Mold Testing: A Must-Have for Every Homeowner's To-Do List

By: Licensed Mold Assessor Brad Fishbein

August 7, 2018

There is so much information out there on the internet in regards to mold testing as the first step to mold detection. Do you do air testing? Swab? Tape? Etc. Each type of sampling serves its own particular purpose.

As a licensed mold inspector , I do many different types of sampling depending on what goal I am looking to accomplish. I designed this section to break down each time of sampling technique to determine what’s best for your situation.

Common Mold Testing

  1. Air Sampling This is the most common method that mold inspectors will do in your home. It involves placing a negative air pump on a tripod or on a table in a room of the home for a certain amount of time with a cassette on the pump. The pump is typically also run on the exterior of the home to establish a baseline. The samples are analyzed by a microbiologist under a microscope. If there is more mold indoors compared to outdoors it could be an indication of a problem indoors.

  2. ERMI Sampling is the same as dust sampling. However, instead of the dust being analyzed under a microscope, it goes through a separate process where DNA is extracted from the dust to determine the type of mold. ERMI only tests for 36 mold species

  3. Tape Sampling is very similar to swab sampling except instead of using cotton you are obviously using tape. The sticky substance is put on the visible mold growth. The tape is then typically put on a glass slide and looked at under a microscope determining what type of mold and how much is present.

  4. Dust Sampling involves the collection of dust throughout one are or the entire home. The dust can be collected from furniture, carpet, the HVAC filter, etc. The dust is then put under the a microscope and analyzed

  5. Bulk Sampling is when instead of a piece of building material such as a wall, floorboard, or any other material is tape or swab sampled, the material itself is collected and tested to determine how much mold is present

  6. Swab Sampling is also often referred to as surface sampling. A cotton swab is used to take a sample of 1 sq inch of building material where mold growth is suspected. It is then put under a microscope to analyze how much concentration of mold and what species is present on the building material.

  7. Wall Cavity Sampling involves taking an air sample but inside of a wall. Behind the walls are accessed behind an electrical outlet, light switch or any other openings. If there are no openings a hole is drilled with a hand tool. A tube is connected to the air sampling cassette and the tube is put inside the wall

  8. Pat Sampling is where air sampling is done but instead of the pump being on a tripod its around building material that is being disturbed. For example, if you want to know if mold spores are in carpet, the carpet would be stepped on to aerosolized the mold particles while sampling is done

At Home Mold Testing

  1. My Mold Detective Review

  2. What Does Mold Smell Like? Mold smells like a unique and often unpleasant odor that many people describe as musty, stale, and earthy. Be sure to learn exactly how to tell if what you are smelling is infact mold.


Meet the author: Brad Fishbein is an ACAC council-certified Microbial Investigator. In the fall of 2012, he became a Licensed Mold Assessor in the State of Florida through the Department of Business & Professional Regulation. Brad has helped homeowners with over 5,000 successfully completed Mold Inspections since 2009.

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