold will continue to recur.  

In other words, it is not proper remediation to kill mold with a chemical or a fog that leaves fragments behind or building material with dead mold behind.  Doing so will allow the mold to grow back and/or continue to allow the fine particulate fragments to circulate in the house, ultimately ending up on your body, skin, hair, in lungs and the blood stream.  This will trigger symptoms in those who are sensitive to mold.

You can expect your mold inspector to take air samples and surface samples in order to validate suspected source areas of concern. The samples collected will include ambient air samples, outdoor baselines, wall/ceiling cavities and swab samples.

Dispersion, Mold Burden, and Toxic Load

Mold, spores, hyphal fragments and toxins from the above-mentioned source areas are dispersed throughout a home and settle in the dust. Most people don’t realize that dust is the enemy because it harbors the mold, spores, hyphal fragments and the toxins that one is being exposed to. Instead, people dismiss dust as innocuous.  They don’t realize that dust is dangerous! 

A home breathes through the pressurization that naturally occurs with differences between indoor and outdoor air densities and temperatures, and when opening windows, doors and/or turning on the HVAC or fans, this breathing circulates the dust in and around the home, HVAC units and duct work. 

You can expect your mold inspector to either take ERMI or EPA 36 samples along with Mycotoxin samples. They will collect the dust in your home to determine the mold burden and toxic load. These types of samples help you to see how the mold, spores, fragments and toxins move out from the source areas into the rest of your home.

Bacteria, VOCs and MVOCs

When a home has water damage, the initial primary colonizer is actually not mold, it is bacteria. Certain molds take 24 to 48 hours to grow. Whereas, bacteria can grow within a couple of hours, very rapidly. The reason for this is because water events often pass or touch building materials that naturally contain bacteria due to being exposed to the elements or the open air. When these bacteria come into contact with a water source they immediately begin to proliferate.  

Bacteria can form into two various subgroups; Gram Negative Bacteria which can release a toxin called Endotoxins and Gram-Positive Bacteria.  The Gram-Positive bacteria are very similar to mold because they can sporulate, produce musty odors and create exotoxins and other biotoxins. 

VOCs (Volatile Organic Compounds) and MVOCs (Microbial Volatile Organic Compounds) can be measured in the home as well. Many building materials release VOCs when wet. MVOCs are the digestive off-gassing of mold growth; which is responsible for that musty smell in moldy homes. 

You can expect your mold inspector to take Endotoxin and Actinomycete swifter samples to determine the bacterial load and a VOC air sampling to detect the VOCs and MVOCs. 

Remediation Company tips

Once completed you can expect your mold inspector to provide you with a comprehensive report outlining all the areas of concern, the lab results from accredited laboratories, along with the remediation strategy needed to help guide your remediator. 

Be sure to give the inspection report to your remediation company and instruct them to call the mold inspector to review the remediation strategy.  The remediator will provide you a breakdown of the cost for remediation based on the recommended protocol in the report. 

It is strongly recommended that the remediation be performed by a certified mold remediation company, experienced in mold remediation.  To take it a step further, the company should have the knowledge and expertise to work with individuals who are hypersensitive and/or have underlying health issues. The standard of care and work performed for this segment of the population is much higher.    

What about just selling the home and buying a mold free home? 

It is common to feel overwhelmed and think “Why don’t I just sell this home and buy a mold free home?”. However, there is no such thing as a mold free home.  

The majority of homes today have water damage:

  • The largest study (Spengler, 1994) ever done on U.S. homes with water damage had reported the prevalence of various moisture-related conditions such as “any dampness or mold category”, had shown that 50% or more of the homes had these conditions. Another study (Maier 1999) had shown that the homes they tested were at 68% for any dampness or mold.
  • 14.6 million homes are at risk of flooding.
  • 98% of basements and/or crawl spaces experience some sort of water damage.
  • On any given day, home water damage emergencies effect 14,000 people.
  • Nationwide, household water damage cost up to $20 billion annually.

With these statistics, it is not possible to know if another home you are considering has a normal fungal ecology indicative of a healthy microbiome.  In fact, the only way to know is to have a mold inspector perform a comprehensive inspection along with proper testing. 

Building a new home also has challenges. Here is one example: The new lumber that is used to set up the wood framing can have what is commonly referred to as benign wood fungus due to the wood not being properly stored; which is a common occurrence. 

However, many times when we test this benign wood fungus that many builders, general contractors, plumbers and maintenance professional say is just wood fungus, often enough, the following molds are found: Aspergillus/Penicillium, Cladosporium, Chaetomium, Ulocladium all of which are indicator molds of water damage.  In these situations when building a new home, it is always advised to have your framing tested before you put up any drywall.  After testing and remediation (if applicable) is completed it is a good idea to encapsulate the framing for ongoing protection.

In conclusion

Proper due diligence will need to be performed on any home you are looking to purchase whether the home is older, new or in between. This includes performing a comprehensive inspection and proper testing of the home to establish the homes current fungal ecology. Whether you stay, move, buy or build a new home there will more than likely be some source areas of concerns that will need to be addressed. 

Having a certified mold inspector provide you with a report that outlines all the issues in the home is the tool you can use to help you determine whether staying in the home or moving is right for you. It will allow you to get a quote from a remediator which will help you to determine the financial impact of remediating the home so you can map out what strategy is best for you. However, here are a few additional variables to consider when determining if staying or leaving is the better option. 

  • What retrofitting needs to be performed and cost considerations to correct the moisture sources? 
  • What degree of remediation is required and the cost associations of the remediation? 
  • What is the build back/renovation cost after remediation is completed? 
  • Most importantly, where will you live when your home is being remediated? It is important to not live in the home during remediation because contaminants will be released in large amounts during the remediation. 

There is most certainly a lot to think about! The good news is that having these data points in order can help you make an educated decision and that is always better than guessing.  Mapping it out, to the best of your ability, can help you figure out what strategy is best over the long run. 

Download our free guide to learn how to find mold in a home.

Writers: Mark Levy — Founder and President, The Mold Guy

Betsy Maldonado — Director of Operations and Education, The Mold Guy

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*For edification, view points in post may not apply to all mold cases and do not reflect the view of Exposing Mold Inc.