Mold - Have you checked your home lately?

Real Estate Agent with JH Realty Partners 6501309180


This year more than years past - we have discovered by home inspections mold in the home.


Many times it was not visible - however a home inspector could smell it or see signs of something that could cause mold and would call for further investigations.


Mold has increasingly become a concern of the home owner or the new home buyer. I tease that I am the mold detector, after years of showing homes with mold,  I have developed quite the allergy, if mold is in the house I will know it,  as I have a hard time breathing and start wheezing and coughing.


The most common places we have found mold,  in attic spaces, damp basements and bathrooms. Most times these are visible. It’s the mold you can not see that worries me so, we have found in ductwork, behind walls and under flooring.


I am no where close to being a mold expert - so I had asked my Realtor- Home inspector community some questions.


I would like to say thank-you to the people who contributed and answered my questions


Nate Thompson - Owner/Inspector A Closer Look Inspection


Brian Marcy - Owner/Inspector at Grand Rapids Commercial Building Inspection LLC and Certified Professional Inspector at Grand Home Inspection LLC


Grant Medich - Owner/Certified Home Inspector at 1st Call Home Inspection, LLC


  1. Is there a way to do an air quality test for mold that you can not see?

Nate Thompson - We do air quality testing and mold/sampling as do some other home inspectors. We do several a week and it is getting more popular. The lab we use has next day results and backs their work with a $3000 warranty against future mold. Standard protocol is to do 1 sample for every 800-1000 sq. ft. of living space and/or 1 sample on each level of the home. You also do a sample outside as the control. Most homes are 3-4 samples. Yes, we have a machine that draws air into a cylinder for ten minutes for each sample. The cylinder then gets sealed off and sent to the lab for analysis.


Brian Marcy - Grand Home does air quality testing for both mold and radon. Scope of the testing is variable depending on home size and level of concern. We have a conversation with the client, make recommendations, and agree to the scope ahead of time. There are two types of tests that we do. There is surface sampling, which is just taking a sample of a concern that's visible and accessible. The part of mold that can be harmful to people is their reproductive spores, which are released into the air and cannot be seen. Those are found with air sampling and it is very accurate. Samples will show types and concentrations of spores that have been detected. Since most people are not familiar with how mold concentration is measured, and it is not regulated like radon is, we also include the recommendations of acceptable levels from 7 different mold studies to help put the numbers in context.


Nate Thompson - The laboratory we use put out statistics that says 95% of mold is hidden behind walls, ceilings and floors. Most of the time it is not visual and that's why we do an air test. Even if the mold is hidden, spores are likely still airborne. I can try and find some statistics on accuracy for more information.

2. Should a air quality test be part of an home inspection

Brain Marcy - Mold can grow any time an organic surface (wood, drywall paper, dust etc.) has a moisture content of 20% or higher. 48 hours of moisture contact is enough for mold to exponentially multiply, so testing is recommended any time there is moisture intrusion from the outdoor and/or plumbing leaks. The EPA recommends annual testing of radon, but most people do not do that. Similarly, mold tests are not usually performed until there is a big enough problem to be detected visually, by smell, or by apparent symptoms. For this reason, it's always a good idea to test during a real estate transaction.


Grant Medich That's an excellent question, Michelle. Mold testing is still considered to be very controversial in some quarters. There are no established, EPA driven, exposure limits like we have with radon gas. Also, mold is a natural part of our environment. Only laboratory clean rooms are nearly mold-free.


Brian Marcy -  I should add that it needs moisture content and contact with a mold spore - mold doesn't come from nowhere. That being said, mold is everywhere. I've done hundreds of mold tests and never found a home with no mold at all. Mold exists outside and comes in every time a window or door is open. Problems start when mold goes from casually drifting through your interior air from the outside to actually growing and thriving in your home. This is why an outdoor control sample is collected - to establish an environmental baseline. If interior levels exceed exterior levels, it is likely growing inside the home.


3. Can you make your home 100% mold free?


Brian Marcy - I have performed hundreds of mold tests and never found a home without any mold. What we look for is excessive mold levels or pathogenic species. There's a big difference between 40 spore counts per cubic meter and 30,000 spores per cubic meter, and I've found both. There's also a difference between aspergillus, which seems to be in every home, and stachybotrys, which is commonly referred to as "black mold." Air quality testing doesn't exist to determine the presence of absence of mold, it exists to determine excessive and potentially hazardous mold contamination.


4. Can I clean up the mold myself by using bleach - I have heard people doing this themselves and  the mold has come back - however after further investigation they did the fix what caused the mold. This too must be addressed.

DO NOT use bleach on mold.



Some government agencies and disaster recovery organizations still recommend using bleach on mold, but that advice is not accurate.


From the Global Indoor Health Network's paper on Diagnosis and Treatment of Illness Caused by Contaminants in Water-Damaged Buildings:


Serious disinformation has been popularized and reflected in the guidelines given healthcare workers and the public encouraging the use of bleach (sodium hypochlorite) and other chlorinated products for cleaning the mold from damp indoor spaces. Biocides, including chlorine bleach, are harmful to humans and pets. Bleach is a strong corrosive material and will irritate the eyes, skin and respiratory tract. It is cytotoxic and genotoxic and has an accumulative effect on the body and can cause damage to organs.


In regard to using bleach on mold, some species propagate via spores that are unaffected by chlorine, acids, caustics or ozone. In addition, chlorinating carbon-based organic toxins increases their toxicity by increasing their mutagenicity and their lipid solubility which allows these poisons to enter the skin and accumulate in lipid


The Center for Disease Control and Prevention recommends you hire a professional to test and remediate however you must do it yourself they give guidelines here


In my research I did find one DIY mold test that looked very official - I have no knowledge of its accuracy and asked about this

Grant Medich response  - The lab accreditation this company mentions is what stands behind their tests, and is very important. I would be slightly concerned about making an accurate placement for such a test. I would also like to see data on how this particular unit has performed over time. Their sizing protocol does not appear to meet that used by certified mold testers.


So in closing, in my opinion mold testing should be considered when conducting a home inspections and possibly every year thereafter or when water has intruded into your home. If you do find mold in your home I am sure these guys can recommend a mold remediator or feel free to reach out to us and can can refer a few companies we have had great success with.


Posted by

Michelle Gordon is a Realtor with JH Realty Partners - Ada, Michigan -  With a team of Realtors who's Focus is 1st time home buyers, Relocation, Luxury listings and Commercial Properties in West Michigan.  You may find Michelle on facebook, twitter or linked in and she invites you to join her.

Comments (2)

John Pusa
Berkshire Hathaway Home Services Crest - Glendale, CA
Your All Time Realtor With Exceptional Service

Michelle Gordon Thanks for the reminder, and the educational report on mold.

Oct 05, 2017 06:03 PM
Michelle Gordon
JH Realty Partners - Ada, MI
Finding Your Place

My pleasure! Thanks for reading!

Oct 05, 2017 06:05 PM