Musty odors in residential structures typically indicate mold growth, but not always.
Generally, when people detect “musty” odors they are smelling microbial volatile organic compounds otherwise known as MVOC’s. When mold is in a “growth cycle” many species of mold emit MVOC’s, this is typically what is detected in the structure. Normally, excessive: moisture, humidity or water are necessary in order for mold to proliferate. This is the reason why we perform extensive water intrusion assessments, which includes the use of infrared thermography, high-quality precision moisture detection instruments and other detection processes.
It is critical to understand that the lack of a musty odor does not indicate the lack of mold being present, it simply indicates that you may not be smelling or detecting mold in a “growth cycle” which is emitting microbial volatile organic compounds. Many scientists believe that structures can be more dangerous to humans when mold is NOT in a growth cycle, because the mycotoxin levels can actually be higher because the mold is aggressively trying to proliferate, according to the Canada Mortgage and Housing Corporation (CMHC, Canada’s equivalent of our FHA organization).
Air sampling is a useful diagnostic tool to determine if there maybe a mold problem or not.
Recently, we performed odor remediation and structural drying in a rental house. The tenants had concerns about musty odors. Two weeks previously there had been a water loss and an emergency response company performed drying operations and indicated they had dried the hardwood floors properly; however, the inexpensive moisture detection equipment that was used was capable of only detecting moisture at a depth of up to 1/2 inch maximum; the hardwood flooring was 3/4 of an inch thick, needless to say that the sub-flooring underneath the hardwood flooring we believe had never been dried properly which led to microbial activity and subsequent musty odors. One of the “takeaways” we hope you gain is: that the use of inexpensive equipment & marginally trained personnel can lead to very costly consequences. The odor remediation processes that we performed took longer to complete then the structural drying work we performed. The hardwood flooring had to be removed completely in order to perform odor remediation and additional structural drying, see pictures below.
Written by Tom Talen