Safe Home Environmental Logo

Mold Testing: Modern Strategies (Part 1)

The modern home inspection includes a host of additional testing services including mold, meth, radon, water quality, and more. And, as the leading home inspection company in Montana, we strive to provide modern testing strategies to our clients. In our previous blog post about mold, we discussed the methods that have been used for a while, and that you’re likely already familiar with. In this three-part blog series we will dive into the history of mold testing (part 1), learn about the latest modern techniques (part 2), and create a decision tree so you know what service is best for you (part 3).

Why Order A Mold Test?

Aside from testing as a component of a real estate transaction, we often get calls from folks who are have health concerns or are experiencing symptoms that lead them to schedule a stand-alone mold air sampling test.  But, nowadays there are other tests available that have been developed over the last decade to improve their usefulness in addressing health concerns.

Part 1: History of Mold Sampling

Mold sampling techniques have evolved significantly over the years, driven by the need for accurate and reliable assessment of indoor mold levels. Two fundamental methods that have emerged are direct sampling and air sampling.


Direct Sampling

Direct sampling involves physically collecting mold samples from visible surfaces or materials. This method has been used for many years and is still one of the most straightforward and cost-effective ways to identify mold presence. Swab, tape, and bulk sampling are common “direct” sampling techniques.

Benefits of Direct Sampling:
  • Identifies Specific Locations: Direct sampling allows for precise identification of mold growth on surfaces. This can be essential for determining the source of the problem and guiding remediation efforts.
  • Low Cost: It is relatively affordable, making it a practical option for routine inspections and localized investigations.
Deficiencies of Direct Sampling:
  • Limited to Visible Mold: Direct sampling only detects mold that is visible and accessible. Hidden mold behind walls or in other concealed areas can go undetected.
  • No Information on Airborne Mold: This method does not provide information about the concentration of airborne mold spores, which can be a significant health concern.


Air Sampling

Air sampling involves the collection of airborne mold spores to assess the overall air quality. This method has gained prominence due to its ability to provide a more comprehensive view of the mold situation in an indoor environment. Common air sampling techniques include impaction, impingement, and cassette samplers. At Safe Home, we use air cassettes.

Benefits of Air Sampling:
  • Detects Airborne Mold: Air sampling provides a broader assessment of the indoor environment, capturing mold spores that may not be visible but could still pose health risks.
  • Quantitative Data: This method quantifies the concentration of mold spores in the air, offering valuable data for risk assessment.
Deficiencies of Air Sampling:
  • Does Not Identify Source: Air sampling does not pinpoint the exact source of the mold problem, making remediation efforts more challenging.
  • Results Variation: Results can vary depending on sampling location and time, making interpretation more complex.


In the next parts of this blog series, we will explore advanced mold sampling methods, including ERMI and HERTSMI-2 testing. These methods offer a more comprehensive assessment of mold in indoor environments and come with their own set of advantages and disadvantages.

Jump to Part 2: Modern Techniques

Jump to Part 3: Decision Tree


** EPA Mold References



Committed to Your Safety and Peace of Mind – Jennifer Thorne Testing Services Manager  | IAC2 Certified for Mold & Radon | NRPP Certified: 113525-RMP, 113629-RMS | DEQ Meth Certified: MCP-0146-C