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Unfinished attics and crawlspaces are two unique spaces inside a home that require special consideration when sampling for mold. Attics and crawl spaces can have drastically different designs depending on the house and climate area, so the info in this blog might not be a “one size fits all” solution. Still, we hope to provide you with a good amount of background knowledge to help you the next time you consider sampling in these spaces!
Let’s start with the easy part: surface sampling.
If you inspect an attic or crawlspace and discover discoloration, you will want to consider collecting a tape lift or swab to determine if the discoloration is mold or not. This process is no different than any other area in a home, and in fact, some of the most common areas to find suspected mold growth can be in attics and crawlspaces. To learn more about when to take a swab or a tape lift, check out our past blog on the topic (link to the old blog). Even if you are sure the discoloration is mold, it is prudent to collect a sample for laboratory analysis for confirmation.
Should I collect an air sample in an attic or crawl space?
In most situations, air samples in attics or crawlspaces should be discouraged. Attics and crawl spaces are commonly vented to the outdoors, allowing for large collections of completely normal outdoor mold spores that have settled into dust in these spaces. Since housekeeping activities are generally very limited in these areas, dust can collect over several years! Once you stir up this dust, you could temporarily reintroduce these spores into the air, therefore affecting the air sample you are collecting. I have seen numerous times where the airborne mold levels in an attic are much higher than outdoors, but there was no actual mold issue in that space!
Crawlspace floors are often soil or gravel over the soil. Because soil naturally holds a large number of microorganisms, it can be expected that the air quality in these spaces might have a higher level of airborne mold compared to other living spaces and the outdoor control sample, but this does not always indicate an issue affecting the building materials.
My Advice
Do a detailed visual inspection of these spaces and collect surface samples as you deem necessary, but to avoid air sampling. Air sampling could be better served in living spaces near access hatches or other openings into the attic/crawlspace to determine if those areas are impacting the IAQ of the adjoining spaces where residents will be spending a significant amount of time.
When collecting samples in the home, you want to ensure your clients’ money is well spent on samples that can help give them actionable information! If you have any specific questions about sampling in attics or crawl spaces please don’t hesitate to reach out.
