Interpreting Mold Tests

Interpreting the results of mold sampling is no easy task.  That’s why many mold inspectors merely hand off some unintelligible lab report and run for it.  Why is it that so many people email me through this blog asking for help to interpret mold test results?  The reason is a failure on the part of the mold inspector to properly understand what they are doing.

You, dear homeowner, deserve more from a mold inspection.

In the comments section of this blog post, feel free to post your question related to mold testing.   However, here are the rules: Continue reading

Mold: More than a Number

Viable Air Sample for Mold

You may take air samples when trying to identify a hidden mold problem.  The total number of spores in the complaint area should be compared to indoor and outdoor controls, or more accurately, “references”.  For example, if you find 10,000 spores per cubic meter in the complaint area, and only 1,000 in the reference samples, there is a high likelihood of indoor amplification.

Although it’s important to look at the total numbers, it’s critical to also make comparisons of the types of mold.  Each type of mold is unique.  There are some types that will predominantly grow on leaves outdoors.  These don’t have an apetite for building materials and will rarely be found growing indoors.  Other types, however, do have the enzymes needed to digest common building materials in its quest for more food.

A few references can help you make a distinction between types of mold typically found outdoors and those that can grow on building materials.  I’ll summarize a few of these references below: Continue reading

Interpreting Mold Spore Counts from EAA, Inc.

Mold Spores

Taking air samples for mold spores is easy. Knowing how to interpret the laboratory results is another matter.

There is no one level of mold that can distinguish a clean and moldy building. Outdoor spore types and concentrations have an important influence on the indoors. Unfortunately, the outdoor types and concentrations of mold vary quite widely over time and space.  In other words, some climates during certain times of year will have extremely high concentrations, and other climates at other times of year will have extremely low levels.  We can compare the indoors to outdoors, but realize that the outdoor concentration is a moving target! Continue reading